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References: <20200830213121.239533-1-tali.perry1@gmail.com>
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From:   Joel Stanley <joel@jms.id.au>
Date:   Mon, 31 Aug 2020 03:35:36 +0000
Message-ID: <CACPK8Xev4w4BxrxR1zQPk=wiHCK2fSGD9tEeAQwPe_uayGw_CA@mail.gmail.com>
Subject: Re: [PATCH v3] i2c: npcm7xx: Fix timeout calculation
To:     Tali Perry <tali.perry1@gmail.com>
Cc:     Kun Yi <kunyi@google.com>, xqiu@google.com,
        Benjamin Fair <benjaminfair@google.com>,
        Avi Fishman <avifishman70@gmail.com>,
        Tomer Maimon <tmaimon77@gmail.com>,
        Wolfram Sang <wsa@the-dreams.de>, linux-i2c@vger.kernel.org,
        OpenBMC Maillist <openbmc@lists.ozlabs.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
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On Sun, 30 Aug 2020 at 21:31, Tali Perry <tali.perry1@gmail.com> wrote:
>
> timeout_usec value calculation was wrong, the calculated value
> was in msec instead of usec.
>
> Signed-off-by: Tali Perry <tali.perry1@gmail.com>
> Reviewed-by: Avi Fishman <avifishman70@gmail.com>

Fixes: 56a1485b102e ("i2c: npcm7xx: Add Nuvoton NPCM I2C controller driver")
Reviewed-by: Joel Stanley <joel@jms.id.au>

Cheers,

Joel

> ---
>  drivers/i2c/busses/i2c-npcm7xx.c | 8 ++++++--
>  1 file changed, 6 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/i2c/busses/i2c-npcm7xx.c b/drivers/i2c/busses/i2c-npcm7xx.c
> index 75f07138a6fa..dfcf04e1967f 100644
> --- a/drivers/i2c/busses/i2c-npcm7xx.c
> +++ b/drivers/i2c/busses/i2c-npcm7xx.c
> @@ -2093,8 +2093,12 @@ 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);
> +       /*
> +        * Adaptive TimeOut: estimated time in usec + 100% margin:
> +        * 2: double the timeout for clock stretching case
> +        * 9: bits per transaction (including the ack/nack)
> +        */
> +       timeout_usec = (2 * 9 * USEC_PER_SEC / 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
>