diff options
Diffstat (limited to 'drivers/iio/adc/ad7291.c')
| -rw-r--r-- | drivers/iio/adc/ad7291.c | 589 |
1 files changed, 589 insertions, 0 deletions
diff --git a/drivers/iio/adc/ad7291.c b/drivers/iio/adc/ad7291.c new file mode 100644 index 000000000..2301a0e27 --- /dev/null +++ b/drivers/iio/adc/ad7291.c @@ -0,0 +1,589 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * AD7291 8-Channel, I2C, 12-Bit SAR ADC with Temperature Sensor + * + * Copyright 2010-2011 Analog Devices Inc. + */ + +#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> + +/* + * 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(indio_dev); + + 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, +}; + +static int ad7291_probe(struct i2c_client *client, + const struct i2c_device_id *id) +{ + 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); + + 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 */ + + chip->reg = devm_regulator_get_optional(&client->dev, "vref"); + if (IS_ERR(chip->reg)) { + if (PTR_ERR(chip->reg) != -ENODEV) + return PTR_ERR(chip->reg); + + chip->reg = NULL; + } + + if (chip->reg) { + ret = regulator_enable(chip->reg); + if (ret) + return ret; + + 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->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 const struct of_device_id ad7291_of_match[] = { + { .compatible = "adi,ad7291" }, + {} +}; +MODULE_DEVICE_TABLE(of, ad7291_of_match); + +static struct i2c_driver ad7291_driver = { + .driver = { + .name = KBUILD_MODNAME, + .of_match_table = ad7291_of_match, + }, + .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"); |