On Mon, Dec 07, 2009 at 23:54:16, Troy Kisky wrote:
> 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 <[email protected]>
> > ---
> > 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.
>
>
Agree. Will include a patch to remove this macro in the next version of this
patch set.
Regards,
Chaithrika
> > + 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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