Re: [PATCH] mfd: Add support for TI LMP92001

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> From: Abhisit Sangjan <s.abhisit@xxxxxxxxx>
> 
> TI LMP92001 Analog System Monitor and Controller

some minor comments, not a full review
 
> 8-bit GPIOs.
> 12 DACs with 12-bit resolution.
> The GPIOs and DACs are shared port function with Cy function pin to
> take control the pin suddenly from external hardware.
> DAC's referance voltage selectable for Internal/External.

typo, reference (here and below)

> 16 + 1 ADCs with 12-bit resolution.
> Built-in internal Temperature Sensor on channel 17.
> Windows Comparator Function is supported on channel 1-3 and 9-11 for

Window (here and below)

> monitoring with interrupt signal (pending to implement for interrupt).
> ADC's referance voltage selectable for Internal/External.

reference

> Signed-off-by: Abhisit Sangjan <s.abhisit@xxxxxxxxx>
> ---
>  Documentation/ABI/testing/sysfs-bus-iio-lmp920001  |  92 ++++
>  .../devicetree/bindings/gpio/gpio-lmp92001.txt     |  22 +
>  .../bindings/iio/adc/ti-lmp92001-adc.txt           |  21 +
>  .../bindings/iio/dac/ti-lmp92001-dac.txt           |  35 ++
>  drivers/gpio/Kconfig                               |   7 +
>  drivers/gpio/Makefile                              |   1 +
>  drivers/gpio/gpio-lmp92001.c                       | 209 +++++++++
>  drivers/iio/adc/Kconfig                            |  10 +
>  drivers/iio/adc/Makefile                           |   1 +
>  drivers/iio/adc/lmp92001-adc.c                     | 500 +++++++++++++++++++++
>  drivers/iio/dac/Kconfig                            |   9 +
>  drivers/iio/dac/Makefile                           |   1 +
>  drivers/iio/dac/lmp92001-dac.c                     | 390 ++++++++++++++++
>  drivers/mfd/Kconfig                                |  12 +
>  drivers/mfd/Makefile                               |   4 +
>  drivers/mfd/lmp92001-core.c                        | 308 +++++++++++++
>  drivers/mfd/lmp92001-debug.c                       |  67 +++
>  drivers/mfd/lmp92001-i2c.c                         | 215 +++++++++
>  include/linux/mfd/lmp92001/core.h                  | 119 +++++
>  include/linux/mfd/lmp92001/debug.h                 |  28 ++
>  20 files changed, 2051 insertions(+)
>  create mode 100644 Documentation/ABI/testing/sysfs-bus-iio-lmp920001
>  create mode 100644 Documentation/devicetree/bindings/gpio/gpio-lmp92001.txt
>  create mode 100644 Documentation/devicetree/bindings/iio/adc/ti-lmp92001-adc.txt
>  create mode 100644 Documentation/devicetree/bindings/iio/dac/ti-lmp92001-dac.txt
>  create mode 100644 drivers/gpio/gpio-lmp92001.c
>  create mode 100644 drivers/iio/adc/lmp92001-adc.c
>  create mode 100644 drivers/iio/dac/lmp92001-dac.c
>  create mode 100644 drivers/mfd/lmp92001-core.c
>  create mode 100644 drivers/mfd/lmp92001-debug.c
>  create mode 100644 drivers/mfd/lmp92001-i2c.c
>  create mode 100644 include/linux/mfd/lmp92001/core.h
>  create mode 100644 include/linux/mfd/lmp92001/debug.h
> 
> diff --git a/Documentation/ABI/testing/sysfs-bus-iio-lmp920001 b/Documentation/ABI/testing/sysfs-bus-iio-lmp920001
> new file mode 100644
> index 0000000..bd4e733
> --- /dev/null
> +++ b/Documentation/ABI/testing/sysfs-bus-iio-lmp920001
> @@ -0,0 +1,92 @@
> +What:           /sys/bus/iio/devices/iio:deviceX/gang
> +Date:		August 2016
> +KernelVersion:  4.1.15

update? (here and below)

> +Contact:        Abhisit Sangjan <s.abhisit@xxxxxxxxx>
> +Description:
> +		Controls the association of analog output channels OUTx with
> +		asynchronous control inputs Cy for DAC.
> +                Can be either:
> +                - "0"
> +                - "1"
> +
> +			Cy to OUTx Assignment
> +		----------------------------------
> +		| Cy | CDAC:GANG=0 | CDAC:GANG=1 |
> +		----------------------------------
> +		| C1 | OUT[1:4]    | OUT[1:3]    |
> +		----------------------------------
> +		| C2 | OUT[5:6]    | OUT[4:6]    |
> +		----------------------------------
> +		| C3 | OUT[7:8]    | OUT[7:9]    |
> +		----------------------------------
> +		| C4 | OUT[9:12]   | OUT[10:12]  |
> +		----------------------------------
> +
> +What:           /sys/bus/iio/devices/iio:deviceX/outx
> +Date:		August 2016
> +KernelVersion:  4.1.15
> +Contact:        Abhisit Sangjan <s.abhisit@xxxxxxxxx>
> +Description:
> +		The pin output mode for DAC.
> +                Can be either:
> +                - "hiz" = High impedance state.
> +                - "dac" = DAC output.
> +		- "0" = Drive it to low.
> +		- "1" = Drive it to high.
> +
> +What:           /sys/bus/iio/devices/iio:deviceX/vref
> +Date:		August 2016
> +KernelVersion:  4.1.15
> +Contact:        Abhisit Sangjan <s.abhisit@xxxxxxxxx>
> +Description:
> +		This is voltage referance source for DACs.
> +                Can be either:
> +                - "external"
> +                - "internal"
> +
> +What:           /sys/devices/socX/soc/XXXXXXX.aips-bus/XXXXXXX.i2c/i2c-X/X-00XX/lmp92001-adc.X.auto/iio:deviceX/en
> +Date:		August 2016
> +KernelVersion:  4.1.15
> +Contact:        Abhisit Sangjan <s.abhisit@xxxxxxxxx>
> +Description:
> +		This is ADC Conversion Enable for each channel.
> +                Can be either:
> +                - "enable"
> +                - "disable"
> +
> +What:           /sys/devices/socX/soc/XXXXXXX.aips-bus/XXXXXXX.i2c/i2c-X/X-00XX/lmp92001-adc.X.auto/iio:deviceX/mode
> +Date:		August 2016
> +KernelVersion:  4.1.15
> +Contact:        Abhisit Sangjan <s.abhisit@xxxxxxxxx>
> +Description:
> +		This is conversion mode for all of ADCs.
> +                Can be either:
> +                - "continuous" = Continuously conversion all the time.
> +                - "single-shot" = Once time conversion and stop.

One time

> +
> +What:           /sys/devices/socX/soc/XXXXXXX.aips-bus/XXXXXXX.i2c/i2c-X/X-00XX/lmp92001-adc.X.auto/iio:deviceX/vref
> +Date:		August 2016
> +KernelVersion:  4.1.15
> +Contact:        Abhisit Sangjan <s.abhisit@xxxxxxxxx>
> +Description:
> +		This is voltage referance source for ADCs.
> +                Can be either:
> +                - "external"
> +                - "internal"
> +
> +What:           /sys/devices/socX/soc/XXXXXXX.aips-bus/XXXXXXX.i2c/i2c-X/X-00XX/lmp92001-adc.X.auto/iio:deviceX/events/in_voltageX_thresh_{falling|rising}_en
> +Date:		August 2016
> +KernelVersion:  4.1.15
> +Contact:        Abhisit Sangjan <s.abhisit@xxxxxxxxx>
> +Description:
> +		This is ADC's Windows Comparator Function enable for falling and rising.
> +		Supported channels are 1-3 and 9-11.
> +
> +What:           /sys/devices/socX/soc/XXXXXXX.aips-bus/XXXXXXX.i2c/i2c-X/X-00XX/lmp92001-adc.X.auto/iio:deviceX/events/in_voltageX_thresh_{falling|rising}_value
> +Date:		August 2016
> +KernelVersion:  4.1.15
> +Contact:        Abhisit Sangjan <s.abhisit@xxxxxxxxx>
> +Description:
> +		This is ADC's Windows Comparator Function value for falling and rising.
> +		Supported channels are 1-3 and 9-11.
> +		The possible range is 0 - 2047.
> diff --git a/Documentation/devicetree/bindings/gpio/gpio-lmp92001.txt b/Documentation/devicetree/bindings/gpio/gpio-lmp92001.txt
> new file mode 100644
> index 0000000..c68784e
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/gpio/gpio-lmp92001.txt
> @@ -0,0 +1,22 @@
> +* Texas Instruments' LMP92001 GPIOs
> +
> +Required properties:
> + - compatible: Must be set to "ti,lmp92001-gpio".
> + - reg: i2c chip address for the device.
> + - gpio-controller: Marks the device node as a gpio controller.
> + - #gpio-cells : Should be two.  The first cell is the pin number and the
> +  second cell is used to specify the gpio polarity:
> +        0 = Active high
> +        1 = Active low
> +
> +Example:
> +lmp92001@20 {
> +        compatible = "ti,lmp92001";
> +        reg = <0x20>;
> +
> +        lmp92001_gpio: lmp92001-gpio {
> +                compatible = "ti,lmp92001-gpio";
> +                gpio-controller;
> +                #gpio-cells = <2>;
> +        };
> +};
> diff --git a/Documentation/devicetree/bindings/iio/adc/ti-lmp92001-adc.txt b/Documentation/devicetree/bindings/iio/adc/ti-lmp92001-adc.txt
> new file mode 100644
> index 0000000..34d7809
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/iio/adc/ti-lmp92001-adc.txt
> @@ -0,0 +1,21 @@
> +* Texas Instruments' LMP92001 ADCs
> +
> +Required properties:
> + - compatible: Must be set to "ti,lmp92001-adc".
> + - reg: i2c chip address for the device.
> + - ti,lmp92001-adc-mode: adc operation, either continuous or single-shot.
> + - ti,lmp92001-adc-mask: bit mask for which channel is enable.
> +        0 = Off
> +        1 = On
> +
> +Example:
> +lmp92001@20 {
> +        compatible = "ti,lmp92001";
> +        reg = <0x20>;
> +
> +        lmp92001-adc {
> +                compatible = "ti,lmp92001-adc";
> +                ti,lmp92001-adc-mode = "continuous";
> +                ti,lmp92001-adc-mask = <0x00000079>;
> +        };
> +};
> \ No newline at end of file
> diff --git a/Documentation/devicetree/bindings/iio/dac/ti-lmp92001-dac.txt b/Documentation/devicetree/bindings/iio/dac/ti-lmp92001-dac.txt
> new file mode 100644
> index 0000000..882db9c
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/iio/dac/ti-lmp92001-dac.txt
> @@ -0,0 +1,35 @@
> +* Texas Instruments' LMP92001 DACs
> +
> +Required properties:
> + - compatible: Must be set to "ti,lmp92001-dac".
> + - reg: i2c chip address for the device.
> + - ti,lmp92001-dac-hiz: hi-impedance control,
> +        1 = Forces all OUT[1:12] outputs to hi-z, 0 = normal
> + - ti,lmp92001-dac-outx:
> +        Cy = 0, 1 = will force associated OUTx outputs to VDD
> +        Cy = 0, 0 = will force associated OUTx outputs to GND
> + - ti,lmp92001-dac-gang: What group of Cy is governed to.
> +        -----------------------------------------
> +        |  Cy   | CDAC:GANG = 0 | CDAC:GANG = 1 |
> +        -----------------------------------------
> +        |  C1   |   OUT[1:4]    |    OUT[1:3]   |
> +        -----------------------------------------
> +        |  C2   |   OUT[5:6]    |    OUT[4:6]   |
> +        -----------------------------------------
> +        |  C3   |   OUT[7:8]    |    OUT[7:9]   |
> +        -----------------------------------------
> +        |  C4   |   OUT[9:12]   |    OUT[10:12] |
> +        -----------------------------------------
> +
> +Example:
> +lmp92001@20 {
> +        compatible = "ti,lmp92001";
> +        reg = <0x20>;
> +
> +        lmp92001-dac {
> +                compatible = "ti,lmp92001-dac";
> +                ti,lmp92001-dac-hiz  = /bits/ 8 <0>;
> +                ti,lmp92001-dac-outx = /bits/ 8 <0>;
> +                ti,lmp92001-dac-gang = /bits/ 8 <0>;
> +        };
> +};
> diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
> index 461d6fc..5962ea0 100644
> --- a/drivers/gpio/Kconfig
> +++ b/drivers/gpio/Kconfig
> @@ -948,6 +948,13 @@ config GPIO_KEMPLD
>  	  This driver can also be built as a module. If so, the module will be
>  	  called gpio-kempld.
>  
> +config GPIO_LMP92001
> +       tristate "LMP92001 GPIOs"
> +       depends on MFD_LMP92001
> +       help
> +         Say yes here to access the GPIO signals of TI LMP92001 Analog System
> +         Monitor and Controller.
> +
>  config GPIO_LP3943
>  	tristate "TI/National Semiconductor LP3943 GPIO expander"
>  	depends on MFD_LP3943
> diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
> index a9fda6c..560d59c 100644
> --- a/drivers/gpio/Makefile
> +++ b/drivers/gpio/Makefile
> @@ -62,6 +62,7 @@ obj-$(CONFIG_GPIO_JANZ_TTL)	+= gpio-janz-ttl.o
>  obj-$(CONFIG_GPIO_KEMPLD)	+= gpio-kempld.o
>  obj-$(CONFIG_ARCH_KS8695)	+= gpio-ks8695.o
>  obj-$(CONFIG_GPIO_INTEL_MID)	+= gpio-intel-mid.o
> +obj-$(CONFIG_GPIO_LMP92001)	+= gpio-lmp92001.o
>  obj-$(CONFIG_GPIO_LOONGSON)	+= gpio-loongson.o
>  obj-$(CONFIG_GPIO_LP3943)	+= gpio-lp3943.o
>  obj-$(CONFIG_GPIO_LPC18XX)	+= gpio-lpc18xx.o
> diff --git a/drivers/gpio/gpio-lmp92001.c b/drivers/gpio/gpio-lmp92001.c
> new file mode 100644
> index 0000000..b80ba4e
> --- /dev/null
> +++ b/drivers/gpio/gpio-lmp92001.c
> @@ -0,0 +1,209 @@
> +/*
> + * gpio-lmp92001.c - Support for TI LMP92001 GPIOs
> + *
> + * Copyright 2016-2017 Celestica Ltd.
> + *
> + * Author: Abhisit Sangjan <s.abhisit@xxxxxxxxx>
> + *
> + * Inspired by wm831x driver.
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License as published by
> + * the Free Software Foundation; either version 2 of the License, or
> + * (at your option) any later version.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + * GNU General Public License for more details.
> + *
> + */
> +
> +#include <linux/bitops.h>
> +#include <linux/gpio/driver.h>
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +
> +#include <linux/mfd/lmp92001/core.h>
> +
> +#define SGEN_GPI	(1 << 0) /* 1 - if any bit in SGPI is set. */

