Re: [PATCH v2 4/4] iio/adc/axp288: add support for axp288 gpadc

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Hello,

> Platform driver for XPowers AXP288 ADC, which is a customized PMIC for Intel

XPower's

> Baytrail-CR platforms. GPADC device enumerates as one of the PMIC MFD cell
> devices. It uses IIO infrastructure to communicate with userspace and
> consumer drivers.
> 
> Usages of ADC channels include battery charging and thermal sensors.
> 
> Based on initial work by:
> Ramakrishna Pallala <ramakrishna.pallala@xxxxxxxxx>

some trivial comments inline

> Signed-off-by: Jacob Pan <jacob.jun.pan@xxxxxxxxxxxxxxx>
> ---
>  drivers/iio/adc/Kconfig        |   8 ++
>  drivers/iio/adc/Makefile       |   1 +
>  drivers/iio/adc/axp288_gpadc.c | 250 +++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 259 insertions(+)
>  create mode 100644 drivers/iio/adc/axp288_gpadc.c
> 
> diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
> index 11b048a..f5c61c0 100644
> --- a/drivers/iio/adc/Kconfig
> +++ b/drivers/iio/adc/Kconfig
> @@ -279,4 +279,12 @@ config XILINX_XADC
>  	  The driver can also be build as a module. If so, the module will be called
>  	  xilinx-xadc.
>  
> +config AXP288_GPADC

alphabetic order please

> +	tristate "X-Power AXP288 GPADC driver"

XPower

> +	depends on MFD_AXP2XX
> +	help
> +	  Say yes here to have support for X-Power power management IC (PMIC) ADC
> +	  device. Depending on platform configuration, this general purpose ADC can
> +	  be used for sampling sensors such as thermal resisters.

resistors

> +
>  endmenu
> diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile
> index ad81b51..8bf0104 100644
> --- a/drivers/iio/adc/Makefile
> +++ b/drivers/iio/adc/Makefile
> @@ -30,3 +30,4 @@ obj-$(CONFIG_VF610_ADC) += vf610_adc.o
>  obj-$(CONFIG_VIPERBOARD_ADC) += viperboard_adc.o
>  xilinx-xadc-y := xilinx-xadc-core.o xilinx-xadc-events.o
>  obj-$(CONFIG_XILINX_XADC) += xilinx-xadc.o
> +obj-$(CONFIG_AXP288_GPADC) += axp288_gpadc.o
> diff --git a/drivers/iio/adc/axp288_gpadc.c b/drivers/iio/adc/axp288_gpadc.c
> new file mode 100644
> index 0000000..7ca6bbf
> --- /dev/null
> +++ b/drivers/iio/adc/axp288_gpadc.c
> @@ -0,0 +1,250 @@
> +/*
> + * axp288_gpadc.c - Xpower AXP288 PMIC GPADC Driver
> + *
> + * Copyright (C) 2014 Intel Corporation
> + *
> + * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> + *
> + * 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; version 2 of the License.
> + *
> + * 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/module.h>
> +#include <linux/kernel.h>
> +#include <linux/device.h>
> +#include <linux/regmap.h>
> +#include <linux/mfd/axp2xx.h>
> +#include <linux/platform_device.h>
> +
> +#include <linux/iio/iio.h>
> +#include <linux/iio/machine.h>
> +#include <linux/iio/driver.h>

newline

> +#define ADC_EN_MASK			0xF1
> +#define ADC_TS_PIN_GPADC                0xF2
> +#define ADC_TS_PIN_ON                   0xF3

use a likely unique prefix for all #defines, functions, e.g. AXP288_ADC_

> +
> +struct gpadc_info {
> +	unsigned int irq;

irq is 'int' in _probe()

> +	struct device *dev;
> +	struct regmap *regmap;
> +};
> +
> +#define ADC_CHANNEL(_type, _channel, _address)	        \
> +	{								\
> +		.indexed = 1,						\
> +		.type = _type,						\
> +		.channel = _channel,					\
> +		.address = _address,					\
> +		.datasheet_name = "CH"#_channel,			\
> +		.scan_index = _channel,					\

