--- /dev/null
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * AD7124 SPI ADC driver
+ *
+ * Copyright 2018 Analog Devices Inc.
+ */
+#include <linux/bitfield.h>
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/regulator/consumer.h>
+#include <linux/spi/spi.h>
+
+#include <linux/iio/iio.h>
+#include <linux/iio/adc/ad_sigma_delta.h>
+#include <linux/iio/sysfs.h>
+
+/* AD7124 registers */
+#define AD7124_COMMS 0x00
+#define AD7124_STATUS 0x00
+#define AD7124_ADC_CONTROL 0x01
+#define AD7124_DATA 0x02
+#define AD7124_IO_CONTROL_1 0x03
+#define AD7124_IO_CONTROL_2 0x04
+#define AD7124_ID 0x05
+#define AD7124_ERROR 0x06
+#define AD7124_ERROR_EN 0x07
+#define AD7124_MCLK_COUNT 0x08
+#define AD7124_CHANNEL(x) (0x09 + (x))
+#define AD7124_CONFIG(x) (0x19 + (x))
+#define AD7124_FILTER(x) (0x21 + (x))
+#define AD7124_OFFSET(x) (0x29 + (x))
+#define AD7124_GAIN(x) (0x31 + (x))
+
+/* AD7124_STATUS */
+#define AD7124_STATUS_POR_FLAG_MSK BIT(4)
+
+/* AD7124_ADC_CONTROL */
+#define AD7124_ADC_CTRL_PWR_MSK GENMASK(7, 6)
+#define AD7124_ADC_CTRL_PWR(x) FIELD_PREP(AD7124_ADC_CTRL_PWR_MSK, x)
+#define AD7124_ADC_CTRL_MODE_MSK GENMASK(5, 2)
+#define AD7124_ADC_CTRL_MODE(x) FIELD_PREP(AD7124_ADC_CTRL_MODE_MSK, x)
+
+/* AD7124_CHANNEL_X */
+#define AD7124_CHANNEL_EN_MSK BIT(15)
+#define AD7124_CHANNEL_EN(x) FIELD_PREP(AD7124_CHANNEL_EN_MSK, x)
+#define AD7124_CHANNEL_SETUP_MSK GENMASK(14, 12)
+#define AD7124_CHANNEL_SETUP(x) FIELD_PREP(AD7124_CHANNEL_SETUP_MSK, x)
+#define AD7124_CHANNEL_AINP_MSK GENMASK(9, 5)
+#define AD7124_CHANNEL_AINP(x) FIELD_PREP(AD7124_CHANNEL_AINP_MSK, x)
+#define AD7124_CHANNEL_AINM_MSK GENMASK(4, 0)
+#define AD7124_CHANNEL_AINM(x) FIELD_PREP(AD7124_CHANNEL_AINM_MSK, x)
+
+/* AD7124_CONFIG_X */
+#define AD7124_CONFIG_BIPOLAR_MSK BIT(11)
+#define AD7124_CONFIG_BIPOLAR(x) FIELD_PREP(AD7124_CONFIG_BIPOLAR_MSK, x)
+#define AD7124_CONFIG_REF_SEL_MSK GENMASK(4, 3)
+#define AD7124_CONFIG_REF_SEL(x) FIELD_PREP(AD7124_CONFIG_REF_SEL_MSK, x)
+#define AD7124_CONFIG_PGA_MSK GENMASK(2, 0)
+#define AD7124_CONFIG_PGA(x) FIELD_PREP(AD7124_CONFIG_PGA_MSK, x)
+
+/* AD7124_FILTER_X */
+#define AD7124_FILTER_FS_MSK GENMASK(10, 0)
+#define AD7124_FILTER_FS(x) FIELD_PREP(AD7124_FILTER_FS_MSK, x)
+
+enum ad7124_ids {
+ ID_AD7124_4,
+ ID_AD7124_8,
+};
+
+enum ad7124_ref_sel {
+ AD7124_REFIN1,
+ AD7124_REFIN2,
+ AD7124_INT_REF,
+ AD7124_AVDD_REF,
+};
+
+enum ad7124_power_mode {
+ AD7124_LOW_POWER,
+ AD7124_MID_POWER,
+ AD7124_FULL_POWER,
+};
+
+static const unsigned int ad7124_gain[8] = {
+ 1, 2, 4, 8, 16, 32, 64, 128
+};
+
+static const int ad7124_master_clk_freq_hz[3] = {
+ [AD7124_LOW_POWER] = 76800,
+ [AD7124_MID_POWER] = 153600,
+ [AD7124_FULL_POWER] = 614400,
+};
+