1 << 0 is 1, maybe BIT(0)?

> +
> +struct lmp92001_gpio {
> +	struct lmp92001 *lmp92001;
> +	struct gpio_chip gpio_chip;
> +};
> +
> +static int lmp92001_gpio_get_direction(struct gpio_chip *chip, unsigned offset)

unsigned vs unsigned int

> +{
> +	struct lmp92001_gpio *lmp92001_gpio = gpiochip_get_data(chip);
> +	struct lmp92001 *lmp92001 = lmp92001_gpio->lmp92001;
> +	unsigned int val;
> +	int ret;
> +
> +	ret = regmap_read(lmp92001->regmap, LMP92001_CGPO, &val);
> +	if (ret < 0)
> +		return ret;
> +
> +	return (val >> offset) & BIT(0);
> +}
> +
> +static int lmp92001_gpio_direction_in(struct gpio_chip *chip, unsigned offset)
> +{
> +	struct lmp92001_gpio *lmp92001_gpio = gpiochip_get_data(chip);
> +	struct lmp92001 *lmp92001 = lmp92001_gpio->lmp92001;
> +
> +	return regmap_update_bits(lmp92001->regmap, LMP92001_CGPO, BIT(offset),
> +					BIT(offset));
> +}
> +
> +static int lmp92001_gpio_get(struct gpio_chip *chip, unsigned offset)
> +{
> +	struct lmp92001_gpio *lmp92001_gpio = gpiochip_get_data(chip);
> +	struct lmp92001 *lmp92001 = lmp92001_gpio->lmp92001;
> +	unsigned int val, sgen;
> +
> +	/*
> +	 * Does the GPIO input mode?
> +	 * Does the GPIO was set?

wording, I don't understand

> +	 * Reading indicated logic level.
> +	 * Clear indicated logic level.
> +	 */
> +	regmap_read(lmp92001->regmap, LMP92001_CGPO, &val);
> +	if ((val >> offset) & BIT(0)) {
> +		regmap_read(lmp92001->regmap, LMP92001_SGEN, &sgen);
> +		if (sgen & SGEN_GPI) {
> +			regmap_read(lmp92001->regmap, LMP92001_SGPI, &val);
> +			regmap_update_bits(lmp92001->regmap, LMP92001_CGPO,
> +						0xFF, val);
> +		}
> +	}
> +
> +	return !!(val & BIT(offset));
> +}
> +
> +static int lmp92001_gpio_direction_out(struct gpio_chip *chip, unsigned offset,
> +	int value)
> +{
> +	struct lmp92001_gpio *lmp92001_gpio = gpiochip_get_data(chip);
> +	struct lmp92001 *lmp92001 = lmp92001_gpio->lmp92001;
> +
> +	return regmap_update_bits(lmp92001->regmap, LMP92001_CGPO, BIT(offset),
> +					0 << offset);
> +}
> +
> +static void lmp92001_gpio_set(struct gpio_chip *chip, unsigned offset,
> +	int value)
> +{
> +	struct lmp92001_gpio *lmp92001_gpio = gpiochip_get_data(chip);
> +	struct lmp92001 *lmp92001 = lmp92001_gpio->lmp92001;
> +
> +	regmap_update_bits(lmp92001->regmap, LMP92001_CGPO, BIT(offset),
> +				value << offset);
> +}
> +
> +#ifdef CONFIG_DEBUG_FS
> +static void lmp92001_gpio_dbg_show(struct seq_file *s, struct gpio_chip *chip)
> +{
> +	struct lmp92001_gpio *lmp92001_gpio = gpiochip_get_data(chip);
> +	struct lmp92001 *lmp92001 = lmp92001_gpio->lmp92001;
> +	int i, gpio;
> +	unsigned int cgpo;
> +	const char *label, *dir, *logic;
> +
> +	for (i = 0; i < chip->ngpio; i++) {
> +		gpio = i + chip->base;
> +
> +		label = gpiochip_is_requested(chip, i);
> +		if (!label)
> +			continue;
> +
> +		regmap_read(lmp92001->regmap, LMP92001_CGPO, &cgpo);

retval is not checked here (and elsewhere)

> +		if ((cgpo>>i) & BIT(0))

space around operator

> +			dir = "in";
> +		else
> +			dir = "out";
> +
> +		if (lmp92001_gpio_get(chip, i))
> +			logic = "hi";
> +		else
> +			logic = "lo";
> +
> +		seq_printf(s, " gpio-%-3d (%-20.20s) %-3.3s %-2.2s\n",
> +				gpio, label, dir, logic);
> +	}
> +}
> +#else
> +#define lmp92001_gpio_dbg_show NULL
> +#endif
> +
> +static struct gpio_chip lmp92001_gpio_chip = {
> +	.label			= "lmp92001",
> +	.owner			= THIS_MODULE,
> +	.get_direction		= lmp92001_gpio_get_direction,
> +	.direction_input	= lmp92001_gpio_direction_in,
> +	.get			= lmp92001_gpio_get,
> +	.direction_output	= lmp92001_gpio_direction_out,
> +	.set			= lmp92001_gpio_set,
> +	.dbg_show		= lmp92001_gpio_dbg_show,
> +};
> +
> +static int lmp92001_gpio_probe(struct platform_device *pdev)
> +{
> +	struct lmp92001 *lmp92001 = dev_get_drvdata(pdev->dev.parent);
> +	struct lmp92001_gpio *lmp92001_gpio;
> +	int ret;
> +
> +	lmp92001_gpio = devm_kzalloc(&pdev->dev, sizeof(*lmp92001_gpio),
> +					GFP_KERNEL);
> +	if (!lmp92001_gpio)
> +		return -ENOMEM;
> +
> +	lmp92001_gpio->lmp92001 = lmp92001;
> +	lmp92001_gpio->gpio_chip = lmp92001_gpio_chip;
> +	lmp92001_gpio->gpio_chip.ngpio = 8;
> +	lmp92001_gpio->gpio_chip.parent = &pdev->dev;
> +	lmp92001_gpio->gpio_chip.base = -1;
> +
> +	ret = devm_gpiochip_add_data(&pdev->dev, &lmp92001_gpio->gpio_chip,
> +					lmp92001_gpio);
> +	if (ret < 0) {
> +		dev_err(&pdev->dev, "could not register gpiochip, %d\n", ret);
> +		return ret;
> +	}
> +
> +	platform_set_drvdata(pdev, lmp92001_gpio);
> +
> +	return ret;
> +}
> +
> +static int lmp92001_gpio_remove(struct platform_device *pdev)
> +{
> +	struct lmp92001_gpio *lmp92001_gpio = platform_get_drvdata(pdev);
> +
> +	devm_gpiochip_remove(&pdev->dev, &lmp92001_gpio->gpio_chip);
> +
> +	return 0;
> +}
> +
> +static struct platform_driver lmp92001_gpio_driver = {
> +	.driver.name	= "lmp92001-gpio",
> +	.probe		= lmp92001_gpio_probe,
> +	.remove		= lmp92001_gpio_remove,
> +};
> +
> +static int __init lmp92001_gpio_init(void)
> +{
> +	return platform_driver_register(&lmp92001_gpio_driver);
> +}
> +subsys_initcall(lmp92001_gpio_init);
> +
> +static void __exit lmp92001_gpio_exit(void)
> +{
> +	platform_driver_unregister(&lmp92001_gpio_driver);
> +}
> +module_exit(lmp92001_gpio_exit);
> +
> +MODULE_AUTHOR("Abhisit Sangjan <s.abhisit@xxxxxxxxx>");
> +MODULE_DESCRIPTION("GPIO interface for TI LMP92001");
> +MODULE_LICENSE("GPL");
> +MODULE_ALIAS("platform:lmp92001-gpio");
> diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
> index 614fa41..2adeba5 100644
> --- a/drivers/iio/adc/Kconfig
> +++ b/drivers/iio/adc/Kconfig
> @@ -331,6 +331,16 @@ config IMX7D_ADC
>  	  This driver can also be built as a module. If so, the module will be
>  	  called imx7d_adc.
>  
> +config LMP92001_ADC
> +       tristate "TI LMP92001 ADC Driver"
> +       depends on MFD_LMP92001
> +       help
> +         If you say yes here you get support for TI LMP92001 ADCs
> +         conversion.
> +
> +         This driver can also be built as a module. If so, the module will
> +         be called lmp92001_adc.
> +
>  config LP8788_ADC
>  	tristate "LP8788 ADC driver"
>  	depends on MFD_LP8788
> diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile
> index b546736a..2ed8986 100644
> --- a/drivers/iio/adc/Makefile
> +++ b/drivers/iio/adc/Makefile
> @@ -31,6 +31,7 @@ obj-$(CONFIG_HI8435) += hi8435.o
>  obj-$(CONFIG_HX711) += hx711.o
>  obj-$(CONFIG_IMX7D_ADC) += imx7d_adc.o
>  obj-$(CONFIG_INA2XX_ADC) += ina2xx-adc.o
> +obj-$(CONFIG_LMP92001_ADC) += lmp92001-adc.o
>  obj-$(CONFIG_LP8788_ADC) += lp8788_adc.o
>  obj-$(CONFIG_LPC18XX_ADC) += lpc18xx_adc.o
>  obj-$(CONFIG_LPC32XX_ADC) += lpc32xx_adc.o
> diff --git a/drivers/iio/adc/lmp92001-adc.c b/drivers/iio/adc/lmp92001-adc.c
> new file mode 100644
> index 0000000..8e64b51
> --- /dev/null
> +++ b/drivers/iio/adc/lmp92001-adc.c
> @@ -0,0 +1,500 @@
> +/*
> + * lmp92001-adc.c - Support for TI LMP92001 ADCs
> + *
> + * Copyright 2016-2017 Celestica Ltd.
> + *
> + * Author: Abhisit Sangjan <s.abhisit@xxxxxxxxx>
> + *
> + * Inspired by wm831x and ad5064 drivers.
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License as published by
> + * the Free Software Foundation; either version 2 of the License, or
> + * (at your option) any later version.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + * GNU General Public License for more details.
> + *
> + */
> +
> +#include <linux/iio/iio.h>
> +#include <linux/interrupt.h>
> +#include <linux/kernel.h>
> +#include <linux/mfd/core.h>
> +#include <linux/module.h>
> +#include <linux/platform_device.h>
> +
> +#include <linux/mfd/lmp92001/core.h>
> +
> +#define CGEN_STRT	(1 << 0) /* Is continuous conversion all of ADCs? */