driver doesn't offer buffered interface, so no scan_index, scan_type 
needed

> +		.scan_type = {						\
> +			.sign = 'u',					\
> +			.realbits = 12,					\
> +			.storagebits = 32,				\
> +			.endianness = IIO_LE,				\
> +		},							\
> +		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),		\
> +	}
> +
> +static const struct iio_chan_spec const axp288_adc_channels[] = {
> +	ADC_CHANNEL(IIO_TEMP, 0, AXP288_TS_ADC_H),
> +	ADC_CHANNEL(IIO_TEMP, 1, AXP288_PMIC_ADC_H),
> +	ADC_CHANNEL(IIO_TEMP, 2, AXP288_GP_ADC_H),

what unit are these values in?
IIO wants milli degrees Celsius

> +	ADC_CHANNEL(IIO_CURRENT, 3, AXP20X_BATT_CHRG_I_H),
> +	ADC_CHANNEL(IIO_CURRENT, 4, AXP20X_BATT_DISCHRG_I_H),

there are no current channels documented in 
Documentation/ABI/testing/sysfs-bus-iio yet, need to describe

what unit?

> +	ADC_CHANNEL(IIO_VOLTAGE, 5, AXP20X_BATT_V_H),
> +};
> +
> +#define ADC_MAP(_adc_channel_label,				\
> +		     _consumer_dev_name,			\
> +		     _consumer_channel)				\
> +	{							\
> +		.adc_channel_label = _adc_channel_label,	\
> +		.consumer_dev_name = _consumer_dev_name,	\
> +		.consumer_channel = _consumer_channel,		\
> +	}
> +
> +/* for consumer drivers */

const probably

> +static struct iio_map axp288_iio_default_maps[] = {
> +	ADC_MAP("TS_PIN", "axp288-batt", "axp288-batt-temp"),
> +	ADC_MAP("PMIC_TEMP", "axp288-pmic", "axp288-pmic-temp"),
> +	ADC_MAP("GPADC", "axp288-gpadc", "axp288-system-temp"),
> +	ADC_MAP("BATT_CHG_I", "axp288-chrg", "axp288-chrg-curr"),
> +	ADC_MAP("BATT_DISCHRG_I", "axp288-chrg", "axp288-chrg-d-curr"),
> +	ADC_MAP("BATT_V", "axp288-batt", "axp288-batt-volt"),
> +	{},
> +};
> +
> +static int axp288_adc_read_raw(struct iio_dev *indio_dev,
> +			struct iio_chan_spec const *chan,
> +			int *val, int *val2, long m)
> +{
> +	int ret;
> +	struct gpadc_info *info = iio_priv(indio_dev);
> +	unsigned int th, tl;
> +
> +	mutex_lock(&indio_dev->mlock);
> +
> +	/* special case for GPADC sample */
> +	if (chan->address == AXP288_GP_ADC_H)
> +		regmap_write(info->regmap, AXP288_ADC_TS_PIN_CTRL,
> +			ADC_TS_PIN_GPADC);
> +
> +	ret = regmap_read(info->regmap, chan->address, &th);
> +	if (ret) {
> +		dev_err(&indio_dev->dev, "sample raw data high failed\n");
> +		goto exit_done;
> +	}
> +
> +	ret = regmap_read(info->regmap, chan->address + 1, &tl);
> +	if (ret) {
> +		dev_err(&indio_dev->dev, "sample raw data low failed\n");
> +		goto exit_done;
> +	}
> +
> +	*val = (th << 4) + ((tl >> 4) & 0x0F);
> +	ret = IIO_VAL_INT;
> +
> +exit_done:
> +	if (chan->address == AXP288_GP_ADC_H)
> +		regmap_write(info->regmap, AXP288_ADC_TS_PIN_CTRL,
> +			ADC_TS_PIN_ON);
> +
> +	mutex_unlock(&indio_dev->mlock);
> +
> +	return ret;
> +}
> +
> +static int axp288_gpadc_enable(struct regmap *regmap, bool enable)
> +{
> +	unsigned int pin_on, adc_en;
> +
> +	if (enable) {
> +		pin_on = ADC_TS_PIN_ON;
> +		adc_en = ADC_EN_MASK;
> +	} else {
> +		pin_on = ~ADC_TS_PIN_ON;
> +		adc_en = ~ADC_EN_MASK;
> +	}
> +	if (regmap_write(regmap, AXP288_ADC_TS_PIN_CTRL, pin_on))
> +		return -EIO;
> +
> +	return regmap_write(regmap, AXP20X_ADC_EN1, ~ADC_EN_MASK);
> +}
> +
> +static const struct iio_info axp288_iio_info = {
> +	.read_raw = &axp288_adc_read_raw,
> +	.driver_module = THIS_MODULE,
> +};
> +
> +static int axp288_gpadc_probe(struct platform_device *pdev)
> +{
> +	int err;
> +	struct gpadc_info *info;
> +	struct iio_dev *indio_dev;
> +	struct axp2xx_dev *axp2xx = dev_get_drvdata(pdev->dev.parent);
> +	int irq;
> +
> +	indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*info));
> +	if (!indio_dev)
> +		return -ENOMEM;
> +
> +	info = iio_priv(indio_dev);
> +	irq = platform_get_irq(pdev, 0);
> +	if (irq < 0) {
> +		dev_err(&pdev->dev, "no irq resource?\n");
> +		return irq;
> +	}
> +	info->irq = irq;
> +	platform_set_drvdata(pdev, indio_dev);
> +	info->regmap = axp2xx->regmap;
> +	axp288_gpadc_enable(axp2xx->regmap, true);
> +
> +	indio_dev->dev.parent = &pdev->dev;
> +	indio_dev->name = pdev->name;
> +	indio_dev->channels = axp288_adc_channels;
> +	indio_dev->num_channels = ARRAY_SIZE(axp288_adc_channels);
> +	indio_dev->info = &axp288_iio_info;
> +	indio_dev->modes = INDIO_DIRECT_MODE;
> +	/* REVISIT: override default map with platform data */
> +	err = iio_map_array_register(indio_dev, axp288_iio_default_maps);
> +	if (err)
> +		goto err_disable_dev;
> +
> +	err = iio_device_register(indio_dev);
> +	if (err < 0) {
> +		dev_err(&pdev->dev, "unable to register iio device\n");
> +		goto err_array_unregister;
> +	}
> +	return 0;
> +
> +err_array_unregister:
> +	iio_map_array_unregister(indio_dev);
> +err_disable_dev:
> +	axp288_gpadc_enable(axp2xx->regmap, false);
> +	return err;
> +}
> +
> +static int axp288_gpadc_remove(struct platform_device *pdev)
> +{
> +	struct iio_dev *indio_dev = platform_get_drvdata(pdev);
> +
> +	iio_device_unregister(indio_dev);
> +	iio_map_array_unregister(indio_dev);

