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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>
This commit is contained in:
Tang Yuantian 2013-06-19 14:50:20 +08:00 committed by Guenter Roeck
parent 87438c2c54
commit 31e7ad74f6
3 changed files with 30 additions and 1 deletions
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22
Documentation/devicetree/bindings/i2c/ina2xx.txt Normal file
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@ -0,0 +1,22 @@
ina2xx properties
Required properties:
- compatible: Must be one of the following:
- "ti,ina219" for ina219
- "ti,ina220" for ina220
- "ti,ina226" for ina226
- "ti,ina230" for ina230
- reg: I2C address
Optional properties:
- shunt-resistor
Shunt resistor value in micro-Ohm
Example:
ina220@44 {
compatible = "ti,ina220";
reg = <0x44>;
shunt-resistor = <1000>;
};

4
Documentation/hwmon/ina2xx
View File

@ -44,4 +44,6 @@ The INA226 monitors both a shunt voltage drop and bus supply voltage.
The INA230 is a high or low side current shunt and power monitor with an I2C
interface. The INA230 monitors both a shunt voltage drop and bus supply voltage.
The shunt value in micro-ohms can be set via platform data.
The shunt value in micro-ohms can be set via platform data or device tree.
Please refer to the Documentation/devicetree/bindings/i2c/ina2xx.txt for bindings
if the device tree is used.

5
drivers/hwmon/ina2xx.c
View File

@ -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)