361 lines
9.1 KiB
C
361 lines
9.1 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* LTC2632 Digital to analog convertors spi driver
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*
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* Copyright 2017 Maxime Roussin-Bélanger
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* expanded by Silvan Murer <silvan.murer@gmail.com>
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*/
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#include <linux/device.h>
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#include <linux/spi/spi.h>
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#include <linux/module.h>
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#include <linux/iio/iio.h>
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#include <linux/regulator/consumer.h>
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#define LTC2632_DAC_CHANNELS 2
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#define LTC2632_ADDR_DAC0 0x0
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#define LTC2632_ADDR_DAC1 0x1
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#define LTC2632_CMD_WRITE_INPUT_N 0x0
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#define LTC2632_CMD_UPDATE_DAC_N 0x1
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#define LTC2632_CMD_WRITE_INPUT_N_UPDATE_ALL 0x2
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#define LTC2632_CMD_WRITE_INPUT_N_UPDATE_N 0x3
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#define LTC2632_CMD_POWERDOWN_DAC_N 0x4
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#define LTC2632_CMD_POWERDOWN_CHIP 0x5
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#define LTC2632_CMD_INTERNAL_REFER 0x6
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#define LTC2632_CMD_EXTERNAL_REFER 0x7
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/**
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* struct ltc2632_chip_info - chip specific information
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* @channels: channel spec for the DAC
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* @vref_mv: internal reference voltage
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*/
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struct ltc2632_chip_info {
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const struct iio_chan_spec *channels;
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const int vref_mv;
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};
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/**
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* struct ltc2632_state - driver instance specific data
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* @spi_dev: pointer to the spi_device struct
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* @powerdown_cache_mask used to show current channel powerdown state
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* @vref_mv used reference voltage (internal or external)
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* @vref_reg regulator for the reference voltage
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*/
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struct ltc2632_state {
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struct spi_device *spi_dev;
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unsigned int powerdown_cache_mask;
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int vref_mv;
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struct regulator *vref_reg;
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};
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enum ltc2632_supported_device_ids {
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ID_LTC2632L12,
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ID_LTC2632L10,
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ID_LTC2632L8,
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ID_LTC2632H12,
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ID_LTC2632H10,
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ID_LTC2632H8,
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};
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static int ltc2632_spi_write(struct spi_device *spi,
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u8 cmd, u8 addr, u16 val, u8 shift)
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{
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u32 data;
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u8 msg[3];
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/*
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* The input shift register is 24 bits wide.
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* The next four are the command bits, C3 to C0,
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* followed by the 4-bit DAC address, A3 to A0, and then the
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* 12-, 10-, 8-bit data-word. The data-word comprises the 12-,
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* 10-, 8-bit input code followed by 4, 6, or 8 don't care bits.
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*/
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data = (cmd << 20) | (addr << 16) | (val << shift);
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msg[0] = data >> 16;
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msg[1] = data >> 8;
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msg[2] = data;
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return spi_write(spi, msg, sizeof(msg));
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}
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static int ltc2632_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 m)
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{
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const struct ltc2632_state *st = iio_priv(indio_dev);
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switch (m) {
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case IIO_CHAN_INFO_SCALE:
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*val = st->vref_mv;
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*val2 = chan->scan_type.realbits;
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return IIO_VAL_FRACTIONAL_LOG2;
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}
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return -EINVAL;
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}
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static int ltc2632_write_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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struct ltc2632_state *st = iio_priv(indio_dev);
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switch (mask) {
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case IIO_CHAN_INFO_RAW:
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if (val >= (1 << chan->scan_type.realbits) || val < 0)
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return -EINVAL;
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return ltc2632_spi_write(st->spi_dev,
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LTC2632_CMD_WRITE_INPUT_N_UPDATE_N,
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chan->address, val,
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chan->scan_type.shift);
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default:
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return -EINVAL;
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}
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}
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static ssize_t ltc2632_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 ltc2632_state *st = iio_priv(indio_dev);
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return sprintf(buf, "%d\n",
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!!(st->powerdown_cache_mask & (1 << chan->channel)));
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}
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static ssize_t ltc2632_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,
