Re: [RFC PATCH 07/12] gpio: amd-fch: add oftree probing support

[Bartosz Golaszewski <bgolaszewski@baylibre.com>]

On Mon, Feb 8, 2021 at 11:22 PM Enrico Weigelt, metux IT consult
<info@metux.net> wrote:
>
> Add support for probing via device tree.
> ---
>  drivers/gpio/gpio-amd-fch.c                     | 58 +++++++++++++++++++++++++
>  include/dt-bindings/gpio/amd-fch-gpio.h         | 36 +++++++++++++++
>  include/linux/platform_data/gpio/gpio-amd-fch.h | 24 ++--------
>  3 files changed, 98 insertions(+), 20 deletions(-)
>  create mode 100644 include/dt-bindings/gpio/amd-fch-gpio.h
>
> diff --git a/drivers/gpio/gpio-amd-fch.c b/drivers/gpio/gpio-amd-fch.c
> index 2a21354ed6a0..32024f99dae5 100644
> --- a/drivers/gpio/gpio-amd-fch.c
> +++ b/drivers/gpio/gpio-amd-fch.c
> @@ -136,12 +136,61 @@ static int amd_fch_gpio_request(struct gpio_chip *chip,
>         return 0;
>  }
>
> +static struct amd_fch_gpio_pdata *load_pdata(struct device *dev)

Please stick to the amd_fch_ prefix to all symbols for consistency.

> +{
> +       struct amd_fch_gpio_pdata *pdata;
> +       int ret;
> +
> +       pdata = devm_kzalloc(dev, sizeof(struct amd_fch_gpio_pdata),
> +                            GFP_KERNEL);
> +       if (!pdata)
> +               goto nomem;
> +
> +       pdata->gpio_num = of_property_count_elems_of_size(dev->of_node,
> +                                                         "gpio-regs",
> +                                                         sizeof(u32));
> +       pdata->gpio_reg = devm_kzalloc(dev, sizeof(int)*pdata->gpio_num,
> +                                      GFP_KERNEL);
> +       if (!pdata->gpio_reg)
> +               goto nomem;
> +
> +       pdata->gpio_names = devm_kzalloc(dev, sizeof(char*)*pdata->gpio_num,
> +                                        GFP_KERNEL);
> +       if (!pdata->gpio_names)
> +               goto nomem;
> +
> +       ret = of_property_read_variable_u32_array(dev->of_node, "gpio-regs",
> +                                                 pdata->gpio_reg,
> +                                                 pdata->gpio_num,
> +                                                 pdata->gpio_num);
> +       if (ret != pdata->gpio_num) {
> +               dev_err(dev, "failed reading gpio-regs from DT: %d\n", ret);
> +               return NULL;
> +       }
> +
> +       ret = of_property_read_string_array(dev->of_node, "gpio-line-names",
> +                                           pdata->gpio_names, pdata->gpio_num);
> +       if (ret != pdata->gpio_num) {
> +               dev_err(dev, "failed reading gpio-names from DT: %d\n", ret);
> +               return NULL;
> +       }

Since you're not iterating over DT nodes nor use any interfaces
specific to OF - I suggest you use the generic device properties to
load the fill the platform data.

> +
> +       return pdata;
> +
> +nomem:
> +       dev_err(dev, "load_pdata: failed allocating memory\n");
> +       return NULL;
> +}
> +
>  static int amd_fch_gpio_probe(struct platform_device *pdev)
>  {
>         struct amd_fch_gpio_priv *priv;
>         struct amd_fch_gpio_pdata *pdata;
>
>         pdata = dev_get_platdata(&pdev->dev);
> +       if (!pdata)
> +               pdata = load_pdata(&pdev->dev);
> +
>         if (!pdata) {
>                 dev_err(&pdev->dev, "no platform_data\n");
>                 return -ENOENT;
> @@ -165,6 +214,9 @@ static int amd_fch_gpio_probe(struct platform_device *pdev)
>         priv->gc.get_direction          = amd_fch_gpio_get_direction;
>         priv->gc.get                    = amd_fch_gpio_get;
>         priv->gc.set                    = amd_fch_gpio_set;
> +#ifdef CONFIG_OF_GPIO
> +       priv->gc.of_node                = pdev->dev.of_node;
> +#endif
>
>         spin_lock_init(&priv->lock);
>
> @@ -177,9 +229,15 @@ static int amd_fch_gpio_probe(struct platform_device *pdev)
>         return devm_gpiochip_add_data(&pdev->dev, &priv->gc, priv);
>  }
>
> +static const struct of_device_id amd_fch_gpio_of_match[] = {
> +       { .compatible = "amd,fch-gpio" },
> +       {}
> +};

Don't you need the module table?