in IIO subsys, we want a prefix for all #defines, so LMP92001_CGEN_STRT
wording of comment
maybe use BIT()

> +#define CGEN_LCK	(1 << 1) /* Is lock the HW register? */
> +#define CGEN_RST	(1 << 7) /* Reset all registers. */
> +
> +#define CREF_AEXT	(1 << 1) /* 1 - ADC external reference.
> +				  * 0 - ADC internal reference.
> +				  */
> +
> +static int lmp92001_read_raw(struct iio_dev *indio_dev,
> +	struct iio_chan_spec const *channel,
> +	int *val, int *val2,
> +	long mask)
> +{
> +	struct lmp92001 *lmp92001 = iio_device_get_drvdata(indio_dev);
> +	unsigned int code, cgen, sgen, try;
> +	int ret;
> +
> +	mutex_lock(&lmp92001->adc_lock);
> +
> +	ret = regmap_read(lmp92001->regmap, LMP92001_CGEN, &cgen);
> +	if (ret < 0)
> +		goto exit;
> +
> +	/*
> +	 * Is not continuous conversion?
> +	 * Lock the HW registers (if needed).
> +	 * Triggering single-short conversion.
> +	 * Waiting for conversion successfully.

successful

> +	 */
> +	if (!(cgen & CGEN_STRT)) {
> +		if (!(cgen & CGEN_LCK)) {
> +			ret = regmap_update_bits(lmp92001->regmap,
> +					LMP92001_CGEN, CGEN_LCK, CGEN_LCK);
> +			if (ret < 0)
> +				goto exit;
> +		}
> +
> +		/* Writing any value to triggered Single-Shot conversion. */

to trigger

> +		ret = regmap_write(lmp92001->regmap, LMP92001_CTRIG, 1);
> +		if (ret < 0)
> +			goto exit;
> +
> +		/* In case of conversion is in-progress, repeat for 10 times. */
> +		try = 10;
> +		do {
> +			ret = regmap_read(lmp92001->regmap,
> +						LMP92001_SGEN, &sgen);
> +			if (ret < 0)
> +				goto exit;
> +		} while ((sgen & CGEN_RST) && (--try > 0));
> +
> +		if (!try) {
> +			ret = -ETIME;
> +			goto exit;
> +		}
> +	}
> +
> +	ret = regmap_read(lmp92001->regmap, 0x1F + channel->channel, &code);
> +	if (ret < 0)
> +		goto exit;

could mutex_unlock() here already

> +
> +	switch (mask) {
> +	case IIO_CHAN_INFO_RAW:
> +		switch (channel->type) {
> +		case IIO_VOLTAGE:
> +		case IIO_TEMP:
> +			*val = code;
> +			ret = IIO_VAL_INT;

simplify control flow, return directly
can save many break lines...

> +			goto exit;
> +		default:
> +			break;
> +		}
> +		break;
> +	default:
> +		break;
> +	}
> +
> +	/* In case of no match channel info/type is return here. */
> +	ret = -EINVAL;
> +
> +exit:
> +	mutex_unlock(&lmp92001->adc_lock);
> +
> +	return ret;
> +}
> +
> +static const struct iio_info lmp92001_info = {
> +	.read_raw = lmp92001_read_raw,
> +	.driver_module = THIS_MODULE,
> +};
> +
> +static ssize_t lmp92001_avref_read(struct iio_dev *indio_dev,
> +	uintptr_t private, struct iio_chan_spec const *channel, char *buf)
> +{
> +	struct lmp92001 *lmp92001 = iio_device_get_drvdata(indio_dev);
> +	unsigned int cref;
> +	int ret;
> +
> +	ret = regmap_read(lmp92001->regmap, LMP92001_CREF, &cref);
> +	if (ret < 0)
> +		return ret;
> +
> +	return sprintf(buf, "%s\n", cref & CREF_AEXT ? "external" : "internal");

maybe parenthesis, (cref & CREF_AEXT) for readability
here and below

> +}
> +
> +static ssize_t lmp92001_avref_write(struct iio_dev *indio_dev,
> +	uintptr_t private, struct iio_chan_spec const *channel,
> +	const char *buf, size_t len)
> +{
> +	struct lmp92001 *lmp92001 = iio_device_get_drvdata(indio_dev);
> +	unsigned int cref;
> +	int ret;
> +
> +	if (strncmp("external", buf, 8) == 0)

why strncmp()? it should match exactly

> +		cref = 2;
> +	else if (strncmp("internal", buf, 8) == 0)
> +		cref = 0;
> +	else
> +		return -EINVAL;
> +
> +	ret = regmap_update_bits(lmp92001->regmap, LMP92001_CREF, CREF_AEXT,
> +					cref);
> +	if (ret < 0)
> +		return ret;
> +
> +	return len;
> +}
> +
> +static ssize_t lmp92001_enable_read(struct iio_dev *indio_dev,
> +	uintptr_t private, struct iio_chan_spec const *channel, char *buf)
> +{
> +	struct lmp92001 *lmp92001 = iio_device_get_drvdata(indio_dev);
> +	unsigned int reg, cad;
> +	int ret;
> +
> +	switch (channel->channel) {
> +	case 1 ... 8:
> +		reg = LMP92001_CAD1;
> +		break;
> +	case 9 ... 16:
> +		reg = LMP92001_CAD2;
> +		break;
> +	case 17:
> +		reg = LMP92001_CAD3;
> +		break;
> +	default:
> +		return -EINVAL;
> +	}
> +
> +	ret = regmap_read(lmp92001->regmap, reg, &cad);
> +	if (ret < 0)
> +		return ret;
> +
> +	if (channel->channel <= 8)
> +		cad >>= channel->channel - 1;
> +	else if (channel->channel > 8)
> +		cad >>= channel->channel - 9;
> +	else if (channel->channel > 16)
> +		cad >>= channel->channel - 17;
> +	else
> +		return -EINVAL;
> +
> +	return sprintf(buf, "%s\n", cad & BIT(0) ? "enable" : "disable");
> +}
> +
> +static ssize_t lmp92001_enable_write(struct iio_dev *indio_dev,
> +	uintptr_t private, struct iio_chan_spec const *channel,
> +	const char *buf, size_t len)
> +{
> +	struct lmp92001 *lmp92001 = iio_device_get_drvdata(indio_dev);
> +	unsigned int reg, enable, shif, mask;
> +	int ret;
> +
> +	switch (channel->channel) {
> +	case 1 ... 8:
> +		reg = LMP92001_CAD1;
> +		shif = (channel->channel - 1);
> +		break;
> +	case 9 ... 16:
> +		reg = LMP92001_CAD2;
> +		shif = (channel->channel - 9);
> +		break;
> +	case 17:
> +		reg = LMP92001_CAD3;
> +		shif = (channel->channel - 17);
> +		break;
> +	default:
> +		return -EINVAL;
> +	}
> +
> +	if (strncmp("enable", buf, 6) == 0)
> +		enable = 1;
> +	else if (strncmp("disable", buf, 7) == 0)
> +		enable = 0;
> +	else
> +		return -EINVAL;
> +
> +	enable <<= shif;
> +	mask = 1 << shif;
> +
> +	ret = regmap_update_bits(lmp92001->regmap, reg, mask, enable);
> +	if (ret < 0)
> +		return ret;
> +
> +	return len;
> +}
> +
> +static ssize_t lmp92001_mode_read(struct iio_dev *indio_dev,
> +	uintptr_t private, struct iio_chan_spec const *channel, char *buf)
> +{
> +	struct lmp92001 *lmp92001 = iio_device_get_drvdata(indio_dev);
> +	unsigned int cgen;
> +	int ret;
> +
> +	ret = regmap_read(lmp92001->regmap, LMP92001_CGEN, &cgen);
> +	if (ret < 0)
> +		return ret;
> +
> +	return sprintf(buf, "%s\n",
> +			cgen & BIT(0) ? "continuous" : "single-shot");
> +}
> +
> +static ssize_t lmp92001_mode_write(struct iio_dev *indio_dev,
> +	uintptr_t private, struct iio_chan_spec const *channel,
> +	const char *buf, size_t len)
> +{
> +	struct lmp92001 *lmp92001 = iio_device_get_drvdata(indio_dev);
> +	unsigned int cgen;
> +	int ret;
> +
> +	if (strncmp("continuous", buf, 10) == 0)

strcmp()

> +		cgen = 1;
> +	else if (strncmp("single-shot", buf, 11) == 0)
> +		cgen = 0;
> +	else
> +		return -EINVAL;
> +

need mutex here?

