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authorLaxman Dewangan <ldewangan@nvidia.com>2012-08-19 00:47:47 +0530
committerStephen Warren <swarren@nvidia.com>2012-09-13 11:40:30 -0600
commitfd301cc4e5ba839050be135a178031bcd0d363a5 (patch)
tree61ceb2864a9e35eed6ef70400328124944ad4e0c /drivers/i2c
parent6ad068ed63100f1bb2f65340e2de9b8727526ef8 (diff)
downloadlinux-linaro-stable-fd301cc4e5ba839050be135a178031bcd0d363a5.tar.gz
i2c: tegra: dynamically control fast clk
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>
Diffstat (limited to 'drivers/i2c')
-rw-r--r--drivers/i2c/busses/i2c-tegra.c35
1 files changed, 28 insertions, 7 deletions
diff --git a/drivers/i2c/busses/i2c-tegra.c b/drivers/i2c/busses/i2c-tegra.c
index ce701474626f..f981ac4e6783 100644
--- a/drivers/i2c/busses/i2c-tegra.c
+++ b/drivers/i2c/busses/i2c-tegra.c
@@ -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;
}