| // SPDX-License-Identifier: GPL-2.0-only |
| /* |
| * AD7303 Digital to analog converters driver |
| * |
| * Copyright 2013 Analog Devices Inc. |
| */ |
| |
| #include <linux/err.h> |
| #include <linux/module.h> |
| #include <linux/mod_devicetable.h> |
| #include <linux/kernel.h> |
| #include <linux/spi/spi.h> |
| #include <linux/slab.h> |
| #include <linux/sysfs.h> |
| #include <linux/regulator/consumer.h> |
| |
| #include <linux/iio/iio.h> |
| #include <linux/iio/sysfs.h> |
| |
| #define AD7303_CFG_EXTERNAL_VREF BIT(15) |
| #define AD7303_CFG_POWER_DOWN(ch) BIT(11 + (ch)) |
| #define AD7303_CFG_ADDR_OFFSET 10 |
| |
| #define AD7303_CMD_UPDATE_DAC (0x3 << 8) |
| |
| /** |
| * struct ad7303_state - driver instance specific data |
| * @spi: the device for this driver instance |
| * @config: cached config register value |
| * @dac_cache: current DAC raw value (chip does not support readback) |
| * @vdd_reg: reference to VDD regulator |
| * @vref_reg: reference to VREF regulator |
| * @lock: protect writes and cache updates |
| * @data: spi transfer buffer |
| */ |
| |
| struct ad7303_state { |
| struct spi_device *spi; |
| uint16_t config; |
| uint8_t dac_cache[2]; |
| |
| struct regulator *vdd_reg; |
| struct regulator *vref_reg; |
| |
| struct mutex lock; |
| /* |
| * DMA (thus cache coherency maintenance) requires the |
| * transfer buffers to live in their own cache lines. |
| */ |
| __be16 data ____cacheline_aligned; |
| }; |
| |
| static int ad7303_write(struct ad7303_state *st, unsigned int chan, |
| uint8_t val) |
| { |
| st->data = cpu_to_be16(AD7303_CMD_UPDATE_DAC | |
| (chan << AD7303_CFG_ADDR_OFFSET) | |
| st->config | val); |
| |
| return spi_write(st->spi, &st->data, sizeof(st->data)); |
| } |
| |
| static ssize_t ad7303_read_dac_powerdown(struct iio_dev *indio_dev, |
| uintptr_t private, const struct iio_chan_spec *chan, char *buf) |
| { |
| struct ad7303_state *st = iio_priv(indio_dev); |
| |
| return sysfs_emit(buf, "%d\n", (bool)(st->config & |
| AD7303_CFG_POWER_DOWN(chan->channel))); |
| } |
| |
| static ssize_t ad7303_write_dac_powerdown(struct iio_dev *indio_dev, |
| uintptr_t private, const struct iio_chan_spec *chan, const char *buf, |
| size_t len) |
| { |
| struct ad7303_state *st = iio_priv(indio_dev); |
| bool pwr_down; |
| int ret; |
| |
| ret = strtobool(buf, &pwr_down); |
| if (ret) |
| return ret; |
| |
| mutex_lock(&st->lock); |
| |
| if (pwr_down) |
| st->config |= AD7303_CFG_POWER_DOWN(chan->channel); |
| else |
| st->config &= ~AD7303_CFG_POWER_DOWN(chan->channel); |
| |
| /* There is no noop cmd which allows us to only update the powerdown |
| * mode, so just write one of the DAC channels again */ |
| ad7303_write(st, chan->channel, st->dac_cache[chan->channel]); |
| |
| mutex_unlock(&st->lock); |
| return len; |
| } |
| |
| static int ad7303_get_vref(struct ad7303_state *st, |
| struct iio_chan_spec const *chan) |
| { |
| int ret; |
| |
| if (st->config & AD7303_CFG_EXTERNAL_VREF) |
| return regulator_get_voltage(st->vref_reg); |
| |
| ret = regulator_get_voltage(st->vdd_reg); |
| if (ret < 0) |
| return ret; |
| return ret / 2; |
| } |
| |
| static int ad7303_read_raw(struct iio_dev *indio_dev, |
| struct iio_chan_spec const *chan, int *val, int *val2, long info) |
| { |
| struct ad7303_state *st = iio_priv(indio_dev); |
| int vref_uv; |
| |
| switch (info) { |
| case IIO_CHAN_INFO_RAW: |
| mutex_lock(&st->lock); |
| *val = st->dac_cache[chan->channel]; |
| mutex_unlock(&st->lock); |
| return IIO_VAL_INT; |
| case IIO_CHAN_INFO_SCALE: |
| vref_uv = ad7303_get_vref(st, chan); |
| if (vref_uv < 0) |
| return vref_uv; |
| |
| *val = 2 * vref_uv / 1000; |
| *val2 = chan->scan_type.realbits; |
| |
| return IIO_VAL_FRACTIONAL_LOG2; |
| default: |
| break; |
| } |
| return -EINVAL; |