> +	/*
> +	 * Unlock the HW registers.
> +	 * Set conversion mode.
> +	 * Lock the HW registers.
> +	 */
> +	ret = regmap_update_bits(lmp92001->regmap, LMP92001_CGEN, CGEN_LCK, 0);
> +	if (ret < 0)
> +		return ret;
> +
> +	ret = regmap_update_bits(lmp92001->regmap, LMP92001_CGEN, CGEN_STRT,
> +					cgen);
> +	if (ret < 0)
> +		return ret;
> +
> +	ret = regmap_update_bits(lmp92001->regmap, LMP92001_CGEN, CGEN_LCK,
> +					CGEN_LCK);
> +	if (ret < 0)
> +		return ret;
> +
> +	return len;
> +}
> +
> +static const struct iio_chan_spec_ext_info lmp92001_ext_info[] = {
> +	{
> +		.name = "vref",
> +		.read = lmp92001_avref_read,
> +		.write = lmp92001_avref_write,
> +	.shared = IIO_SHARED_BY_ALL,

indentation

> +	},
> +	{
> +		.name = "en",
> +		.read = lmp92001_enable_read,
> +		.write = lmp92001_enable_write,
> +		.shared = IIO_SEPARATE,
> +	},
> +	{
> +		.name = "mode",
> +		.read = lmp92001_mode_read,
> +		.write = lmp92001_mode_write,
> +		.shared = IIO_SHARED_BY_ALL,
> +	},
> +	{ },
> +};
> +
> +static const struct iio_event_spec lmp92001_events[] = {
> +	{
> +		.type = IIO_EV_TYPE_THRESH,
> +		.dir = IIO_EV_DIR_RISING,
> +		.mask_separate = BIT(IIO_EV_INFO_ENABLE) |
> +			BIT(IIO_EV_INFO_VALUE),
> +	},
> +	{
> +		.type = IIO_EV_TYPE_THRESH,
> +		.dir = IIO_EV_DIR_FALLING,
> +		.mask_separate = BIT(IIO_EV_INFO_ENABLE) |
> +			BIT(IIO_EV_INFO_VALUE),
> +	},
> +	{ },
> +};
> +
> +#define LMP92001_CHAN_SPEC(_ch, _type, _event, _nevent) \
> +{ \
> +	.channel = _ch, \
> +	.type = _type, \
> +	.indexed = 1, \
> +	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
> +	.event_spec = _event, \
> +	.num_event_specs = _nevent, \
> +	.ext_info = lmp92001_ext_info, \
> +}
> +
> +static const struct iio_chan_spec lmp92001_adc_channels[] = {
> +	LMP92001_CHAN_SPEC(1, IIO_VOLTAGE, lmp92001_events,
> +			ARRAY_SIZE(lmp92001_events)),
> +	LMP92001_CHAN_SPEC(2, IIO_VOLTAGE, lmp92001_events,
> +			ARRAY_SIZE(lmp92001_events)),
> +	LMP92001_CHAN_SPEC(3, IIO_VOLTAGE, lmp92001_events,
> +			ARRAY_SIZE(lmp92001_events)),
> +	LMP92001_CHAN_SPEC(4, IIO_VOLTAGE, NULL, 0),
> +	LMP92001_CHAN_SPEC(5, IIO_VOLTAGE, NULL, 0),
> +	LMP92001_CHAN_SPEC(6, IIO_VOLTAGE, NULL, 0),
> +	LMP92001_CHAN_SPEC(7, IIO_VOLTAGE, NULL, 0),
> +	LMP92001_CHAN_SPEC(8, IIO_VOLTAGE, NULL, 0),
> +	LMP92001_CHAN_SPEC(9, IIO_VOLTAGE, lmp92001_events,
> +			ARRAY_SIZE(lmp92001_events)),
> +	LMP92001_CHAN_SPEC(10, IIO_VOLTAGE, lmp92001_events,
> +			ARRAY_SIZE(lmp92001_events)),
> +	LMP92001_CHAN_SPEC(11, IIO_VOLTAGE, lmp92001_events,
> +			ARRAY_SIZE(lmp92001_events)),
> +	LMP92001_CHAN_SPEC(12, IIO_VOLTAGE, NULL, 0),
> +	LMP92001_CHAN_SPEC(13, IIO_VOLTAGE, NULL, 0),
> +	LMP92001_CHAN_SPEC(14, IIO_VOLTAGE, NULL, 0),
> +	LMP92001_CHAN_SPEC(15, IIO_VOLTAGE, NULL, 0),
> +	LMP92001_CHAN_SPEC(16, IIO_VOLTAGE, NULL, 0),
> +	LMP92001_CHAN_SPEC(17,    IIO_TEMP, NULL, 0),

wondering in what unit VOLTAGE and TEMP is returned? likely need _SCALE

> +};
> +
> +static int lmp92001_adc_probe(struct platform_device *pdev)
> +{
> +	struct lmp92001 *lmp92001 = dev_get_drvdata(pdev->dev.parent);
> +	struct iio_dev *indio_dev;
> +	struct device_node *np = pdev->dev.of_node;
> +	const char *conversion;
> +	unsigned int cgen = 0, cad1, cad2, cad3;
> +	u32 mask;
> +	int ret;
> +
> +	indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*lmp92001));
> +	if (!indio_dev)
> +		return -ENOMEM;
> +
> +	mutex_init(&lmp92001->adc_lock);
> +
> +	iio_device_set_drvdata(indio_dev, lmp92001);
> +
> +	indio_dev->name = pdev->name;
> +	indio_dev->dev.parent = &pdev->dev;
> +	indio_dev->modes = INDIO_DIRECT_MODE;
> +	indio_dev->info = &lmp92001_info;
> +	indio_dev->channels = lmp92001_adc_channels;
> +	indio_dev->num_channels = ARRAY_SIZE(lmp92001_adc_channels);
> +
> +	ret = regmap_update_bits(lmp92001->regmap, LMP92001_CGEN,
> +					CGEN_RST, CGEN_RST);
> +	if (ret < 0) {
> +		dev_err(&pdev->dev, "failed to self reset all registers\n");
> +		return ret;
> +	}
> +
> +	/*
> +	 * Turn on all of them, if you are pretty sure they are must be
> +	 * real-time update or specify which channel is needed to be used to
> +	 * save conversion time for a cycle.
> +	 */
> +	ret = of_property_read_u32(np, "ti,lmp92001-adc-mask", &mask);
> +	if (ret < 0) {
> +		cad1 = cad2 = cad3 = 0xFF;
> +		dev_info(&pdev->dev, "turn on all of channels by default\n");
> +	} else {
> +		cad1 = mask & 0xFF;
> +		cad2 = (mask >> 8) & 0xFF;
> +		cad3 = (mask >> 16) & 0xFF;
> +	}
> +
> +	ret = regmap_update_bits(lmp92001->regmap, LMP92001_CAD1, 0xFF, cad1);
> +	if (ret < 0) {
> +		dev_err(&pdev->dev, "failed to enable/disable channels 1-8\n");
> +		return ret;
> +	}
> +
> +	ret = regmap_update_bits(lmp92001->regmap, LMP92001_CAD2, 0xFF, cad2);
> +	if (ret < 0) {
> +		dev_err(&pdev->dev, "failed to enable/disable channels 9-16\n");
> +		return ret;
> +	}
> +
> +	ret = regmap_update_bits(lmp92001->regmap, LMP92001_CAD3, BIT(0), cad3);
> +	if (ret < 0) {
> +		dev_err(&pdev->dev,
> +			"failed to enable/disable channel 17 (temperature)\n");
> +		return ret;
> +	}
> +
> +	ret = of_property_read_string_index(np, "ti,lmp92001-adc-mode", 0,
> +						&conversion);
> +	if (!ret) {
> +		if (strncmp("continuous", conversion, 10) == 0) {
> +			cgen |= 1;
> +		} else if (strncmp("single-shot", conversion, 11) == 0) {
> +			/* Okay */
> +		} else {
> +			dev_warn(&pdev->dev,
> +			"wrong adc mode! set to single-short conversion\n");
> +		}
> +	} else
> +		dev_info(&pdev->dev,
> +			"single-short conversion was chosen by default\n");
> +
> +	/* Lock the HW registers and set conversion mode. */
> +	ret = regmap_update_bits(lmp92001->regmap,
> +					LMP92001_CGEN, CGEN_LCK | CGEN_STRT,
> +					cgen | CGEN_LCK);
> +	if (ret < 0)
> +		return ret;
> +
> +	platform_set_drvdata(pdev, indio_dev);
> +
> +	return devm_iio_device_register(&pdev->dev, indio_dev);
> +}
> +
> +static int lmp92001_adc_remove(struct platform_device *pdev)
> +{
> +	struct iio_dev *indio_dev = platform_get_drvdata(pdev);
> +	struct lmp92001 *lmp92001 = iio_device_get_drvdata(indio_dev);
> +
> +	/*
> +	 * To stop ADC conversion to save power
> +	 *
> +	 * Unlock the HW registers.
> +	 * Set conversion mode to single-shot.
> +	 * Lock the HW registers.
> +	 */
> +	regmap_update_bits(lmp92001->regmap, LMP92001_CGEN, CGEN_LCK, 0);
> +	regmap_update_bits(lmp92001->regmap, LMP92001_CGEN, CGEN_STRT, 0);
> +	regmap_update_bits(lmp92001->regmap, LMP92001_CGEN, CGEN_LCK, CGEN_LCK);
> +
> +	devm_iio_device_unregister(&pdev->dev, indio_dev);

the unregister is called automatically since devm_


> +
> +	return 0;
> +}
> +
> +static struct platform_driver lmp92001_adc_driver = {
> +	.driver.name	= "lmp92001-adc",
> +	.probe		= lmp92001_adc_probe,
> +	.remove		= lmp92001_adc_remove,
> +};
> +
> +static int __init lmp92001_adc_init(void)
> +{
> +	return platform_driver_register(&lmp92001_adc_driver);
> +}
> +subsys_initcall(lmp92001_adc_init);
> +
> +static void __exit lmp92001_adc_exit(void)
> +{
> +	platform_driver_unregister(&lmp92001_adc_driver);
> +}
> +module_exit(lmp92001_adc_exit);
> +
> +MODULE_AUTHOR("Abhisit Sangjan <s.abhisit@xxxxxxxxx>");
> +MODULE_DESCRIPTION("IIO ADC interface for TI LMP92001");
> +MODULE_LICENSE("GPL");
> +MODULE_ALIAS("platform:lmp92001-adc");
> diff --git a/drivers/iio/dac/Kconfig b/drivers/iio/dac/Kconfig
> index 25bed2d..3e0d816 100644
> --- a/drivers/iio/dac/Kconfig
> +++ b/drivers/iio/dac/Kconfig
> @@ -221,6 +221,15 @@ config DPOT_DAC
>  	  To compile this driver as a module, choose M here: the module will be
>  	  called dpot-dac.
>  
> +config LMP92001_DAC
> +        tristate "TI LMP92001 DAC Driver"
> +        depends on MFD_LMP92001
> +        help
> +          If you say yes here you get support for TI LMP92001 DACs.
> +
> +          This driver can also be built as a module. If so, the module will
> +          be called lmp92001_dac.
> +
>  config LPC18XX_DAC
>  	tristate "NXP LPC18xx DAC driver"
>  	depends on ARCH_LPC18XX || COMPILE_TEST
> diff --git a/drivers/iio/dac/Makefile b/drivers/iio/dac/Makefile
> index 603587c..516d2be 100644
> --- a/drivers/iio/dac/Makefile
> +++ b/drivers/iio/dac/Makefile
> @@ -23,6 +23,7 @@ obj-$(CONFIG_AD7303) += ad7303.o
>  obj-$(CONFIG_AD8801) += ad8801.o
>  obj-$(CONFIG_CIO_DAC) += cio-dac.o
>  obj-$(CONFIG_DPOT_DAC) += dpot-dac.o
> +obj-$(CONFIG_LMP92001_DAC) += lmp92001-dac.o
>  obj-$(CONFIG_LPC18XX_DAC) += lpc18xx_dac.o
>  obj-$(CONFIG_LTC2632) += ltc2632.o
>  obj-$(CONFIG_M62332) += m62332.o
> diff --git a/drivers/iio/dac/lmp92001-dac.c b/drivers/iio/dac/lmp92001-dac.c
> new file mode 100644
> index 0000000..8ea981b
> --- /dev/null
> +++ b/drivers/iio/dac/lmp92001-dac.c
> @@ -0,0 +1,390 @@
> +/*
> + * lmp92001-dac.c - Support for TI LMP92001 DACs
> + *
> + * Copyright 2016-2017 Celestica Ltd.
> + *
> + * Author: Abhisit Sangjan <s.abhisit@xxxxxxxxx>
> + *
> + * Inspired by wm831x driver.
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License as published by
> + * the Free Software Foundation; either version 2 of the License, or
> + * (at your option) any later version.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + * GNU General Public License for more details.
> + *
> + */
> +
> +#include <linux/iio/iio.h>
> +#include <linux/kernel.h>
> +#include <linux/mfd/core.h>
> +#include <linux/module.h>
> +#include <linux/platform_device.h>
> +
> +#include <linux/mfd/lmp92001/core.h>
> +
> +#define CREF_DEXT	(1 << 0) /* 1 - DAC external reference.

