[PATCH v5 1/3] gpio: gpio-generic: Add 16 and 32 bit big endian byte order support

[Andreas Larsson]

There is no general support for 64-bit big endian accesses, so that is
left unsupported.

Signed-off-by: Andreas Larsson <andr...@gaisler.com>
---
 drivers/gpio/gpio-generic.c     |   56 ++++++++++++++++++++++++++++++++-------
 include/linux/basic_mmio_gpio.h |    1 +
 2 files changed, 48 insertions(+), 9 deletions(-)

diff --git a/drivers/gpio/gpio-generic.c b/drivers/gpio/gpio-generic.c
index 05fcc0f..42d4706 100644
--- a/drivers/gpio/gpio-generic.c
+++ b/drivers/gpio/gpio-generic.c
@@ -104,6 +104,26 @@ static unsigned long bgpio_read64(void __iomem *reg)
 }
 #endif /* BITS_PER_LONG >= 64 */
 
+static void bgpio_write16be(void __iomem *reg, unsigned long data)
+{
+       iowrite16be(data, reg);
+}
+
+static unsigned long bgpio_read16be(void __iomem *reg)
+{
+       return ioread16be(reg);
+}
+
+static void bgpio_write32be(void __iomem *reg, unsigned long data)
+{
+       iowrite32be(data, reg);
+}
+
+static unsigned long bgpio_read32be(void __iomem *reg)
+{
+       return ioread32be(reg);
+}
+
 static unsigned long bgpio_pin2mask(struct bgpio_chip *bgc, unsigned int pin)
 {
        return 1 << pin;
@@ -249,7 +269,8 @@ static int bgpio_dir_out_inv(struct gpio_chip *gc, unsigned 
int gpio, int val)
 
 static int bgpio_setup_accessors(struct device *dev,
                                 struct bgpio_chip *bgc,
-                                bool be)
+                                bool bit_be,
+                                bool byte_be)
 {
 
        switch (bgc->bits) {
@@ -258,17 +279,33 @@ static int bgpio_setup_accessors(struct device *dev,
                bgc->write_reg  = bgpio_write8;
                break;
        case 16:
-               bgc->read_reg   = bgpio_read16;
-               bgc->write_reg  = bgpio_write16;
+               if (byte_be) {
+                       bgc->read_reg   = bgpio_read16be;
+                       bgc->write_reg  = bgpio_write16be;
+               } else {
+                       bgc->read_reg   = bgpio_read16;
+                       bgc->write_reg  = bgpio_write16;
+               }
                break;
        case 32:
-               bgc->read_reg   = bgpio_read32;
-               bgc->write_reg  = bgpio_write32;
+               if (byte_be) {
+                       bgc->read_reg   = bgpio_read32be;
+                       bgc->write_reg  = bgpio_write32be;
+               } else {
+                       bgc->read_reg   = bgpio_read32;
+                       bgc->write_reg  = bgpio_write32;
+               }
                break;
 #if BITS_PER_LONG >= 64
        case 64:
-               bgc->read_reg   = bgpio_read64;
-               bgc->write_reg  = bgpio_write64;
+               if (byte_be) {
+                       dev_err(dev,
+                               "64 bit big endian byte order unsupported\n");
+                       return -EINVAL;
+               } else {
+                       bgc->read_reg   = bgpio_read64;
+                       bgc->write_reg  = bgpio_write64;
+               }
                break;
 #endif /* BITS_PER_LONG >= 64 */
        default:
@@ -276,7 +313,7 @@ static int bgpio_setup_accessors(struct device *dev,
                return -EINVAL;
        }
 
-       bgc->pin2mask = be ? bgpio_pin2mask_be : bgpio_pin2mask;
+       bgc->pin2mask = bit_be ? bgpio_pin2mask_be : bgpio_pin2mask;
 
        return 0;
 }
@@ -385,7 +422,8 @@ int bgpio_init(struct bgpio_chip *bgc, struct device *dev,
        if (ret)
                return ret;
 
-       ret = bgpio_setup_accessors(dev, bgc, flags & BGPIOF_BIG_ENDIAN);
+       ret = bgpio_setup_accessors(dev, bgc, flags & BGPIOF_BIG_ENDIAN,
+                                   flags & BGPIOF_BIG_ENDIAN_BYTE_ORDER);
        if (ret)
                return ret;
 
diff --git a/include/linux/basic_mmio_gpio.h b/include/linux/basic_mmio_gpio.h
index 1c504ca..d8a97ec 100644
--- a/include/linux/basic_mmio_gpio.h
+++ b/include/linux/basic_mmio_gpio.h
@@ -72,5 +72,6 @@ int bgpio_init(struct bgpio_chip *bgc, struct device *dev,
 #define BGPIOF_BIG_ENDIAN              BIT(0)
 #define BGPIOF_UNREADABLE_REG_SET      BIT(1) /* reg_set is unreadable */
 #define BGPIOF_UNREADABLE_REG_DIR      BIT(2) /* reg_dir is unreadable */
+#define BGPIOF_BIG_ENDIAN_BYTE_ORDER   BIT(3)
 
 #endif /* __BASIC_MMIO_GPIO_H */
-- 
1.7.10.4

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/