| } |
| |
| static int ad7303_write_raw(struct iio_dev *indio_dev, |
| struct iio_chan_spec const *chan, int val, int val2, long mask) |
| { |
| struct ad7303_state *st = iio_priv(indio_dev); |
| int ret; |
| |
| switch (mask) { |
| case IIO_CHAN_INFO_RAW: |
| if (val >= (1 << chan->scan_type.realbits) || val < 0) |
| return -EINVAL; |
| |
| mutex_lock(&st->lock); |
| ret = ad7303_write(st, chan->address, val); |
| if (ret == 0) |
| st->dac_cache[chan->channel] = val; |
| mutex_unlock(&st->lock); |
| break; |
| default: |
| ret = -EINVAL; |
| } |
| |
| return ret; |
| } |
| |
| static const struct iio_info ad7303_info = { |
| .read_raw = ad7303_read_raw, |
| .write_raw = ad7303_write_raw, |
| }; |
| |
| static const struct iio_chan_spec_ext_info ad7303_ext_info[] = { |
| { |
| .name = "powerdown", |
| .read = ad7303_read_dac_powerdown, |
| .write = ad7303_write_dac_powerdown, |
| .shared = IIO_SEPARATE, |
| }, |
| { }, |
| }; |
| |
| #define AD7303_CHANNEL(chan) { \ |
| .type = IIO_VOLTAGE, \ |
| .indexed = 1, \ |
| .output = 1, \ |
| .channel = (chan), \ |
| .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \ |
| .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \ |
| .address = (chan), \ |
| .scan_type = { \ |
| .sign = 'u', \ |
| .realbits = 8, \ |
| .storagebits = 8, \ |
| .shift = 0, \ |
| }, \ |
| .ext_info = ad7303_ext_info, \ |
| } |
| |
| static const struct iio_chan_spec ad7303_channels[] = { |
| AD7303_CHANNEL(0), |
| AD7303_CHANNEL(1), |
| }; |
| |
| static void ad7303_reg_disable(void *reg) |
| { |
| regulator_disable(reg); |
| } |
| |
| static int ad7303_probe(struct spi_device *spi) |
| { |
| const struct spi_device_id *id = spi_get_device_id(spi); |
| struct iio_dev *indio_dev; |
| struct ad7303_state *st; |
| int ret; |
| |
| indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st)); |
| if (indio_dev == NULL) |
| return -ENOMEM; |
| |
| st = iio_priv(indio_dev); |
| |
| st->spi = spi; |
| |
| mutex_init(&st->lock); |
| |
| st->vdd_reg = devm_regulator_get(&spi->dev, "Vdd"); |
| if (IS_ERR(st->vdd_reg)) |
| return PTR_ERR(st->vdd_reg); |
| |
| ret = regulator_enable(st->vdd_reg); |
| if (ret) |
| return ret; |
| |
| ret = devm_add_action_or_reset(&spi->dev, ad7303_reg_disable, st->vdd_reg); |
| if (ret) |
| return ret; |
| |
| st->vref_reg = devm_regulator_get_optional(&spi->dev, "REF"); |
| if (IS_ERR(st->vref_reg)) { |
| ret = PTR_ERR(st->vref_reg); |
| if (ret != -ENODEV) |
| return ret; |
| st->vref_reg = NULL; |
| } |
| |
| if (st->vref_reg) { |
| ret = regulator_enable(st->vref_reg); |
| if (ret) |
| return ret; |
| |
| ret = devm_add_action_or_reset(&spi->dev, ad7303_reg_disable, |
| st->vref_reg); |
| if (ret) |
| return ret; |
| |
| st->config |= AD7303_CFG_EXTERNAL_VREF; |
| } |
| |
| indio_dev->name = id->name; |
| indio_dev->info = &ad7303_info; |
| indio_dev->modes = INDIO_DIRECT_MODE; |
| indio_dev->channels = ad7303_channels; |
| indio_dev->num_channels = ARRAY_SIZE(ad7303_channels); |
| |
| return devm_iio_device_register(&spi->dev, indio_dev); |
| } |
| |
| static const struct of_device_id ad7303_spi_of_match[] = { |
| { .compatible = "adi,ad7303", }, |
| { /* sentinel */ }, |
| }; |
| MODULE_DEVICE_TABLE(of, ad7303_spi_of_match); |
| |
| static const struct spi_device_id ad7303_spi_ids[] = { |
| { "ad7303", 0 }, |
| {} |
| }; |
| MODULE_DEVICE_TABLE(spi, ad7303_spi_ids); |
| |
| static struct spi_driver ad7303_driver = { |
| .driver = { |
| .name = "ad7303", |
| .of_match_table = ad7303_spi_of_match, |
| }, |
| .probe = ad7303_probe, |
| .id_table = ad7303_spi_ids, |
| }; |
| module_spi_driver(ad7303_driver); |
| |
| MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>"); |
| MODULE_DESCRIPTION("Analog Devices AD7303 DAC driver"); |
| MODULE_LICENSE("GPL v2"); |