hwmon: (adc128d818) Implement mode selection via dt

Implement operation mode selection using the optional 'ti,mode' devicetree
property (see [1]). The ADC128D818 supports four operation modes differing
in the number and type of input readings (see datasheet, sec. 8.4.1), of
which mode 0 is the default.

We only add handling of the 'ti,mode' property here, the driver still
supports nothing else than the default mode 0.

[1] Documentation/devicetree/bindings/hwmon/adc128d818.txt

Signed-off-by: Alexander Koch <mail@alexanderkoch.net>
Acked-by: Michael Hornung <mhornung.linux@gmail.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

diff --git a/drivers/hwmon/adc128d818.c b/drivers/hwmon/adc128d818.c
index ad2b47e..2b61936 100644 (file)
--- a/drivers/hwmon/adc128d818.c
+++ b/drivers/hwmon/adc128d818.c
@@ -28,6 +28,7 @@
 #include <linux/regulator/consumer.h>
 #include <linux/mutex.h>
 #include <linux/bitops.h>
+#include <linux/of.h>
 
 /* Addresses to scan
  * The chip also supports addresses 0x35..0x37. Don't scan those addresses
@@ -63,6 +64,7 @@ struct adc128_data {
        struct regulator *regulator;
        int vref;               /* Reference voltage in mV */
        struct mutex update_lock;
+       u8 mode;                /* Operation mode */
        bool valid;             /* true if following fields are valid */
        unsigned long last_updated;     /* In jiffies */
 
@@ -387,6 +389,15 @@ static int adc128_init_client(struct adc128_data *data)
        if (err)
                return err;
 
+       /* Set operation mode, if non-default */
+       if (data->mode != 0) {
+               err = i2c_smbus_write_byte_data(client,
+                                               ADC128_REG_CONFIG_ADV,
+                                               data->mode << 1);
+               if (err)
+                       return err;
+       }
+
        /* Start monitoring */
        err = i2c_smbus_write_byte_data(client, ADC128_REG_CONFIG, 0x01);
        if (err)
@@ -433,6 +444,19 @@ static int adc128_probe(struct i2c_client *client,
                data->vref = 2560;      /* 2.56V, in mV */
        }
 
+       /* Operation mode is optional and defaults to mode 0 */
+       if (of_property_read_u8(dev->of_node, "ti,mode", &data->mode) == 0) {
+               /* Currently only mode 0 supported */
+               if (data->mode != 0) {
+                       dev_err(dev, "unsupported operation mode %d\n",
+                               data->mode);
+                       err = -EINVAL;
+                       goto error;
+               }
+       } else {
+               data->mode = 0;
+       }
+
        data->client = client;
        i2c_set_clientdata(client, data);
        mutex_init(&data->update_lock);