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Diffstat (limited to 'kernel/drivers/hwmon/ads7828.c')
-rw-r--r--kernel/drivers/hwmon/ads7828.c10
1 files changed, 10 insertions, 0 deletions
diff --git a/kernel/drivers/hwmon/ads7828.c b/kernel/drivers/hwmon/ads7828.c
index 6c99ee7ba..ee396ff16 100644
--- a/kernel/drivers/hwmon/ads7828.c
+++ b/kernel/drivers/hwmon/ads7828.c
@@ -120,6 +120,7 @@ static int ads7828_probe(struct i2c_client *client,
unsigned int vref_mv = ADS7828_INT_VREF_MV;
bool diff_input = false;
bool ext_vref = false;
+ unsigned int regval;
data = devm_kzalloc(dev, sizeof(struct ads7828_data), GFP_KERNEL);
if (!data)
@@ -154,6 +155,15 @@ static int ads7828_probe(struct i2c_client *client,
if (!diff_input)
data->cmd_byte |= ADS7828_CMD_SD_SE;
+ /*
+ * Datasheet specifies internal reference voltage is disabled by
+ * default. The internal reference voltage needs to be enabled and
+ * voltage needs to settle before getting valid ADC data. So perform a
+ * dummy read to enable the internal reference voltage.
+ */
+ if (!ext_vref)
+ regmap_read(data->regmap, data->cmd_byte, &regval);
+
hwmon_dev = devm_hwmon_device_register_with_groups(dev, client->name,
data,
ads7828_groups);