Messages in this thread | | | Date | Mon, 15 Aug 2022 08:59:03 -0500 | Subject | Re: [PATCH v4 2/2] iio: pressure: dps310: Reset chip if MEAS_CFG is corrupt | From | Eddie James <> |
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On 8/12/22 17:13, Andy Shevchenko wrote: > On Wed, Aug 10, 2022 at 12:12 AM 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. > Looks like both patches miss the Fixes tag. Can you add them?
Well this isn't really a software fix - there's no identifiable bug in the driver. Just trying to recover the chip in this observed mystery scenario.
> > ... > >> +/* >> + * 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; > Please, split definition and assignment.
Ack.
> >> + /* 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; >> @@ -405,16 +443,26 @@ 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; >> + } > If you split the condition body to a helper, it can be rewritten like > (also note special definition for positive returned numbers): > > rc = ..._reset_meas_cfg(...); > if (rc == DPS310_MEAS_NOT_READY) > rc = ..._new_helper_func(...); > if (rc) > goto done; > > and looking at this it might be worth considering calling that > conditional in the middle in the _reset_meas_cfg(), so the latter will > return either 0 or negative error code.
To be honest that looks more complicated than the way it is now? And I don't think I can make it common between the temp and pressure without some complicated macro business.
> >> + 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); > Okay, I see this function is different, but still you may realize a > helper from below and something like above suggestion can still be > achieved. > >> + 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) > Why out of a sudden ' < 0'?
Good point, I'll fix that.
> >> + goto done; >> + } > As per above. > >> rc = dps310_read_temp_ready(data); >
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