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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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