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