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authorMagnus Damm <damm@igel.co.jp>2009-08-14 10:48:59 +0000
committerPaul Mundt <lethal@linux-sh.org>2009-08-23 18:03:19 +0900
commitf1a3b994f9dfd12111dc034402aed256fac66dfe (patch)
tree3b19f55fb74932a0c4e9b17b79f960302f4d1637 /drivers/i2c
parent6a93dde1e8216f7af9b2551a60fb1a5eeac4a89f (diff)
i2c: Runtime PM for SuperH Mobile I2C
This patch modifies the SuperH Mobile I2C driver to support Runtime PM. These changes is all that is needed for proper Runtime PM support in this driver. Driver callbacks for Runtime PM are empty because the device registers are always re-initialized after pm_runtime_get_sync(). Signed-off-by: Magnus Damm <damm@igel.co.jp> Signed-off-by: Paul Mundt <lethal@linux-sh.org>
Diffstat (limited to 'drivers/i2c')
-rw-r--r--drivers/i2c/busses/i2c-sh_mobile.c39
1 files changed, 37 insertions, 2 deletions
diff --git a/drivers/i2c/busses/i2c-sh_mobile.c b/drivers/i2c/busses/i2c-sh_mobile.c
index 820487d0d5c..86a9d4e8147 100644
--- a/drivers/i2c/busses/i2c-sh_mobile.c
+++ b/drivers/i2c/busses/i2c-sh_mobile.c
@@ -28,6 +28,7 @@
#include <linux/interrupt.h>
#include <linux/i2c.h>
#include <linux/err.h>
+#include <linux/pm_runtime.h>
#include <linux/clk.h>
#include <linux/io.h>
@@ -165,7 +166,8 @@ static void activate_ch(struct sh_mobile_i2c_data *pd)
u_int32_t denom;
u_int32_t tmp;
- /* Make sure the clock is enabled */
+ /* Wake up device and enable clock */
+ pm_runtime_get_sync(pd->dev);
clk_enable(pd->clk);
/* Get clock rate after clock is enabled */
@@ -213,8 +215,9 @@ static void deactivate_ch(struct sh_mobile_i2c_data *pd)
/* Disable channel */
iowrite8(ioread8(ICCR(pd)) & ~ICCR_ICE, ICCR(pd));
- /* Disable clock */
+ /* Disable clock and mark device as idle */
clk_disable(pd->clk);
+ pm_runtime_put_sync(pd->dev);
}
static unsigned char i2c_op(struct sh_mobile_i2c_data *pd,
@@ -572,6 +575,19 @@ static int sh_mobile_i2c_probe(struct platform_device *dev)
goto err_irq;
}
+ /* Enable Runtime PM for this device.
+ *
+ * Also tell the Runtime PM core to ignore children
+ * for this device since it is valid for us to suspend
+ * this I2C master driver even though the slave devices
+ * on the I2C bus may not be suspended.
+ *
+ * The state of the I2C hardware bus is unaffected by
+ * the Runtime PM state.
+ */
+ pm_suspend_ignore_children(&dev->dev, true);
+ pm_runtime_enable(&dev->dev);
+
/* setup the private data */
adap = &pd->adap;
i2c_set_adapdata(adap, pd);
@@ -614,14 +630,33 @@ static int sh_mobile_i2c_remove(struct platform_device *dev)
iounmap(pd->reg);
sh_mobile_i2c_hook_irqs(dev, 0);
clk_put(pd->clk);
+ pm_runtime_disable(&dev->dev);
kfree(pd);
return 0;
}
+static int sh_mobile_i2c_runtime_nop(struct device *dev)
+{
+ /* Runtime PM callback shared between ->runtime_suspend()
+ * and ->runtime_resume(). Simply returns success.
+ *
+ * This driver re-initializes all registers after
+ * pm_runtime_get_sync() anyway so there is no need
+ * to save and restore registers here.
+ */
+ return 0;
+}
+
+static struct dev_pm_ops sh_mobile_i2c_dev_pm_ops = {
+ .runtime_suspend = sh_mobile_i2c_runtime_nop,
+ .runtime_resume = sh_mobile_i2c_runtime_nop,
+};
+
static struct platform_driver sh_mobile_i2c_driver = {
.driver = {
.name = "i2c-sh_mobile",
.owner = THIS_MODULE,
+ .pm = &sh_mobile_i2c_dev_pm_ops,
},
.probe = sh_mobile_i2c_probe,
.remove = sh_mobile_i2c_remove,