[RFC PATCH v2 2/4] hwmon: adc128d818: Implement mode selection via dt

From: Alexander Koch
Date: Fri Dec 23 2016 - 17:13:53 EST


Implement operation mode selection using the optional '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 '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@xxxxxxxxxxxxxxxxx>
---
drivers/hwmon/adc128d818.c | 24 ++++++++++++++++++++++++
1 file changed, 24 insertions(+)

diff --git a/drivers/hwmon/adc128d818.c b/drivers/hwmon/adc128d818.c
index ad2b47e40345..8667f454ea11 100644
--- 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, "mode", &data->mode) == 0) {
+ /* Currently only mode 0 supported */
+ if (data->mode != 0) {
+ dev_err(dev, "unsupported operation mode %d",
+ data->mode);
+ err = -EINVAL;
+ goto error;
+ }
+ } else {
+ data->mode = 0;
+ }
+
data->client = client;
i2c_set_clientdata(client, data);
mutex_init(&data->update_lock);
--
2.11.0