Re: [PATCH v4] hwmon: (pmbus/mp2975) Fix driver initialization for MP2975 device

[Guenter Roeck]

On 1/27/24 01:25, Konstantin Aladyshev wrote:
> The commit 1feb31e810b0 ("hwmon: (pmbus/mp2975) Simplify VOUT code")
> has introduced a bug that makes it impossible to initialize MP2975
> device:
> """
> mp2975 5-0020: Failed to identify chip capabilities
> i2c i2c-5: new_device: Instantiated device mp2975 at 0x20
> i2c i2c-5: delete_device: Deleting device mp2975 at 0x20
> """
> Since the 'read_byte_data' function was removed from the
> 'pmbus_driver_info ' structure the driver no longer reports correctly
> that VOUT mode is direct. Therefore 'pmbus_identify_common' fails
> with error, making it impossible to initialize the device.
>
> Restore 'read_byte_data' function to fix the issue.
>
> Tested:
> - before: it is not possible to initialize MP2975 device with the
> 'mp2975' driver,
> - after: 'mp2975' correctly initializes MP2975 device and all sensor
> data is correct.
>
> Fixes: 1feb31e810b0 ("hwmon: (pmbus/mp2975) Simplify VOUT code")
>
> Signed-off-by: Konstantin Aladyshev <aladyshev22@xxxxxxxxx>
> ---
> Changes in v4:
>   - Correct comment inside the 'mp2975_read_byte_data' function as
> suggested by Patrick Rudolph

I already applied version 3 of the patch. Feel free to send a follow-up
to that patch. It is too late for a v4 of the original patch.

Guenter