i2c: i2c-ocores: Use reg-shift property

Deprecate 'regstep' property and use the standard 'reg-shift' property
for register offset shifts. 'regstep' will still be supported as an
optional property, but will give a warning when used.

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, 29 insertions, 17 deletions

diff --git a/Documentation/devicetree/bindings/i2c/i2c-ocores.txt b/Documentation/devicetree/bindings/i2c/i2c-ocores.txt
index bfec8941509c..1c9334bfc39c 100644
--- a/Documentation/devicetree/bindings/i2c/i2c-ocores.txt
+++ b/Documentation/devicetree/bindings/i2c/i2c-ocores.txt
@@ -4,11 +4,14 @@ Required properties:
 - compatible      : "opencores,i2c-ocores"
 - reg             : bus address start and address range size of device
 - interrupts      : interrupt number
-- regstep         : size of device registers in bytes
 - clock-frequency : frequency of bus clock in Hz
 - #address-cells  : should be <1>
 - #size-cells     : should be <0>
 
+Optional properties:
+- reg-shift       : device register offsets are shifted by this value
+- regstep         : deprecated, use reg-shift above
+
 Example:
 
         i2c0: ocores@a0000000 {
@@ -17,9 +20,10 @@ Example:
                 compatible = "opencores,i2c-ocores";
                 reg = <0xa0000000 0x8>;
                 interrupts = <10>;
-                regstep = <1>;
                 clock-frequency = <20000000>;
 
+                reg-shift = <0>;        /* 8 bit registers */
+
                 dummy@60 {
                         compatible = "dummy";
                         reg = <0x60>;
diff --git a/drivers/i2c/busses/i2c-ocores.c b/drivers/i2c/busses/i2c-ocores.c
index f6e7ad9f60e9..9e0709d5fb36 100644
--- a/drivers/i2c/busses/i2c-ocores.c
+++ b/drivers/i2c/busses/i2c-ocores.c
@@ -25,10 +25,11 @@
 #include <linux/slab.h>
 #include <linux/io.h>
 #include <linux/of_i2c.h>
+#include <linux/log2.h>
 
 struct ocores_i2c {
         void __iomem *base;
-        int regstep;
+        u32 reg_shift;
         wait_queue_head_t wait;
         struct i2c_adapter adap;
         struct i2c_msg *msg;
@@ -71,12 +72,12 @@ struct ocores_i2c {
 
 static inline void oc_setreg(struct ocores_i2c *i2c, int reg, u8 value)
 {
-        iowrite8(value, i2c->base + reg * i2c->regstep);
+        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->regstep);
+        return ioread8(i2c->base + (reg << i2c->reg_shift));
 }
 
 static void ocores_process(struct ocores_i2c *i2c)
@@ -219,22 +220,29 @@ static struct i2c_adapter ocores_adapter = {
 static int ocores_i2c_of_probe(struct platform_device *pdev,
                                 struct ocores_i2c *i2c)
 {
-        const __be32* val;
-
-        val = of_get_property(pdev->dev.of_node, "regstep", NULL);
-        if (!val) {
-                dev_err(&pdev->dev, "Missing required parameter 'regstep'\n");
-                return -ENODEV;
+        struct device_node *np = pdev->dev.of_node;
+        u32 val;
+
+        if (of_property_read_u32(np, "reg-shift", &i2c->reg_shift)) {
+                /* no 'reg-shift', check for deprecated 'regstep' */
+                if (!of_property_read_u32(np, "regstep", &val)) {
+                        if (!is_power_of_2(val)) {
+                                dev_err(&pdev->dev, "invalid regstep %d\n",
+                                        val);
+                                return -EINVAL;
+                        }
+                        i2c->reg_shift = ilog2(val);
+                        dev_warn(&pdev->dev,
+                                "regstep property deprecated, use reg-shift\n");
+                }
         }
-        i2c->regstep = be32_to_cpup(val);
 
-        val = of_get_property(pdev->dev.of_node, "clock-frequency", NULL);
-        if (!val) {
+        if (of_property_read_u32(np, "clock-frequency", &val)) {
                 dev_err(&pdev->dev,
                         "Missing required parameter 'clock-frequency'\n");
                 return -ENODEV;
         }
-        i2c->clock_khz = be32_to_cpup(val) / 1000;
+        i2c->clock_khz = val / 1000;
 
         return 0;
 }
@@ -277,7 +285,7 @@ static int __devinit ocores_i2c_probe(struct platform_device *pdev)
 
         pdata = pdev->dev.platform_data;
         if (pdata) {
-                i2c->regstep = pdata->regstep;
+                i2c->reg_shift = pdata->reg_shift;
                 i2c->clock_khz = pdata->clock_khz;
         } else {
                 ret = ocores_i2c_of_probe(pdev, i2c);
diff --git a/include/linux/i2c-ocores.h b/include/linux/i2c-ocores.h
index 4d5e57ff6614..5d95df2436f4 100644
--- a/include/linux/i2c-ocores.h
+++ b/include/linux/i2c-ocores.h
@@ -12,7 +12,7 @@
 #define _LINUX_I2C_OCORES_H
 
 struct ocores_i2c_platform_data {
-        u32 regstep;   /* distance between registers */
+        u32 reg_shift; /* register offset shift value */
         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 */