use prefix
BIT()

> +				  * 0 - DAC internal reference.
> +				  */
> +#define CDAC_OFF	(1 << 0) /* 1 - Forces all outputs to high impedance. */
> +#define CDAC_OLVL	(1 << 1) /* 1 - Cy=0 will force associated OUTx outputs
> +				  *     to VDD.
> +				  * 0 - Cy=0 will force associated OUTx outputs
> +				  *     to GND.
> +				  */
> +#define CDAC_GANG	(1 << 2) /* Controls the association of analog output

I think I've seen this before... can avoid duplication?

> +				  * channels OUTx with asynchronous control
> +				  * inputs Cy.
> +				  *
> +				  *         Cy to OUTx Assignment
> +				  * --------------------------------------
> +				  * | Cy | CDAC:GANG = 0 | CDAC:GANG = 1 |
> +				  * --------------------------------------
> +				  * | C1 | OUT[1:4]      | OUT[1:3]      |
> +				  * --------------------------------------
> +				  * | C2 | OUT[5:6]      | OUT[4:6]      |
> +				  * --------------------------------------
> +				  * | C3 | OUT[7:8]      | OUT[7:9]      |
> +				  * --------------------------------------
> +				  * | C4 | OUT[9:12]     | OUT[10:12]    |
> +				  * --------------------------------------
> +				  */
> +
> +static int lmp92001_read_raw(struct iio_dev *indio_dev,
> +	struct iio_chan_spec const *channel,
> +	int *val, int *val2,
> +	long mask)
> +{
> +	struct lmp92001 *lmp92001 = iio_device_get_drvdata(indio_dev);
> +	int ret;
> +
> +	mutex_lock(&lmp92001->dac_lock);

please restructure code there, this can be a lot simpler and with less 
lines

> +
> +	switch (mask) {
> +	case IIO_CHAN_INFO_RAW:
> +		switch (channel->type) {
> +		case IIO_VOLTAGE:
> +			ret = regmap_read(lmp92001->regmap,
> +					0x7F + channel->channel, val);
> +			if (ret < 0)
> +				goto exit;
> +
> +			ret = IIO_VAL_INT;
> +			goto exit;
> +			break;
> +		default:
> +			break;
> +		}
> +		break;
> +	default:
> +		break;
> +	}
> +
> +	/* In case of no match channel info/type is return here. */
> +	ret = -EINVAL;
> +
> +exit:
> +	mutex_unlock(&lmp92001->dac_lock);
> +
> +	return ret;
> +}
> +
> +int lmp92001_write_raw(struct iio_dev *indio_dev,

static

> +	struct iio_chan_spec const *channel,
> +	int val, int val2,
> +	long mask)
> +{
> +	struct lmp92001 *lmp92001 = iio_device_get_drvdata(indio_dev);
> +	int ret;
> +
> +	mutex_lock(&lmp92001->dac_lock);

restructure code; lock only needed only around _write() if at all

> +
> +	if (val < 0 || val > 4095) {
> +		ret = -EINVAL;
> +		goto exit;
> +	}
> +
> +	switch (mask) {
> +	case IIO_CHAN_INFO_RAW:
> +		switch (channel->type) {
> +		case IIO_VOLTAGE:
> +			ret = regmap_write(lmp92001->regmap,
> +					0x7F + channel->channel, val);
> +			if (ret < 0)
> +				goto exit;
> +
> +			ret = 0;
> +			goto exit;
> +			break;
> +		default:
> +			break;
> +		}
> +		break;
> +	default:
> +		break;
> +	}
> +
> +	/* In case of no match channel info/type is return here. */
> +	ret = -EINVAL;
> +
> +exit:
> +	mutex_unlock(&lmp92001->dac_lock);
> +
> +	return ret;
> +}
> +
> +static const struct iio_info lmp92001_info = {
> +	.read_raw = lmp92001_read_raw,
> +	.write_raw = lmp92001_write_raw,
> +	.driver_module = THIS_MODULE,
> +};
> +
> +ssize_t lmp92001_dvref_read(struct iio_dev *indio_dev, uintptr_t private,

static

> +	struct iio_chan_spec const *channel, char *buf)
> +{
> +	struct lmp92001 *lmp92001 = iio_device_get_drvdata(indio_dev);
> +	unsigned int cref;
> +	int ret;
> +
> +	ret = regmap_read(lmp92001->regmap, LMP92001_CREF, &cref);
> +	if (ret < 0)
> +		return ret;
> +
> +	return sprintf(buf, "%s\n", cref & CREF_DEXT ? "external" : "internal");
> +}
> +
> +ssize_t lmp92001_dvref_write(struct iio_dev *indio_dev, uintptr_t private,
> +	struct iio_chan_spec const *channel, const char *buf, size_t len)
> +{
> +	struct lmp92001 *lmp92001 = iio_device_get_drvdata(indio_dev);
> +	unsigned int cref;
> +	int ret;
> +
> +	if (strncmp("external", buf, 8) == 0)

strcmp()

> +		cref = 1;
> +	else if (strncmp("internal", buf, 8) == 0)
> +		cref = 0;
> +	else
> +		return -EINVAL;
> +
> +	ret = regmap_update_bits(lmp92001->regmap, LMP92001_CREF, CREF_DEXT,
> +					cref);
> +	if (ret < 0)
> +		return ret;
> +
> +	return len;
> +}
> +
> +ssize_t lmp92001_outx_read(struct iio_dev *indio_dev, uintptr_t private,

static

> +	struct iio_chan_spec const *channel, char *buf)
> +{
> +	struct lmp92001 *lmp92001 = iio_device_get_drvdata(indio_dev);
> +	unsigned int cdac;
> +	const char *outx;
> +	int ret;
> +
> +	ret = regmap_read(lmp92001->regmap, LMP92001_CDAC, &cdac);
> +	if (ret < 0)
> +		return ret;
> +
> +	if (cdac & CDAC_OFF)
> +		outx = "hiz";
> +	else {
> +		if (cdac & CDAC_OLVL)
> +			outx = "1 or dac";
> +		else
> +			outx = "0 or dac";
> +	}
> +
> +	return sprintf(buf, "%s\n", outx);
> +}
> +
> +ssize_t lmp92001_outx_write(struct iio_dev *indio_dev, uintptr_t private,

static

> +	struct iio_chan_spec const *channel, const char *buf, size_t len)
> +{
> +	struct lmp92001 *lmp92001 = iio_device_get_drvdata(indio_dev);
> +	unsigned int cdac, mask;
> +	int ret;
> +
> +	if (strncmp("hiz", buf, 3) == 0) {
> +		cdac = CDAC_OFF;
> +		mask = CDAC_OFF;
> +	} else if (strncmp("dac", buf, 3) == 0) {
> +		cdac = ~CDAC_OFF;
> +		mask = CDAC_OFF;
> +	} else if (strncmp("0", buf, 1) == 0) {
> +		cdac = ~(CDAC_OLVL | CDAC_OFF);
> +		mask = CDAC_OLVL | CDAC_OFF;
> +	} else if (strncmp("1", buf, 1) == 0) {
> +		cdac = CDAC_OLVL;
> +		mask = CDAC_OLVL | CDAC_OFF;
> +	} else
> +		return -EINVAL;
> +
> +	ret = regmap_update_bits(lmp92001->regmap, LMP92001_CDAC, mask, cdac);
> +	if (ret < 0)
> +		return ret;
> +
> +	return len;
> +}
> +
> +ssize_t lmp92001_gang_read(struct iio_dev *indio_dev, uintptr_t private,
> +	struct iio_chan_spec const *channel, char *buf)
> +{
> +	struct lmp92001 *lmp92001 = iio_device_get_drvdata(indio_dev);
> +	unsigned int cdac;
> +	int ret;
> +
> +	ret = regmap_read(lmp92001->regmap, LMP92001_CDAC, &cdac);
> +	if (ret < 0)
> +		return ret;
> +
> +	return sprintf(buf, "%s\n", cdac & CDAC_GANG ? "1" : "0");
> +}
> +
> +ssize_t lmp92001_gang_write(struct iio_dev *indio_dev, uintptr_t private,

