405 lines
9.3 KiB
C
405 lines
9.3 KiB
C
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/*
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* iio/dac/max5821.c
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* Copyright (C) 2014 Philippe Reynes
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/i2c.h>
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#include <linux/iio/iio.h>
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#include <linux/regulator/consumer.h>
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#define MAX5821_MAX_DAC_CHANNELS 2
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/* command bytes */
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#define MAX5821_LOAD_DAC_A_IN_REG_B 0x00
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#define MAX5821_LOAD_DAC_B_IN_REG_A 0x10
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#define MAX5821_EXTENDED_COMMAND_MODE 0xf0
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#define MAX5821_READ_DAC_A_COMMAND 0xf1
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#define MAX5821_READ_DAC_B_COMMAND 0xf2
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#define MAX5821_EXTENDED_POWER_UP 0x00
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#define MAX5821_EXTENDED_POWER_DOWN_MODE0 0x01
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#define MAX5821_EXTENDED_POWER_DOWN_MODE1 0x02
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#define MAX5821_EXTENDED_POWER_DOWN_MODE2 0x03
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#define MAX5821_EXTENDED_DAC_A 0x04
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#define MAX5821_EXTENDED_DAC_B 0x08
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enum max5821_device_ids {
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ID_MAX5821,
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};
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struct max5821_data {
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struct i2c_client *client;
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struct regulator *vref_reg;
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unsigned short vref_mv;
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bool powerdown[MAX5821_MAX_DAC_CHANNELS];
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u8 powerdown_mode[MAX5821_MAX_DAC_CHANNELS];
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struct mutex lock;
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};
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static const char * const max5821_powerdown_modes[] = {
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"three_state",
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"1kohm_to_gnd",
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"100kohm_to_gnd",
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};
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enum {
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MAX5821_THREE_STATE,
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MAX5821_1KOHM_TO_GND,
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MAX5821_100KOHM_TO_GND
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};
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static int max5821_get_powerdown_mode(struct iio_dev *indio_dev,
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const struct iio_chan_spec *chan)
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{
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struct max5821_data *st = iio_priv(indio_dev);
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return st->powerdown_mode[chan->channel];
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}
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static int max5821_set_powerdown_mode(struct iio_dev *indio_dev,
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const struct iio_chan_spec *chan,
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unsigned int mode)
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{
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struct max5821_data *st = iio_priv(indio_dev);
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st->powerdown_mode[chan->channel] = mode;
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return 0;
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}
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static const struct iio_enum max5821_powerdown_mode_enum = {
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.items = max5821_powerdown_modes,
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.num_items = ARRAY_SIZE(max5821_powerdown_modes),
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.get = max5821_get_powerdown_mode,
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.set = max5821_set_powerdown_mode,
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};
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static ssize_t max5821_read_dac_powerdown(struct iio_dev *indio_dev,
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uintptr_t private,
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const struct iio_chan_spec *chan,
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char *buf)
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{
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struct max5821_data *st = iio_priv(indio_dev);
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return sprintf(buf, "%d\n", st->powerdown[chan->channel]);
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}
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static int max5821_sync_powerdown_mode(struct max5821_data *data,
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const struct iio_chan_spec *chan)
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{
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u8 outbuf[2];
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outbuf[0] = MAX5821_EXTENDED_COMMAND_MODE;
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if (chan->channel == 0)
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outbuf[1] = MAX5821_EXTENDED_DAC_A;
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else
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outbuf[1] = MAX5821_EXTENDED_DAC_B;
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if (data->powerdown[chan->channel])
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outbuf[1] |= data->powerdown_mode[chan->channel] + 1;
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else
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outbuf[1] |= MAX5821_EXTENDED_POWER_UP;
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return i2c_master_send(data->client, outbuf, 2);
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}
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static ssize_t max5821_write_dac_powerdown(struct iio_dev *indio_dev,
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uintptr_t private,
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const struct iio_chan_spec *chan,
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const char *buf, size_t len)
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{
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struct max5821_data *data = iio_priv(indio_dev);
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bool powerdown;
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int ret;
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ret = strtobool(buf, &powerdown);
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if (ret)
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return ret;
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data->powerdown[chan->channel] = powerdown;
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ret = max5821_sync_powerdown_mode(data, chan);
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if (ret < 0)
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return ret;
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return len;
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}
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static const struct iio_chan_spec_ext_info max5821_ext_info[] = {
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{
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.name = "powerdown",
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.read = max5821_read_dac_powerdown,
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.write = max5821_write_dac_powerdown,
