linux-kernel - Re: [PATCH v7 2/2] iio: pressure: dps310: Reset chip after timeout

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Message-ID: <CAHp75Vfo4Ke9d-ZJ-BffYDbT9ppEQVOQbVpu1y_F2vXd+52YPQ@mail.gmail.com>
Date:   Wed, 14 Sep 2022 13:57:20 +0300
From:   Andy Shevchenko <andy.shevchenko@...il.com>
To:     Eddie James <eajames@...ux.ibm.com>
Cc:     jic23@...nel.org, lars@...afoo.de, linux-iio@...r.kernel.org,
        joel@....id.au, linux-kernel@...r.kernel.org,
        stable@...r.kernel.org
Subject: Re: [PATCH v7 2/2] iio: pressure: dps310: Reset chip after timeout

On Tue, Sep 13, 2022 at 12:27 AM Eddie James <eajames@...ux.ibm.com> wrote:
>
> The DPS310 chip has been observed to get "stuck" such that pressure
> and temperature measurements are never indicated as "ready" in the
> MEAS_CFG register. The only solution is to reset the device and try
> again. In order to avoid continual failures, use a boolean flag to
> only try the reset after timeout once if errors persist.

...

> +static int dps310_ready_status(struct dps310_data *data, int ready_bit, int timeout)
> +{
> +       int ready;
> +       int sleep = DPS310_POLL_SLEEP_US(timeout);

Longer line first?

> +       return regmap_read_poll_timeout(data->regmap, DPS310_MEAS_CFG, ready, ready & ready_bit,
> +                                       sleep, timeout);
> +}

...

> +static int dps310_ready(struct dps310_data *data, int ready_bit, int timeout)
> +{
> +       int rc;
> +
> +       rc = dps310_ready_status(data, ready_bit, timeout);
> +       if (rc) {
> +               if (rc == -ETIMEDOUT && !data->timeout_recovery_failed) {
> +                       int rc2;
> +
> +                       /* Reset and reinitialize the chip. */
> +                       rc2 = dps310_reset_reinit(data);
> +                       if (rc2) {

With below in mind this might become

  if (dps310_reset_init(...))
    ... = true;

> +                               data->timeout_recovery_failed = true;
> +                       } else {
> +                               /* Try again to get sensor ready status. */

> +                               rc2 = dps310_ready_status(data, ready_bit, timeout);
> +                               if (rc2)
> +                                       data->timeout_recovery_failed = true;

Shouldn't you re-use rc here again?

> +                               else
> +                                       return 0;
> +                       }
> +               }
> +
> +               return rc;
> +       }

-- 
With Best Regards,
Andy Shevchenko