If the operation mode is non-zero and an external reference voltage is set,
first the operation mode is written to the advanced configuration register,
followed by the externel reference enable bit,
resetting the configuration mode to 0.
To fix this, first compose the value of the advanced configuration register
based on the configuration mode and the external reference voltage.
The advanced configuration register is then written to the device,
if it is different from the default register value (0x0).
Signed-off-by: Roy van Doormaal <roy.van.doormaal@prodrive-technologies.com>
Link: https://lore.kernel.org/r/20200728151846.231785-1-roy.van.doormaal@prodrive-technologies.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
{
struct i2c_client *client = data->client;
int err;
+ u8 regval = 0x0;
/*
* Reset chip to defaults.
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 (data->mode != 0)
+ regval |= data->mode << 1;
+
+ /* If external vref is selected, configure the chip to use it */
+ if (data->regulator)
+ regval |= 0x01;
+
+ /* Write advanced configuration register */
+ if (regval != 0x0) {
+ err = i2c_smbus_write_byte_data(client, ADC128_REG_CONFIG_ADV,
+ regval);
if (err)
return err;
}
if (err)
return err;
- /* If external vref is selected, configure the chip to use it */
- if (data->regulator) {
- err = i2c_smbus_write_byte_data(client,
- ADC128_REG_CONFIG_ADV, 0x01);
- if (err)
- return err;
- }
-
return 0;
}