Re: [PATCH 1/3] gpio: Adjust of_xlate API to support multiple GPIO chips

[Roland Stigge <stigge@antcom.de>]

On 05/17/2012 10:04 PM, Grant Likely wrote:
> This patch changes the of_xlate API to make it possible for multiple
> gpio_chips to refer to the same device tree node.  This is useful for
> banked GPIO controllers that use multiple gpio_chips for a single
> device.  With this change the core code will try calling of_xlate on
> each gpio_chip that references the device_node and will return the
> gpio number for the first one to return 'true'.
> 
> Cc: Roland Stigge <stigge@antcom.de>
> Signed-off-by: Grant Likely <grant.likely@secretlab.ca>

Tested-by: Roland Stigge <stigge@antcom.de>

> ---
>  arch/arm/mach-imx/mach-mx35_3ds.c |    3 +-
>  drivers/gpio/gpiolib-of.c         |   80 ++++++++++++++++++-------------------
>  drivers/gpio/gpiolib.c            |    2 +-
>  include/asm-generic/gpio.h        |    2 +-
>  include/linux/of_gpio.h           |    1 -
>  5 files changed, 41 insertions(+), 47 deletions(-)
> 
> diff --git a/arch/arm/mach-imx/mach-mx35_3ds.c b/arch/arm/mach-imx/mach-mx35_3ds.c
> index 6ae51c6..6a7cf91 100644
> --- a/arch/arm/mach-imx/mach-mx35_3ds.c
> +++ b/arch/arm/mach-imx/mach-mx35_3ds.c
> @@ -96,8 +96,7 @@ static struct i2c_board_info __initdata i2c_devices_3ds[] = {
>  
>  static int lcd_power_gpio = -ENXIO;
>  
> -static int mc9s08dz60_gpiochip_match(struct gpio_chip *chip,
> -						     const void *data)
> +static int mc9s08dz60_gpiochip_match(struct gpio_chip *chip, void *data)
>  {
>  	return !strcmp(chip->label, data);
>  }
> diff --git a/drivers/gpio/gpiolib-of.c b/drivers/gpio/gpiolib-of.c
> index bf984b6..d18068a 100644
> --- a/drivers/gpio/gpiolib-of.c
> +++ b/drivers/gpio/gpiolib-of.c
> @@ -15,11 +15,39 @@
>  #include <linux/errno.h>
>  #include <linux/module.h>
>  #include <linux/io.h>
> +#include <linux/gpio.h>
>  #include <linux/of.h>
>  #include <linux/of_address.h>
>  #include <linux/of_gpio.h>
>  #include <linux/slab.h>
>  
> +/* Private data structure for of_gpiochip_is_match */
> +struct gg_data {
> +	enum of_gpio_flags *flags;
> +	struct of_phandle_args gpiospec;
> +
> +	int out_gpio;
> +};
> +
> +/* Private function for resolving node pointer to gpio_chip */
> +static int of_gpiochip_find_and_xlate(struct gpio_chip *gc, void *data)
> +{
> +	struct gg_data *gg_data = data;
> +	int ret;
> +
> +	if ((gc->of_node != gg_data->gpiospec.np) ||
> +	    (gc->of_gpio_n_cells != gg_data->gpiospec.args_count) ||
> +	    (!gc->of_xlate))
> +		return false;
> +
> +	ret = gc->of_xlate(gc, &gg_data->gpiospec, gg_data->flags);
> +	if (ret < 0)
> +		return false;
> +
> +	gg_data->out_gpio = ret + gc->base;
> +	return true;
> +}
> +
>  /**
>   * of_get_named_gpio_flags() - Get a GPIO number and flags to use with GPIO API
>   * @np:		device node to get GPIO from
> @@ -34,46 +62,25 @@
>  int of_get_named_gpio_flags(struct device_node *np, const char *propname,
>                             int index, enum of_gpio_flags *flags)
>  {
> +	struct gg_data gg_data = { .flags = flags, .out_gpio = -ENODEV };
>  	int ret;
> -	struct gpio_chip *gc;
> -	struct of_phandle_args gpiospec;
> +
> +	/* .of_xlate might decide to not fill in the flags, so clear it. */
