i2c: davinci: Add helper functions for power management

Add i2c reset control and clock divider calculation functions
which will be useful for power management features.

Signed-off-by: Chaithrika U S <chaithrika@ti.com>
Acked-by: Kevin Hilman <khilman@deeprootsystems.com>

1 files changed, 37 insertions, 19 deletions

diff --git a/drivers/i2c/busses/i2c-davinci.c b/drivers/i2c/busses/i2c-davinci.c
index 4e33909dd3f0..9afd9af4f550 100644
--- a/drivers/i2c/busses/i2c-davinci.c
+++ b/drivers/i2c/busses/i2c-davinci.c
@@ -126,12 +126,21 @@ static inline u16 davinci_i2c_read_reg(struct davinci_i2c_dev *i2c_dev, int reg)
         return __raw_readw(i2c_dev->base + reg);
 }
 
-/*
- * This functions configures I2C and brings I2C out of reset.
- * This function is called during I2C init function. This function
- * also gets called if I2C encounters any errors.
- */
-static int i2c_davinci_init(struct davinci_i2c_dev *dev)
+static inline void davinci_i2c_reset_ctrl(struct davinci_i2c_dev *i2c_dev,
+                                                                int val)
+{
+        u16 w;
+
+        w = davinci_i2c_read_reg(i2c_dev, DAVINCI_I2C_MDR_REG);
+        if (!val)       /* put I2C into reset */
+                w &= ~DAVINCI_I2C_MDR_IRS;
+        else            /* take I2C out of reset */
+                w |= DAVINCI_I2C_MDR_IRS;
+
+        davinci_i2c_write_reg(i2c_dev, DAVINCI_I2C_MDR_REG, w);
+}
+
+static void i2c_davinci_calc_clk_dividers(struct davinci_i2c_dev *dev)
 {
         struct davinci_i2c_platform_data *pdata = dev->dev->platform_data;
         u16 psc;
@@ -140,15 +149,6 @@ static int i2c_davinci_init(struct davinci_i2c_dev *dev)
         u32 clkh;
         u32 clkl;
         u32 input_clock = clk_get_rate(dev->clk);
-        u16 w;
-
-        if (!pdata)
-                pdata = &davinci_i2c_platform_data_default;
-
-        /* put I2C into reset */
-        w = davinci_i2c_read_reg(dev, DAVINCI_I2C_MDR_REG);
-        w &= ~DAVINCI_I2C_MDR_IRS;
-        davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, w);
 
         /* NOTE: I2C Clock divider programming info
          * As per I2C specs the following formulas provide prescaler
@@ -180,12 +180,32 @@ static int i2c_davinci_init(struct davinci_i2c_dev *dev)
         davinci_i2c_write_reg(dev, DAVINCI_I2C_CLKH_REG, clkh);
         davinci_i2c_write_reg(dev, DAVINCI_I2C_CLKL_REG, clkl);
 
+        dev_dbg(dev->dev, "input_clock = %d, CLK = %d\n", input_clock, clk);
+}
+
+/*
+ * This function configures I2C and brings I2C out of reset.
+ * This function is called during I2C init function. This function
+ * also gets called if I2C encounters any errors.
+ */
+static int i2c_davinci_init(struct davinci_i2c_dev *dev)
+{
+        struct davinci_i2c_platform_data *pdata = dev->dev->platform_data;
+
+        if (!pdata)
+                pdata = &davinci_i2c_platform_data_default;
+
+        /* put I2C into reset */
+        davinci_i2c_reset_ctrl(dev, 0);
+
+        /* compute clock dividers */
+        i2c_davinci_calc_clk_dividers(dev);
+
         /* Respond at reserved "SMBus Host" slave address" (and zero);
          * we seem to have no option to not respond...
          */
         davinci_i2c_write_reg(dev, DAVINCI_I2C_OAR_REG, 0x08);
 
-        dev_dbg(dev->dev, "input_clock = %d, CLK = %d\n", input_clock, clk);
         dev_dbg(dev->dev, "PSC  = %d\n",
                 davinci_i2c_read_reg(dev, DAVINCI_I2C_PSC_REG));
         dev_dbg(dev->dev, "CLKL = %d\n",
@@ -196,9 +216,7 @@ static int i2c_davinci_init(struct davinci_i2c_dev *dev)
                 pdata->bus_freq, pdata->bus_delay);
 
         /* Take the I2C module out of reset: */
-        w = davinci_i2c_read_reg(dev, DAVINCI_I2C_MDR_REG);
-        w |= DAVINCI_I2C_MDR_IRS;
-        davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, w);
+        davinci_i2c_reset_ctrl(dev, 1);
 
         /* Enable interrupts */
         davinci_i2c_write_reg(dev, DAVINCI_I2C_IMR_REG, I2C_DAVINCI_INTR_ALL);