+static const char * const ad7124_ref_names[] = {
+ [AD7124_REFIN1] = "refin1",
+ [AD7124_REFIN2] = "refin2",
+ [AD7124_INT_REF] = "int",
+ [AD7124_AVDD_REF] = "avdd",
+};
+
+struct ad7124_chip_info {
+ unsigned int num_inputs;
+};
+
+struct ad7124_channel_config {
+ enum ad7124_ref_sel refsel;
+ bool bipolar;
+ unsigned int ain;
+ unsigned int vref_mv;
+ unsigned int pga_bits;
+ unsigned int odr;
+};
+
+struct ad7124_state {
+ const struct ad7124_chip_info *chip_info;
+ struct ad_sigma_delta sd;
+ struct ad7124_channel_config channel_config[4];
+ struct regulator *vref[4];
+ struct clk *mclk;
+ unsigned int adc_control;
+ unsigned int num_channels;
+};
+
+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),
+ .scan_type = {
+ .sign = 'u',
+ .realbits = 24,
+ .storagebits = 32,
+ .shift = 8,
+ .endianness = IIO_BE,
+ },
+};
+
+static struct ad7124_chip_info ad7124_chip_info_tbl[] = {
+ [ID_AD7124_4] = {
+ .num_inputs = 8,
+ },
+ [ID_AD7124_8] = {
+ .num_inputs = 16,
+ },
+};
+
+static int ad7124_find_closest_match(const int *array,
+ unsigned int size, int val)
+{
+ int i, idx;
+ unsigned int diff_new, diff_old;
+
+ diff_old = U32_MAX;
+ idx = 0;
+
+ for (i = 0; i < size; i++) {
+ diff_new = abs(val - array[i]);
+ if (diff_new < diff_old) {
+ diff_old = diff_new;
+ idx = i;
+ }
+ }
+
+ return idx;
+}
+
+static int ad7124_spi_write_mask(struct ad7124_state *st,
+ unsigned int addr,
+ unsigned long mask,
+ unsigned int val,
+ unsigned int bytes)
+{
+ unsigned int readval;
+ int ret;
+
+ ret = ad_sd_read_reg(&st->sd, addr, bytes, &readval);
+ if (ret < 0)
+ return ret;
+
+ readval &= ~mask;
+ readval |= val;
+
+ return ad_sd_write_reg(&st->sd, addr, bytes, readval);
+}
+
+static int ad7124_set_mode(struct ad_sigma_delta *sd,
+ enum ad_sigma_delta_mode mode)
+{
+ struct ad7124_state *st = container_of(sd, struct ad7124_state, sd);
+
+ st->adc_control &= ~AD7124_ADC_CTRL_MODE_MSK;
+ st->adc_control |= AD7124_ADC_CTRL_MODE(mode);
+
+ return ad_sd_write_reg(&st->sd, AD7124_ADC_CONTROL, 2, st->adc_control);
+}
+
+static int ad7124_set_channel(struct ad_sigma_delta *sd, unsigned int channel)
+{
+ struct ad7124_state *st = container_of(sd, struct ad7124_state, sd);
+ unsigned int val;
+
+ val = st->channel_config[channel].ain | AD7124_CHANNEL_EN(1) |
+ AD7124_CHANNEL_SETUP(channel);
+
+ return ad_sd_write_reg(&st->sd, AD7124_CHANNEL(channel), 2, val);
+}
+
+static const struct ad_sigma_delta_info ad7124_sigma_delta_info = {
+ .set_channel = ad7124_set_channel,
+ .set_mode = ad7124_set_mode,
+ .has_registers = true,
+ .addr_shift = 0,
+ .read_mask = BIT(6),
+ .data_reg = AD7124_DATA,
+};
+
+static int ad7124_set_channel_odr(struct ad7124_state *st,
+ unsigned int channel,
+ unsigned int odr)
+{
