diff options
Diffstat (limited to 'drivers/iio/adc/ad7091r-base.c')
| -rw-r--r-- | drivers/iio/adc/ad7091r-base.c | 297 |
1 files changed, 297 insertions, 0 deletions
diff --git a/drivers/iio/adc/ad7091r-base.c b/drivers/iio/adc/ad7091r-base.c new file mode 100644 index 000000000..811f04448 --- /dev/null +++ b/drivers/iio/adc/ad7091r-base.c @@ -0,0 +1,297 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * AD7091RX Analog to Digital converter driver + * + * Copyright 2014-2019 Analog Devices Inc. + */ + +#include <linux/bitops.h> +#include <linux/iio/events.h> +#include <linux/iio/iio.h> +#include <linux/interrupt.h> +#include <linux/module.h> +#include <linux/regmap.h> +#include <linux/regulator/consumer.h> + +#include "ad7091r-base.h" + +#define AD7091R_REG_RESULT 0 +#define AD7091R_REG_CHANNEL 1 +#define AD7091R_REG_CONF 2 +#define AD7091R_REG_ALERT 3 +#define AD7091R_REG_CH_LOW_LIMIT(ch) ((ch) * 3 + 4) +#define AD7091R_REG_CH_HIGH_LIMIT(ch) ((ch) * 3 + 5) +#define AD7091R_REG_CH_HYSTERESIS(ch) ((ch) * 3 + 6) + +/* AD7091R_REG_RESULT */ +#define AD7091R_REG_RESULT_CH_ID(x) (((x) >> 13) & 0x3) +#define AD7091R_REG_RESULT_CONV_RESULT(x) ((x) & 0xfff) + +/* AD7091R_REG_CONF */ +#define AD7091R_REG_CONF_AUTO BIT(8) +#define AD7091R_REG_CONF_CMD BIT(10) + +#define AD7091R_REG_CONF_MODE_MASK \ + (AD7091R_REG_CONF_AUTO | AD7091R_REG_CONF_CMD) + +enum ad7091r_mode { + AD7091R_MODE_SAMPLE, + AD7091R_MODE_COMMAND, + AD7091R_MODE_AUTOCYCLE, +}; + +struct ad7091r_state { + struct device *dev; + struct regmap *map; + struct regulator *vref; + const struct ad7091r_chip_info *chip_info; + enum ad7091r_mode mode; + struct mutex lock; /*lock to prevent concurent reads */ +}; + +static int ad7091r_set_mode(struct ad7091r_state *st, enum ad7091r_mode mode) +{ + int ret, conf; + + switch (mode) { + case AD7091R_MODE_SAMPLE: + conf = 0; + break; + case AD7091R_MODE_COMMAND: + conf = AD7091R_REG_CONF_CMD; + break; + case AD7091R_MODE_AUTOCYCLE: + conf = AD7091R_REG_CONF_AUTO; + break; + default: + return -EINVAL; + } + + ret = regmap_update_bits(st->map, AD7091R_REG_CONF, + AD7091R_REG_CONF_MODE_MASK, conf); + if (ret) + return ret; + + st->mode = mode; + + return 0; +} + +static int ad7091r_set_channel(struct ad7091r_state *st, unsigned int channel) +{ + unsigned int dummy; + int ret; + + /* AD7091R_REG_CHANNEL specified which channels to be converted */ + ret = regmap_write(st->map, AD7091R_REG_CHANNEL, + BIT(channel) | (BIT(channel) << 8)); + if (ret) + return ret; + + /* + * There is a latency of one conversion before the channel conversion + * sequence is updated + */ + return regmap_read(st->map, AD7091R_REG_RESULT, &dummy); +} + +static int ad7091r_read_one(struct iio_dev *iio_dev, + unsigned int channel, unsigned int *read_val) +{ + struct ad7091r_state *st = iio_priv(iio_dev); + unsigned int val; + int ret; + + ret = ad7091r_set_channel(st, channel); + if (ret) + return ret; + + ret = regmap_read(st->map, AD7091R_REG_RESULT, &val); + if (ret) + return ret; + + if (AD7091R_REG_RESULT_CH_ID(val) != channel) + return -EIO; + + *read_val = AD7091R_REG_RESULT_CONV_RESULT(val); + + return 0; +} + +static int ad7091r_read_raw(struct iio_dev *iio_dev, + struct iio_chan_spec const *chan, + int *val, int *val2, long m) +{ + struct ad7091r_state *st = iio_priv(iio_dev); + unsigned int read_val; + int ret; + + mutex_lock(&st->lock); + + switch (m) { + case IIO_CHAN_INFO_RAW: + if (st->mode != AD7091R_MODE_COMMAND) { + ret = -EBUSY; + goto unlock; + } + + ret = ad7091r_read_one(iio_dev, chan->channel, &read_val); + if (ret) + goto unlock; + + *val = read_val; + ret = IIO_VAL_INT; + break; + + case IIO_CHAN_INFO_SCALE: + if (st->vref) { + ret = regulator_get_voltage(st->vref); + if (ret < 0) + goto unlock; + + *val = ret / 1000; + } else { + *val = st->chip_info->vref_mV; + } + + *val2 = chan->scan_type.realbits; + ret = IIO_VAL_FRACTIONAL_LOG2; + break; + + default: + ret = -EINVAL; + break; + } + +unlock: + mutex_unlock(&st->lock); + return ret; +} + +static const struct iio_info ad7091r_info = { + .read_raw = ad7091r_read_raw, +}; + +static irqreturn_t ad7091r_event_handler(int irq, void *private) +{ + struct iio_dev *iio_dev = private; + struct ad7091r_state *st = iio_priv(iio_dev); + unsigned int i, read_val; + int ret; + s64 timestamp = iio_get_time_ns(iio_dev); + + ret = regmap_read(st->map, AD7091R_REG_ALERT, &read_val); + if (ret) + return IRQ_HANDLED; + + for (i = 0; i < st->chip_info->num_channels; i++) { + if (read_val & BIT(i * 2)) + iio_push_event(iio_dev, + IIO_UNMOD_EVENT_CODE(IIO_VOLTAGE, i, + IIO_EV_TYPE_THRESH, + IIO_EV_DIR_RISING), timestamp); + if (read_val & BIT(i * 2 + 1)) + iio_push_event(iio_dev, + IIO_UNMOD_EVENT_CODE(IIO_VOLTAGE, i, + IIO_EV_TYPE_THRESH, + IIO_EV_DIR_FALLING), timestamp); + } + + return IRQ_HANDLED; +} + +static void ad7091r_remove(void *data) +{ + struct ad7091r_state *st = data; + + regulator_disable(st->vref); +} + +int ad7091r_probe(struct device *dev, const char *name, + const struct ad7091r_chip_info *chip_info, + struct regmap *map, int irq) +{ + struct iio_dev *iio_dev; + struct ad7091r_state *st; + int ret; + + iio_dev = devm_iio_device_alloc(dev, sizeof(*st)); + if (!iio_dev) + return -ENOMEM; + + st = iio_priv(iio_dev); + st->dev = dev; + st->chip_info = chip_info; + st->map = map; + + iio_dev->name = name; + iio_dev->info = &ad7091r_info; + iio_dev->modes = INDIO_DIRECT_MODE; + + iio_dev->num_channels = chip_info->num_channels; + iio_dev->channels = chip_info->channels; + + if (irq) { + ret = devm_request_threaded_irq(dev, irq, NULL, + ad7091r_event_handler, + IRQF_TRIGGER_FALLING | IRQF_ONESHOT, name, iio_dev); + if (ret) + return ret; + } + + st->vref = devm_regulator_get_optional(dev, "vref"); + if (IS_ERR(st->vref)) { + if (PTR_ERR(st->vref) == -EPROBE_DEFER) + return -EPROBE_DEFER; + st->vref = NULL; + } else { + ret = regulator_enable(st->vref); + if (ret) + return ret; + ret = devm_add_action_or_reset(dev, ad7091r_remove, st); + if (ret) + return ret; + } + + /* Use command mode by default to convert only desired channels*/ + ret = ad7091r_set_mode(st, AD7091R_MODE_COMMAND); + if (ret) + return ret; + + return devm_iio_device_register(dev, iio_dev); +} +EXPORT_SYMBOL_GPL(ad7091r_probe); + +static bool ad7091r_writeable_reg(struct device *dev, unsigned int reg) +{ + switch (reg) { + case AD7091R_REG_RESULT: + case AD7091R_REG_ALERT: + return false; + default: + return true; + } +} + +static bool ad7091r_volatile_reg(struct device *dev, unsigned int reg) +{ + switch (reg) { + case AD7091R_REG_RESULT: + case AD7091R_REG_ALERT: + return true; + default: + return false; + } +} + +const struct regmap_config ad7091r_regmap_config = { + .reg_bits = 8, + .val_bits = 16, + .writeable_reg = ad7091r_writeable_reg, + .volatile_reg = ad7091r_volatile_reg, +}; +EXPORT_SYMBOL_GPL(ad7091r_regmap_config); + +MODULE_AUTHOR("Beniamin Bia <beniamin.bia@analog.com>"); +MODULE_DESCRIPTION("Analog Devices AD7091Rx multi-channel converters"); +MODULE_LICENSE("GPL v2"); |