static

> +	struct iio_chan_spec const *channel, const char *buf, size_t len)
> +{
> +	struct lmp92001 *lmp92001 = iio_device_get_drvdata(indio_dev);
> +	unsigned int cdac = 0;
> +	int ret;
> +
> +	if (strncmp("0", buf, 1) == 0)
> +		cdac = ~CDAC_GANG;
> +	else if (strncmp("1", buf, 1) == 0)
> +		cdac = CDAC_GANG;
> +	else
> +		return -EINVAL;
> +
> +	ret = regmap_update_bits(lmp92001->regmap, LMP92001_CDAC, CDAC_GANG,
> +					cdac);
> +	if (ret < 0)
> +		return ret;
> +
> +	return len;
> +}
> +
> +static const struct iio_chan_spec_ext_info lmp92001_ext_info[] = {
> +	{
> +		.name = "vref",
> +		.read = lmp92001_dvref_read,
> +		.write = lmp92001_dvref_write,
> +		.shared = IIO_SHARED_BY_ALL,
> +	},
> +	{
> +		.name = "outx",
> +		.read = lmp92001_outx_read,
> +		.write = lmp92001_outx_write,
> +		.shared = IIO_SHARED_BY_ALL,
> +	},
> +	{
> +		.name = "gang",
> +		.read = lmp92001_gang_read,
> +		.write = lmp92001_gang_write,
> +		.shared = IIO_SHARED_BY_ALL,
> +	},
> +	{ },
> +};
> +
> +#define LMP92001_CHAN_SPEC(_ch) \
> +{ \
> +	.channel = _ch, \
> +	.type = IIO_VOLTAGE, \
> +	.indexed = 1, \
> +	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
> +	.ext_info = lmp92001_ext_info, \
> +	.output = 1, \
> +}
> +
> +static const struct iio_chan_spec lmp92001_dac_channels[] = {
> +	LMP92001_CHAN_SPEC(1),
> +	LMP92001_CHAN_SPEC(2),
> +	LMP92001_CHAN_SPEC(3),
> +	LMP92001_CHAN_SPEC(4),
> +	LMP92001_CHAN_SPEC(5),
> +	LMP92001_CHAN_SPEC(6),
> +	LMP92001_CHAN_SPEC(7),
> +	LMP92001_CHAN_SPEC(8),
> +	LMP92001_CHAN_SPEC(9),
> +	LMP92001_CHAN_SPEC(10),
> +	LMP92001_CHAN_SPEC(11),
> +	LMP92001_CHAN_SPEC(12),
> +};
> +
> +static int lmp92001_dac_probe(struct platform_device *pdev)
> +{
> +	struct lmp92001 *lmp92001 = dev_get_drvdata(pdev->dev.parent);
> +	struct iio_dev *indio_dev;
> +	struct device_node *np = pdev->dev.of_node;
> +	u8 gang = 0, outx = 0, hiz = 0;
> +	unsigned int cdac = 0;
> +	int ret;
> +
> +	indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*lmp92001));
> +	if (!indio_dev)
> +		return -ENOMEM;
> +
> +	mutex_init(&lmp92001->dac_lock);
> +
> +	iio_device_set_drvdata(indio_dev, lmp92001);
> +
> +	indio_dev->name = pdev->name;
> +	indio_dev->modes = INDIO_DIRECT_MODE;
> +	indio_dev->info = &lmp92001_info;
> +	indio_dev->channels = lmp92001_dac_channels;
> +	indio_dev->num_channels = ARRAY_SIZE(lmp92001_dac_channels);
> +
> +	of_property_read_u8(np, "ti,lmp92001-dac-hiz", &hiz);
> +	cdac |= hiz;
> +
> +	of_property_read_u8(np, "ti,lmp92001-dac-outx", &outx);
> +	cdac |= outx << 1;
> +
> +	of_property_read_u8(np, "ti,lmp92001-dac-gang", &gang);
> +	cdac |= gang << 2;
> +
> +	ret = regmap_update_bits(lmp92001->regmap, LMP92001_CDAC,
> +					CDAC_GANG | CDAC_OLVL | CDAC_OFF, cdac);
> +	if (ret < 0)
> +		return ret;
> +
> +	platform_set_drvdata(pdev, indio_dev);
> +
> +	return devm_iio_device_register(&pdev->dev, indio_dev);
> +}
> +
> +static int lmp92001_dac_remove(struct platform_device *pdev)
> +{
> +	struct iio_dev *indio_dev = platform_get_drvdata(pdev);
> +
> +	devm_iio_device_unregister(&pdev->dev, indio_dev);

