From: Angelo Dureghello Date: Fri, 6 Jun 2025 14:19:22 +0000 (+0200) Subject: iio: adc: ad7606: add gain calibration support X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=126cbd0deb9b88754f5f67cbd4c3399c74688bdc;p=users%2Fjedix%2Flinux-maple.git iio: adc: ad7606: add gain calibration support Add gain calibration support, using resistor values set on devicetree, values to be set accordingly with ADC external RFilter, as explained in the ad7606c-16 datasheet, rev0, page 37. Usage example in the fdt yaml documentation. Signed-off-by: Angelo Dureghello Reviewed-by: Andy Shevchenko Link: https://patch.msgid.link/20250606-wip-bl-ad7606-calibration-v9-7-6e014a1f92a2@baylibre.com Signed-off-by: Jonathan Cameron --- diff --git a/drivers/iio/adc/ad7606.c b/drivers/iio/adc/ad7606.c index d19682186e7c..d9271894f091 100644 --- a/drivers/iio/adc/ad7606.c +++ b/drivers/iio/adc/ad7606.c @@ -33,6 +33,10 @@ #include "ad7606.h" +#define AD7606_CALIB_GAIN_MIN 0 +#define AD7606_CALIB_GAIN_STEP 1024 +#define AD7606_CALIB_GAIN_MAX (63 * AD7606_CALIB_GAIN_STEP) + /* * Scales are computed as 5000/32768 and 10000/32768 respectively, * so that when applied to the raw values they provide mV values. @@ -180,6 +184,7 @@ const struct ad7606_chip_info ad7606b_info = { .scale_setup_cb = ad7606_16bit_chan_scale_setup, .sw_setup_cb = ad7606b_sw_mode_setup, .offload_storagebits = 32, + .calib_gain_avail = true, .calib_offset_avail = ad7606_calib_offset_avail, .calib_phase_avail = ad7606b_calib_phase_avail, }; @@ -195,6 +200,7 @@ const struct ad7606_chip_info ad7606c_16_info = { .scale_setup_cb = ad7606c_16bit_chan_scale_setup, .sw_setup_cb = ad7606b_sw_mode_setup, .offload_storagebits = 32, + .calib_gain_avail = true, .calib_offset_avail = ad7606_calib_offset_avail, .calib_phase_avail = ad7606c_calib_phase_avail, }; @@ -246,6 +252,7 @@ const struct ad7606_chip_info ad7606c_18_info = { .scale_setup_cb = ad7606c_18bit_chan_scale_setup, .sw_setup_cb = ad7606b_sw_mode_setup, .offload_storagebits = 32, + .calib_gain_avail = true, .calib_offset_avail = ad7606c_18bit_calib_offset_avail, .calib_phase_avail = ad7606c_calib_phase_avail, }; @@ -306,6 +313,7 @@ static int ad7606_get_chan_config(struct iio_dev *indio_dev, int ch, bool *bipolar, bool *differential) { struct ad7606_state *st = iio_priv(indio_dev); + struct ad7606_chan_info *ci; unsigned int num_channels = st->chip_info->num_adc_channels; struct device *dev = st->dev; int ret; @@ -349,6 +357,14 @@ static int ad7606_get_chan_config(struct iio_dev *indio_dev, int ch, return -EINVAL; } + ci = &st->chan_info[reg - 1]; + + ci->r_gain = 0; + ret = fwnode_property_read_u32(child, "adi,rfilter-ohms", + &ci->r_gain); + if (ret == 0 && ci->r_gain > AD7606_CALIB_GAIN_MAX) + return -EINVAL; + return 0; } @@ -1352,6 +1368,23 @@ static int ad7606b_sw_mode_setup(struct iio_dev *indio_dev) return st->bops->sw_mode_config(indio_dev); } +static int ad7606_set_gain_calib(struct ad7606_state *st) +{ + struct ad7606_chan_info *ci; + int i, ret; + + for (i = 0; i < st->chip_info->num_adc_channels; i++) { + ci = &st->chan_info[i]; + ret = st->bops->reg_write(st, AD7606_CALIB_GAIN(i), + DIV_ROUND_CLOSEST(ci->r_gain, + AD7606_CALIB_GAIN_STEP)); + if (ret) + return ret; + } + + return 0; +} + static int ad7606_probe_channels(struct iio_dev *indio_dev) { struct ad7606_state *st = iio_priv(indio_dev); @@ -1630,6 +1663,12 @@ int ad7606_probe(struct device *dev, int irq, void __iomem *base_address, st->chip_info->sw_setup_cb(indio_dev); } + if (st->sw_mode_en && st->chip_info->calib_gain_avail) { + ret = ad7606_set_gain_calib(st); + if (ret) + return ret; + } + return devm_iio_device_register(dev, indio_dev); } EXPORT_SYMBOL_NS_GPL(ad7606_probe, "IIO_AD7606"); diff --git a/drivers/iio/adc/ad7606.h b/drivers/iio/adc/ad7606.h index 26db8e3c724f..2951bb731354 100644 --- a/drivers/iio/adc/ad7606.h +++ b/drivers/iio/adc/ad7606.h @@ -66,6 +66,7 @@ typedef int (*ad7606_sw_setup_cb_t)(struct iio_dev *indio_dev); * @init_delay_ms: required delay in milliseconds for initialization * after a restart * @offload_storagebits: storage bits used by the offload hw implementation + * @calib_gain_avail: chip supports gain calibration * @calib_offset_avail: pointer to offset calibration range/limits array * @calib_phase_avail: pointer to phase calibration range/limits array */ @@ -81,6 +82,7 @@ struct ad7606_chip_info { bool os_req_reset; unsigned long init_delay_ms; u8 offload_storagebits; + bool calib_gain_avail; const int *calib_offset_avail; const int (*calib_phase_avail)[2]; }; @@ -92,6 +94,8 @@ struct ad7606_chip_info { * @range: voltage range selection, selects which scale to apply * @reg_offset: offset for the register value, to be applied when * writing the value of 'range' to the register value + * @r_gain: gain resistor value in ohms, to be set to match the + * external r_filter value */ struct ad7606_chan_info { #define AD760X_MAX_SCALES 16 @@ -99,6 +103,7 @@ struct ad7606_chan_info { unsigned int num_scales; unsigned int range; unsigned int reg_offset; + unsigned int r_gain; }; /**