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hwmon: (ads7828) Accept optional parameters from device tree

Adding the ability for the ads7828 and ads7830 to use device tree to
get optional parameters instead of using platform devices. This allows
people using custom boards to also use the ads7828 in a non-default manner.

Signed-off-by: Sam Povilus <kernel.development@povil.us>
[groeck: Fixed whitespace errors in ads7828.txt]
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
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Sam Povilus authored and groeck committed Mar 30, 2017
1 parent a4811b6 commit a8ddfea09566c37aabe70fbb6d07ff232982c9f4
Showing with 40 additions and 0 deletions.
  1. +25 −0 Documentation/devicetree/bindings/hwmon/ads7828.txt
  2. +15 −0 drivers/hwmon/ads7828.c
@@ -0,0 +1,25 @@
ads7828 properties
Required properties:
- compatible: Should be one of
ti,ads7828
ti,ads7830
- reg: I2C address
Optional properties:
- ti,differential-input
Set to use the device in differential mode.
- vref-supply
The external reference on the device is set to this regulators output. If it
does not exists the internal reference will be used and output by the ads78xx
on the "external vref" pin.
Example ADS7828 node:
ads7828: ads@48 {
comatible = "ti,ads7828";
reg = <0x48>;
vref-supply = <&vref>;
ti,differential-input;
};
@@ -35,6 +35,7 @@
#include <linux/platform_data/ads7828.h>
#include <linux/regmap.h>
#include <linux/slab.h>
#include <linux/regulator/consumer.h>
/* The ADS7828 registers */
#define ADS7828_CMD_SD_SE 0x80 /* Single ended inputs */
@@ -119,10 +120,12 @@ static int ads7828_probe(struct i2c_client *client,
struct ads7828_data *data;
struct device *hwmon_dev;
unsigned int vref_mv = ADS7828_INT_VREF_MV;
unsigned int vref_uv;
bool diff_input = false;
bool ext_vref = false;
unsigned int regval;
enum ads7828_chips chip;
struct regulator *reg;
data = devm_kzalloc(dev, sizeof(struct ads7828_data), GFP_KERNEL);
if (!data)
@@ -133,6 +136,18 @@ static int ads7828_probe(struct i2c_client *client,
ext_vref = pdata->ext_vref;
if (ext_vref && pdata->vref_mv)
vref_mv = pdata->vref_mv;
} else if (dev->of_node) {
diff_input = of_property_read_bool(dev->of_node,
"ti,differential-input");
reg = devm_regulator_get_optional(dev, "vref");
if (!IS_ERR(reg)) {
vref_uv = regulator_get_voltage(reg);
vref_mv = DIV_ROUND_CLOSEST(vref_uv, 1000);
if (vref_mv < ADS7828_EXT_VREF_MV_MIN ||
vref_mv > ADS7828_EXT_VREF_MV_MAX)
return -EINVAL;
ext_vref = true;
}
}
if (client->dev.of_node)

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