--- /dev/null
+/*
+ * AD7291 8-Channel, I2C, 12-Bit SAR ADC with Temperature Sensor
+ *
+ * Copyright 2010-2011 Analog Devices Inc.
+ *
+ * Licensed under the GPL-2 or later.
+ */
+
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/i2c.h>
+#include <linux/interrupt.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/regulator/consumer.h>
+#include <linux/slab.h>
+#include <linux/sysfs.h>
+
+#include <linux/iio/iio.h>
+#include <linux/iio/sysfs.h>
+#include <linux/iio/events.h>
+
+#include <linux/platform_data/ad7291.h>
+
+/*
+ * Simplified handling
+ *
+ * If no events enabled - single polled channel read
+ * If event enabled direct reads disable unless channel
+ * is in the read mask.
+ *
+ * The noise-delayed bit as per datasheet suggestion is always enabled.
+ */
+
+/*
+ * AD7291 registers definition
+ */
+#define AD7291_COMMAND 0x00
+#define AD7291_VOLTAGE 0x01
+#define AD7291_T_SENSE 0x02
+#define AD7291_T_AVERAGE 0x03
+#define AD7291_DATA_HIGH(x) ((x) * 3 + 0x4)
+#define AD7291_DATA_LOW(x) ((x) * 3 + 0x5)
+#define AD7291_HYST(x) ((x) * 3 + 0x6)
+#define AD7291_VOLTAGE_ALERT_STATUS 0x1F
+#define AD7291_T_ALERT_STATUS 0x20
+
+#define AD7291_BITS 12
+#define AD7291_VOLTAGE_LIMIT_COUNT 8
+
+
+/*
+ * AD7291 command
+ */
+#define AD7291_AUTOCYCLE BIT(0)
+#define AD7291_RESET BIT(1)
+#define AD7291_ALERT_CLEAR BIT(2)
+#define AD7291_ALERT_POLARITY BIT(3)
+#define AD7291_EXT_REF BIT(4)
+#define AD7291_NOISE_DELAY BIT(5)
+#define AD7291_T_SENSE_MASK BIT(7)
+#define AD7291_VOLTAGE_MASK GENMASK(15, 8)
+#define AD7291_VOLTAGE_OFFSET 8
+
+/*
+ * AD7291 value masks
+ */
+#define AD7291_VALUE_MASK GENMASK(11, 0)
+
+/*
+ * AD7291 alert register bits
+ */
+#define AD7291_T_LOW BIT(0)
+#define AD7291_T_HIGH BIT(1)
+#define AD7291_T_AVG_LOW BIT(2)
+#define AD7291_T_AVG_HIGH BIT(3)
+#define AD7291_V_LOW(x) BIT((x) * 2)
+#define AD7291_V_HIGH(x) BIT((x) * 2 + 1)
+
+
+struct ad7291_chip_info {
+ struct i2c_client *client;
+ struct regulator *reg;
+ u16 command;
+ u16 c_mask; /* Active voltage channels for events */
+ struct mutex state_lock;
+};
+
+static int ad7291_i2c_read(struct ad7291_chip_info *chip, u8 reg, u16 *data)
+{
+ struct i2c_client *client = chip->client;
+ int ret = 0;
+
+ ret = i2c_smbus_read_word_swapped(client, reg);
+ if (ret < 0) {
+ dev_err(&client->dev, "I2C read error\n");
+ return ret;
+ }
+
+ *data = ret;
+
+ return 0;
+}
+
+static int ad7291_i2c_write(struct ad7291_chip_info *chip, u8 reg, u16 data)
+{
+ return i2c_smbus_write_word_swapped(chip->client, reg, data);
+}
+
+static irqreturn_t ad7291_event_handler(int irq, void *private)
+{
+ struct iio_dev *indio_dev = private;
+ struct ad7291_chip_info *chip = iio_priv(private);
+ u16 t_status, v_status;
+ u16 command;
+ int i;
