On 1/7/25 2:48 AM, Julien Stephan wrote: > The alert functionality is an out of range indicator and can be used as > an early indicator of an out of bounds conversion result. > > ALERT_LOW_THRESHOLD and ALERT_HIGH_THRESHOLD registers are common to all > channels. > > When using 1 SDO line (only mode supported by the driver right now), i.e > data outputs only on SDOA, SDOB (or SDOD for 4 channels variants) is > used as an alert pin. The alert pin is updated at the end of the > conversion (set to low if an alert occurs) and is cleared on a falling > edge of CS. > > The ALERT register contains information about the exact alert status: > channel and direction. ALERT register can be accessed using debugfs if > enabled. > > User can set high/low thresholds and enable alert detection using the > regular iio events attributes: > > events/in_thresh_falling_value events/in_thresh_rising_value > events/thresh_either_en > > In most use cases, user will hardwire the alert pin to trigger a shutdown. > > In theory, we could generate userspace IIO events for alerts, but this > is not implemented yet for several reasons [1]. This can be implemented > later if a real use case actually requires it. > > Signed-off-by: Julien Stephan <jstephan@xxxxxxxxxxxx> > > [1] https://lore.kernel.org/all/4be16272-5197-4fa1-918c-c4cdfcaee02e@xxxxxxxxxxxx/ > --- ... > +static int ad7380_read_event_config(struct iio_dev *indio_dev, > + const struct iio_chan_spec *chan, > + enum iio_event_type type, > + enum iio_event_direction dir) > +{ > + struct ad7380_state *st = iio_priv(indio_dev); > + int alert_en, tmp, ret; > + > + ret = iio_device_claim_direct_mode(indio_dev); > + if (ret) > + return ret; > + > + ret = regmap_read(st->regmap, AD7380_REG_ADDR_CONFIG1, &tmp); > + > + iio_device_release_direct_mode(indio_dev); > + > + if (ret) > + return ret; > + > + alert_en = FIELD_GET(AD7380_CONFIG1_ALERTEN, tmp); nit: return directly and drop alter_en. > + > + return alert_en; > +} > + > +static int ad7380_write_event_config(struct iio_dev *indio_dev, > + const struct iio_chan_spec *chan, > + enum iio_event_type type, > + enum iio_event_direction dir, > + bool state) > +{ > + struct ad7380_state *st = iio_priv(indio_dev); > + int ret; > + > + ret = iio_device_claim_direct_mode(indio_dev); > + if (ret) > + return ret; > + > + ret = regmap_update_bits(st->regmap, > + AD7380_REG_ADDR_CONFIG1, > + AD7380_CONFIG1_ALERTEN, > + FIELD_PREP(AD7380_CONFIG1_ALERTEN, state)); > + > + iio_device_release_direct_mode(indio_dev); > + > + if (ret) > + return ret; > + > + return 0; return ret; > +} > + > +static int ad7380_read_event_value(struct iio_dev *indio_dev, > + const struct iio_chan_spec *chan, > + enum iio_event_type type, > + enum iio_event_direction dir, > + enum iio_event_info info, > + int *val, int *val2) > +{ > + struct ad7380_state *st = iio_priv(indio_dev); > + int ret, tmp; > + > + switch (info) { > + case IIO_EV_INFO_VALUE: > + ret = iio_device_claim_direct_mode(indio_dev); > + > + switch (dir) { > + case IIO_EV_DIR_RISING: > + ret = regmap_read(st->regmap, > + AD7380_REG_ADDR_ALERT_HIGH_TH, > + &tmp); > + if (ret) > + return ret; Can't return directly here without releasing direct mode. Suggest to move everything between claim and release to a helper function to simplify things (avoiding goto and break). > + > + *val = FIELD_GET(AD7380_ALERT_HIGH_TH, tmp); > + ret = IIO_VAL_INT; > + break; > + case IIO_EV_DIR_FALLING: > + ret = regmap_read(st->regmap, > + AD7380_REG_ADDR_ALERT_LOW_TH, > + &tmp); > + if (ret) > + return ret; > + > + FIELD_GET(AD7380_ALERT_LOW_TH, tmp); > + ret = IIO_VAL_INT; > + break; > + default: > + ret = -EINVAL; > + break; > + } > + > + iio_device_release_direct_mode(indio_dev); > + return ret; > + default: > + return -EINVAL; > + } > +} > + > +static int ad7380_write_event_value(struct iio_dev *indio_dev, > + const struct iio_chan_spec *chan, > + enum iio_event_type type, > + enum iio_event_direction dir, > + enum iio_event_info info, > + int val, int val2) > +{ > + struct ad7380_state *st = iio_priv(indio_dev); > + const struct iio_scan_type *scan_type; > + int ret; > + u16 th; > + > + switch (info) { > + case IIO_EV_INFO_VALUE: > + ret = iio_device_claim_direct_mode(indio_dev); > + if (ret) > + return ret; > + > + /* > + * According to the datasheet, > + * AD7380_REG_ADDR_ALERT_HIGH_TH[11:0] are the 12 MSB of the > + * 16-bits internal alert high register. LSB are set to 0xf. > + * AD7380_REG_ADDR_ALERT_LOW_TH[11:0] are the 12 MSB of the > + * 16 bits internal alert low register. LSB are set to 0x0. > + * > + * When alert is enabled the conversion from the adc is compared > + * immediately to the alert high/low thresholds, before any > + * oversampling. This means that the thresholds are the same for > + * normal mode and oversampling mode. > + */ > + > + /* Extract the 12 MSB of val */ > + scan_type = iio_get_current_scan_type(indio_dev, chan); > + if (IS_ERR(scan_type)) > + return PTR_ERR(scan_type); Same with this function, it isn't releasing on error, so we can use a helper here too to solve it. > + > + th = val >> (scan_type->realbits - 12); > + > + switch (dir) { > + case IIO_EV_DIR_RISING: > + ret = regmap_write(st->regmap, > + AD7380_REG_ADDR_ALERT_HIGH_TH, > + th); > + if (ret) > + return ret; > + > + break; > + case IIO_EV_DIR_FALLING: > + ret = regmap_write(st->regmap, > + AD7380_REG_ADDR_ALERT_LOW_TH, > + th); > + if (ret) > + return ret; > + > + break; > + default: > + ret = -EINVAL; > + break; > + } > + > + iio_device_release_direct_mode(indio_dev); > + return ret; > + default: > + return -EINVAL; > + } > +} > +