+ unsigned int fclk, odr_sel_bits;
+ int ret;
+
+ fclk = clk_get_rate(st->mclk);
+ /*
+ * FS[10:0] = fCLK / (fADC x 32) where:
+ * fADC is the output data rate
+ * fCLK is the master clock frequency
+ * FS[10:0] are the bits in the filter register
+ * FS[10:0] can have a value from 1 to 2047
+ */
+ odr_sel_bits = DIV_ROUND_CLOSEST(fclk, odr * 32);
+ if (odr_sel_bits < 1)
+ odr_sel_bits = 1;
+ else if (odr_sel_bits > 2047)
+ odr_sel_bits = 2047;
+
+ ret = ad7124_spi_write_mask(st, AD7124_FILTER(channel),
+ AD7124_FILTER_FS_MSK,
+ AD7124_FILTER_FS(odr_sel_bits), 3);
+ if (ret < 0)
+ return ret;
+ /* fADC = fCLK / (FS[10:0] x 32) */
+ st->channel_config[channel].odr =
+ DIV_ROUND_CLOSEST(fclk, odr_sel_bits * 32);
+
+ return 0;
+}
+
+static int ad7124_set_channel_gain(struct ad7124_state *st,
+ unsigned int channel,
+ unsigned int gain)
+{
+ unsigned int res;
+ int ret;
+
+ res = ad7124_find_closest_match(ad7124_gain,
+ ARRAY_SIZE(ad7124_gain), gain);
+ ret = ad7124_spi_write_mask(st, AD7124_CONFIG(channel),
+ AD7124_CONFIG_PGA_MSK,
+ AD7124_CONFIG_PGA(res), 2);
+ if (ret < 0)
+ return ret;
+
+ st->channel_config[channel].pga_bits = res;
+
+ return 0;
+}
+
+static int ad7124_read_raw(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *chan,
+ int *val, int *val2, long info)
+{
+ struct ad7124_state *st = iio_priv(indio_dev);
+ int idx, ret;
+
+ switch (info) {
+ case IIO_CHAN_INFO_RAW:
+ ret = ad_sigma_delta_single_conversion(indio_dev, chan, val);
+ if (ret < 0)
+ return ret;
+
+ /* After the conversion is performed, disable the channel */
+ ret = ad_sd_write_reg(&st->sd,
+ AD7124_CHANNEL(chan->address), 2,
+ st->channel_config[chan->address].ain |
+ AD7124_CHANNEL_EN(0));
+ if (ret < 0)
+ return ret;
+
+ return IIO_VAL_INT;
+ case IIO_CHAN_INFO_SCALE:
+ idx = st->channel_config[chan->address].pga_bits;
+ *val = st->channel_config[chan->address].vref_mv;
+ if (st->channel_config[chan->address].bipolar)
+ *val2 = chan->scan_type.realbits - 1 + idx;
+ else
+ *val2 = chan->scan_type.realbits + idx;
+
+ return IIO_VAL_FRACTIONAL_LOG2;
+ case IIO_CHAN_INFO_OFFSET:
+ if (st->channel_config[chan->address].bipolar)
+ *val = -(1 << (chan->scan_type.realbits - 1));
+ else
+ *val = 0;
+
+ return IIO_VAL_INT;
+ case IIO_CHAN_INFO_SAMP_FREQ:
+ *val = st->channel_config[chan->address].odr;
+
+ return IIO_VAL_INT;
+ default:
+ return -EINVAL;
+ }
+}
+
+static int ad7124_write_raw(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *chan,
+ int val, int val2, long info)
+{
+ struct ad7124_state *st = iio_priv(indio_dev);
+ unsigned int res, gain, full_scale, vref;
+
+ switch (info) {
+ case IIO_CHAN_INFO_SAMP_FREQ:
+ if (val2 != 0)
+ return -EINVAL;
+
+ return ad7124_set_channel_odr(st, chan->address, val);
