On Thu, Oct 19, 2017 at 03:57:08PM -0500, eajames@xxxxxxxxxxxxxxxxxx wrote:
> From: "Edward A. James" <eajames@xxxxxxxxxx>
>
> 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.
>
If the device only has two pages, it is highly unlikely that it is possible
to select another page which is not supported; any attempts to do so should
result in a command error.
Is this theory or based on an actual problem observed ? If so, it will require
some additional explanation.
Thanks,
Guenter
> Signed-off-by: Edward A. James <eajames@xxxxxxxxxx>
> ---
> 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 8b906b4..9a53930 100644
> --- a/drivers/hwmon/pmbus/ir35221.c
> +++ b/drivers/hwmon/pmbus/ir35221.c
> @@ -267,6 +267,12 @@ 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");
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