iio: adc: ad7124: Implement system calibration

Allow triggering both zero-scale and full-scale calibration via sysfs in
the same way as it's done for ad7173.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@baylibre.com>
Link: https://patch.msgid.link/20250303114659.1672695-18-u.kleine-koenig@baylibre.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

diff --git a/drivers/iio/adc/ad7124.c b/drivers/iio/adc/ad7124.c
index 382f46ff2b5117ed443d0e4c56b2e125a732ce35..ad27522f429f3c483c785b21820b886771560f1b 100644 (file)
--- a/drivers/iio/adc/ad7124.c
+++ b/drivers/iio/adc/ad7124.c
@@ -181,6 +181,7 @@ struct ad7124_channel {
        struct ad7124_channel_config cfg;
        unsigned int ain;
        unsigned int slot;
+       u8 syscalib_mode;
 };
 
 struct ad7124_state {
@@ -202,23 +203,6 @@ struct ad7124_state {
        DECLARE_KFIFO(live_cfgs_fifo, struct ad7124_channel_config *, AD7124_MAX_CONFIGS);
 };
 
-static const struct iio_chan_spec ad7124_channel_template = {
-       .type = IIO_VOLTAGE,
-       .indexed = 1,
-       .differential = 1,
-       .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
-               BIT(IIO_CHAN_INFO_SCALE) |
-               BIT(IIO_CHAN_INFO_OFFSET) |
-               BIT(IIO_CHAN_INFO_SAMP_FREQ) |
-               BIT(IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY),
-       .scan_type = {
-               .sign = 'u',
-               .realbits = 24,
-               .storagebits = 32,
-               .endianness = IIO_BE,
-       },
-};
-
 static struct ad7124_chip_info ad7124_chip_info_tbl[] = {
        [ID_AD7124_4] = {
                .name = "ad7124-4",
@@ -903,6 +887,140 @@ static int ad7124_check_chip_id(struct ad7124_state *st)
        return 0;
 }
 
+enum {
+       AD7124_SYSCALIB_ZERO_SCALE,
+       AD7124_SYSCALIB_FULL_SCALE,
+};
+
+static int ad7124_syscalib_locked(struct ad7124_state *st, const struct iio_chan_spec *chan)
+{
+       struct device *dev = &st->sd.spi->dev;
+       struct ad7124_channel *ch = &st->channels[chan->channel];
+       int ret;
+
+       if (ch->syscalib_mode == AD7124_SYSCALIB_ZERO_SCALE) {
+               ch->cfg.calibration_offset = 0x800000;
+
+               ret = ad_sd_calibrate(&st->sd, AD7124_MODE_CAL_SYS_ZERO,
+                                     chan->address);
+               if (ret < 0)
+                       return ret;
+
+               ret = ad_sd_read_reg(&st->sd, AD7124_OFFSET(ch->cfg.cfg_slot), 3,
+                                    &ch->cfg.calibration_offset);
+               if (ret < 0)
+                       return ret;
+
+               dev_dbg(dev, "offset for channel %d after zero-scale calibration: 0x%x\n",
+                       chan->channel, ch->cfg.calibration_offset);
+       } else {
+               ch->cfg.calibration_gain = st->gain_default;
+
+               ret = ad_sd_calibrate(&st->sd, AD7124_MODE_CAL_SYS_FULL,
+                                     chan->address);
+               if (ret < 0)
+                       return ret;
+
+               ret = ad_sd_read_reg(&st->sd, AD7124_GAIN(ch->cfg.cfg_slot), 3,
+                                    &ch->cfg.calibration_gain);
+               if (ret < 0)
+                       return ret;
+
+               dev_dbg(dev, "gain for channel %d after full-scale calibration: 0x%x\n",
+                       chan->channel, ch->cfg.calibration_gain);
+       }
+
+       return 0;
+}
+
+static ssize_t ad7124_write_syscalib(struct iio_dev *indio_dev,
+                                    uintptr_t private,
+                                    const struct iio_chan_spec *chan,
+                                    const char *buf, size_t len)
+{
+       struct ad7124_state *st = iio_priv(indio_dev);
+       bool sys_calib;
+       int ret;
+
+       ret = kstrtobool(buf, &sys_calib);
+       if (ret)
+               return ret;
+
+       if (!sys_calib)
+               return len;
+
+       if (!iio_device_claim_direct(indio_dev))
+               return -EBUSY;
+
+       ret = ad7124_syscalib_locked(st, chan);
+
+       iio_device_release_direct(indio_dev);
+
+       return ret ?: len;
+}
+
+static const char * const ad7124_syscalib_modes[] = {
+       [AD7124_SYSCALIB_ZERO_SCALE] = "zero_scale",
+       [AD7124_SYSCALIB_FULL_SCALE] = "full_scale",
+};
+
+static int ad7124_set_syscalib_mode(struct iio_dev *indio_dev,
+                                   const struct iio_chan_spec *chan,
+                                   unsigned int mode)
+{
+       struct ad7124_state *st = iio_priv(indio_dev);
+
+       st->channels[chan->channel].syscalib_mode = mode;
+
+       return 0;
+}
+
+static int ad7124_get_syscalib_mode(struct iio_dev *indio_dev,
+                                   const struct iio_chan_spec *chan)
+{
+       struct ad7124_state *st = iio_priv(indio_dev);
+
+       return st->channels[chan->channel].syscalib_mode;
+}
+
+static const struct iio_enum ad7124_syscalib_mode_enum = {
+       .items = ad7124_syscalib_modes,
+       .num_items = ARRAY_SIZE(ad7124_syscalib_modes),
+       .set = ad7124_set_syscalib_mode,
+       .get = ad7124_get_syscalib_mode
+};
+
+static const struct iio_chan_spec_ext_info ad7124_calibsys_ext_info[] = {
+       {
+               .name = "sys_calibration",
+               .write = ad7124_write_syscalib,
+               .shared = IIO_SEPARATE,
+       },
+       IIO_ENUM("sys_calibration_mode", IIO_SEPARATE,
+                &ad7124_syscalib_mode_enum),
+       IIO_ENUM_AVAILABLE("sys_calibration_mode", IIO_SHARED_BY_TYPE,
+                          &ad7124_syscalib_mode_enum),
+       { }
+};
+
+static const struct iio_chan_spec ad7124_channel_template = {
+       .type = IIO_VOLTAGE,
+       .indexed = 1,
+       .differential = 1,
+       .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
+               BIT(IIO_CHAN_INFO_SCALE) |
+               BIT(IIO_CHAN_INFO_OFFSET) |
+               BIT(IIO_CHAN_INFO_SAMP_FREQ) |
+               BIT(IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY),
+       .scan_type = {
+               .sign = 'u',
+               .realbits = 24,
+               .storagebits = 32,
+               .endianness = IIO_BE,
+       },
+       .ext_info = ad7124_calibsys_ext_info,
+};
+
 /*
  * Input specifiers 8 - 15 are explicitly reserved for ad7124-4
  * while they are fine for ad7124-8. Values above 31 don't fit