+ case IIO_CHAN_INFO_SCALE:
+ if (val != 0)
+ return -EINVAL;
+
+ if (st->channel_config[chan->address].bipolar)
+ full_scale = 1 << (chan->scan_type.realbits - 1);
+ else
+ full_scale = 1 << chan->scan_type.realbits;
+
+ vref = st->channel_config[chan->address].vref_mv * 1000000LL;
+ res = DIV_ROUND_CLOSEST(vref, full_scale);
+ gain = DIV_ROUND_CLOSEST(res, val2);
+
+ return ad7124_set_channel_gain(st, chan->address, gain);
+ default:
+ return -EINVAL;
+ }
+}
+
+static IIO_CONST_ATTR(in_voltage_scale_available,
+ "0.000001164 0.000002328 0.000004656 0.000009313 0.000018626 0.000037252 0.000074505 0.000149011 0.000298023");
+
+static struct attribute *ad7124_attributes[] = {
+ &iio_const_attr_in_voltage_scale_available.dev_attr.attr,
+ NULL,
+};
+
+static const struct attribute_group ad7124_attrs_group = {
+ .attrs = ad7124_attributes,
+};
+
+static const struct iio_info ad7124_info = {
+ .read_raw = ad7124_read_raw,
+ .write_raw = ad7124_write_raw,
+ .validate_trigger = ad_sd_validate_trigger,
+ .attrs = &ad7124_attrs_group,
+};
+
+static int ad7124_soft_reset(struct ad7124_state *st)
+{
+ unsigned int readval, timeout;
+ int ret;
+
+ ret = ad_sd_reset(&st->sd, 64);
+ if (ret < 0)
+ return ret;
+
+ timeout = 100;
+ do {
+ ret = ad_sd_read_reg(&st->sd, AD7124_STATUS, 1, &readval);
+ if (ret < 0)
+ return ret;
+
+ if (!(readval & AD7124_STATUS_POR_FLAG_MSK))
+ return 0;
+
+ /* The AD7124 requires typically 2ms to power up and settle */
+ usleep_range(100, 2000);
+ } while (--timeout);
+
+ dev_err(&st->sd.spi->dev, "Soft reset failed\n");
+
+ return -EIO;
+}
+
+static int ad7124_init_channel_vref(struct ad7124_state *st,
+ unsigned int channel_number)
+{
+ unsigned int refsel = st->channel_config[channel_number].refsel;
+
+ switch (refsel) {
+ case AD7124_REFIN1:
+ case AD7124_REFIN2:
+ case AD7124_AVDD_REF:
+ if (IS_ERR(st->vref[refsel])) {
+ dev_err(&st->sd.spi->dev,
+ "Error, trying to use external voltage reference without a %s regulator.\n",
+ ad7124_ref_names[refsel]);
+ return PTR_ERR(st->vref[refsel]);
+ }
+ st->channel_config[channel_number].vref_mv =
+ regulator_get_voltage(st->vref[refsel]);
+ /* Conversion from uV to mV */
+ st->channel_config[channel_number].vref_mv /= 1000;
+ break;
+ case AD7124_INT_REF:
+ st->channel_config[channel_number].vref_mv = 2500;
+ break;
+ default:
+ dev_err(&st->sd.spi->dev, "Invalid reference %d\n", refsel);
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+static int ad7124_of_parse_channel_config(struct iio_dev *indio_dev,
+ struct device_node *np)
+{
+ struct ad7124_state *st = iio_priv(indio_dev);
+ struct device_node *child;
+ struct iio_chan_spec *chan;
+ unsigned int ain[2], channel = 0, tmp;
+ int ret;
+
