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From:   Avi Fishman <avifishman70@gmail.com>
Date:   Sun, 30 Aug 2020 11:47:10 +0300
Message-ID: <CAKKbWA4f64TxfwVr0p=-TT4e=yznO8WCJuie9cxF3J7u5hELPA@mail.gmail.com>
Subject: Re: [PATCH v1] i2c: npcm7xx: bug fix timeout (usec instead of msec)
To:     Tali Perry <tali.perry1@gmail.com>
Cc:     kunyi@google.com, xqiu@google.com,
        Benjamin Fair <benjaminfair@google.com>,
        Joel Stanley <joel@jms.id.au>,
        Tomer Maimon <tmaimon77@gmail.com>, wsa@the-dreams.de,
        OpenBMC Maillist <openbmc@lists.ozlabs.org>,
        linux-i2c@vger.kernel.org,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
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Hi Tali,

On Sun, Aug 30, 2020 at 11:09 AM Tali Perry <tali.perry1@gmail.com> wrote:
>
> i2c: npcm7xx: bug fix timeout (usec instead of msec)
>
> Signed-off-by: Tali Perry <tali.perry1@gmail.com>
> ---
>  drivers/i2c/busses/i2c-npcm7xx.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/i2c/busses/i2c-npcm7xx.c b/drivers/i2c/busses/i2c-npcm7xx.c
> index 75f07138a6fa..c118f93a2610 100644
> --- a/drivers/i2c/busses/i2c-npcm7xx.c
> +++ b/drivers/i2c/busses/i2c-npcm7xx.c
> @@ -2094,7 +2094,7 @@ static int npcm_i2c_master_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs,
>         }
>
>         /* Adaptive TimeOut: astimated time in usec + 100% margin */
> -       timeout_usec = (2 * 10000 / bus->bus_freq) * (2 + nread + nwrite);

I suggest to add a short description like:
2: double the timeout for clock stretching case
9: bits per transaction (including the avk/nack)
1000000: micro second in a second
timeout_usec = (2 * 9 * 1000000 / bus->bus_freq) * (2 + nread + nwrite);

> +       timeout_usec = (2 * 10000000 / bus->bus_freq) * (2 + nread + nwrite);
>         timeout = max(msecs_to_jiffies(35), usecs_to_jiffies(timeout_usec));
>         if (nwrite >= 32 * 1024 || nread >= 32 * 1024) {
>                 dev_err(bus->dev, "i2c%d buffer too big\n", bus->num);
>
> base-commit: d012a7190fc1fd72ed48911e77ca97ba4521bccd
> --
> 2.22.0
>


-- 
Regards,
Avi