of/gpio: Kill of_gpio_chip and add members directly to gpio_chip

The OF gpio infrastructure is great for describing GPIO connections within
the device tree.  However, using a GPIO binding still requires changes to
the gpio controller just to add an of_gpio structure.  In most cases, the
gpio controller doesn't actually need any special support and the simple
OF gpio mapping function is more than sufficient.  Additional, the current
scheme of using of_gpio_chip requires a convoluted scheme to maintain
1:1 mappings between of_gpio_chip and gpio_chip instances.

If the struct of_gpio_chip data members were moved into struct gpio_chip,
then it would simplify the processing of OF gpio bindings, and it would
make it trivial to use device tree OF connections on existing gpiolib
controller drivers.

This patch eliminates the of_gpio_chip structure and moves the relevant
fields into struct gpio_chip (conditional on CONFIG_OF_GPIO).  This move
simplifies the existing code and prepares for adding automatic device tree
support to existing drivers.

Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Anton Vorontsov <avorontsov@ru.mvista.com>
Cc: Grant Likely <grant.likely@secretlab.ca>
Cc: David Brownell <dbrownell@users.sourceforge.net>
Cc: Bill Gatliff <bgat@billgatliff.com>
Cc: Dmitry Eremin-Solenikov <dbaryshkov@gmail.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Jean Delvare <khali@linux-fr.org>

2 files changed, 17 insertions, 24 deletions

diff --git a/include/asm-generic/gpio.h b/include/asm-generic/gpio.h
index 4f3d75e1ad3..af2544ef0b5 100644
--- a/include/asm-generic/gpio.h
+++ b/include/asm-generic/gpio.h
@@ -31,6 +31,7 @@ static inline int gpio_is_valid(int number)
 struct device;
 struct seq_file;
 struct module;
+struct device_node;
 
 /**
  * struct gpio_chip - abstract a GPIO controller
@@ -106,6 +107,17 @@ struct gpio_chip {
         const char              *const *names;
         unsigned                can_sleep:1;
         unsigned                exported:1;
+
+#if defined(CONFIG_OF_GPIO)
+        /*
+         * If CONFIG_OF is enabled, then all GPIO controllers described in the
+         * device tree automatically may have an OF translation
+         */
+        struct device_node *of_node;
+        int of_gpio_n_cells;
+        int (*of_xlate)(struct gpio_chip *gc, struct device_node *np,
+                        const void *gpio_spec, u32 *flags);
+#endif
 };
 
 extern const char *gpiochip_is_requested(struct gpio_chip *chip,
diff --git a/include/linux/of_gpio.h b/include/linux/of_gpio.h
index fc2472c3c25..460d6810c5e 100644
--- a/include/linux/of_gpio.h
+++ b/include/linux/of_gpio.h
@@ -33,34 +33,17 @@ enum of_gpio_flags {
 #ifdef CONFIG_OF_GPIO
 
 /*
- * Generic OF GPIO chip
- */
-struct of_gpio_chip {
-        struct gpio_chip gc;
-        int gpio_cells;
-        int (*xlate)(struct of_gpio_chip *of_gc, struct device_node *np,
-                     const void *gpio_spec, enum of_gpio_flags *flags);
-};
-
-static inline struct of_gpio_chip *to_of_gpio_chip(struct gpio_chip *gc)
-{
-        return container_of(gc, struct of_gpio_chip, gc);
-}
-
-/*
  * OF GPIO chip for memory mapped banks
  */
 struct of_mm_gpio_chip {
-        struct of_gpio_chip of_gc;
+        struct gpio_chip gc;
         void (*save_regs)(struct of_mm_gpio_chip *mm_gc);
         void __iomem *regs;
 };
 
 static inline struct of_mm_gpio_chip *to_of_mm_gpio_chip(struct gpio_chip *gc)
 {
-        struct of_gpio_chip *of_gc = to_of_gpio_chip(gc);
-
-        return container_of(of_gc, struct of_mm_gpio_chip, of_gc);
+        return container_of(gc, struct of_mm_gpio_chip, gc);
 }
 
 extern int of_get_gpio_flags(struct device_node *np, int index,
@@ -69,11 +52,9 @@ extern unsigned int of_gpio_count(struct device_node *np);
 
 extern int of_mm_gpiochip_add(struct device_node *np,
                               struct of_mm_gpio_chip *mm_gc);
-extern int of_gpio_simple_xlate(struct of_gpio_chip *of_gc,
-                                struct device_node *np,
-                                const void *gpio_spec,
-                                enum of_gpio_flags *flags);
-#else
+extern int of_gpio_simple_xlate(struct gpio_chip *gc, struct device_node *np,
+                                const void *gpio_spec, u32 *flags);
+#else /* CONFIG_OF_GPIO */
 
 /* Drivers may not strictly depend on the GPIO support, so let them link. */
 static inline int of_get_gpio_flags(struct device_node *np, int index,