i2c: i2c-ocores: support for 16bit and 32bit IO

Some architectures supports only 16-bit or 32-bit read/write access to
their IO space. Add a 'reg-io-width' platform and OF parameter which
specifies the IO width to support these platforms.

reg-io-width can be specified as 1, 2 or 4, and has a default value
of 1 if it is unspecified.

Signed-off-by: Ganesan Ramalingam <ganesanr@broadcom.com>
Signed-off-by: Jayachandran C <jayachandranc@netlogicmicro.com>
Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>

3 files changed, 22 insertions, 2 deletions

diff --git a/Documentation/devicetree/bindings/i2c/i2c-ocores.txt b/Documentation/devicetree/bindings/i2c/i2c-ocores.txt
index 1c9334bfc39c..c15781f4dc8c 100644
--- a/Documentation/devicetree/bindings/i2c/i2c-ocores.txt
+++ b/Documentation/devicetree/bindings/i2c/i2c-ocores.txt
@@ -10,6 +10,7 @@ Required properties:
 
 Optional properties:
 - reg-shift       : device register offsets are shifted by this value
+- reg-io-width    : io register width in bytes (1, 2 or 4)
 - regstep         : deprecated, use reg-shift above
 
 Example:
@@ -23,6 +24,7 @@ Example:
                 clock-frequency = <20000000>;
 
                 reg-shift = <0>;        /* 8 bit registers */
+                reg-io-width = <1>;     /* 8 bit read/write */
 
                 dummy@60 {
                         compatible = "dummy";
diff --git a/drivers/i2c/busses/i2c-ocores.c b/drivers/i2c/busses/i2c-ocores.c
index 9e0709d5fb36..bffd5501ac2d 100644
--- a/drivers/i2c/busses/i2c-ocores.c
+++ b/drivers/i2c/busses/i2c-ocores.c
@@ -30,6 +30,7 @@
 struct ocores_i2c {
         void __iomem *base;
         u32 reg_shift;
+        u32 reg_io_width;
         wait_queue_head_t wait;
         struct i2c_adapter adap;
         struct i2c_msg *msg;
@@ -72,12 +73,22 @@ struct ocores_i2c {
 
 static inline void oc_setreg(struct ocores_i2c *i2c, int reg, u8 value)
 {
-        iowrite8(value, i2c->base + (reg << i2c->reg_shift));
+        if (i2c->reg_io_width == 4)
+                iowrite32(value, i2c->base + (reg << i2c->reg_shift));
+        else if (i2c->reg_io_width == 2)
+                iowrite16(value, i2c->base + (reg << i2c->reg_shift));
+        else
+                iowrite8(value, i2c->base + (reg << i2c->reg_shift));
 }
 
 static inline u8 oc_getreg(struct ocores_i2c *i2c, int reg)
 {
-        return ioread8(i2c->base + (reg << i2c->reg_shift));
+        if (i2c->reg_io_width == 4)
+                return ioread32(i2c->base + (reg << i2c->reg_shift));
+        else if (i2c->reg_io_width == 2)
+                return ioread16(i2c->base + (reg << i2c->reg_shift));
+        else
+                return ioread8(i2c->base + (reg << i2c->reg_shift));
 }
 
 static void ocores_process(struct ocores_i2c *i2c)
@@ -244,6 +255,8 @@ static int ocores_i2c_of_probe(struct platform_device *pdev,
         }
         i2c->clock_khz = val / 1000;
 
+        of_property_read_u32(pdev->dev.of_node, "reg-io-width",
+                                &i2c->reg_io_width);
         return 0;
 }
 #else
@@ -286,6 +299,7 @@ static int __devinit ocores_i2c_probe(struct platform_device *pdev)
         pdata = pdev->dev.platform_data;
         if (pdata) {
                 i2c->reg_shift = pdata->reg_shift;
+                i2c->reg_io_width = pdata->reg_io_width;
                 i2c->clock_khz = pdata->clock_khz;
         } else {
                 ret = ocores_i2c_of_probe(pdev, i2c);
@@ -293,6 +307,9 @@ static int __devinit ocores_i2c_probe(struct platform_device *pdev)
                         return ret;
         }
 
+        if (i2c->reg_io_width == 0)
+                i2c->reg_io_width = 1; /* Set to default value */
+
         ocores_init(i2c);
 
         init_waitqueue_head(&i2c->wait);
diff --git a/include/linux/i2c-ocores.h b/include/linux/i2c-ocores.h
index 5d95df2436f4..1c06b5c7c308 100644
--- a/include/linux/i2c-ocores.h
+++ b/include/linux/i2c-ocores.h
@@ -13,6 +13,7 @@
 
 struct ocores_i2c_platform_data {
         u32 reg_shift; /* register offset shift value */
+        u32 reg_io_width; /* register io read/write width */
         u32 clock_khz; /* input clock in kHz */
         u8 num_devices; /* number of devices in the devices list */
         struct i2c_board_info const *devices; /* devices connected to the bus */