Re: [PATCH v5 1/2] gpio: add GPO driver for PCA9570

[Bartosz Golaszewski <bgolaszewski@xxxxxxxxxxxx>]

On Sun, Jul 5, 2020 at 3:31 PM Sungbo Eo <mans0n@xxxxxxxxxx> wrote:
>
> NXP PCA9570 is a 4-bit I2C GPO expander without interrupt functionality.
> Its ports are controlled only by a data byte without register address.
>
> Datasheet: https://www.nxp.com/docs/en/data-sheet/PCA9570.pdf
>
> Signed-off-by: Sungbo Eo <mans0n@xxxxxxxxxx>
> ---
> v5:
> * amended the commit message
> * removed unnecessary castings
> * added data to of_match_table
>
> v4:
> * removed ->direction_input() and ->direction_output()
>   (Seems unnecessary to me)
> * removed ->set_multiple()
>   (I'm not sure this implementation is really correct)
> * added ->get()
>   (DS says we can read the status from the device)
> * read current status during probe
>
> v3:
> * remove mutex
> * rename buffer to out
> * simplify return statements
> * replace ->probe() to ->probe_new()
> * move ngpio to driver_data
>   (PCA9571 is 8-bit so I thought making ngpio configurable is a good idea)

This driver looks nice now but why did you remove the mutex in v3? I
think when Andy commented on that, he meant not understanding why the
error check is protected, not the i2c operations.

Are you sure you don't need this lock?

Bartosz