298 lines
6.4 KiB
C
298 lines
6.4 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* AD7091RX Analog to Digital converter driver
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*
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* Copyright 2014-2019 Analog Devices Inc.
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*/
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#include <linux/bitops.h>
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#include <linux/iio/events.h>
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#include <linux/iio/iio.h>
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#include <linux/interrupt.h>
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#include <linux/module.h>
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#include <linux/regmap.h>
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#include <linux/regulator/consumer.h>
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#include "ad7091r-base.h"
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#define AD7091R_REG_RESULT 0
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#define AD7091R_REG_CHANNEL 1
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#define AD7091R_REG_CONF 2
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#define AD7091R_REG_ALERT 3
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#define AD7091R_REG_CH_LOW_LIMIT(ch) ((ch) * 3 + 4)
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#define AD7091R_REG_CH_HIGH_LIMIT(ch) ((ch) * 3 + 5)
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#define AD7091R_REG_CH_HYSTERESIS(ch) ((ch) * 3 + 6)
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/* AD7091R_REG_RESULT */
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#define AD7091R_REG_RESULT_CH_ID(x) (((x) >> 13) & 0x3)
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#define AD7091R_REG_RESULT_CONV_RESULT(x) ((x) & 0xfff)
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/* AD7091R_REG_CONF */
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#define AD7091R_REG_CONF_AUTO BIT(8)
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#define AD7091R_REG_CONF_CMD BIT(10)
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#define AD7091R_REG_CONF_MODE_MASK \
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(AD7091R_REG_CONF_AUTO | AD7091R_REG_CONF_CMD)
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enum ad7091r_mode {
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AD7091R_MODE_SAMPLE,
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AD7091R_MODE_COMMAND,
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AD7091R_MODE_AUTOCYCLE,
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};
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struct ad7091r_state {
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struct device *dev;
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struct regmap *map;
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struct regulator *vref;
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const struct ad7091r_chip_info *chip_info;
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enum ad7091r_mode mode;
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struct mutex lock; /*lock to prevent concurent reads */
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};
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static int ad7091r_set_mode(struct ad7091r_state *st, enum ad7091r_mode mode)
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{
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int ret, conf;
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switch (mode) {
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case AD7091R_MODE_SAMPLE:
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conf = 0;
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break;
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case AD7091R_MODE_COMMAND:
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conf = AD7091R_REG_CONF_CMD;
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break;
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case AD7091R_MODE_AUTOCYCLE:
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conf = AD7091R_REG_CONF_AUTO;
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break;
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default:
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return -EINVAL;
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}
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ret = regmap_update_bits(st->map, AD7091R_REG_CONF,
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AD7091R_REG_CONF_MODE_MASK, conf);
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if (ret)
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return ret;
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st->mode = mode;
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return 0;
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}
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static int ad7091r_set_channel(struct ad7091r_state *st, unsigned int channel)
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{
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unsigned int dummy;
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int ret;
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/* AD7091R_REG_CHANNEL specified which channels to be converted */
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ret = regmap_write(st->map, AD7091R_REG_CHANNEL,
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BIT(channel) | (BIT(channel) << 8));
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if (ret)
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return ret;
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/*
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* There is a latency of one conversion before the channel conversion
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* sequence is updated
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*/
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return regmap_read(st->map, AD7091R_REG_RESULT, &dummy);
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}
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static int ad7091r_read_one(struct iio_dev *iio_dev,
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unsigned int channel, unsigned int *read_val)
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{
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struct ad7091r_state *st = iio_priv(iio_dev);
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unsigned int val;
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int ret;
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ret = ad7091r_set_channel(st, channel);
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if (ret)
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return ret;
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ret = regmap_read(st->map, AD7091R_REG_RESULT, &val);
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if (ret)
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return ret;
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if (AD7091R_REG_RESULT_CH_ID(val) != channel)
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return -EIO;
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*read_val = AD7091R_REG_RESULT_CONV_RESULT(val);
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return 0;
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}
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static int ad7091r_read_raw(struct iio_dev *iio_dev,
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struct iio_chan_spec const *chan,
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int *val, int *val2, long m)
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{
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struct ad7091r_state *st = iio_priv(iio_dev);
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unsigned int read_val;
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int ret;
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mutex_lock(&st->lock);
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switch (m) {
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case IIO_CHAN_INFO_RAW:
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if (st->mode != AD7091R_MODE_COMMAND) {
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ret = -EBUSY;
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goto unlock;
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}
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ret = ad7091r_read_one(iio_dev, chan->channel, &read_val);
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if (ret)
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goto unlock;
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*val = read_val;
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ret = IIO_VAL_INT;
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break;
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case IIO_CHAN_INFO_SCALE:
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if (st->vref) {
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ret = regulator_get_voltage(st->vref);
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if (ret < 0)
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goto unlock;
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*val = ret / 1000;
