linux-kernel - Re: [PATCH 1/2] i2c: mux: pca9541: Change to correct bus control commands

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Date:   Tue, 2 Jun 2020 06:40:11 -0700
From:   Guenter Roeck <linux@...ck-us.net>
To:     Quentin Strydom <quentin.strydom@...wireless.com>,
        Peter Rosin <peda@...ntia.se>,
        Wolfram Sang <wsa@...-dreams.de>, linux-i2c@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/2] i2c: mux: pca9541: Change to correct bus control
 commands

On 6/2/20 5:12 AM, Quentin Strydom wrote:
> Change current bus commands to match the pca9541a datasheet
> (see table 12 on page 14 of
> https://www.nxp.com/docs/en/data-sheet/PCA9541A.pdf). Also
> where entries are marked as no change the current control
> command is repeated as the current master reading the
> control register has control of the bus and bus is on.
> 
> Signed-off-by: Quentin Strydom <quentin.strydom@...wireless.com>

I am not going to reply to your other e-mail. After all, it is marked
confidential with a lot of legalese around it.

- Split long lines in your e-mails.
- Do not just send the patch again, reply to the original patch
  with a comment such as "ping"
- If you resend (for example because still no one replied after
  more time, or you missed some mailing lists/reviewers), mark the
  patch subject with "PATCH RESEND"
- Never under any circumstances send an e-mail to a public list that
  states that "This email and any files transmitted with it are
  confidential ...".

For my part I did not reply because I have no access to the hardware
anymore, and thus can not validate if the code still works after this
change (or why I didn't notice the problem when I wrote the code initially).

Guenter

> ---
>  drivers/i2c/muxes/i2c-mux-pca9541.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/i2c/muxes/i2c-mux-pca9541.c b/drivers/i2c/muxes/i2c-mux-pca9541.c
> index 6a39ada..50808fa 100644
> --- a/drivers/i2c/muxes/i2c-mux-pca9541.c
> +++ b/drivers/i2c/muxes/i2c-mux-pca9541.c
> @@ -211,7 +211,7 @@ static void pca9541_release_bus(struct i2c_client *client)
>  
>  /* Control commands per PCA9541 datasheet */
>  static const u8 pca9541_control[16] = {
> -	4, 0, 1, 5, 4, 4, 5, 5, 0, 0, 1, 1, 0, 4, 5, 1
> +	4, 4, 5, 5, 4, 4, 5, 7, 8, 0, 1, 11, 0, 0, 1, 1
>  };
>  
>  /*
>