Re: [PATCH v10 1/3] gpio: exar: add gpio for exar cards

[Andy Shevchenko <andy.shevchenko@xxxxxxxxx>]

On Fri, Jan 20, 2017 at 12:23 AM, Sudip Mukherjee
<sudipm.mukherjee@xxxxxxxxx> wrote:
> From: Sudip Mukherjee <sudip.mukherjee@xxxxxxxxxxxxxxx>
>
> Exar XR17V352/354/358 chips have 16 multi-purpose inputs/outputs which
> can be controlled using gpio interface.
>
> Add the gpio specific code.
>

Looks nice and clean!

FWIW:
Reviewed-by: Andy Shevchenko <andy.shevchenko@xxxxxxxxx>

> Signed-off-by: Sudip Mukherjee <sudip.mukherjee@xxxxxxxxxxxxxxx>
> ---
>  drivers/gpio/Kconfig     |   7 ++
>  drivers/gpio/Makefile    |   1 +
>  drivers/gpio/gpio-exar.c | 200 +++++++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 208 insertions(+)
>  create mode 100644 drivers/gpio/gpio-exar.c
>
> diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
> index ed37e59..89033d6 100644
> --- a/drivers/gpio/Kconfig
> +++ b/drivers/gpio/Kconfig
> @@ -185,6 +185,13 @@ config GPIO_ETRAXFS
>         help
>           Say yes here to support the GPIO controller on Axis ETRAX FS SoCs.
>
> +config GPIO_EXAR
> +       tristate "Support for GPIO pins on XR17V352/354/358"
> +       depends on SERIAL_8250_EXAR
> +       help
> +         Selecting this option will enable handling of GPIO pins present
> +         on Exar XR17V352/354/358 chips.
> +
>  config GPIO_GE_FPGA
>         bool "GE FPGA based GPIO"
>         depends on GE_FPGA
> diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
> index d074c22..d4d44f8 100644
> --- a/drivers/gpio/Makefile
> +++ b/drivers/gpio/Makefile
> @@ -44,6 +44,7 @@ obj-$(CONFIG_GPIO_DWAPB)      += gpio-dwapb.o
>  obj-$(CONFIG_GPIO_EM)          += gpio-em.o
>  obj-$(CONFIG_GPIO_EP93XX)      += gpio-ep93xx.o
>  obj-$(CONFIG_GPIO_ETRAXFS)     += gpio-etraxfs.o
> +obj-$(CONFIG_GPIO_EXAR)                += gpio-exar.o
>  obj-$(CONFIG_GPIO_F7188X)      += gpio-f7188x.o
>  obj-$(CONFIG_GPIO_GE_FPGA)     += gpio-ge.o
>  obj-$(CONFIG_GPIO_GPIO_MM)     += gpio-gpio-mm.o
> diff --git a/drivers/gpio/gpio-exar.c b/drivers/gpio/gpio-exar.c
> new file mode 100644
> index 0000000..05c8946
> --- /dev/null
> +++ b/drivers/gpio/gpio-exar.c
> @@ -0,0 +1,200 @@
> +/*
> + * GPIO driver for Exar XR17V35X chip
> + *
> + * Copyright (C) 2015 Sudip Mukherjee <sudip.mukherjee@xxxxxxxxxxxxxxx>
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 as
> + * published by the Free Software Foundation.
> + */
> +#include <linux/bitops.h>
> +#include <linux/device.h>
> +#include <linux/gpio/driver.h>
> +#include <linux/init.h>
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/pci.h>
> +#include <linux/platform_device.h>
> +
> +#define EXAR_OFFSET_MPIOLVL_LO 0x90
> +#define EXAR_OFFSET_MPIOSEL_LO 0x93
> +#define EXAR_OFFSET_MPIOLVL_HI 0x96
> +#define EXAR_OFFSET_MPIOSEL_HI 0x99
> +
> +#define DRIVER_NAME "gpio_exar"
> +
> +static DEFINE_IDA(ida_index);
> +
> +struct exar_gpio_chip {
> +       struct gpio_chip gpio_chip;
> +       struct mutex lock;
> +       int index;
> +       void __iomem *regs;
> +       char name[20];
> +};
> +
> +static void exar_update(struct gpio_chip *chip, unsigned int reg, int val,
> +                       unsigned int offset)
> +{
> +       struct exar_gpio_chip *exar_gpio = gpiochip_get_data(chip);
> +       int temp;
> +
> +       mutex_lock(&exar_gpio->lock);
> +       temp = readb(exar_gpio->regs + reg);
> +       temp &= ~BIT(offset);
> +       if (val)
> +               temp |= BIT(offset);
> +       writeb(temp, exar_gpio->regs + reg);
> +       mutex_unlock(&exar_gpio->lock);
> +}
> +
> +static int exar_set_direction(struct gpio_chip *chip, int direction,
> +                             unsigned int offset)
> +{
> +       unsigned int bank = offset / 8;
> +       unsigned int addr;
> +
> +       addr = bank ? EXAR_OFFSET_MPIOSEL_HI : EXAR_OFFSET_MPIOSEL_LO;
> +       exar_update(chip, addr, direction, offset % 8);
> +       return 0;
> +}
> +
> +static int exar_direction_output(struct gpio_chip *chip, unsigned int offset,
> +                                int value)
> +{
> +       return exar_set_direction(chip, 0, offset);
> +}
> +
> +static int exar_direction_input(struct gpio_chip *chip, unsigned int offset)
> +{
> +       return exar_set_direction(chip, 1, offset);
> +}
> +