+ st->num_channels = of_get_available_child_count(np);
+ if (!st->num_channels) {
+ dev_err(indio_dev->dev.parent, "no channel children\n");
+ return -ENODEV;
+ }
+
+ chan = devm_kcalloc(indio_dev->dev.parent, st->num_channels,
+ sizeof(*chan), GFP_KERNEL);
+ if (!chan)
+ return -ENOMEM;
+
+ indio_dev->channels = chan;
+ indio_dev->num_channels = st->num_channels;
+
+ for_each_available_child_of_node(np, child) {
+ ret = of_property_read_u32(child, "reg", &channel);
+ if (ret)
+ goto err;
+
+ ret = of_property_read_u32_array(child, "diff-channels",
+ ain, 2);
+ if (ret)
+ goto err;
+
+ if (ain[0] >= st->chip_info->num_inputs ||
+ ain[1] >= st->chip_info->num_inputs) {
+ dev_err(indio_dev->dev.parent,
+ "Input pin number out of range.\n");
+ ret = -EINVAL;
+ goto err;
+ }
+ st->channel_config[channel].ain = AD7124_CHANNEL_AINP(ain[0]) |
+ AD7124_CHANNEL_AINM(ain[1]);
+ st->channel_config[channel].bipolar =
+ of_property_read_bool(child, "bipolar");
+
+ ret = of_property_read_u32(child, "adi,reference-select", &tmp);
+ if (ret)
+ st->channel_config[channel].refsel = AD7124_INT_REF;
+ else
+ st->channel_config[channel].refsel = tmp;
+
+ *chan = ad7124_channel_template;
+ chan->address = channel;
+ chan->scan_index = channel;
+ chan->channel = ain[0];
+ chan->channel2 = ain[1];
+
+ chan++;
+ }
+
+ return 0;
+err:
+ of_node_put(child);
+
+ return ret;
+}
+
+static int ad7124_setup(struct ad7124_state *st)
+{
+ unsigned int val, fclk, power_mode;
+ int i, ret;
+
+ fclk = clk_get_rate(st->mclk);
+ if (!fclk)
+ return -EINVAL;
+
+ /* The power mode changes the master clock frequency */
+ power_mode = ad7124_find_closest_match(ad7124_master_clk_freq_hz,
+ ARRAY_SIZE(ad7124_master_clk_freq_hz),
+ fclk);
+ if (fclk != ad7124_master_clk_freq_hz[power_mode]) {
+ ret = clk_set_rate(st->mclk, fclk);
+ if (ret)
+ return ret;
+ }
+
+ /* Set the power mode */
+ st->adc_control &= ~AD7124_ADC_CTRL_PWR_MSK;
+ st->adc_control |= AD7124_ADC_CTRL_PWR(power_mode);
+ ret = ad_sd_write_reg(&st->sd, AD7124_ADC_CONTROL, 2, st->adc_control);
+ if (ret < 0)
+ return ret;
+
+ for (i = 0; i < st->num_channels; i++) {
+ val = st->channel_config[i].ain | AD7124_CHANNEL_SETUP(i);
+ ret = ad_sd_write_reg(&st->sd, AD7124_CHANNEL(i), 2, val);
+ if (ret < 0)
+ return ret;
+
+ ret = ad7124_init_channel_vref(st, i);
+ if (ret < 0)
+ return ret;
+
+ val = AD7124_CONFIG_BIPOLAR(st->channel_config[i].bipolar) |
+ AD7124_CONFIG_REF_SEL(st->channel_config[i].refsel);
+ ret = ad_sd_write_reg(&st->sd, AD7124_CONFIG(i), 2, val);
+ if (ret < 0)
+ return ret;
+ /*
+ * 9.38 SPS is the minimum output data rate supported
+ * regardless of the selected power mode. Round it up to 10 and
+ * set all the enabled channels to this default value.
