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Message-ID: <CACxGe6u6p0jdNW2N5PzesMDT-UN+r1WRB6m553OmmM1GCHQ2Jg@mail.gmail.com>
Date: Thu, 17 May 2012 14:10:50 -0600
From: Grant Likely <grant.likely@...retlab.ca>
To: linux-kernel@...r.kernel.org
Cc: Grant Likely <grant.likely@...retlab.ca>,
Roland Stigge <stigge@...com.de>
Subject: Re: [PATCH 1/3] gpio: Adjust of_xlate API to support multiple GPIO chips
On Thu, May 17, 2012 at 2:04 PM, Grant Likely <grant.likely@...retlab.ca> 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@...com.de>
> Signed-off-by: Grant Likely <grant.likely@...retlab.ca>
This applies on my gpio/next branch on
git://git.secretlab.ca/git/linux-2.6 gpio/next
> ---
> 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);
> --
> 1.7.9.5
>
--
Grant Likely, B.Sc., P.Eng.
Secret Lab Technologies Ltd.
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