[PATCH linux dev-4.10] drivers (pmbus): ir35221: Set PMBUS_PAGE before reading id and model

[Eddie James]

From: "Edward A. James" <eajames at us.ibm.com>

The MFR_ID and MFR_MODEL, which are manually read before probing the
pmbus core,  are only valid for the two pages that the ir35221 has
available. Since we don't know the state of the device when we start
probing, set the page number first before reading id and model.

Signed-off-by: Edward A. James <eajames at us.ibm.com>
---
 drivers/hwmon/pmbus/ir35221.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/hwmon/pmbus/ir35221.c b/drivers/hwmon/pmbus/ir35221.c
index cc7b3b5..9aae633 100644
--- a/drivers/hwmon/pmbus/ir35221.c
+++ b/drivers/hwmon/pmbus/ir35221.c
@@ -243,6 +243,12 @@ static int ir35221_probe(struct i2c_client *client,
 				| I2C_FUNC_SMBUS_READ_BLOCK_DATA))
 		return -ENODEV;
 
+	ret = i2c_smbus_write_byte_data(client, PMBUS_PAGE, 0);
+	if (ret < 0) {
+		dev_err(&client->dev, "Failed to set PMBUS_PAGE\n");
+		return ret;
+	}
+
 	ret = i2c_smbus_read_block_data(client, PMBUS_MFR_ID, buf);
 	if (ret < 0) {
 		dev_err(&client->dev, "Failed to read PMBUS_MFR_ID\n");
-- 
1.8.3.1