hwmon: (lm75) Add suspend/resume feature

There is a shutdown feature at suspend it can be enabled to
reduce current consumption and resume it can be switched off.

Signed-off-by: Shubhrajyoti Datta <shubhrajyoti@ti.com>
Signed-off-by: Jean Delvare <khali@linux-fr.org>

2 files changed, 40 insertions, 0 deletions

diff --git a/drivers/hwmon/lm75.c b/drivers/hwmon/lm75.c
index 393f354f92a4..ab5b87a81677 100644
--- a/drivers/hwmon/lm75.c
+++ b/drivers/hwmon/lm75.c
@@ -280,10 +280,49 @@ static int lm75_detect(struct i2c_client *new_client,
         return 0;
 }
 
+#ifdef CONFIG_PM
+static int lm75_suspend(struct device *dev)
+{
+        int status;
+        struct i2c_client *client = to_i2c_client(dev);
+        status = lm75_read_value(client, LM75_REG_CONF);
+        if (status < 0) {
+                dev_dbg(&client->dev, "Can't read config? %d\n", status);
+                return status;
+        }
+        status = status | LM75_SHUTDOWN;
+        lm75_write_value(client, LM75_REG_CONF, status);
+        return 0;
+}
+
+static int lm75_resume(struct device *dev)
+{
+        int status;
+        struct i2c_client *client = to_i2c_client(dev);
+        status = lm75_read_value(client, LM75_REG_CONF);
+        if (status < 0) {
+                dev_dbg(&client->dev, "Can't read config? %d\n", status);
+                return status;
+        }
+        status = status & ~LM75_SHUTDOWN;
+        lm75_write_value(client, LM75_REG_CONF, status);
+        return 0;
+}
+
+static const struct dev_pm_ops lm75_dev_pm_ops = {
+        .suspend        = lm75_suspend,
+        .resume         = lm75_resume,
+};
+#define LM75_DEV_PM_OPS (&lm75_dev_pm_ops)
+#else
+#define LM75_DEV_PM_OPS NULL
+#endif /* CONFIG_PM */
+
 static struct i2c_driver lm75_driver = {
         .class          = I2C_CLASS_HWMON,
         .driver = {
                 .name   = "lm75",
+                .pm     = LM75_DEV_PM_OPS,
         },
         .probe          = lm75_probe,
         .remove         = lm75_remove,
diff --git a/drivers/hwmon/lm75.h b/drivers/hwmon/lm75.h
index 7c93454bb4e3..e547a3eb4de3 100644
--- a/drivers/hwmon/lm75.h
+++ b/drivers/hwmon/lm75.h
@@ -30,6 +30,7 @@
 /* straight from the datasheet */
 #define LM75_TEMP_MIN (-55000)
 #define LM75_TEMP_MAX 125000
+#define LM75_SHUTDOWN 0x01
 
 /* TEMP: 0.001C/bit (-55C to +125C)
    REG: (0.5C/bit, two's complement) << 7 */