1 files changed, 52 insertions, 2 deletions

diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c
index 10be7b5fbe97..3202a86f420e 100644
--- a/drivers/i2c/i2c-core.c
+++ b/drivers/i2c/i2c-core.c
@@ -34,6 +34,7 @@
 #include <linux/hardirq.h>
 #include <linux/irqflags.h>
 #include <linux/rwsem.h>
+#include <linux/pm_runtime.h>
 #include <asm/uaccess.h>
 
 #include "i2c-core.h"
@@ -184,6 +185,52 @@ static int i2c_device_pm_resume(struct device *dev)
 #define i2c_device_pm_resume    NULL
 #endif
 
+#ifdef CONFIG_PM_RUNTIME
+static int i2c_device_runtime_suspend(struct device *dev)
+{
+        const struct dev_pm_ops *pm;
+
+        if (!dev->driver)
+                return 0;
+        pm = dev->driver->pm;
+        if (!pm || !pm->runtime_suspend)
+                return 0;
+        return pm->runtime_suspend(dev);
+}
+
+static int i2c_device_runtime_resume(struct device *dev)
+{
+        const struct dev_pm_ops *pm;
+
+        if (!dev->driver)
+                return 0;
+        pm = dev->driver->pm;
+        if (!pm || !pm->runtime_resume)
+                return 0;
+        return pm->runtime_resume(dev);
+}
+
+static int i2c_device_runtime_idle(struct device *dev)
+{
+        const struct dev_pm_ops *pm = NULL;
+        int ret;
+
+        if (dev->driver)
+                pm = dev->driver->pm;
+        if (pm && pm->runtime_idle) {
+                ret = pm->runtime_idle(dev);
+                if (ret)
+                        return ret;
+        }
+
+        return pm_runtime_suspend(dev);
+}
+#else
+#define i2c_device_runtime_suspend      NULL
+#define i2c_device_runtime_resume       NULL
+#define i2c_device_runtime_idle         NULL
+#endif
+
 static int i2c_device_suspend(struct device *dev, pm_message_t mesg)
 {
         struct i2c_client *client = i2c_verify_client(dev);
@@ -251,6 +298,9 @@ static const struct attribute_group *i2c_dev_attr_groups[] = {
 static const struct dev_pm_ops i2c_device_pm_ops = {
         .suspend = i2c_device_pm_suspend,
         .resume = i2c_device_pm_resume,
+        .runtime_suspend = i2c_device_runtime_suspend,
+        .runtime_resume = i2c_device_runtime_resume,
+        .runtime_idle = i2c_device_runtime_idle,
 };
 
 struct bus_type i2c_bus_type = {
@@ -1133,7 +1183,7 @@ EXPORT_SYMBOL(i2c_transfer);
  * i2c_master_send - issue a single I2C message in master transmit mode
  * @client: Handle to slave device
  * @buf: Data that will be written to the slave
- * @count: How many bytes to write
+ * @count: How many bytes to write, must be less than 64k since msg.len is u16
  *
  * Returns negative errno, or else the number of bytes written.
  */
@@ -1160,7 +1210,7 @@ EXPORT_SYMBOL(i2c_master_send);
  * i2c_master_recv - issue a single I2C message in master receive mode
  * @client: Handle to slave device
  * @buf: Where to store data read from slave
- * @count: How many bytes to read
+ * @count: How many bytes to read, must be less than 64k since msg.len is u16
  *
  * Returns negative errno, or else the number of bytes read.
  */