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    Subject[PATCH 1/2] gpio: Adjust of_xlate API to support multiple GPIO chips
    Date
    From: Grant Likely <grant.likely@secretlab.ca>

    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);
    --
    1.7.9.5


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