devm_.._unregister()  not needed

> +
> +	return 0;
> +}
> +
> +static struct platform_driver lmp92001_dac_driver = {
> +	.driver.name	= "lmp92001-dac",
> +	.probe		= lmp92001_dac_probe,
> +	.remove		= lmp92001_dac_remove,
> +};
> +
> +static int __init lmp92001_dac_init(void)
> +{
> +	return platform_driver_register(&lmp92001_dac_driver);
> +}
> +subsys_initcall(lmp92001_dac_init);
> +
> +static void __exit lmp92001_dac_exit(void)
> +{
> +	platform_driver_unregister(&lmp92001_dac_driver);
> +}
> +module_exit(lmp92001_dac_exit);
> +
> +MODULE_AUTHOR("Abhisit Sangjan <s.abhisit@xxxxxxxxx>");
> +MODULE_DESCRIPTION("IIO DAC interface for TI LMP92001");
> +MODULE_LICENSE("GPL");
> +MODULE_ALIAS("platform:lmp92001-dac");
> diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
> index 94ad2c1..a20389a 100644
> --- a/drivers/mfd/Kconfig
> +++ b/drivers/mfd/Kconfig
> @@ -1528,6 +1528,18 @@ config MFD_LM3533
>  	  additional drivers must be enabled in order to use the LED,
>  	  backlight or ambient-light-sensor functionality of the device.
>  
> +config MFD_LMP92001
> +       tristate "TI LMP92001 Analog System Monitor and Controller"
> +       depends on I2C
> +       select MFD_CORE
> +       select REGMAP_I2C
> +       help
> +         Say yes here to enable support for TI LMP92001 Analog System
> +         Monitor and Controller
> +
> +         This driver provide support for 16 ADC, 12 DAC, Voltage Reference,
> +         Analog Temperature Sensor and 8-bit GPIO Port.
> +
>  config MFD_TIMBERDALE
>  	tristate "Timberdale FPGA"
>  	select MFD_CORE
> diff --git a/drivers/mfd/Makefile b/drivers/mfd/Makefile
> index 080793b..20d2e65 100644
> --- a/drivers/mfd/Makefile
> +++ b/drivers/mfd/Makefile
> @@ -199,6 +199,10 @@ obj-$(CONFIG_MFD_RN5T618)	+= rn5t618.o
>  obj-$(CONFIG_MFD_SEC_CORE)	+= sec-core.o sec-irq.o
>  obj-$(CONFIG_MFD_SYSCON)	+= syscon.o
>  obj-$(CONFIG_MFD_LM3533)	+= lm3533-core.o lm3533-ctrlbank.o
> +
> +lmp92001-objs			:= lmp92001-core.o lmp92001-i2c.o lmp92001-debug.o
> +obj-$(CONFIG_MFD_LMP92001)	+= lmp92001.o
> +
>  obj-$(CONFIG_MFD_VEXPRESS_SYSREG)	+= vexpress-sysreg.o
>  obj-$(CONFIG_MFD_RETU)		+= retu-mfd.o
>  obj-$(CONFIG_MFD_AS3711)	+= as3711.o
> diff --git a/drivers/mfd/lmp92001-core.c b/drivers/mfd/lmp92001-core.c
> new file mode 100644
> index 0000000..55bc9ab
> --- /dev/null
> +++ b/drivers/mfd/lmp92001-core.c
> @@ -0,0 +1,308 @@
> +/*
> + * lmp92001-core.c - Device access for TI LMP92001
> + *
> + * Copyright 2016-2017 Celestica Ltd.
> + *
> + * Author: Abhisit Sangjan <s.abhisit@xxxxxxxxx>
> + *
> + * Inspired by wm831x driver.
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License as published by
> + * the Free Software Foundation; either version 2 of the License, or
> + * (at your option) any later version.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + * GNU General Public License for more details.
> + *
> + */
> +
> +#include <linux/mfd/lmp92001/core.h>
> +#include <linux/mfd/lmp92001/debug.h>
> +
> +static const struct mfd_cell lmp92001_devs[] = {
> +	{
> +		.name = "lmp92001-gpio",
> +		.of_compatible = "ti,lmp92001-gpio",
> +	},
> +	{
> +		.name = "lmp92001-adc",
> +		.of_compatible = "ti,lmp92001-adc",
> +	},
> +	{
> +		.name = "lmp92001-dac",
> +		.of_compatible = "ti,lmp92001-dac",
> +	},
> +};
> +
> +static struct reg_default lmp92001_defaults[] = {
> +	{ LMP92001_SGEN,  0x40   },
> +	{ LMP92001_SHIL,  0x00   },
> +	{ LMP92001_SLOL,  0x00   },
> +	{ LMP92001_CGEN,  0x00   },
> +	{ LMP92001_CDAC,  0x03   },
> +	{ LMP92001_CGPO,  0xFF   },
> +	{ LMP92001_CINH,  0x00   },
> +	{ LMP92001_CINL,  0x00   },
> +	{ LMP92001_CAD1,  0x00   },
> +	{ LMP92001_CAD2,  0x00   },
> +	{ LMP92001_CAD3,  0x00   },
> +	{ LMP92001_CTRIG, 0x00   },
> +	{ LMP92001_CREF,  0x07   },
> +	{ LMP92001_ADC1,  0x0000 },
> +	{ LMP92001_ADC2,  0x0000 },
> +	{ LMP92001_ADC3,  0x0000 },
> +	{ LMP92001_ADC4,  0x0000 },
> +	{ LMP92001_ADC5,  0x0000 },
> +	{ LMP92001_ADC6,  0x0000 },
> +	{ LMP92001_ADC7,  0x0000 },
> +	{ LMP92001_ADC8,  0x0000 },
> +	{ LMP92001_ADC9,  0x0000 },
> +	{ LMP92001_ADC10, 0x0000 },
> +	{ LMP92001_ADC11, 0x0000 },
> +	{ LMP92001_ADC12, 0x0000 },
> +	{ LMP92001_ADC13, 0x0000 },
> +	{ LMP92001_ADC14, 0x0000 },
> +	{ LMP92001_ADC15, 0x0000 },
> +	{ LMP92001_ADC16, 0x0000 },
> +	{ LMP92001_LIH1,  0x0FFF },
> +	{ LMP92001_LIH2,  0x0FFF },
> +	{ LMP92001_LIH3,  0x0FFF },
> +	{ LMP92001_LIH9,  0x0FFF },
> +	{ LMP92001_LIH10, 0x0FFF },
> +	{ LMP92001_LIH11, 0x0FFF },
> +	{ LMP92001_LIL1,  0x0000 },
> +	{ LMP92001_LIL2,  0x0000 },
> +	{ LMP92001_LIL3,  0x0000 },
> +	{ LMP92001_LIL9,  0x0000 },
> +	{ LMP92001_LIL10, 0x0000 },
> +	{ LMP92001_LIL11, 0x0000 },
> +	{ LMP92001_DAC1,  0x0000 },
> +	{ LMP92001_DAC2,  0x0000 },
> +	{ LMP92001_DAC3,  0x0000 },
> +	{ LMP92001_DAC4,  0x0000 },
> +	{ LMP92001_DAC5,  0x0000 },
> +	{ LMP92001_DAC6,  0x0000 },
> +	{ LMP92001_DAC7,  0x0000 },
> +	{ LMP92001_DAC8,  0x0000 },
> +	{ LMP92001_DAC9,  0x0000 },
> +	{ LMP92001_DAC10, 0x0000 },
> +	{ LMP92001_DAC11, 0x0000 },
> +	{ LMP92001_DAC12, 0x0000 },
> +	{ LMP92001_DALL,  0x0000 },
> +};
> +
> +static bool lmp92001_reg_readable(struct device *dev, unsigned int reg)
> +{
> +	switch (reg) {
> +	case LMP92001_ID:
> +	case LMP92001_VER:
> +	case LMP92001_SGEN:
> +	case LMP92001_SGPI:
> +	case LMP92001_SHIL:
> +	case LMP92001_SLOL:
> +	case LMP92001_CGEN:
> +	case LMP92001_CDAC:
> +	case LMP92001_CGPO:
> +	case LMP92001_CINH:
> +	case LMP92001_CINL:
> +	case LMP92001_CAD1:
> +	case LMP92001_CAD2:
> +	case LMP92001_CAD3:
> +	case LMP92001_ADC1:
> +	case LMP92001_ADC2:
> +	case LMP92001_ADC3:
> +	case LMP92001_ADC4:
> +	case LMP92001_ADC5:
> +	case LMP92001_ADC6:
> +	case LMP92001_ADC7:
> +	case LMP92001_ADC8:
> +	case LMP92001_ADC9:
> +	case LMP92001_ADC10:
> +	case LMP92001_ADC11:
> +	case LMP92001_ADC12:
> +	case LMP92001_ADC13:
> +	case LMP92001_ADC14:
> +	case LMP92001_ADC15:
> +	case LMP92001_ADC16:
> +	case LMP92001_ADC17:
> +	case LMP92001_LIH1:
> +	case LMP92001_LIH2:
> +	case LMP92001_LIH3:
> +	case LMP92001_LIH9:
> +	case LMP92001_LIH10:
> +	case LMP92001_LIH11:
> +	case LMP92001_LIL1:
> +	case LMP92001_LIL2:
> +	case LMP92001_LIL3:
> +	case LMP92001_LIL9:
> +	case LMP92001_LIL10:
> +	case LMP92001_LIL11:
> +	case LMP92001_CREF:
> +	case LMP92001_DAC1:
> +	case LMP92001_DAC2:
> +	case LMP92001_DAC3:
> +	case LMP92001_DAC4:
> +	case LMP92001_DAC5:
> +	case LMP92001_DAC6:
> +	case LMP92001_DAC7:
> +	case LMP92001_DAC8:
> +	case LMP92001_DAC9:
> +	case LMP92001_DAC10:
> +	case LMP92001_DAC11:
> +	case LMP92001_DAC12:
> +	case LMP92001_BLK0:
> +	case LMP92001_BLK1:
> +	case LMP92001_BLK2:
> +	case LMP92001_BLK3:
> +	case LMP92001_BLK4:
> +	case LMP92001_BLK5:
> +		return true;
> +	default:
> +		return false;
> +	}
> +}
> +
> +static bool lmp92001_reg_writeable(struct device *dev, unsigned int reg)
> +{
> +	switch (reg) {
> +	case LMP92001_CGEN:
> +	case LMP92001_CDAC:
> +	case LMP92001_CGPO:
> +	case LMP92001_CINH:
> +	case LMP92001_CINL:
> +	case LMP92001_CAD1:
> +	case LMP92001_CAD2:
> +	case LMP92001_CAD3:
> +	case LMP92001_CTRIG:
> +	case LMP92001_LIH1:
> +	case LMP92001_LIH2:
> +	case LMP92001_LIH3:
> +	case LMP92001_LIH9:
> +	case LMP92001_LIH10:
> +	case LMP92001_LIH11:
> +	case LMP92001_LIL1:
> +	case LMP92001_LIL2:
> +	case LMP92001_LIL3:
> +	case LMP92001_LIL9:
> +	case LMP92001_LIL10:
> +	case LMP92001_LIL11:
> +	case LMP92001_CREF:
> +	case LMP92001_DAC1:
> +	case LMP92001_DAC2:
> +	case LMP92001_DAC3:
> +	case LMP92001_DAC4:
> +	case LMP92001_DAC5:
> +	case LMP92001_DAC6:
> +	case LMP92001_DAC7:
> +	case LMP92001_DAC8:
> +	case LMP92001_DAC9:
> +	case LMP92001_DAC10:
> +	case LMP92001_DAC11:
> +	case LMP92001_DAC12:
> +	case LMP92001_DALL:
> +	case LMP92001_BLK0:
> +	case LMP92001_BLK1:
> +	case LMP92001_BLK4:
> +	case LMP92001_BLK5:
> +		return true;
> +	default:
> +		return false;
> +	}
> +}
> +
> +static bool lmp92001_reg_volatile(struct device *dev, unsigned int reg)
> +{
> +	switch (reg) {
> +	case LMP92001_SGEN:
> +	case LMP92001_SGPI:
> +	case LMP92001_SHIL:
> +	case LMP92001_SLOL:
> +	case LMP92001_CGEN:
> +	case LMP92001_ADC1:
> +	case LMP92001_ADC2:
> +	case LMP92001_ADC3:
> +	case LMP92001_ADC4:
> +	case LMP92001_ADC5:
> +	case LMP92001_ADC6:
> +	case LMP92001_ADC7:
> +	case LMP92001_ADC8:
> +	case LMP92001_ADC9:
> +	case LMP92001_ADC10:
> +	case LMP92001_ADC11:
> +	case LMP92001_ADC12:
> +	case LMP92001_ADC13:
> +	case LMP92001_ADC14:
> +	case LMP92001_ADC15:
> +	case LMP92001_ADC16:
> +	case LMP92001_ADC17:
> +	case LMP92001_BLK2:
> +	case LMP92001_BLK3:
> +		return true;
> +	default:
> +		return false;
> +	}
> +}
> +
> +struct regmap_config lmp92001_regmap_config = {
> +	.reg_bits = 8,
> +	.val_bits = 16,
> +
> +	.cache_type = REGCACHE_RBTREE,
> +
> +	.reg_defaults = lmp92001_defaults,
> +	.num_reg_defaults = ARRAY_SIZE(lmp92001_defaults),
> +
> +	.max_register = LMP92001_BLK5,
> +	.readable_reg = lmp92001_reg_readable,
> +	.writeable_reg = lmp92001_reg_writeable,
> +	.volatile_reg = lmp92001_reg_volatile,
> +};
> +
> +int lmp92001_device_init(struct lmp92001 *lmp92001, unsigned long id, int irq)
> +{
> +	int ret;
> +	unsigned int comid, ver;
> +
> +	dev_set_drvdata(lmp92001->dev, lmp92001);
> +
> +	ret  = regmap_read(lmp92001->regmap, LMP92001_ID, &comid);
> +	if (ret < 0) {
> +		dev_err(lmp92001->dev, "failed to read Company ID: %d\n", ret);
> +		goto exit;
> +	}
> +
> +	ret  = regmap_read(lmp92001->regmap, LMP92001_VER, &ver);
> +	if (ret < 0) {
> +		dev_err(lmp92001->dev, "failed to read Version: %d\n", ret);
> +		goto exit;
> +	}
> +
> +	dev_info(lmp92001->dev, "Company ID 0x%.2x, Version 0x%.2x\n",
> +			comid, ver);
> +
> +	ret = mfd_add_devices(lmp92001->dev, PLATFORM_DEVID_AUTO,
> +				lmp92001_devs, ARRAY_SIZE(lmp92001_devs),
> +				NULL, 0, NULL);
> +	if (ret != 0) {
> +		dev_err(lmp92001->dev, "failed to add children\n");
> +		goto exit;
> +	}
> +
> +	ret = lmp92001_debug_init(lmp92001);
> +	if (ret < 0) {
> +		dev_err(lmp92001->dev, "failed to initial debug fs.\n");
> +		goto exit;
> +	}
> +
> +exit:
> +	return ret;
> +}
> +
> +void lmp92001_device_exit(struct lmp92001 *lmp92001)
> +{
> +	lmp92001_debug_exit(lmp92001);
> +	mfd_remove_devices(lmp92001->dev);
> +}
> diff --git a/drivers/mfd/lmp92001-debug.c b/drivers/mfd/lmp92001-debug.c
> new file mode 100644
> index 0000000..d733e67
> --- /dev/null
> +++ b/drivers/mfd/lmp92001-debug.c
> @@ -0,0 +1,67 @@
> +/*
> + * lmp92001-debug.c - Debug file system for TI LMP92001
> + *
> + * Copyright 2016-2017 Celestica Ltd.
> + *
> + * Author: Abhisit Sangjan <s.abhisit@xxxxxxxxx>
> + *
> + * Inspired by wm831x driver.
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License as published by
> + * the Free Software Foundation; either version 2 of the License, or
> + * (at your option) any later version.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + * GNU General Public License for more details.
> + *
> + */
> +
> +#include <linux/kernel.h>
> +
> +#include <linux/mfd/lmp92001/core.h>
> +
> +static ssize_t lmp92001_id_ver_show(struct device *dev,
> +	struct device_attribute *attr, char *buf)
> +{
> +	struct lmp92001 *lmp92001 = dev_get_drvdata(dev);
> +	int ret;
> +	unsigned int comid, ver;
> +
> +	ret = regmap_read(lmp92001->regmap, LMP92001_ID, &comid);
> +	if (ret < 0) {
