i2c: imx: disable clock when it's possible to save power.
Enable clock before START, disable it after STOP.
Signed-off-by: Richard Zhao <linuxzsc@gmail.com>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
diff --git a/drivers/i2c/busses/i2c-imx.c b/drivers/i2c/busses/i2c-imx.c
index 671d37c..e3654d6 100644
--- a/drivers/i2c/busses/i2c-imx.c
+++ b/drivers/i2c/busses/i2c-imx.c
@@ -121,6 +121,7 @@
unsigned long i2csr;
unsigned int disable_delay;
int stopped;
+ unsigned int ifdr; /* IMX_I2C_IFDR */
};
/** Functions for IMX I2C adapter driver ***************************************
@@ -192,6 +193,8 @@
dev_dbg(&i2c_imx->adapter.dev, "<%s>\n", __func__);
+ clk_enable(i2c_imx->clk);
+ writeb(i2c_imx->ifdr, i2c_imx->base + IMX_I2C_IFDR);
/* Enable I2C controller */
writeb(0, i2c_imx->base + IMX_I2C_I2SR);
writeb(I2CR_IEN, i2c_imx->base + IMX_I2C_I2CR);
@@ -238,6 +241,7 @@
/* Disable I2C controller */
writeb(0, i2c_imx->base + IMX_I2C_I2CR);
+ clk_disable(i2c_imx->clk);
}
static void __init i2c_imx_set_clk(struct imx_i2c_struct *i2c_imx,
@@ -257,8 +261,8 @@
else
for (i = 0; i2c_clk_div[i][0] < div; i++);
- /* Write divider value to register */
- writeb(i2c_clk_div[i][1], i2c_imx->base + IMX_I2C_IFDR);
+ /* Store divider value */
+ i2c_imx->ifdr = i2c_clk_div[i][1];
/*
* There dummy delay is calculated.
@@ -528,7 +532,6 @@
dev_err(&pdev->dev, "can't get I2C clock\n");
goto fail3;
}
- clk_enable(i2c_imx->clk);
/* Request IRQ */
ret = request_irq(i2c_imx->irq, i2c_imx_isr, 0, pdev->name, i2c_imx);
@@ -577,7 +580,6 @@
fail5:
free_irq(i2c_imx->irq, i2c_imx);
fail4:
- clk_disable(i2c_imx->clk);
clk_put(i2c_imx->clk);
fail3:
release_mem_region(i2c_imx->res->start, resource_size(res));
@@ -614,8 +616,6 @@
if (pdata && pdata->exit)
pdata->exit(&pdev->dev);
- /* Disable I2C clock */
- clk_disable(i2c_imx->clk);
clk_put(i2c_imx->clk);
release_mem_region(i2c_imx->res->start, resource_size(i2c_imx->res));