iio: adc: ad7380: add support for adaq4370-4 and adaq4380-4

adaq4370-4 (2MSPS) and adaq4380-4 (4MSPS) are quad-channel precision data
acquisition signal chain μModule solutions compatible with the ad738x
family, with the following differences:

- pin selectable gain in front of each 4 adc
- internal reference is 3V derived from refin-supply (5V)
- additional supplies

This implies that IIO_CHAN_INFO_SCALE can not be shared by type for
these new devices.

Signed-off-by: Julien Stephan <jstephan@baylibre.com>
Reviewed-by: David Lechner <dlechner@baylibre.com>
Link: https://patch.msgid.link/20241030-ad7380-add-adaq4380-4-support-v4-4-864ff02babae@baylibre.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

diff --git a/drivers/iio/adc/ad7380.c b/drivers/iio/adc/ad7380.c
index 206c894953f057acca20805fb30185cb7ab8a902..4f32cb22f140442b831dc9a4f275e88e4ab2388e 100644 (file)
--- a/drivers/iio/adc/ad7380.c
+++ b/drivers/iio/adc/ad7380.c
@@ -13,6 +13,8 @@
  * ad7381-4 : https://www.analog.com/media/en/technical-documentation/data-sheets/ad7381-4.pdf
  * ad7383/4-4 : https://www.analog.com/media/en/technical-documentation/data-sheets/ad7383-4-ad7384-4.pdf
  * ad7386/7/8-4 : https://www.analog.com/media/en/technical-documentation/data-sheets/ad7386-4-7387-4-7388-4.pdf
+ * adaq4370-4 : https://www.analog.com/media/en/technical-documentation/data-sheets/adaq4370-4.pdf
+ * adaq4380-4 : https://www.analog.com/media/en/technical-documentation/data-sheets/adaq4380-4.pdf
  */
 
 #include <linux/align.h>
@@ -22,11 +24,14 @@
 #include <linux/device.h>
 #include <linux/err.h>
 #include <linux/kernel.h>
+#include <linux/math.h>
 #include <linux/module.h>
 #include <linux/regmap.h>
 #include <linux/regulator/consumer.h>
 #include <linux/slab.h>
 #include <linux/spi/spi.h>
+#include <linux/units.h>
+#include <linux/util_macros.h>
 
 #include <linux/iio/buffer.h>
 #include <linux/iio/iio.h>
@@ -36,6 +41,8 @@
 #define MAX_NUM_CHANNELS               8
 /* 2.5V internal reference voltage */
 #define AD7380_INTERNAL_REF_MV         2500
+/* 3.3V internal reference voltage for ADAQ */
+#define ADAQ4380_INTERNAL_REF_MV       3300
 
 /* reading and writing registers is more reliable at lower than max speed */
 #define AD7380_REG_WR_SPEED_HZ         10000000
@@ -82,6 +89,7 @@
  * supports only 1 SDO line (standard SPI transaction)
  */
 #define AD7380_NUM_SDO_LINES           1
+#define AD7380_DEFAULT_GAIN_MILLI      1000
 
 struct ad7380_timing_specs {
        const unsigned int t_csh_ns;    /* CS minimum high time */
@@ -92,10 +100,12 @@ struct ad7380_chip_info {
        const struct iio_chan_spec *channels;
        unsigned int num_channels;
        unsigned int num_simult_channels;
+       bool has_hardware_gain;
        bool has_mux;
        const char * const *supplies;
        unsigned int num_supplies;
        bool external_ref_only;
+       bool adaq_internal_ref_only;
        const char * const *vcm_supplies;
        unsigned int num_vcm_supplies;
        const unsigned long *available_scan_masks;
@@ -187,11 +197,12 @@ static const struct iio_scan_type ad7380_scan_type_16_u[] = {
        },
 };
 
-#define AD7380_CHANNEL(index, bits, diff, sign) {                              \
+#define _AD7380_CHANNEL(index, bits, diff, sign, gain) {                       \
        .type = IIO_VOLTAGE,                                                    \
        .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |                          \
+               ((gain) ? BIT(IIO_CHAN_INFO_SCALE) : 0) |                       \
                ((diff) ? 0 : BIT(IIO_CHAN_INFO_OFFSET)),                       \
-       .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) |                  \
+       .info_mask_shared_by_type = ((gain) ? 0 : BIT(IIO_CHAN_INFO_SCALE)) |   \
                BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO),                          \
        .info_mask_shared_by_type_available =                                   \
                BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO),                          \
@@ -205,6 +216,12 @@ static const struct iio_scan_type ad7380_scan_type_16_u[] = {
        .num_ext_scan_type = ARRAY_SIZE(ad7380_scan_type_##bits##_##sign),      \
 }
 
