/* * 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");