+ s64 timestamp = iio_get_time_ns();
+
+ if (ad7291_i2c_read(chip, AD7291_T_ALERT_STATUS, &t_status))
+ return IRQ_HANDLED;
+
+ if (ad7291_i2c_read(chip, AD7291_VOLTAGE_ALERT_STATUS, &v_status))
+ return IRQ_HANDLED;
+
+ if (!(t_status || v_status))
+ return IRQ_HANDLED;
+
+ command = chip->command | AD7291_ALERT_CLEAR;
+ ad7291_i2c_write(chip, AD7291_COMMAND, command);
+
+ command = chip->command & ~AD7291_ALERT_CLEAR;
+ ad7291_i2c_write(chip, AD7291_COMMAND, command);
+
+ /* For now treat t_sense and t_sense_average the same */
+ if ((t_status & AD7291_T_LOW) || (t_status & AD7291_T_AVG_LOW))
+ iio_push_event(indio_dev,
+ IIO_UNMOD_EVENT_CODE(IIO_TEMP,
+ 0,
+ IIO_EV_TYPE_THRESH,
+ IIO_EV_DIR_FALLING),
+ timestamp);
+ if ((t_status & AD7291_T_HIGH) || (t_status & AD7291_T_AVG_HIGH))
+ iio_push_event(indio_dev,
+ IIO_UNMOD_EVENT_CODE(IIO_TEMP,
+ 0,
+ IIO_EV_TYPE_THRESH,
+ IIO_EV_DIR_RISING),
+ timestamp);
+
+ for (i = 0; i < AD7291_VOLTAGE_LIMIT_COUNT; i++) {
+ if (v_status & AD7291_V_LOW(i))
+ iio_push_event(indio_dev,
+ IIO_UNMOD_EVENT_CODE(IIO_VOLTAGE,
+ i,
+ IIO_EV_TYPE_THRESH,
+ IIO_EV_DIR_FALLING),
+ timestamp);
+ if (v_status & AD7291_V_HIGH(i))
+ iio_push_event(indio_dev,
+ IIO_UNMOD_EVENT_CODE(IIO_VOLTAGE,
+ i,
+ IIO_EV_TYPE_THRESH,
+ IIO_EV_DIR_RISING),
+ timestamp);
+ }
+
+ return IRQ_HANDLED;
+}
+
+static unsigned int ad7291_threshold_reg(const struct iio_chan_spec *chan,
+ enum iio_event_direction dir,
+ enum iio_event_info info)
+{
+ unsigned int offset;
+
+ switch (chan->type) {
+ case IIO_VOLTAGE:
+ offset = chan->channel;
+ break;
+ case IIO_TEMP:
+ offset = AD7291_VOLTAGE_OFFSET;
+ break;
+ default:
+ return 0;
+ }
+
+ switch (info) {
+ case IIO_EV_INFO_VALUE:
+ if (dir == IIO_EV_DIR_FALLING)
+ return AD7291_DATA_HIGH(offset);
+ else
+ return AD7291_DATA_LOW(offset);
+ case IIO_EV_INFO_HYSTERESIS:
+ return AD7291_HYST(offset);
+ default:
+ break;
+ }
+ return 0;
+}
+
+static int ad7291_read_event_value(struct iio_dev *indio_dev,
+ const struct iio_chan_spec *chan,
+ enum iio_event_type type,
+ enum iio_event_direction dir,
+ enum iio_event_info info,
+ int *val, int *val2)
+{
+ struct ad7291_chip_info *chip = iio_priv(indio_dev);
+ int ret;
+ u16 uval;
+
+ ret = ad7291_i2c_read(chip, ad7291_threshold_reg(chan, dir, info),
+ &uval);
+ if (ret < 0)
+ return ret;
+
+ if (info == IIO_EV_INFO_HYSTERESIS || chan->type == IIO_VOLTAGE)
+ *val = uval & AD7291_VALUE_MASK;
+
+ else
+ *val = sign_extend32(uval, 11);
+
+ return IIO_VAL_INT;
+}
+
+static int ad7291_write_event_value(struct iio_dev *indio_dev,
+ const struct iio_chan_spec *chan,
+ enum iio_event_type type,
+ enum iio_event_direction dir,
+ enum iio_event_info info,
+ int val, int val2)
+{
+ struct ad7291_chip_info *chip = iio_priv(indio_dev);