+#define AD7380_CHANNEL(index, bits, diff, sign)                \
+       _AD7380_CHANNEL(index, bits, diff, sign, false)
+
+#define ADAQ4380_CHANNEL(index, bits, diff, sign)      \
+       _AD7380_CHANNEL(index, bits, diff, sign, true)
+
 #define DEFINE_AD7380_2_CHANNEL(name, bits, diff, sign)        \
 static const struct iio_chan_spec name[] = {           \
        AD7380_CHANNEL(0, bits, diff, sign),            \
@@ -221,6 +238,15 @@ static const struct iio_chan_spec name[] = {               \
        IIO_CHAN_SOFT_TIMESTAMP(4),                     \
 }
 
+#define DEFINE_ADAQ4380_4_CHANNEL(name, bits, diff, sign)      \
+static const struct iio_chan_spec name[] = {                   \
+       ADAQ4380_CHANNEL(0, bits, diff, sign),                  \
+       ADAQ4380_CHANNEL(1, bits, diff, sign),                  \
+       ADAQ4380_CHANNEL(2, bits, diff, sign),                  \
+       ADAQ4380_CHANNEL(3, bits, diff, sign),                  \
+       IIO_CHAN_SOFT_TIMESTAMP(4),                             \
+}
+
 #define DEFINE_AD7380_8_CHANNEL(name, bits, diff, sign)        \
 static const struct iio_chan_spec name[] = {           \
        AD7380_CHANNEL(0, bits, diff, sign),            \
@@ -239,6 +265,7 @@ DEFINE_AD7380_2_CHANNEL(ad7380_channels, 16, 1, s);
 DEFINE_AD7380_2_CHANNEL(ad7381_channels, 14, 1, s);
 DEFINE_AD7380_4_CHANNEL(ad7380_4_channels, 16, 1, s);
 DEFINE_AD7380_4_CHANNEL(ad7381_4_channels, 14, 1, s);
+DEFINE_ADAQ4380_4_CHANNEL(adaq4380_4_channels, 16, 1, s);
 /* pseudo differential */
 DEFINE_AD7380_2_CHANNEL(ad7383_channels, 16, 0, s);
 DEFINE_AD7380_2_CHANNEL(ad7384_channels, 14, 0, s);
@@ -257,6 +284,10 @@ static const char * const ad7380_supplies[] = {
        "vcc", "vlogic",
 };
 
+static const char * const adaq4380_supplies[] = {
+       "ldo", "vcc", "vlogic", "vs-p", "vs-n", "refin",
+};
+
 static const char * const ad7380_2_channel_vcm_supplies[] = {
        "aina", "ainb",
 };
@@ -347,6 +378,11 @@ static const int ad7380_oversampling_ratios[] = {
        1, 2, 4, 8, 16, 32,
 };
 
+/* Gains stored as fractions of 1000 so they can be expressed by integers. */
+static const int ad7380_gains[] = {
+       300, 600, 1000, 1600,
+};
+
 static const struct ad7380_chip_info ad7380_chip_info = {
        .name = "ad7380",
        .channels = ad7380_channels,
@@ -516,6 +552,32 @@ static const struct ad7380_chip_info ad7388_4_chip_info = {
        .timing_specs = &ad7380_4_timing,
 };
 
+static const struct ad7380_chip_info adaq4370_4_chip_info = {
+       .name = "adaq4370-4",
+       .channels = adaq4380_4_channels,
+       .num_channels = ARRAY_SIZE(adaq4380_4_channels),
+       .num_simult_channels = 4,
+       .supplies = adaq4380_supplies,
+       .num_supplies = ARRAY_SIZE(adaq4380_supplies),
+       .adaq_internal_ref_only = true,
+       .has_hardware_gain = true,
+       .available_scan_masks = ad7380_4_channel_scan_masks,
+       .timing_specs = &ad7380_4_timing,
+};
+
+static const struct ad7380_chip_info adaq4380_4_chip_info = {
+       .name = "adaq4380-4",
+       .channels = adaq4380_4_channels,
+       .num_channels = ARRAY_SIZE(adaq4380_4_channels),
+       .num_simult_channels = 4,
+       .supplies = adaq4380_supplies,
+       .num_supplies = ARRAY_SIZE(adaq4380_supplies),
+       .adaq_internal_ref_only = true,
+       .has_hardware_gain = true,
+       .available_scan_masks = ad7380_4_channel_scan_masks,
+       .timing_specs = &ad7380_4_timing,
+};
+
 struct ad7380_state {
        const struct ad7380_chip_info *chip_info;
        struct spi_device *spi;
@@ -526,6 +588,7 @@ struct ad7380_state {
        bool seq;
        unsigned int vref_mv;
        unsigned int vcm_mv[MAX_NUM_CHANNELS];
+       unsigned int gain_milli[MAX_NUM_CHANNELS];
        /* xfers, message an buffer for reading sample data */
        struct spi_transfer normal_xfer[2];
        struct spi_message normal_msg;
@@ -876,8 +939,15 @@ static int ad7380_read_raw(struct iio_dev *indio_dev,
                 *    * (2 × VREF) / 2^N, for differential chips
                 *    * VREF / 2^N, for pseudo-differential chips
                 * where N is the ADC resolution (i.e realbits)
+                *
+                * The gain is stored as a fraction of 1000 and, as we need to
+                * divide vref_mv by the gain, we invert the gain/1000 fraction.
                 */
-               *val = st->vref_mv;
+               if (st->chip_info->has_hardware_gain)
+                       *val = mult_frac(st->vref_mv, MILLI,
+                                        st->gain_milli[chan->scan_index]);
+               else
+                       *val = st->vref_mv;
                *val2 = scan_type->realbits - chan->differential;
 
