Chaithrika U S wrote:
> Add i2c reset control and clock divider calculation functions
> which will be useful for power management features.
>
> Signed-off-by: Chaithrika U S <chaithrika@xxxxxx>
> ---
> drivers/i2c/busses/i2c-davinci.c | 56 +++++++++++++++++++++++++-------------
> 1 files changed, 37 insertions(+), 19 deletions(-)
>
> diff --git a/drivers/i2c/busses/i2c-davinci.c b/drivers/i2c/busses/i2c-davinci.c
> index c89687a..5f3838c 100644
> --- a/drivers/i2c/busses/i2c-davinci.c
> +++ b/drivers/i2c/busses/i2c-davinci.c
> @@ -133,12 +133,21 @@ 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 */
> + MOD_REG_BIT(w, DAVINCI_I2C_MDR_IRS, 0);
> + else /* take I2C out of reset */
> + MOD_REG_BIT(w, DAVINCI_I2C_MDR_IRS, 1);
> +
I dislike the MOD_REG_BIT macro. Maybe if you wrote
MOD_REG_BIT(w, DAVINCI_I2C_MDR_IRS, val);
it would be slightly better, but I still wouldn't like it.
Please use w &= ~DAVINCI_I2C_MDR_IRS and
w |= DAVINCI_I2C_MDR_IRS directly.
I know the code you're replacing uses this obfuscating macro
but this is a good time to remove it.
> + 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;
> @@ -147,15 +156,6 @@ 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);
> - MOD_REG_BIT(w, DAVINCI_I2C_MDR_IRS, 0);
> - 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
> @@ -187,12 +187,32 @@ 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 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)
> +{
> + 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",
> @@ -203,9 +223,7 @@ 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);
> - MOD_REG_BIT(w, DAVINCI_I2C_MDR_IRS, 1);
> - 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);
--
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