+
+ if (info == IIO_EV_INFO_HYSTERESIS || chan->type == IIO_VOLTAGE) {
+ if (val > AD7291_VALUE_MASK || val < 0)
+ return -EINVAL;
+ } else {
+ if (val > 2047 || val < -2048)
+ return -EINVAL;
+ }
+
+ return ad7291_i2c_write(chip, ad7291_threshold_reg(chan, dir, info),
+ val);
+}
+
+static int ad7291_read_event_config(struct iio_dev *indio_dev,
+ const struct iio_chan_spec *chan,
+ enum iio_event_type type,
+ enum iio_event_direction dir)
+{
+ struct ad7291_chip_info *chip = iio_priv(indio_dev);
+ /*
+ * To be enabled the channel must simply be on. If any are enabled
+ * we are in continuous sampling mode
+ */
+
+ switch (chan->type) {
+ case IIO_VOLTAGE:
+ return !!(chip->c_mask & BIT(15 - chan->channel));
+ case IIO_TEMP:
+ /* always on */
+ return 1;
+ default:
+ return -EINVAL;
+ }
+
+}
+
+static int ad7291_write_event_config(struct iio_dev *indio_dev,
+ const struct iio_chan_spec *chan,
+ enum iio_event_type type,
+ enum iio_event_direction dir,
+ int state)
+{
+ int ret = 0;
+ struct ad7291_chip_info *chip = iio_priv(indio_dev);
+ unsigned int mask;
+ u16 regval;
+
+ mutex_lock(&chip->state_lock);
+ regval = chip->command;
+ /*
+ * To be enabled the channel must simply be on. If any are enabled
+ * use continuous sampling mode.
+ * Possible to disable temp as well but that makes single read tricky.
+ */
+
+ mask = BIT(15 - chan->channel);
+
+ switch (chan->type) {
+ case IIO_VOLTAGE:
+ if ((!state) && (chip->c_mask & mask))
+ chip->c_mask &= ~mask;
+ else if (state && (!(chip->c_mask & mask)))
+ chip->c_mask |= mask;
+ else
+ break;
+
+ regval &= ~AD7291_AUTOCYCLE;
+ regval |= chip->c_mask;
+ if (chip->c_mask) /* Enable autocycle? */
+ regval |= AD7291_AUTOCYCLE;
+
+ ret = ad7291_i2c_write(chip, AD7291_COMMAND, regval);
+ if (ret < 0)
+ goto error_ret;
+
+ chip->command = regval;
+ break;
+ default:
+ ret = -EINVAL;
+ }
+
+error_ret:
+ mutex_unlock(&chip->state_lock);
+ return ret;
+}
+
+static int ad7291_read_raw(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *chan,
+ int *val,
+ int *val2,
+ long mask)
+{
+ int ret;
+ struct ad7291_chip_info *chip = iio_priv(indio_dev);
+ u16 regval;
+
+ switch (mask) {
+ case IIO_CHAN_INFO_RAW:
+ switch (chan->type) {
+ case IIO_VOLTAGE:
+ mutex_lock(&chip->state_lock);
+ /* If in autocycle mode drop through */
+ if (chip->command & AD7291_AUTOCYCLE) {
+ mutex_unlock(&chip->state_lock);
+ return -EBUSY;
+ }
+ /* Enable this channel alone */
+ regval = chip->command & (~AD7291_VOLTAGE_MASK);
+ regval |= BIT(15 - chan->channel);
+ ret = ad7291_i2c_write(chip, AD7291_COMMAND, regval);
+ if (ret < 0) {
+ mutex_unlock(&chip->state_lock);
+ return ret;
+ }
+ /* Read voltage */
+ ret = i2c_smbus_read_word_swapped(chip->client,
+ AD7291_VOLTAGE);
+ if (ret < 0) {