                return IIO_VAL_FRACTIONAL_LOG2;
@@ -1059,7 +1129,19 @@ static int ad7380_probe(struct spi_device *spi)
                                     "Failed to enable power supplies\n");
        fsleep(T_POWERUP_US);
 
-       if (st->chip_info->external_ref_only) {
+       if (st->chip_info->adaq_internal_ref_only) {
+               /*
+                * ADAQ chips use fixed internal reference but still
+                * require a specific reference supply to power it.
+                * "refin" is already enabled with other power supplies
+                * in bulk_get_enable().
+                */
+
+               st->vref_mv = ADAQ4380_INTERNAL_REF_MV;
+
+               /* these chips don't have a register bit for this */
+               external_ref_en = false;
+       } else if (st->chip_info->external_ref_only) {
                ret = devm_regulator_get_enable_read_voltage(dev, "refin");
                if (ret < 0)
                        return dev_err_probe(dev, ret,
@@ -1103,6 +1185,42 @@ static int ad7380_probe(struct spi_device *spi)
                st->vcm_mv[i] = ret / 1000;
        }
 
+       for (i = 0; i < MAX_NUM_CHANNELS; i++)
+               st->gain_milli[i] = AD7380_DEFAULT_GAIN_MILLI;
+
+       if (st->chip_info->has_hardware_gain) {
+               device_for_each_child_node_scoped(dev, node) {
+                       unsigned int channel, gain;
+                       int gain_idx;
+
+                       ret = fwnode_property_read_u32(node, "reg", &channel);
+                       if (ret)
+                               return dev_err_probe(dev, ret,
+                                                    "Failed to read reg property\n");
+
+                       if (channel >= st->chip_info->num_channels - 1)
+                               return dev_err_probe(dev, -EINVAL,
+                                                    "Invalid channel number %i\n",
+                                                    channel);
+
+                       ret = fwnode_property_read_u32(node, "adi,gain-milli",
+                                                      &gain);
+                       if (ret && ret != -EINVAL)
+                               return dev_err_probe(dev, ret,
+                                                    "Failed to read gain for channel %i\n",
+                                                    channel);
+                       if (ret != -EINVAL) {
+                               /*
+                                * Match gain value from dt to one of supported
+                                * gains
+                                */
+                               gain_idx = find_closest(gain, ad7380_gains,
+                                                       ARRAY_SIZE(ad7380_gains));
+                               st->gain_milli[channel] = ad7380_gains[gain_idx];
+                       }
+               }
+       }
+
        st->regmap = devm_regmap_init(dev, NULL, st, &ad7380_regmap_config);
        if (IS_ERR(st->regmap))
                return dev_err_probe(dev, PTR_ERR(st->regmap),
@@ -1185,6 +1303,8 @@ static const struct of_device_id ad7380_of_match_table[] = {
        { .compatible = "adi,ad7386-4", .data = &ad7386_4_chip_info },
        { .compatible = "adi,ad7387-4", .data = &ad7387_4_chip_info },
        { .compatible = "adi,ad7388-4", .data = &ad7388_4_chip_info },
+       { .compatible = "adi,adaq4370-4", .data = &adaq4370_4_chip_info },
+       { .compatible = "adi,adaq4380-4", .data = &adaq4380_4_chip_info },
        { }
 };
 
@@ -1203,6 +1323,8 @@ static const struct spi_device_id ad7380_id_table[] = {
        { "ad7386-4", (kernel_ulong_t)&ad7386_4_chip_info },
        { "ad7387-4", (kernel_ulong_t)&ad7387_4_chip_info },
        { "ad7388-4", (kernel_ulong_t)&ad7388_4_chip_info },
+       { "adaq4370-4", (kernel_ulong_t)&adaq4370_4_chip_info },
+       { "adaq4380-4", (kernel_ulong_t)&adaq4380_4_chip_info },
        { }
 };
 MODULE_DEVICE_TABLE(spi, ad7380_id_table);