diff options
Diffstat (limited to 'drivers/iio/adc/ad7124.c')
| -rw-r--r-- | drivers/iio/adc/ad7124.c | 684 |
1 files changed, 684 insertions, 0 deletions
diff --git a/drivers/iio/adc/ad7124.c b/drivers/iio/adc/ad7124.c new file mode 100644 index 000000000000..7d5e5311d8de --- /dev/null +++ b/drivers/iio/adc/ad7124.c @@ -0,0 +1,684 @@ +// 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"); |