+ mutex_unlock(&chip->state_lock);
+ return ret;
+ }
+ *val = ret & AD7291_VALUE_MASK;
+ mutex_unlock(&chip->state_lock);
+ return IIO_VAL_INT;
+ case IIO_TEMP:
+ /* Assumes tsense bit of command register always set */
+ ret = i2c_smbus_read_word_swapped(chip->client,
+ AD7291_T_SENSE);
+ if (ret < 0)
+ return ret;
+ *val = sign_extend32(ret, 11);
+ return IIO_VAL_INT;
+ default:
+ return -EINVAL;
+ }
+ case IIO_CHAN_INFO_AVERAGE_RAW:
+ ret = i2c_smbus_read_word_swapped(chip->client,
+ AD7291_T_AVERAGE);
+ if (ret < 0)
+ return ret;
+ *val = sign_extend32(ret, 11);
+ return IIO_VAL_INT;
+ case IIO_CHAN_INFO_SCALE:
+ switch (chan->type) {
+ case IIO_VOLTAGE:
+ if (chip->reg) {
+ int vref;
+
+ vref = regulator_get_voltage(chip->reg);
+ if (vref < 0)
+ return vref;
+ *val = vref / 1000;
+ } else {
+ *val = 2500;
+ }
+ *val2 = AD7291_BITS;
+ return IIO_VAL_FRACTIONAL_LOG2;
+ case IIO_TEMP:
+ /*
+ * One LSB of the ADC corresponds to 0.25 deg C.
+ * The temperature reading is in 12-bit twos
+ * complement format
+ */
+ *val = 250;
+ return IIO_VAL_INT;
+ default:
+ return -EINVAL;
+ }
+ default:
+ return -EINVAL;
+ }
+}
+
+static const struct iio_event_spec ad7291_events[] = {
+ {
+ .type = IIO_EV_TYPE_THRESH,
+ .dir = IIO_EV_DIR_RISING,
+ .mask_separate = BIT(IIO_EV_INFO_VALUE) |
+ BIT(IIO_EV_INFO_ENABLE),
+ }, {
+ .type = IIO_EV_TYPE_THRESH,
+ .dir = IIO_EV_DIR_FALLING,
+ .mask_separate = BIT(IIO_EV_INFO_VALUE) |
+ BIT(IIO_EV_INFO_ENABLE),
+ }, {
+ .type = IIO_EV_TYPE_THRESH,
+ .dir = IIO_EV_DIR_EITHER,
+ .mask_separate = BIT(IIO_EV_INFO_HYSTERESIS),
+ },
+};
+
+#define AD7291_VOLTAGE_CHAN(_chan) \
+{ \
+ .type = IIO_VOLTAGE, \
+ .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
+ .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
+ .indexed = 1, \
+ .channel = _chan, \
+ .event_spec = ad7291_events, \
+ .num_event_specs = ARRAY_SIZE(ad7291_events), \
+}
+
+static const struct iio_chan_spec ad7291_channels[] = {
+ AD7291_VOLTAGE_CHAN(0),
+ AD7291_VOLTAGE_CHAN(1),
+ AD7291_VOLTAGE_CHAN(2),
+ AD7291_VOLTAGE_CHAN(3),
+ AD7291_VOLTAGE_CHAN(4),
+ AD7291_VOLTAGE_CHAN(5),
+ AD7291_VOLTAGE_CHAN(6),
+ AD7291_VOLTAGE_CHAN(7),
+ {
+ .type = IIO_TEMP,
+ .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
+ BIT(IIO_CHAN_INFO_AVERAGE_RAW) |
+ BIT(IIO_CHAN_INFO_SCALE),
+ .indexed = 1,
+ .channel = 0,
+ .event_spec = ad7291_events,
+ .num_event_specs = ARRAY_SIZE(ad7291_events),
+ }
+};
+
+static const struct iio_info ad7291_info = {
+ .read_raw = &ad7291_read_raw,
+ .read_event_config = &ad7291_read_event_config,
+ .write_event_config = &ad7291_write_event_config,
+ .read_event_value = &ad7291_read_event_value,
+ .write_event_value = &ad7291_write_event_value,
+ .driver_module = THIS_MODULE,
+};
+