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} else {
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*val = st->chip_info->vref_mV;
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}
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*val2 = chan->scan_type.realbits;
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ret = IIO_VAL_FRACTIONAL_LOG2;
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break;
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default:
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ret = -EINVAL;
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break;
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}
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unlock:
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mutex_unlock(&st->lock);
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return ret;
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}
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static const struct iio_info ad7091r_info = {
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.read_raw = ad7091r_read_raw,
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};
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static irqreturn_t ad7091r_event_handler(int irq, void *private)
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{
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struct ad7091r_state *st = (struct ad7091r_state *) private;
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struct iio_dev *iio_dev = dev_get_drvdata(st->dev);
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unsigned int i, read_val;
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int ret;
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s64 timestamp = iio_get_time_ns(iio_dev);
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ret = regmap_read(st->map, AD7091R_REG_ALERT, &read_val);
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if (ret)
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return IRQ_HANDLED;
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for (i = 0; i < st->chip_info->num_channels; i++) {
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if (read_val & BIT(i * 2))
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iio_push_event(iio_dev,
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IIO_UNMOD_EVENT_CODE(IIO_VOLTAGE, i,
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IIO_EV_TYPE_THRESH,
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IIO_EV_DIR_RISING), timestamp);
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if (read_val & BIT(i * 2 + 1))
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iio_push_event(iio_dev,
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IIO_UNMOD_EVENT_CODE(IIO_VOLTAGE, i,
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IIO_EV_TYPE_THRESH,
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IIO_EV_DIR_FALLING), timestamp);
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}
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return IRQ_HANDLED;
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}
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static void ad7091r_remove(void *data)
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{
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struct ad7091r_state *st = data;
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regulator_disable(st->vref);
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}
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int ad7091r_probe(struct device *dev, const char *name,
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const struct ad7091r_chip_info *chip_info,
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struct regmap *map, int irq)
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{
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struct iio_dev *iio_dev;
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struct ad7091r_state *st;
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int ret;
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iio_dev = devm_iio_device_alloc(dev, sizeof(*st));
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if (!iio_dev)
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return -ENOMEM;
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st = iio_priv(iio_dev);
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st->dev = dev;
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st->chip_info = chip_info;
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st->map = map;
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iio_dev->name = name;
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iio_dev->info = &ad7091r_info;
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iio_dev->modes = INDIO_DIRECT_MODE;
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iio_dev->num_channels = chip_info->num_channels;
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iio_dev->channels = chip_info->channels;
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if (irq) {
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ret = devm_request_threaded_irq(dev, irq, NULL,
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ad7091r_event_handler,
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IRQF_TRIGGER_FALLING | IRQF_ONESHOT, name, st);
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if (ret)
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return ret;
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}
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st->vref = devm_regulator_get_optional(dev, "vref");
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if (IS_ERR(st->vref)) {
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if (PTR_ERR(st->vref) == -EPROBE_DEFER)
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return -EPROBE_DEFER;
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st->vref = NULL;
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} else {
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ret = regulator_enable(st->vref);
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if (ret)
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return ret;
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ret = devm_add_action_or_reset(dev, ad7091r_remove, st);
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if (ret)
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return ret;
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}
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/* Use command mode by default to convert only desired channels*/
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ret = ad7091r_set_mode(st, AD7091R_MODE_COMMAND);
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if (ret)
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return ret;
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return devm_iio_device_register(dev, iio_dev);
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}
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EXPORT_SYMBOL_NS_GPL(ad7091r_probe, IIO_AD7091R);
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static bool ad7091r_writeable_reg(struct device *dev, unsigned int reg)
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{
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switch (reg) {
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case AD7091R_REG_RESULT:
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case AD7091R_REG_ALERT:
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return false;
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default:
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return true;
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}
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}
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static bool ad7091r_volatile_reg(struct device *dev, unsigned int reg)
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{
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switch (reg) {
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case AD7091R_REG_RESULT:
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case AD7091R_REG_ALERT:
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return true;
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default:
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return false;
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}
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}
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const struct regmap_config ad7091r_regmap_config = {
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.reg_bits = 8,
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.val_bits = 16,
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.writeable_reg = ad7091r_writeable_reg,
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.volatile_reg = ad7091r_volatile_reg,
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};
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EXPORT_SYMBOL_NS_GPL(ad7091r_regmap_config, IIO_AD7091R);
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MODULE_AUTHOR("Beniamin Bia <beniamin.bia@analog.com>");
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MODULE_DESCRIPTION("Analog Devices AD7091Rx multi-channel converters");
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MODULE_LICENSE("GPL v2");
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