1 files changed, 32 insertions, 6 deletions

diff --git a/drivers/i2c/busses/i2c-at91.c b/drivers/i2c/busses/i2c-at91.c
index e05a672db3e5..76d16713508f 100644
--- a/drivers/i2c/busses/i2c-at91.c
+++ b/drivers/i2c/busses/i2c-at91.c
@@ -31,10 +31,12 @@
 #include <linux/platform_device.h>
 #include <linux/slab.h>
 #include <linux/platform_data/dma-atmel.h>
+#include <linux/pm_runtime.h>
 
 #define DEFAULT_TWI_CLK_HZ              100000          /* max 400 Kbits/s */
 #define AT91_I2C_TIMEOUT        msecs_to_jiffies(100)   /* transfer timeout */
 #define AT91_I2C_DMA_THRESHOLD  8                       /* enable DMA if transfer size is bigger than this threshold */
+#define AUTOSUSPEND_TIMEOUT             2000
 
 /* AT91 TWI register definitions */
 #define AT91_TWI_CR             0x0000  /* Control Register */
@@ -481,6 +483,10 @@ static int at91_twi_xfer(struct i2c_adapter *adap, struct i2c_msg *msg, int num)
 
         dev_dbg(&adap->dev, "at91_xfer: processing %d messages:\n", num);
 
+        ret = pm_runtime_get_sync(dev->dev);
+        if (ret < 0)
+                goto out;
+
         /*
          * The hardware can handle at most two messages concatenated by a
          * repeated start via it's internal address feature.
@@ -488,18 +494,21 @@ static int at91_twi_xfer(struct i2c_adapter *adap, struct i2c_msg *msg, int num)
         if (num > 2) {
                 dev_err(dev->dev,
                         "cannot handle more than two concatenated messages.\n");
-                return 0;
+                ret = 0;
+                goto out;
         } else if (num == 2) {
                 int internal_address = 0;
                 int i;
 
                 if (msg->flags & I2C_M_RD) {
                         dev_err(dev->dev, "first transfer must be write.\n");
-                        return -EINVAL;
+                        ret = -EINVAL;
+                        goto out;
                 }
                 if (msg->len > 3) {
                         dev_err(dev->dev, "first message size must be <= 3.\n");
-                        return -EINVAL;
+                        ret = -EINVAL;
+                        goto out;
                 }
 
                 /* 1st msg is put into the internal address, start with 2nd */
@@ -523,7 +532,12 @@ static int at91_twi_xfer(struct i2c_adapter *adap, struct i2c_msg *msg, int num)
 
         ret = at91_do_twi_transfer(dev);
 
-        return (ret < 0) ? ret : num;
+        ret = (ret < 0) ? ret : num;
+out:
+        pm_runtime_mark_last_busy(dev->dev);
+        pm_runtime_put_autosuspend(dev->dev);
+
+        return ret;
 }
 
 static u32 at91_twi_func(struct i2c_adapter *adapter)
@@ -795,11 +809,20 @@ static int at91_twi_probe(struct platform_device *pdev)
         dev->adapter.timeout = AT91_I2C_TIMEOUT;
         dev->adapter.dev.of_node = pdev->dev.of_node;
 
+        pm_runtime_set_autosuspend_delay(dev->dev, AUTOSUSPEND_TIMEOUT);
+        pm_runtime_use_autosuspend(dev->dev);
+        pm_runtime_set_active(dev->dev);
+        pm_runtime_enable(dev->dev);
+
         rc = i2c_add_numbered_adapter(&dev->adapter);
         if (rc) {
                 dev_err(dev->dev, "Adapter %s registration failed\n",
                         dev->adapter.name);
                 clk_disable_unprepare(dev->clk);
+
+                pm_runtime_disable(dev->dev);
+                pm_runtime_set_suspended(dev->dev);
+
                 return rc;
         }
 
@@ -814,6 +837,9 @@ static int at91_twi_remove(struct platform_device *pdev)
         i2c_del_adapter(&dev->adapter);
         clk_disable_unprepare(dev->clk);
 
+        pm_runtime_disable(dev->dev);
+        pm_runtime_set_suspended(dev->dev);
+
         return 0;
 }
 
@@ -823,7 +849,7 @@ static int at91_twi_runtime_suspend(struct device *dev)
 {
         struct at91_twi_dev *twi_dev = dev_get_drvdata(dev);
 
-        clk_disable(twi_dev->clk);
+        clk_disable_unprepare(twi_dev->clk);
 
         return 0;
 }
@@ -832,7 +858,7 @@ static int at91_twi_runtime_resume(struct device *dev)
 {
         struct at91_twi_dev *twi_dev = dev_get_drvdata(dev);
 
-        return clk_enable(twi_dev->clk);
+        return clk_prepare_enable(twi_dev->clk);
 }
 
 static const struct dev_pm_ops at91_twi_pm = {