+ */
+ ret = ad7124_set_channel_odr(st, i, 10);
+ }
+
+ return ret;
+}
+
+static int ad7124_probe(struct spi_device *spi)
+{
+ const struct spi_device_id *id;
+ struct ad7124_state *st;
+ struct iio_dev *indio_dev;
+ int i, ret;
+
+ indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
+ if (!indio_dev)
+ return -ENOMEM;
+
+ st = iio_priv(indio_dev);
+
+ id = spi_get_device_id(spi);
+ st->chip_info = &ad7124_chip_info_tbl[id->driver_data];
+
+ ad_sd_init(&st->sd, indio_dev, spi, &ad7124_sigma_delta_info);
+
+ spi_set_drvdata(spi, indio_dev);
+
+ indio_dev->dev.parent = &spi->dev;
+ indio_dev->name = spi_get_device_id(spi)->name;
+ indio_dev->modes = INDIO_DIRECT_MODE;
+ indio_dev->info = &ad7124_info;
+
+ ret = ad7124_of_parse_channel_config(indio_dev, spi->dev.of_node);
+ if (ret < 0)
+ return ret;
+
+ for (i = 0; i < ARRAY_SIZE(st->vref); i++) {
+ if (i == AD7124_INT_REF)
+ continue;
+
+ st->vref[i] = devm_regulator_get_optional(&spi->dev,
+ ad7124_ref_names[i]);
+ if (PTR_ERR(st->vref[i]) == -ENODEV)
+ continue;
+ else if (IS_ERR(st->vref[i]))
+ return PTR_ERR(st->vref[i]);
+
+ ret = regulator_enable(st->vref[i]);
+ if (ret)
+ return ret;
+ }
+
+ st->mclk = devm_clk_get(&spi->dev, "mclk");
+ if (IS_ERR(st->mclk)) {
+ ret = PTR_ERR(st->mclk);
+ goto error_regulator_disable;
+ }
+
+ ret = clk_prepare_enable(st->mclk);
+ if (ret < 0)
+ goto error_regulator_disable;
+
+ ret = ad7124_soft_reset(st);
+ if (ret < 0)
+ goto error_clk_disable_unprepare;
+
+ ret = ad7124_setup(st);
+ if (ret < 0)
+ goto error_clk_disable_unprepare;
+
+ ret = ad_sd_setup_buffer_and_trigger(indio_dev);
+ if (ret < 0)
+ goto error_clk_disable_unprepare;
+
+ ret = iio_device_register(indio_dev);
+ if (ret < 0) {
+ dev_err(&spi->dev, "Failed to register iio device\n");
+ goto error_remove_trigger;
+ }
+
+ return 0;
+
+error_remove_trigger:
+ ad_sd_cleanup_buffer_and_trigger(indio_dev);
+error_clk_disable_unprepare:
+ clk_disable_unprepare(st->mclk);
+error_regulator_disable:
+ for (i = ARRAY_SIZE(st->vref) - 1; i >= 0; i--) {
+ if (!IS_ERR_OR_NULL(st->vref[i]))
+ regulator_disable(st->vref[i]);
+ }
+
+ return ret;
+}
+
+static int ad7124_remove(struct spi_device *spi)
+{
+ struct iio_dev *indio_dev = spi_get_drvdata(spi);
+ struct ad7124_state *st = iio_priv(indio_dev);
+ int i;
+
+ iio_device_unregister(indio_dev);
+ ad_sd_cleanup_buffer_and_trigger(indio_dev);
+ clk_disable_unprepare(st->mclk);
+
+ for (i = ARRAY_SIZE(st->vref) - 1; i >= 0; i--) {
+ if (!IS_ERR_OR_NULL(st->vref[i]))
+ regulator_disable(st->vref[i]);
+ }
+
+ return 0;
+}
+
+static const struct spi_device_id ad7124_id_table[] = {
+ { "ad7124-4", ID_AD7124_4 },
+ { "ad7124-8", ID_AD7124_8 },
+ {}
+};
+MODULE_DEVICE_TABLE(spi, ad7124_id_table);
+
+static const struct of_device_id ad7124_of_match[] = {
+ { .compatible = "adi,ad7124-4" },
+ { .compatible = "adi,ad7124-8" },
+ { },
+};
+MODULE_DEVICE_TABLE(of, ad7124_of_match);
+
+static struct spi_driver ad71124_driver = {
+ .driver = {
+ .name = "ad7124",
+ .of_match_table = ad7124_of_match,
+ },
+ .probe = ad7124_probe,
+ .remove = ad7124_remove,
+ .id_table = ad7124_id_table,
+};
+module_spi_driver(ad71124_driver);
+
+MODULE_AUTHOR("Stefan Popa <stefan.popa@analog.com>");
+MODULE_DESCRIPTION("Analog Devices AD7124 SPI driver");
+MODULE_LICENSE("GPL");
projects / openwrt / staging / blogic.git / commitdiff