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i2c: tegra: dynamically control fast clk

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Tegra I2C driver enables the fast clock during initialization
and does not disable till driver removed.
Enable this clock before transfer and disable after transfer done.

Signed-off-by: Laxman Dewangan <ldewangan@nvidia.com>
Reviewed-by: Wolfram Sang <w.sang@pengutronix.de>
Signed-off-by: Stephen Warren <swarren@nvidia.com>
This commit is contained in:
Laxman Dewangan 2012-08-19 00:47:47 +05:30 committed by Stephen Warren
parent 6ad068ed63
commit fd301cc4e5
1 changed files with 28 additions and 7 deletions
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35
drivers/i2c/busses/i2c-tegra.c
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@ -363,12 +363,36 @@ static void tegra_dvc_init(struct tegra_i2c_dev *i2c_dev)
dvc_writel(i2c_dev, val, DVC_CTRL_REG1);
}
static inline int tegra_i2c_clock_enable(struct tegra_i2c_dev *i2c_dev)
{
int ret;
ret = clk_prepare_enable(i2c_dev->fast_clk);
if (ret < 0) {
dev_err(i2c_dev->dev,
"Enabling fast clk failed, err %d\n", ret);
return ret;
}
ret = clk_prepare_enable(i2c_dev->div_clk);
if (ret < 0) {
dev_err(i2c_dev->dev,
"Enabling div clk failed, err %d\n", ret);
clk_disable_unprepare(i2c_dev->fast_clk);
}
return ret;
}
static inline void tegra_i2c_clock_disable(struct tegra_i2c_dev *i2c_dev)
{
clk_disable_unprepare(i2c_dev->div_clk);
clk_disable_unprepare(i2c_dev->fast_clk);
}
static int tegra_i2c_init(struct tegra_i2c_dev *i2c_dev)
{
u32 val;
int err = 0;
clk_prepare_enable(i2c_dev->div_clk);
tegra_i2c_clock_enable(i2c_dev);
tegra_periph_reset_assert(i2c_dev->div_clk);
udelay(2);
@ -399,7 +423,7 @@ static int tegra_i2c_init(struct tegra_i2c_dev *i2c_dev)
if (tegra_i2c_flush_fifos(i2c_dev))
err = -ETIMEDOUT;
clk_disable_unprepare(i2c_dev->div_clk);
tegra_i2c_clock_disable(i2c_dev);
if (i2c_dev->irq_disabled) {
i2c_dev->irq_disabled = 0;
@ -575,7 +599,7 @@ static int tegra_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[],
if (i2c_dev->is_suspended)
return -EBUSY;
clk_prepare_enable(i2c_dev->div_clk);
tegra_i2c_clock_enable(i2c_dev);
for (i = 0; i < num; i++) {
enum msg_end_type end_type = MSG_END_STOP;
if (i < (num - 1)) {
@ -588,7 +612,7 @@ static int tegra_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[],
if (ret)
break;
}
clk_disable_unprepare(i2c_dev->div_clk);
tegra_i2c_clock_disable(i2c_dev);
return ret ?: i;
}
@ -724,8 +748,6 @@ static int __devinit tegra_i2c_probe(struct platform_device *pdev)
return ret;
}
clk_prepare_enable(i2c_dev->fast_clk);
i2c_set_adapdata(&i2c_dev->adapter, i2c_dev);
i2c_dev->adapter.owner = THIS_MODULE;
i2c_dev->adapter.class = I2C_CLASS_HWMON;
@ -739,7 +761,6 @@ static int __devinit tegra_i2c_probe(struct platform_device *pdev)
ret = i2c_add_numbered_adapter(&i2c_dev->adapter);
if (ret) {
dev_err(&pdev->dev, "Failed to add I2C adapter\n");
clk_disable_unprepare(i2c_dev->fast_clk);
return ret;
}