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Subject[PATCH v2 1/2] hwmon: adt7411: set sane values for CFG1 and CFG3
Date
According to the datasheet we have to set some bits as 0 and others as 1.
Make sure we do this for CFG1 and CFG3.

Signed-off-by: Michael Walle <michael@walle.cc>
---
changes v2:
- remove unnecessary locking in adt7411_init_device()

drivers/hwmon/adt7411.c | 48 ++++++++++++++++++++++++++++++++++++++++++++----
1 file changed, 44 insertions(+), 4 deletions(-)

diff --git a/drivers/hwmon/adt7411.c b/drivers/hwmon/adt7411.c
index a7f8869..fc1e65a 100644
--- a/drivers/hwmon/adt7411.c
+++ b/drivers/hwmon/adt7411.c
@@ -30,6 +30,7 @@

#define ADT7411_REG_CFG1 0x18
#define ADT7411_CFG1_START_MONITOR (1 << 0)
+#define ADT7411_CFG1_RESERVED_BIT1 (1 << 1)
#define ADT7411_CFG1_RESERVED_BIT3 (1 << 3)

#define ADT7411_REG_CFG2 0x19
@@ -37,6 +38,9 @@

#define ADT7411_REG_CFG3 0x1a
#define ADT7411_CFG3_ADC_CLK_225 (1 << 0)
+#define ADT7411_CFG3_RESERVED_BIT1 (1 << 1)
+#define ADT7411_CFG3_RESERVED_BIT2 (1 << 2)
+#define ADT7411_CFG3_RESERVED_BIT3 (1 << 3)
#define ADT7411_CFG3_REF_VDD (1 << 4)

#define ADT7411_REG_DEVICE_ID 0x4d
@@ -280,6 +284,45 @@ static int adt7411_detect(struct i2c_client *client,
return 0;
}

+static int adt7411_init_device(struct adt7411_data *data)
+{
+ int ret;
+ u8 val;
+
+ ret = i2c_smbus_read_byte_data(data->client, ADT7411_REG_CFG3);
+ if (ret < 0)
+ return ret;
+
+ /*
+ * We must only write zero to bit 1 and bit 2 and only one to bit 3
+ * according to the datasheet.
+ */
+ val = ret;
+ val &= ~(ADT7411_CFG3_RESERVED_BIT1 | ADT7411_CFG3_RESERVED_BIT2);
+ val |= ADT7411_CFG3_RESERVED_BIT3;
+
+ ret = i2c_smbus_write_byte_data(data->client, ADT7411_REG_CFG3, val);
+ if (ret < 0)
+ return ret;
+
+ ret = i2c_smbus_read_byte_data(data->client, ADT7411_REG_CFG1);
+ if (ret < 0)
+ return ret;
+
+ /*
+ * We must only write zero to bit 1 and only one to bit 3 according to
+ * the datasheet.
+ */
+ val = ret;
+ val &= ~ADT7411_CFG1_RESERVED_BIT1;
+ val |= ADT7411_CFG1_RESERVED_BIT3;
+
+ /* enable monitoring */
+ val |= ADT7411_CFG1_START_MONITOR;
+
+ return i2c_smbus_write_byte_data(data->client, ADT7411_REG_CFG1, val);
+}
+
static int adt7411_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
@@ -297,10 +340,7 @@ static int adt7411_probe(struct i2c_client *client,
mutex_init(&data->device_lock);
mutex_init(&data->update_lock);

- /* According to the datasheet, we must only write 1 to bit 3 */
- ret = adt7411_modify_bit(client, ADT7411_REG_CFG1,
- ADT7411_CFG1_RESERVED_BIT3
- | ADT7411_CFG1_START_MONITOR, 1);
+ ret = adt7411_init_device(data);
if (ret < 0)
return ret;

--
2.1.4
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