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,