axp288_gpadc_enable(axp2xx->regmap, false);

> +
> +	return 0;
> +}
> +
> +#if defined(CONFIG_PM_SLEEP) || defined(CONFIG_PM_RUNTIME)
> +static int axp288_gpadc_suspend(struct device *dev)
> +{
> +	int ret;
> +	struct iio_dev *indio_dev = dev_get_drvdata(dev);
> +	struct gpadc_info *info = iio_priv(indio_dev);
> +
> +	mutex_lock(&indio_dev->mlock);
> +	ret = axp288_gpadc_enable(info->regmap, false);
> +	mutex_unlock(&indio_dev->mlock);
> +
> +	return ret;
> +}
> +
> +static int axp288_gpadc_resume(struct device *dev)
> +{
> +	int ret;
> +	struct iio_dev *indio_dev = dev_get_drvdata(dev);
> +	struct gpadc_info *info = iio_priv(indio_dev);
> +
> +	mutex_lock(&indio_dev->mlock);
> +	ret = axp288_gpadc_enable(info->regmap, true);
> +	mutex_unlock(&indio_dev->mlock);
> +
> +	return ret;
> +}
> +#endif
> +
> +static UNIVERSAL_DEV_PM_OPS(axp288_gpadc_pm_ops, axp288_gpadc_suspend,
> +			axp288_gpadc_resume, NULL);
> +
> +static struct platform_driver axp288_gpadc_driver = {
> +	.probe = axp288_gpadc_probe,
> +	.remove = axp288_gpadc_remove,
> +	.driver = {
> +		.name = "axp288_adc",
> +		.owner = THIS_MODULE,
> +		.pm = &axp288_gpadc_pm_ops,
> +	},
> +};
> +
> +module_platform_driver(axp288_gpadc_driver);
> +
> +MODULE_AUTHOR("Jacob Pan <jacob.jun.pan@xxxxxxxxxxxxxxx>");
> +MODULE_DESCRIPTION("Dollar Cove Xpower AXP288 General Purpose ADC Driver");
> +MODULE_LICENSE("GPL");
> 

-- 

Peter Meerwald
+43-664-2444418 (mobile)
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