basic_mmio_gpio: split into a gpio library and platform device

Allow GPIO_BASIC_MMIO_CORE to be used to provide an accessor library
for implementing GPIO drivers whilst abstracting the register access
detail.  Based on a patch from Anton Vorontsov[1] and adapted to allow
bgpio_chip to be embedded in another structure.

Changes since v1:
	- Register the gpio_chip in the platform device probe

1. https://lkml.org/lkml/2011/4/19/401

Signed-off-by: Anton Vorontsov <cbouatmailru@gmail.com>
Signed-off-by: Jamie Iles <jamie@jamieiles.com>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>

1 files changed, 55 insertions, 0 deletions

diff --git a/include/linux/basic_mmio_gpio.h b/include/linux/basic_mmio_gpio.h
index f23ec73b944b..1ae12710d732 100644
--- a/include/linux/basic_mmio_gpio.h
+++ b/include/linux/basic_mmio_gpio.h
@@ -13,9 +13,64 @@
 #ifndef __BASIC_MMIO_GPIO_H
 #define __BASIC_MMIO_GPIO_H
 
+#include <linux/gpio.h>
+#include <linux/types.h>
+#include <linux/compiler.h>
+
 struct bgpio_pdata {
         int base;
         int ngpio;
 };
 
+struct device;
+
+struct bgpio_chip {
+        struct gpio_chip gc;
+
+        unsigned long (*read_reg)(void __iomem *reg);
+        void (*write_reg)(void __iomem *reg, unsigned long data);
+
+        void __iomem *reg_dat;
+        void __iomem *reg_set;
+        void __iomem *reg_clr;
+        void __iomem *reg_dir;
+
+        /* Number of bits (GPIOs): <register width> * 8. */
+        int bits;
+
+        /*
+         * Some GPIO controllers work with the big-endian bits notation,
+         * e.g. in a 8-bits register, GPIO7 is the least significant bit.
+         */
+        unsigned long (*pin2mask)(struct bgpio_chip *bgc, unsigned int pin);
+
+        /*
+         * Used to lock bgpio_chip->data. Also, this is needed to keep
+         * shadowed and real data registers writes together.
+         */
+        spinlock_t lock;
+
+        /* Shadowed data register to clear/set bits safely. */
+        unsigned long data;
+
+        /* Shadowed direction registers to clear/set direction safely. */
+        unsigned long dir;
+};
+
+static inline struct bgpio_chip *to_bgpio_chip(struct gpio_chip *gc)
+{
+        return container_of(gc, struct bgpio_chip, gc);
+}
+
+int __devexit bgpio_remove(struct bgpio_chip *bgc);
+int __devinit bgpio_init(struct bgpio_chip *bgc,
+                         struct device *dev,
+                         unsigned long sz,
+                         void __iomem *dat,
+                         void __iomem *set,
+                         void __iomem *clr,
+                         void __iomem *dirout,
+                         void __iomem *dirin,
+                         bool big_endian);
+
 #endif /* __BASIC_MMIO_GPIO_H */