+static int ad7291_probe(struct i2c_client *client,
+ const struct i2c_device_id *id)
+{
+ struct ad7291_platform_data *pdata = client->dev.platform_data;
+ struct ad7291_chip_info *chip;
+ struct iio_dev *indio_dev;
+ int ret;
+
+ indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*chip));
+ if (!indio_dev)
+ return -ENOMEM;
+ chip = iio_priv(indio_dev);
+
+ if (pdata && pdata->use_external_ref) {
+ chip->reg = devm_regulator_get(&client->dev, "vref");
+ if (IS_ERR(chip->reg))
+ return PTR_ERR(chip->reg);
+
+ ret = regulator_enable(chip->reg);
+ if (ret)
+ return ret;
+ }
+
+ mutex_init(&chip->state_lock);
+ /* this is only used for device removal purposes */
+ i2c_set_clientdata(client, indio_dev);
+
+ chip->client = client;
+
+ chip->command = AD7291_NOISE_DELAY |
+ AD7291_T_SENSE_MASK | /* Tsense always enabled */
+ AD7291_ALERT_POLARITY; /* set irq polarity low level */
+
+ if (pdata && pdata->use_external_ref)
+ chip->command |= AD7291_EXT_REF;
+
+ indio_dev->name = id->name;
+ indio_dev->channels = ad7291_channels;
+ indio_dev->num_channels = ARRAY_SIZE(ad7291_channels);
+
+ indio_dev->dev.parent = &client->dev;
+ indio_dev->info = &ad7291_info;
+ indio_dev->modes = INDIO_DIRECT_MODE;
+
+ ret = ad7291_i2c_write(chip, AD7291_COMMAND, AD7291_RESET);
+ if (ret) {
+ ret = -EIO;
+ goto error_disable_reg;
+ }
+
+ ret = ad7291_i2c_write(chip, AD7291_COMMAND, chip->command);
+ if (ret) {
+ ret = -EIO;
+ goto error_disable_reg;
+ }
+
+ if (client->irq > 0) {
+ ret = request_threaded_irq(client->irq,
+ NULL,
+ &ad7291_event_handler,
+ IRQF_TRIGGER_LOW | IRQF_ONESHOT,
+ id->name,
+ indio_dev);
+ if (ret)
+ goto error_disable_reg;
+ }
+
+ ret = iio_device_register(indio_dev);
+ if (ret)
+ goto error_unreg_irq;
+
+ return 0;
+
+error_unreg_irq:
+ if (client->irq)
+ free_irq(client->irq, indio_dev);
+error_disable_reg:
+ if (chip->reg)
+ regulator_disable(chip->reg);
+
+ return ret;
+}
+
+static int ad7291_remove(struct i2c_client *client)
+{
+ struct iio_dev *indio_dev = i2c_get_clientdata(client);
+ struct ad7291_chip_info *chip = iio_priv(indio_dev);
+
+ iio_device_unregister(indio_dev);
+
+ if (client->irq)
+ free_irq(client->irq, indio_dev);
+
+ if (chip->reg)
+ regulator_disable(chip->reg);
+
+ return 0;
+}
+
+static const struct i2c_device_id ad7291_id[] = {
+ { "ad7291", 0 },
+ {}
+};
+
+MODULE_DEVICE_TABLE(i2c, ad7291_id);
+
+static struct i2c_driver ad7291_driver = {
+ .driver = {
+ .name = KBUILD_MODNAME,
+ },
+ .probe = ad7291_probe,
+ .remove = ad7291_remove,
+ .id_table = ad7291_id,
+};
+module_i2c_driver(ad7291_driver);
+
+MODULE_AUTHOR("Sonic Zhang <sonic.zhang@analog.com>");
+MODULE_DESCRIPTION("Analog Devices AD7291 ADC driver");
+MODULE_LICENSE("GPL v2");
Code Review / kvmfornfv.git / blobdiff