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Commit 5ae5b113 authored by Chaithrika U S's avatar Chaithrika U S Committed by Kevin Hilman
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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: default avatarChaithrika U S <chaithrika@ti.com>
Acked-by: default avatarKevin Hilman <khilman@deeprootsystems.com>
parent c062a251
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+37 −19
Original line number Original line Diff line number Diff line
@@ -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);
	return __raw_readw(i2c_dev->base + reg);
}
}


/*
static inline void davinci_i2c_reset_ctrl(struct davinci_i2c_dev *i2c_dev,
 * This functions configures I2C and brings I2C out of reset.
								int val)
 * This function is called during I2C init function. This function
{
 * also gets called if I2C encounters any errors.
	u16 w;
 */

static int i2c_davinci_init(struct davinci_i2c_dev *dev)
	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;
	struct davinci_i2c_platform_data *pdata = dev->dev->platform_data;
	u16 psc;
	u16 psc;
@@ -140,15 +149,6 @@ static int i2c_davinci_init(struct davinci_i2c_dev *dev)
	u32 clkh;
	u32 clkh;
	u32 clkl;
	u32 clkl;
	u32 input_clock = clk_get_rate(dev->clk);
	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
	/* NOTE: I2C Clock divider programming info
	 * As per I2C specs the following formulas provide prescaler
	 * 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_CLKH_REG, clkh);
	davinci_i2c_write_reg(dev, DAVINCI_I2C_CLKL_REG, clkl);
	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);
	/* Respond at reserved "SMBus Host" slave address" (and zero);
	 * we seem to have no option to not respond...
	 * we seem to have no option to not respond...
	 */
	 */
	davinci_i2c_write_reg(dev, DAVINCI_I2C_OAR_REG, 0x08);
	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",
	dev_dbg(dev->dev, "PSC  = %d\n",
		davinci_i2c_read_reg(dev, DAVINCI_I2C_PSC_REG));
		davinci_i2c_read_reg(dev, DAVINCI_I2C_PSC_REG));
	dev_dbg(dev->dev, "CLKL = %d\n",
	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);
		pdata->bus_freq, pdata->bus_delay);


	/* Take the I2C module out of reset: */
	/* Take the I2C module out of reset: */
	w = davinci_i2c_read_reg(dev, DAVINCI_I2C_MDR_REG);
	davinci_i2c_reset_ctrl(dev, 1);
	w |= DAVINCI_I2C_MDR_IRS;
	davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, w);


	/* Enable interrupts */
	/* Enable interrupts */
	davinci_i2c_write_reg(dev, DAVINCI_I2C_IMR_REG, I2C_DAVINCI_INTR_ALL);
	davinci_i2c_write_reg(dev, DAVINCI_I2C_IMR_REG, I2C_DAVINCI_INTR_ALL);