> +static int exar_get(struct gpio_chip *chip, unsigned int reg)
> +{
> +       struct exar_gpio_chip *exar_gpio = gpiochip_get_data(chip);
> +       int value;
> +
> +       mutex_lock(&exar_gpio->lock);
> +       value = readb(exar_gpio->regs + reg);
> +       mutex_unlock(&exar_gpio->lock);
> +
> +       return !!value;
> +}
> +
> +static int exar_get_direction(struct gpio_chip *chip, unsigned int offset)
> +{
> +       unsigned int bank = offset / 8;
> +       unsigned int addr;
> +       int val;
> +
> +       addr = bank ? EXAR_OFFSET_MPIOSEL_HI : EXAR_OFFSET_MPIOSEL_LO;
> +       val = exar_get(chip, addr) >> (offset % 8);
> +
> +       return !!val;
> +}
> +
> +static int exar_get_value(struct gpio_chip *chip, unsigned int offset)
> +{
> +       unsigned int bank = offset / 8;
> +       unsigned int addr;
> +       int val;
> +
> +       addr = bank ? EXAR_OFFSET_MPIOLVL_LO : EXAR_OFFSET_MPIOLVL_HI;
> +       val = exar_get(chip, addr) >> (offset % 8);
> +
> +       return !!val;
> +}
> +
> +static void exar_set_value(struct gpio_chip *chip, unsigned int offset,
> +                          int value)
> +{
> +       unsigned int bank = offset / 8;
> +       unsigned int addr;
> +
> +       addr = bank ? EXAR_OFFSET_MPIOLVL_HI : EXAR_OFFSET_MPIOLVL_LO;
> +       exar_update(chip, addr, value, offset % 8);
> +}
> +
> +static int gpio_exar_probe(struct platform_device *pdev)
> +{
> +       struct pci_dev *pcidev = platform_get_drvdata(pdev);
> +       struct exar_gpio_chip *exar_gpio;
> +       void __iomem *p;
> +       int index, ret;
> +
> +       if (pcidev->vendor != PCI_VENDOR_ID_EXAR)
> +               return -ENODEV;
> +
> +       /*
> +        * Map the pci device to get the register addresses.
> +        * We will need to read and write those registers to control
> +        * the GPIO pins.
> +        * Using managed functions will save us from unmaping on exit.
> +        * As the device is enabled using managed functions by the
> +        * UART driver we can also use managed functions here.
> +        */
> +       p = pcim_iomap(pcidev, 0, 0);
> +       if (!p)
> +               return -ENOMEM;
> +
> +       exar_gpio = devm_kzalloc(&pcidev->dev, sizeof(*exar_gpio), GFP_KERNEL);
> +       if (!exar_gpio)
> +               return -ENOMEM;
> +
> +       mutex_init(&exar_gpio->lock);
> +
> +       index = ida_simple_get(&ida_index, 0, 0, GFP_KERNEL);
> +
> +       sprintf(exar_gpio->name, "exar_gpio%d", index);
> +       exar_gpio->gpio_chip.label = exar_gpio->name;
> +       exar_gpio->gpio_chip.parent = &pcidev->dev;
> +       exar_gpio->gpio_chip.direction_output = exar_direction_output;
> +       exar_gpio->gpio_chip.direction_input = exar_direction_input;
> +       exar_gpio->gpio_chip.get_direction = exar_get_direction;
> +       exar_gpio->gpio_chip.get = exar_get_value;
> +       exar_gpio->gpio_chip.set = exar_set_value;
> +       exar_gpio->gpio_chip.base = -1;
> +       exar_gpio->gpio_chip.ngpio = 16;
> +       exar_gpio->regs = p;
> +       exar_gpio->index = index;
> +
> +       ret = devm_gpiochip_add_data(&pcidev->dev,
> +                                    &exar_gpio->gpio_chip, exar_gpio);
> +       if (ret)
> +               goto err_destroy;
> +
> +       platform_set_drvdata(pdev, exar_gpio);
> +
> +       return 0;
> +
> +err_destroy:
> +       ida_simple_remove(&ida_index, index);
> +       mutex_destroy(&exar_gpio->lock);
> +       return ret;
> +}
> +
> +static int gpio_exar_remove(struct platform_device *pdev)
> +{
> +       struct exar_gpio_chip *exar_gpio = platform_get_drvdata(pdev);
> +
> +       ida_simple_remove(&ida_index, exar_gpio->index);
> +       mutex_destroy(&exar_gpio->lock);
> +
> +       return 0;
> +}
> +
> +static struct platform_driver gpio_exar_driver = {
> +       .probe  = gpio_exar_probe,
> +       .remove = gpio_exar_remove,
> +       .driver = {
> +               .name = DRIVER_NAME,
> +       },
> +};
> +
> +module_platform_driver(gpio_exar_driver);
> +
> +MODULE_ALIAS("platform:" DRIVER_NAME);
> +MODULE_DESCRIPTION("Exar GPIO driver");
> +MODULE_AUTHOR("Sudip Mukherjee <sudip.mukherjee@xxxxxxxxxxxxxxx>");
> +MODULE_LICENSE("GPL");
> --
> 1.9.1
>



-- 
With Best Regards,
Andy Shevchenko
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