> +
>  static struct platform_driver amd_fch_gpio_driver = {
>         .driver = {
>                 .name = AMD_FCH_GPIO_DRIVER_NAME,
> +               .of_match_table = amd_fch_gpio_of_match,
>         },
>         .probe = amd_fch_gpio_probe,
>  };
> diff --git a/include/dt-bindings/gpio/amd-fch-gpio.h b/include/dt-bindings/gpio/amd-fch-gpio.h
> new file mode 100644
> index 000000000000..7a47e6debcdb
> --- /dev/null
> +++ b/include/dt-bindings/gpio/amd-fch-gpio.h
> @@ -0,0 +1,36 @@
> +/* SPDX-License-Identifier: GPL-2.0+ */
> +
> +/*
> + * AMD FCH gpio platform data definitions
> + *
> + * Copyright (C) 2020 metux IT consult
> + * Author: Enrico Weigelt <info@metux.net>
> + *
> + */
> +
> +#ifndef __DT_BINDINGS_GPIO_AMD_FCH_REGS_H
> +#define __DT_BINDINGS_GPIO_AMD_FCH_REGS_H
> +
> +/*
> + * gpio registers addresses
> + *
> + * these regs need to be assigned by board setup, since they're wired
> + * in very board specifici was, rarely documented, this should not be
> + * available to users.
> + */
> +#define AMD_FCH_GPIO_REG_GPIO49                0x40
> +#define AMD_FCH_GPIO_REG_GPIO50                0x41
> +#define AMD_FCH_GPIO_REG_GPIO51                0x42
> +#define AMD_FCH_GPIO_REG_GPIO55_DEVSLP0        0x43
> +#define AMD_FCH_GPIO_REG_GPIO57                0x44
> +#define AMD_FCH_GPIO_REG_GPIO58                0x45
> +#define AMD_FCH_GPIO_REG_GPIO59_DEVSLP1        0x46
> +#define AMD_FCH_GPIO_REG_GPIO64                0x47
> +#define AMD_FCH_GPIO_REG_GPIO68                0x48
> +#define AMD_FCH_GPIO_REG_GPIO66_SPKR   0x5B
> +#define AMD_FCH_GPIO_REG_GPIO71                0x4D
> +#define AMD_FCH_GPIO_REG_GPIO32_GE1    0x59
> +#define AMD_FCH_GPIO_REG_GPIO33_GE2    0x5A
> +#define AMT_FCH_GPIO_REG_GEVT22                0x09
> +
> +#endif /* __DT_BINDINGS_GPIO_AMD_FCH_REGS_H */
> diff --git a/include/linux/platform_data/gpio/gpio-amd-fch.h b/include/linux/platform_data/gpio/gpio-amd-fch.h
> index 255d51c9d36d..336f7387e82c 100644
> --- a/include/linux/platform_data/gpio/gpio-amd-fch.h
> +++ b/include/linux/platform_data/gpio/gpio-amd-fch.h
> @@ -11,25 +11,9 @@
>  #ifndef __LINUX_PLATFORM_DATA_GPIO_AMD_FCH_H
>  #define __LINUX_PLATFORM_DATA_GPIO_AMD_FCH_H
>
> -#define AMD_FCH_GPIO_DRIVER_NAME "gpio_amd_fch"
> +#include <dt-bindings/gpio/amd-fch-gpio.h>
>
> -/*
> - * gpio register index definitions
> - */
> -#define AMD_FCH_GPIO_REG_GPIO49                0x40
> -#define AMD_FCH_GPIO_REG_GPIO50                0x41
> -#define AMD_FCH_GPIO_REG_GPIO51                0x42
> -#define AMD_FCH_GPIO_REG_GPIO55_DEVSLP0        0x43
> -#define AMD_FCH_GPIO_REG_GPIO57                0x44
> -#define AMD_FCH_GPIO_REG_GPIO58                0x45
> -#define AMD_FCH_GPIO_REG_GPIO59_DEVSLP1        0x46
> -#define AMD_FCH_GPIO_REG_GPIO64                0x47
> -#define AMD_FCH_GPIO_REG_GPIO68                0x48
> -#define AMD_FCH_GPIO_REG_GPIO66_SPKR   0x5B
> -#define AMD_FCH_GPIO_REG_GPIO71                0x4D
> -#define AMD_FCH_GPIO_REG_GPIO32_GE1    0x59
> -#define AMD_FCH_GPIO_REG_GPIO33_GE2    0x5A
> -#define AMT_FCH_GPIO_REG_GEVT22                0x09
> +#define AMD_FCH_GPIO_DRIVER_NAME "gpio_amd_fch"
>
>  /*
>   * struct amd_fch_gpio_pdata - GPIO chip platform data
> @@ -39,8 +23,8 @@
>   */
>  struct amd_fch_gpio_pdata {
>         int                     gpio_num;
> -       int                     *gpio_reg;
> -       const char * const      *gpio_names;
> +       u32                     *gpio_reg;
> +       const char *            *gpio_names;
>  };
>
>  #endif /* __LINUX_PLATFORM_DATA_GPIO_AMD_FCH_H */
> --
> 2.11.0
>

Bartosz