> +		dev_err(lmp92001->dev, "failed to read Company ID: %d\n", ret);
> +		return 0;
> +	}
> +
> +	ret = regmap_read(lmp92001->regmap, LMP92001_VER, &ver);
> +	if (ret < 0) {
> +		dev_err(lmp92001->dev, "failed to read Version: %d\n", ret);
> +		return 0;
> +	}
> +
> +	ret = sprintf(buf, "Company ID 0x%02x (%d), Version 0x%02x (%d)\n",
> +			comid, comid, ver, ver);
> +
> +	return ret;
> +}
> +static DEVICE_ATTR(lmp92001_id_ver, 0444, lmp92001_id_ver_show, NULL);
> +
> +int lmp92001_debug_init(struct lmp92001 *lmp92001)
> +{
> +	int ret;
> +
> +	ret = device_create_file(lmp92001->dev, &dev_attr_lmp92001_id_ver);
> +	if (ret != 0)
> +		dev_err(lmp92001->dev,
> +			"unique ID attribute is not created: %d\n", ret);
> +
> +	return ret;
> +}
> +
> +void lmp92001_debug_exit(struct lmp92001 *lmp92001)
> +{
> +	device_remove_file(lmp92001->dev, &dev_attr_lmp92001_id_ver);
> +}
> diff --git a/drivers/mfd/lmp92001-i2c.c b/drivers/mfd/lmp92001-i2c.c
> new file mode 100644
> index 0000000..bbb1dad
> --- /dev/null
> +++ b/drivers/mfd/lmp92001-i2c.c
> @@ -0,0 +1,215 @@
> +/*
> + * lmp92001-i2c.c - I2C access for TI LMP92001
> + *
> + * Copyright 2016-2017 Celestica Ltd.
> + *
> + * Author: Abhisit Sangjan <s.abhisit@xxxxxxxxx>
> + *
> + * Inspired by wm831x driver.
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License as published by
> + * the Free Software Foundation; either version 2 of the License, or
> + * (at your option) any later version.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + * GNU General Public License for more details.
> + *
> + */
> +
> +#include <linux/err.h>
> +#include <linux/i2c.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/of_device.h>
> +#include <linux/of_gpio.h>
> +#include <linux/platform_device.h>
> +#include <linux/slab.h>
> +
> +#include <linux/mfd/lmp92001/core.h>
> +
> +static const unsigned short lmp92001_i2c_addresses[] = {
> +	0x40, 0x42, 0x44, 0x46, 0x48, 0x4A, 0x4C, 0x4E, 0x50, I2C_CLIENT_END
> +};
> +
> +/* TODO: To read/write block access, it may need to re-ordering endianness! */
> +static int lmp92001_reg_read(void *context, unsigned int reg, unsigned int *val)
> +{
> +	struct device *dev = context;
> +	struct i2c_client *i2c = to_i2c_client(dev);
> +	int ret;
> +
> +	if (reg > 0xff)
> +		return -EINVAL;
> +
> +	switch (reg) {
> +	case LMP92001_ID ... LMP92001_CTRIG:
> +	case LMP92001_CREF:
> +		ret = i2c_smbus_read_byte_data(i2c, reg);
> +		break;
> +	case LMP92001_ADC1 ... LMP92001_LIL11:
> +	case LMP92001_DAC1 ... LMP92001_DALL:
> +		ret = i2c_smbus_read_word_swapped(i2c, reg);
> +		break;
> +	case LMP92001_BLK0 ... LMP92001_BLK5:
> +		ret = i2c_smbus_read_block_data(i2c, reg,
> +						(u8 *)((uintptr_t)*val));
> +		break;
> +	default:
> +		return -EINVAL;
> +	}
> +
> +	if (ret < 0)
> +		return ret;
> +
> +	if (reg <= LMP92001_DALL)
> +		*val = ret;
> +
> +	return 0;
> +}
> +
> +static int lmp92001_reg_write(void *context, unsigned int reg, unsigned int val)
> +{
> +	struct device *dev = context;
> +	struct i2c_client *i2c = to_i2c_client(dev);
> +	int ret;
> +
> +	if (reg > 0xff)
> +		return -EINVAL;
> +
> +	switch (reg) {
> +	case LMP92001_ID ... LMP92001_CTRIG:
> +	case LMP92001_CREF:
> +		ret = i2c_smbus_write_byte_data(i2c, reg, val);
> +		break;
> +	case LMP92001_ADC1 ... LMP92001_LIL11:
> +	case LMP92001_DAC1 ... LMP92001_DALL:
> +		ret = i2c_smbus_write_word_swapped(i2c, reg, val);
> +		break;
> +	/* To call this function/case, must be passed val as pointer */
> +	case LMP92001_BLK0:
> +	case LMP92001_BLK4:
> +		ret = i2c_smbus_write_block_data(i2c, reg, 24,
> +						(u8 *)((uintptr_t)val));
> +		break;
> +	case LMP92001_BLK1:
> +	case LMP92001_BLK5:
> +		ret = i2c_smbus_write_block_data(i2c, reg, 12,
> +						(u8 *)((uintptr_t)val));
> +		break;
> +	case LMP92001_BLK2:
> +		ret = i2c_smbus_write_block_data(i2c, reg, 34,
> +						(u8 *)((uintptr_t)val));
> +		break;
> +	case LMP92001_BLK3:
> +		ret = i2c_smbus_write_block_data(i2c, reg, 18,
> +						(u8 *)((uintptr_t)val));
> +		break;
> +	default:
> +		return -EINVAL;
> +	}
> +
> +	return ret;
> +}
> +
> +static int lmp92001_i2c_probe(struct i2c_client *i2c,
> +	const struct i2c_device_id *id)
> +{
> +	struct lmp92001 *lmp92001;
> +	int ret;
> +
> +	lmp92001 = devm_kzalloc(&i2c->dev, sizeof(struct lmp92001), GFP_KERNEL);
> +	if (!lmp92001)
> +		return -ENOMEM;
> +
> +	i2c_set_clientdata(i2c, lmp92001);
> +	lmp92001->dev = &i2c->dev;
> +
> +	lmp92001_regmap_config.reg_read = lmp92001_reg_read;
> +	lmp92001_regmap_config.reg_write = lmp92001_reg_write;
> +
> +	lmp92001->regmap = devm_regmap_init(&i2c->dev, NULL, &i2c->dev,
> +						&lmp92001_regmap_config);
> +	if (IS_ERR(lmp92001->regmap)) {
> +		ret = PTR_ERR(lmp92001->regmap);
> +		dev_err(lmp92001->dev, "failed to allocate register map: %d\n",
> +				ret);
> +		return ret;
> +	}
> +
> +	return lmp92001_device_init(lmp92001, id->driver_data, i2c->irq);
> +}
> +
> +static int lmp92001_i2c_remove(struct i2c_client *i2c)
> +{
> +	struct lmp92001 *lmp92001 = i2c_get_clientdata(i2c);
> +
> +	lmp92001_device_exit(lmp92001);
> +
> +	return 0;
> +}
> +
> +#ifdef CONFIG_OF
> +static const struct of_device_id lmp92001_dt_ids[] = {
> +	{ .compatible = "ti,lmp92001", },
> +	{ },
> +};
> +MODULE_DEVICE_TABLE(of, lmp92001_dt_ids);
> +#endif
> +
> +static const struct i2c_device_id lmp92001_i2c_ids[] = {
> +	{ "lmp92001" },
> +	{ },
> +};
> +MODULE_DEVICE_TABLE(i2c, lmp92001_i2c_ids);
> +
> +static int lmp92001_i2c_detect(struct i2c_client *i2c,
> +	struct i2c_board_info *info)
> +{
> +	struct i2c_adapter *adapter = i2c->adapter;
> +	s32 comid, ver;
> +
> +	if (!i2c_check_functionality(adapter,
> +					I2C_FUNC_SMBUS_BYTE_DATA |
> +					I2C_FUNC_SMBUS_WORD_DATA |
> +					I2C_FUNC_SMBUS_BLOCK_DATA))
> +		return -ENODEV;
> +
> +	comid = i2c_smbus_read_byte_data(i2c, LMP92001_ID);
> +	ver = i2c_smbus_read_byte_data(i2c, LMP92001_VER);
> +
> +	if (comid != 0x01 || ver != 0x10)
> +		return -ENODEV;
> +
> +	return 0;
> +}
> +
> +static struct i2c_driver lmp92001_i2c_driver = {
> +	.driver = {
> +		.name = "lmp92001",
> +		.of_match_table = of_match_ptr(lmp92001_dt_ids),
> +	},
> +	.probe		= lmp92001_i2c_probe,
> +	.remove		= lmp92001_i2c_remove,
> +	.id_table	= lmp92001_i2c_ids,
> +	.detect		= lmp92001_i2c_detect,
> +	.address_list	= lmp92001_i2c_addresses,
> +};
> +
> +static int __init lmp92001_i2c_init(void)
> +{
> +	return i2c_add_driver(&lmp92001_i2c_driver);
> +}
> +subsys_initcall(lmp92001_i2c_init);
> +
> +static void __exit lmp92001_i2c_exit(void)
> +{
> +	i2c_del_driver(&lmp92001_i2c_driver);
> +}
> +module_exit(lmp92001_i2c_exit);
> +
> +MODULE_DESCRIPTION("i2c driver for TI LMP92001");
> +MODULE_AUTHOR("Abhisit Sangjan <s.abhisit@xxxxxxxxx>");
> +MODULE_LICENSE("GPL");
> diff --git a/include/linux/mfd/lmp92001/core.h b/include/linux/mfd/lmp92001/core.h
> new file mode 100644
> index 0000000..9039000
> --- /dev/null
> +++ b/include/linux/mfd/lmp92001/core.h
> @@ -0,0 +1,119 @@
> +/*
> + * include/linux/mfd/lmp92001/core.h - Core interface for TI LMP92001
> + *
> + * Copyright 2016-2017 Celestica Ltd.
> + *
> + * Author: Abhisit Sangjan <s.abhisit@xxxxxxxxx>
> + *
> + * Inspired by wm831x driver.
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License as published by
> + * the Free Software Foundation; either version 2 of the License, or
> + * (at your option) any later version.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + * GNU General Public License for more details.
> + *
> + */
> +
> +#ifndef __MFD_LMP92001_CORE_H__
> +#define __MFD_LMP92001_CORE_H__
> +
> +#include <linux/device.h>
> +#include <linux/mfd/core.h>
> +#include <linux/mutex.h>
> +#include <linux/regmap.h>
> +
> +/*
> + * Register values.
> + */
> +/* ID */
> +#define LMP92001_ID	0x0E
> +#define LMP92001_VER	0x0F
> +/* STATUS */
> +#define LMP92001_SGEN	0x10
> +#define LMP92001_SGPI	0x11
> +#define LMP92001_SHIL	0x12
> +#define LMP92001_SLOL	0x13
> +/* CONTROL */
> +#define LMP92001_CGEN	0x14
> +#define LMP92001_CDAC	0x15
> +#define LMP92001_CGPO	0x16
> +#define LMP92001_CINH	0x17
> +#define LMP92001_CINL	0x18
> +#define LMP92001_CAD1	0x19
> +#define LMP92001_CAD2	0x1A
> +#define LMP92001_CAD3	0x1B
> +#define LMP92001_CTRIG	0x1C
> +/* ADC OUTPUT DATA */
> +#define LMP92001_ADC1	0x20
> +#define LMP92001_ADC2	0x21
> +#define LMP92001_ADC3	0x22
> +#define LMP92001_ADC4	0x23
> +#define LMP92001_ADC5	0x24
> +#define LMP92001_ADC6	0x25
> +#define LMP92001_ADC7	0x26
> +#define LMP92001_ADC8	0x27
> +#define LMP92001_ADC9	0x28
> +#define LMP92001_ADC10	0x29
> +#define LMP92001_ADC11	0x2A
> +#define LMP92001_ADC12	0x2B
> +#define LMP92001_ADC13	0x2C
> +#define LMP92001_ADC14	0x2D
> +#define LMP92001_ADC15	0x2E
> +#define LMP92001_ADC16	0x2F
> +#define LMP92001_ADC17	0x30
> +/* ADC WINDOW COMPARATOR LIMITS */
> +#define LMP92001_LIH1	0x40
> +#define LMP92001_LIH2	0x41
> +#define LMP92001_LIH3	0x42
> +#define LMP92001_LIH9	0x43
> +#define LMP92001_LIH10	0x44
> +#define LMP92001_LIH11	0x45
> +#define LMP92001_LIL1	0x46
> +#define LMP92001_LIL2	0x47
> +#define LMP92001_LIL3	0x48
> +#define LMP92001_LIL9	0x49
> +#define LMP92001_LIL10	0x4A
> +#define LMP92001_LIL11	0x4B
> +/* INTERNAL REFERENCE CONTROL */
> +#define LMP92001_CREF	0x66
> +/* DAC INPUT DATA */
> +#define LMP92001_DAC1	0x80
> +#define LMP92001_DAC2	0x81
> +#define LMP92001_DAC3	0x82
> +#define LMP92001_DAC4	0x83
> +#define LMP92001_DAC5	0x84
> +#define LMP92001_DAC6	0x85
> +#define LMP92001_DAC7	0x86
> +#define LMP92001_DAC8	0x87
> +#define LMP92001_DAC9	0x88
> +#define LMP92001_DAC10	0x89
> +#define LMP92001_DAC11	0x8A
> +#define LMP92001_DAC12	0x8B
> +#define LMP92001_DALL	0x90
> +/* MEMORY MAPPED BLOCK COMMANDS */
> +#define LMP92001_BLK0	0xF0
> +#define LMP92001_BLK1	0xF1
> +#define LMP92001_BLK2	0xF2
> +#define LMP92001_BLK3	0xF3
> +#define LMP92001_BLK4	0xF4
> +#define LMP92001_BLK5	0xF5
> +
> +struct lmp92001 {
> +	struct device *dev;
> +	struct regmap *regmap;
> +
> +	struct mutex adc_lock;
> +	struct mutex dac_lock;
> +};
> +
> +extern struct regmap_config lmp92001_regmap_config;
> +
> +int lmp92001_device_init(struct lmp92001 *lmp92001, unsigned long id, int irq);
> +void lmp92001_device_exit(struct lmp92001 *lmp92001);
> +
> +#endif /* __MFD_LMP92001_CORE_H__ */
> diff --git a/include/linux/mfd/lmp92001/debug.h b/include/linux/mfd/lmp92001/debug.h
> new file mode 100644
> index 0000000..efef95f
> --- /dev/null
> +++ b/include/linux/mfd/lmp92001/debug.h
> @@ -0,0 +1,28 @@
> +/*
> + * include/linux/mfd/lmp92001/debug.h - Debug interface for TI 92001
> + *
> + * Copyright 2016-2017 Celestica Ltd.
> + *
> + * Author: Abhisit Sangjan <s.abhisit@xxxxxxxxx>
> + *
> + * Inspired by wm831x driver.
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License as published by
> + * the Free Software Foundation; either version 2 of the License, or
> + * (at your option) any later version.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + * GNU General Public License for more details.
> + *
> + */
> +
> +#ifndef __MFD_LMP92001_DEBUG_H__
> +#define __MFD_LMP92001_DEBUG_H__
> +
> +int lmp92001_debug_init(struct lmp92001 *lmp92001);
> +void lmp92001_debug_exit(struct lmp92001 *lmp92001);
> +
> +#endif /* __MFD_LMP92001_DEBUG_H__ */
> 

-- 

Peter Meerwald-Stadler
Mobile: +43 664 24 44 418
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