hwmon: (ina2xx) Add device tree support to pass the shunt resistor

Adding another way that is device tree to pass the shunt resistor
value to driver except for platform data.

Signed-off-by: Tang Yuantian <Yuantian.Tang@freescale.com>
[Guenter Roeck: Added missing of.h include]
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

1 files changed, 5 insertions, 0 deletions

diff --git a/drivers/hwmon/ina2xx.c b/drivers/hwmon/ina2xx.c
index 4958b2f89dce..d917a2d8c30f 100644
--- a/drivers/hwmon/ina2xx.c
+++ b/drivers/hwmon/ina2xx.c
@@ -34,6 +34,7 @@
 #include <linux/hwmon.h>
 #include <linux/hwmon-sysfs.h>
 #include <linux/jiffies.h>
+#include <linux/of.h>
 
 #include <linux/platform_data/ina2xx.h>
 
@@ -221,6 +222,7 @@ static int ina2xx_probe(struct i2c_client *client,
         struct ina2xx_data *data;
         struct ina2xx_platform_data *pdata;
         int ret;
+        u32 val;
         long shunt = 10000; /* default shunt value 10mOhms */
 
         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_WORD_DATA))
@@ -234,6 +236,9 @@ static int ina2xx_probe(struct i2c_client *client,
                 pdata =
                   (struct ina2xx_platform_data *)client->dev.platform_data;
                 shunt = pdata->shunt_uohms;
+        } else if (!of_property_read_u32(client->dev.of_node,
+                                "shunt-resistor", &val)) {
+                        shunt = val;
         }
 
         if (shunt <= 0)