Re: [PATCH v3 2/2] iio: pressure: dps310: Reset chip if MEAS_CFG is corrupt

Joel Stanley
2022-05-25T01:00:16Z

On Tue, 24 May 2022 at 20:17, Eddie James <eajames@linux.ibm.com> wrote:
>
> Corruption of the MEAS_CFG register has been observed soon after
> system boot. In order to recover this scenario, check MEAS_CFG if
> measurement isn't ready, and if it's incorrect, reset the DPS310
> and execute the startup procedure.
>
> Signed-off-by: Eddie James <eajames@linux.ibm.com>

Reviewed-by: Joel Stanley <joel@jms.id.au>

> ---
> drivers/iio/pressure/dps310.c | 88 +++++++++++++++++++++++++++++------
> 1 file changed, 73 insertions(+), 15 deletions(-)
>
> diff --git a/drivers/iio/pressure/dps310.c b/drivers/iio/pressure/dps310.c
> index f79b274bb38d..fbceaa2cd71c 100644
> --- a/drivers/iio/pressure/dps310.c
> +++ b/drivers/iio/pressure/dps310.c
> @@ -397,6 +397,44 @@ static int dps310_get_temp_k(struct dps310_data *data)
> return scale_factors[ilog2(rc)];
> }
>
> +/*
> + * Called with lock held. Returns a negative value on error, a positive value
> + * when the device is not ready, and zero when the device is ready.
> + */
> +static int dps310_check_reset_meas_cfg(struct dps310_data *data, int ready_bit)
> +{
> + int meas_cfg;
> + int rc = regmap_read(data->regmap, DPS310_MEAS_CFG, &meas_cfg);
> +
> + if (rc < 0)
> + return rc;
> +
> + /* Device is ready, proceed to measurement */
> + if (meas_cfg & ready_bit)
> + return 0;
> +
> + /* Device is OK, just not ready */
> + if (meas_cfg & (DPS310_PRS_EN | DPS310_TEMP_EN | DPS310_BACKGROUND))
> + return 1;
> +
> + /* DPS310 register state corrupt, better start from scratch */
> + rc = regmap_write(data->regmap, DPS310_RESET, DPS310_RESET_MAGIC);
> + if (rc < 0)
> + return rc;
> +
> + /* Wait for device chip access: 2.5ms in specification */
> + usleep_range(2500, 12000);
> +
> + /* Reinitialize the chip */
> + rc = dps310_startup(data);
> + if (rc)
> + return rc;
> +
> + dev_info(&data->client->dev,
> + "recovered from corrupted MEAS_CFG=%02x\n", meas_cfg);
> + return 1;
> +}
> +
> static int dps310_read_pres_raw(struct dps310_data *data)
> {
> int rc;
> @@ -409,16 +447,26 @@ static int dps310_read_pres_raw(struct dps310_data *data)
> if (mutex_lock_interruptible(&data->lock))
> return -EINTR;
>
> - rate = dps310_get_pres_samp_freq(data);
> - timeout = DPS310_POLL_TIMEOUT_US(rate);
> -
> - /* Poll for sensor readiness; base the timeout upon the sample rate. */
> - rc = regmap_read_poll_timeout(data->regmap, DPS310_MEAS_CFG, ready,
> - ready & DPS310_PRS_RDY,
> - DPS310_POLL_SLEEP_US(timeout), timeout);
> - if (rc)
> + rc = dps310_check_reset_meas_cfg(data, DPS310_PRS_RDY);
> + if (rc < 0)
> goto done;
>
> + if (rc > 0) {
> + rate = dps310_get_pres_samp_freq(data);
> + timeout = DPS310_POLL_TIMEOUT_US(rate);
> +
> + /*
> + * Poll for sensor readiness; base the timeout upon the sample
> + * rate.
> + */
> + rc = regmap_read_poll_timeout(data->regmap, DPS310_MEAS_CFG,
> + ready, ready & DPS310_PRS_RDY,
> + DPS310_POLL_SLEEP_US(timeout),
> + timeout);
> + if (rc)
> + goto done;
> + }
> +
> rc = regmap_bulk_read(data->regmap, DPS310_PRS_BASE, val, sizeof(val));
> if (rc < 0)
> goto done;
> @@ -458,16 +506,26 @@ static int dps310_read_temp_raw(struct dps310_data *data)
> if (mutex_lock_interruptible(&data->lock))
> return -EINTR;
>
> - rate = dps310_get_temp_samp_freq(data);
> - timeout = DPS310_POLL_TIMEOUT_US(rate);
> -
> - /* Poll for sensor readiness; base the timeout upon the sample rate. */
> - rc = regmap_read_poll_timeout(data->regmap, DPS310_MEAS_CFG, ready,
> - ready & DPS310_TMP_RDY,
> - DPS310_POLL_SLEEP_US(timeout), timeout);
> + rc = dps310_check_reset_meas_cfg(data, DPS310_TMP_RDY);
> if (rc < 0)
> goto done;
>
> + if (rc > 0) {
> + rate = dps310_get_temp_samp_freq(data);
> + timeout = DPS310_POLL_TIMEOUT_US(rate);
> +
> + /*
> + * Poll for sensor readiness; base the timeout upon the sample
> + * rate.
> + */
> + rc = regmap_read_poll_timeout(data->regmap, DPS310_MEAS_CFG,
> + ready, ready & DPS310_TMP_RDY,
> + DPS310_POLL_SLEEP_US(timeout),
> + timeout);
> + if (rc < 0)
> + goto done;
> + }
> +
> rc = dps310_read_temp_ready(data);
>
> done:
> --
> 2.27.0
>