[ARM] S3C: Add GPIO chip tracking

The gpiolib driver keeps its chip array to itself
and having a separate array for s3c-only gpios stops
any non-s3c gpio being used in one of the s3c specific
configuration calls.

Signed-off-by: Ben Dooks <ben-linux@fluff.org>

3 files changed, 49 insertions, 1 deletions

diff --git a/arch/arm/plat-s3c/Kconfig b/arch/arm/plat-s3c/Kconfig
index d7767e0305d0..77fc38f51874 100644
--- a/arch/arm/plat-s3c/Kconfig
+++ b/arch/arm/plat-s3c/Kconfig
@@ -114,6 +114,12 @@ config S3C_GPIO_SPACE
 	  one bank to another to be caught, at the expense of using a little
 	  more memory.
 
+config S3C_GPIO_TRACK
+	bool
+	help
+	  Internal configuration option to enable the s3c specific gpio
+	  chip tracking if the platform requires it.
+
 # device definitions to compile in
 
 config S3C_DEV_HSMMC
diff --git a/arch/arm/plat-s3c/gpio.c b/arch/arm/plat-s3c/gpio.c
index f035d4550c43..d71dd6d9ce5c 100644
--- a/arch/arm/plat-s3c/gpio.c
+++ b/arch/arm/plat-s3c/gpio.c
@@ -18,6 +18,22 @@
 
 #include <plat/gpio-core.h>
 
+#ifdef CONFIG_S3C_GPIO_TRACK
+struct s3c_gpio_chip *s3c_gpios[S3C_GPIO_END];
+
+static __init void s3c_gpiolib_track(struct s3c_gpio_chip *chip)
+{
+	unsigned int gpn;
+	int i;
+
+	gpn = chip->chip.base;
+	for (i = 0; i < chip->chip.ngpio; i++, gpn++) {
+		BUG_ON(gpn > ARRAY_SIZE(s3c_gpios));
+		s3c_gpios[gpn] = chip;
+	}
+}
+#endif /* CONFIG_S3C_GPIO_TRACK */
+
 /* Default routines for controlling GPIO, based on the original S3C24XX
  * GPIO functions which deal with the case where each gpio bank of the
  * chip is as following:
@@ -109,6 +125,7 @@ static int s3c_gpiolib_get(struct gpio_chip *chip, unsigned offset)
 __init void s3c_gpiolib_add(struct s3c_gpio_chip *chip)
 {
 	struct gpio_chip *gc = &chip->chip;
+	int ret;
 
 	BUG_ON(!chip->base);
 	BUG_ON(!gc->label);
@@ -124,5 +141,7 @@ __init void s3c_gpiolib_add(struct s3c_gpio_chip *chip)
 		gc->get = s3c_gpiolib_get;
 
 	/* gpiochip_add() prints own failure message on error. */
-	gpiochip_add(gc);
+	ret = gpiochip_add(gc);
+	if (ret >= 0)
+		s3c_gpiolib_track(chip);
 }
diff --git a/arch/arm/plat-s3c/include/plat/gpio-core.h b/arch/arm/plat-s3c/include/plat/gpio-core.h
index 3cb9105c4811..ad68b32a7f9d 100644
--- a/arch/arm/plat-s3c/include/plat/gpio-core.h
+++ b/arch/arm/plat-s3c/include/plat/gpio-core.h
@@ -47,3 +47,26 @@ static inline struct s3c_gpio_chip *to_s3c_gpio(struct gpio_chip *gpc)
  * other parts of the system.
  */
 extern void s3c_gpiolib_add(struct s3c_gpio_chip *chip);
+
+
+/* CONFIG_S3C_GPIO_TRACK enables the tracking of the s3c specific gpios
+ * for use with the configuration calls, and other parts of the s3c gpiolib
+ * support code.
+ *
+ * Not all s3c support code will need this, as some configurations of cpu
+ * may only support one or two different configuration options and have an
+ * easy gpio to s3c_gpio_chip mapping function. If this is the case, then
+ * the machine support file should provide its own s3c_gpiolib_getchip()
+ * and any other necessary functions.
+ */
+
+#ifdef CONFIG_S3C_GPIO_TRACK
+extern struct s3c_gpio_chip *s3c_gpios[S3C_GPIO_END];
+
+static inline struct s3c_gpio_chip *s3c_gpiolib_getchip(unsigned int chip)
+{
+	return s3c_gpios[chip];
+}
+#else
+static inline void s3c_gpiolib_track(struct s3c_gpio_chip *chip) { }
+#endif