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.shared = IIO_SEPARATE,
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},
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IIO_ENUM("powerdown_mode", IIO_SEPARATE, &max5821_powerdown_mode_enum),
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IIO_ENUM_AVAILABLE("powerdown_mode", &max5821_powerdown_mode_enum),
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{ },
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};
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#define MAX5821_CHANNEL(chan) { \
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.type = IIO_VOLTAGE, \
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.indexed = 1, \
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.output = 1, \
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.channel = (chan), \
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.info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
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.info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SCALE), \
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.ext_info = max5821_ext_info, \
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}
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static const struct iio_chan_spec max5821_channels[] = {
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MAX5821_CHANNEL(0),
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MAX5821_CHANNEL(1)
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};
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static const u8 max5821_read_dac_command[] = {
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MAX5821_READ_DAC_A_COMMAND,
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MAX5821_READ_DAC_B_COMMAND
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};
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static const u8 max5821_load_dac_command[] = {
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MAX5821_LOAD_DAC_A_IN_REG_B,
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MAX5821_LOAD_DAC_B_IN_REG_A
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};
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static int max5821_get_value(struct iio_dev *indio_dev,
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int *val, int channel)
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{
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struct max5821_data *data = iio_priv(indio_dev);
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struct i2c_client *client = data->client;
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u8 outbuf[1];
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u8 inbuf[2];
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int ret;
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if ((channel != 0) && (channel != 1))
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return -EINVAL;
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outbuf[0] = max5821_read_dac_command[channel];
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mutex_lock(&data->lock);
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ret = i2c_master_send(client, outbuf, 1);
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if (ret < 0) {
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mutex_unlock(&data->lock);
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return ret;
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} else if (ret != 1) {
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mutex_unlock(&data->lock);
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return -EIO;
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}
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ret = i2c_master_recv(client, inbuf, 2);
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if (ret < 0) {
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mutex_unlock(&data->lock);
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return ret;
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} else if (ret != 2) {
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mutex_unlock(&data->lock);
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return -EIO;
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}
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mutex_unlock(&data->lock);
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*val = ((inbuf[0] & 0x0f) << 6) | (inbuf[1] >> 2);
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return IIO_VAL_INT;
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}
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static int max5821_set_value(struct iio_dev *indio_dev,
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int val, int channel)
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{
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struct max5821_data *data = iio_priv(indio_dev);
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struct i2c_client *client = data->client;
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u8 outbuf[2];
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int ret;
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if ((val < 0) || (val > 1023))
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return -EINVAL;
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if ((channel != 0) && (channel != 1))
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return -EINVAL;
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outbuf[0] = max5821_load_dac_command[channel];
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outbuf[0] |= val >> 6;
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outbuf[1] = (val & 0x3f) << 2;
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ret = i2c_master_send(client, outbuf, 2);
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if (ret < 0)
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return ret;
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else if (ret != 2)
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return -EIO;
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else
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return 0;
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}
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static int max5821_read_raw(struct iio_dev *indio_dev,
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struct iio_chan_spec const *chan,
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int *val, int *val2, long mask)
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{
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struct max5821_data *data = iio_priv(indio_dev);
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switch (mask) {
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case IIO_CHAN_INFO_RAW:
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return max5821_get_value(indio_dev, val, chan->channel);
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case IIO_CHAN_INFO_SCALE:
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*val = data->vref_mv;
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*val2 = 10;
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return IIO_VAL_FRACTIONAL_LOG2;
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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 max5821_write_raw(struct iio_dev *indio_dev,
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struct iio_chan_spec const *chan,
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int val, int val2, long mask)
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{
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if (val2 != 0)
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return -EINVAL;
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switch (mask) {
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case IIO_CHAN_INFO_RAW:
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return max5821_set_value(indio_dev, val, chan->channel);
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default:
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return -EINVAL;
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}
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}
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#ifdef CONFIG_PM_SLEEP
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static int max5821_suspend(struct device *dev)
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{