> +	if (flags)
> +		*flags = 0;
>  
>  	ret = of_parse_phandle_with_args(np, propname, "#gpio-cells", index,
> -					 &gpiospec);
> +					 &gg_data.gpiospec);
>  	if (ret) {
>  		pr_debug("%s: can't parse gpios property\n", __func__);
> -		goto err0;
> -	}
> -
> -	gc = of_node_to_gpiochip(gpiospec.np);
> -	if (!gc) {
> -		pr_debug("%s: gpio controller %s isn't registered\n",
> -			 np->full_name, gpiospec.np->full_name);
> -		ret = -ENODEV;
> -		goto err1;
> -	}
> -
> -	if (gpiospec.args_count != gc->of_gpio_n_cells) {
> -		pr_debug("%s: wrong #gpio-cells for %s\n",
> -			 np->full_name, gpiospec.np->full_name);
> -		ret = -EINVAL;
> -		goto err1;
> +		return -EINVAL;
>  	}
>  
> -	/* .xlate might decide to not fill in the flags, so clear it. */
> -	if (flags)
> -		*flags = 0;
> -
> -	ret = gc->of_xlate(gc, &gpiospec, flags);
> -	if (ret < 0)
> -		goto err1;
> +	gpiochip_find(&gg_data, of_gpiochip_find_and_xlate);
>  
> -	ret += gc->base;
> -err1:
> -	of_node_put(gpiospec.np);
> -err0:
> +	of_node_put(gg_data.gpiospec.np);
>  	pr_debug("%s exited with status %d\n", __func__, ret);
> -	return ret;
> +	return gg_data.out_gpio;
>  }
>  EXPORT_SYMBOL(of_get_named_gpio_flags);
>  
> @@ -227,14 +234,3 @@ void of_gpiochip_remove(struct gpio_chip *chip)
>  	if (chip->of_node)
>  		of_node_put(chip->of_node);
>  }
> -
> -/* Private function for resolving node pointer to gpio_chip */
> -static int of_gpiochip_is_match(struct gpio_chip *chip, const void *data)
> -{
> -	return chip->of_node == data;
> -}
> -
> -struct gpio_chip *of_node_to_gpiochip(struct device_node *np)
> -{
> -	return gpiochip_find(np, of_gpiochip_is_match);
> -}
> diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
> index 566d012..38353c0 100644
> --- a/drivers/gpio/gpiolib.c
> +++ b/drivers/gpio/gpiolib.c
> @@ -1156,7 +1156,7 @@ EXPORT_SYMBOL_GPL(gpiochip_remove);
>   */
>  struct gpio_chip *gpiochip_find(const void *data,
>  				int (*match)(struct gpio_chip *chip,
> -					     const void *data))
> +					     void *data))
>  {
>  	struct gpio_chip *chip = NULL;
>  	unsigned long flags;
> diff --git a/include/asm-generic/gpio.h b/include/asm-generic/gpio.h
> index 5f52690..1cb3dd1 100644
> --- a/include/asm-generic/gpio.h
> +++ b/include/asm-generic/gpio.h
> @@ -144,7 +144,7 @@ extern int gpiochip_add(struct gpio_chip *chip);
>  extern int __must_check gpiochip_remove(struct gpio_chip *chip);
>  extern struct gpio_chip *gpiochip_find(const void *data,
>  					int (*match)(struct gpio_chip *chip,
> -						     const void *data));
> +						     void *data));
>  
>  
>  /* Always use the library code for GPIO management calls,
> diff --git a/include/linux/of_gpio.h b/include/linux/of_gpio.h
> index 81733d1..c454f57 100644
> --- a/include/linux/of_gpio.h
> +++ b/include/linux/of_gpio.h
> @@ -58,7 +58,6 @@ extern int of_mm_gpiochip_add(struct device_node *np,
>  
>  extern void of_gpiochip_add(struct gpio_chip *gc);
>  extern void of_gpiochip_remove(struct gpio_chip *gc);
> -extern struct gpio_chip *of_node_to_gpiochip(struct device_node *np);
>  extern int of_gpio_simple_xlate(struct gpio_chip *gc,
>  				const struct of_phandle_args *gpiospec,
>  				u32 *flags);