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u8 outbuf[2] = { MAX5821_EXTENDED_COMMAND_MODE,
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MAX5821_EXTENDED_DAC_A |
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MAX5821_EXTENDED_DAC_B |
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MAX5821_EXTENDED_POWER_DOWN_MODE2 };
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return i2c_master_send(to_i2c_client(dev), outbuf, 2);
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}
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static int max5821_resume(struct device *dev)
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{
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u8 outbuf[2] = { MAX5821_EXTENDED_COMMAND_MODE,
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MAX5821_EXTENDED_DAC_A |
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MAX5821_EXTENDED_DAC_B |
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MAX5821_EXTENDED_POWER_UP };
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return i2c_master_send(to_i2c_client(dev), outbuf, 2);
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}
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static SIMPLE_DEV_PM_OPS(max5821_pm_ops, max5821_suspend, max5821_resume);
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#define MAX5821_PM_OPS (&max5821_pm_ops)
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#else
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#define MAX5821_PM_OPS NULL
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#endif /* CONFIG_PM_SLEEP */
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static const struct iio_info max5821_info = {
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.read_raw = max5821_read_raw,
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.write_raw = max5821_write_raw,
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.driver_module = THIS_MODULE,
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};
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static int max5821_probe(struct i2c_client *client,
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const struct i2c_device_id *id)
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{
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struct max5821_data *data;
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struct iio_dev *indio_dev;
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u32 tmp;
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int ret;
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indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
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if (!indio_dev)
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return -ENOMEM;
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data = iio_priv(indio_dev);
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i2c_set_clientdata(client, indio_dev);
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data->client = client;
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mutex_init(&data->lock);
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/* max5821 start in powerdown mode 100Kohm to ground */
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for (tmp = 0; tmp < MAX5821_MAX_DAC_CHANNELS; tmp++) {
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data->powerdown[tmp] = true;
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data->powerdown_mode[tmp] = MAX5821_100KOHM_TO_GND;
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}
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data->vref_reg = devm_regulator_get(&client->dev, "vref");
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if (IS_ERR(data->vref_reg)) {
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ret = PTR_ERR(data->vref_reg);
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dev_err(&client->dev,
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"Failed to get vref regulator: %d\n", ret);
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goto error_free_reg;
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}
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ret = regulator_enable(data->vref_reg);
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if (ret) {
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dev_err(&client->dev,
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"Failed to enable vref regulator: %d\n", ret);
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goto error_free_reg;
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}
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ret = regulator_get_voltage(data->vref_reg);
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if (ret < 0) {
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dev_err(&client->dev,
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"Failed to get voltage on regulator: %d\n", ret);
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goto error_disable_reg;
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}
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data->vref_mv = ret / 1000;
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indio_dev->name = id->name;
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indio_dev->dev.parent = &client->dev;
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indio_dev->num_channels = ARRAY_SIZE(max5821_channels);
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indio_dev->channels = max5821_channels;
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indio_dev->modes = INDIO_DIRECT_MODE;
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indio_dev->info = &max5821_info;
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return iio_device_register(indio_dev);
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error_disable_reg:
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regulator_disable(data->vref_reg);
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error_free_reg:
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return ret;
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}
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static int max5821_remove(struct i2c_client *client)
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{
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struct iio_dev *indio_dev = i2c_get_clientdata(client);
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struct max5821_data *data = iio_priv(indio_dev);
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iio_device_unregister(indio_dev);
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regulator_disable(data->vref_reg);
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return 0;
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}
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static const struct i2c_device_id max5821_id[] = {
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{ "max5821", ID_MAX5821 },
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{ }
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};
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MODULE_DEVICE_TABLE(i2c, max5821_id);
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static const struct of_device_id max5821_of_match[] = {
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{ .compatible = "maxim,max5821" },
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{ }
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};
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static struct i2c_driver max5821_driver = {
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.driver = {
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.name = "max5821",
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.pm = MAX5821_PM_OPS,
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},
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.probe = max5821_probe,
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.remove = max5821_remove,
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.id_table = max5821_id,
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};
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module_i2c_driver(max5821_driver);
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MODULE_AUTHOR("Philippe Reynes <tremyfr@yahoo.fr>");
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MODULE_DESCRIPTION("MAX5821 DAC");
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MODULE_LICENSE("GPL v2");
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