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size_t len)
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{
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bool pwr_down;
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int ret;
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struct ltc2632_state *st = iio_priv(indio_dev);
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ret = strtobool(buf, &pwr_down);
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if (ret)
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return ret;
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if (pwr_down)
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st->powerdown_cache_mask |= (1 << chan->channel);
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else
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st->powerdown_cache_mask &= ~(1 << chan->channel);
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ret = ltc2632_spi_write(st->spi_dev,
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LTC2632_CMD_POWERDOWN_DAC_N,
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chan->channel, 0, 0);
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return ret ? ret : len;
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}
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static const struct iio_info ltc2632_info = {
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.write_raw = ltc2632_write_raw,
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.read_raw = ltc2632_read_raw,
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};
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static const struct iio_chan_spec_ext_info ltc2632_ext_info[] = {
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{
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.name = "powerdown",
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.read = ltc2632_read_dac_powerdown,
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.write = ltc2632_write_dac_powerdown,
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.shared = IIO_SEPARATE,
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},
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{ },
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};
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#define LTC2632_CHANNEL(_chan, _bits) { \
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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_type = BIT(IIO_CHAN_INFO_SCALE), \
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.address = (_chan), \
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.scan_type = { \
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.realbits = (_bits), \
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.shift = 16 - (_bits), \
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}, \
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.ext_info = ltc2632_ext_info, \
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}
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#define DECLARE_LTC2632_CHANNELS(_name, _bits) \
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const struct iio_chan_spec _name ## _channels[] = { \
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LTC2632_CHANNEL(0, _bits), \
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LTC2632_CHANNEL(1, _bits), \
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}
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static DECLARE_LTC2632_CHANNELS(ltc2632l12, 12);
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static DECLARE_LTC2632_CHANNELS(ltc2632l10, 10);
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static DECLARE_LTC2632_CHANNELS(ltc2632l8, 8);
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static DECLARE_LTC2632_CHANNELS(ltc2632h12, 12);
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static DECLARE_LTC2632_CHANNELS(ltc2632h10, 10);
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static DECLARE_LTC2632_CHANNELS(ltc2632h8, 8);
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static const struct ltc2632_chip_info ltc2632_chip_info_tbl[] = {
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[ID_LTC2632L12] = {
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.channels = ltc2632l12_channels,
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.vref_mv = 2500,
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},
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[ID_LTC2632L10] = {
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.channels = ltc2632l10_channels,
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.vref_mv = 2500,
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},
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[ID_LTC2632L8] = {
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.channels = ltc2632l8_channels,
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.vref_mv = 2500,
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},
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[ID_LTC2632H12] = {
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.channels = ltc2632h12_channels,
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.vref_mv = 4096,
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},
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[ID_LTC2632H10] = {
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.channels = ltc2632h10_channels,
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.vref_mv = 4096,
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},
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[ID_LTC2632H8] = {
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.channels = ltc2632h8_channels,
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.vref_mv = 4096,
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},
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};
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static int ltc2632_probe(struct spi_device *spi)
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{
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struct ltc2632_state *st;
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struct iio_dev *indio_dev;
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struct ltc2632_chip_info *chip_info;
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int ret;
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indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
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if (!indio_dev)
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return -ENOMEM;
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st = iio_priv(indio_dev);
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spi_set_drvdata(spi, indio_dev);
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st->spi_dev = spi;
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chip_info = (struct ltc2632_chip_info *)
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spi_get_device_id(spi)->driver_data;
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st->vref_reg = devm_regulator_get_optional(&spi->dev, "vref");
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if (PTR_ERR(st->vref_reg) == -ENODEV) {
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/* use internal reference voltage */
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st->vref_reg = NULL;
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st->vref_mv = chip_info->vref_mv;
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ret = ltc2632_spi_write(spi, LTC2632_CMD_INTERNAL_REFER,
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0, 0, 0);
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if (ret) {
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dev_err(&spi->dev,
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"Set internal reference command failed, %d\n",
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ret);
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return ret;
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}
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} else if (IS_ERR(st->vref_reg)) {
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dev_err(&spi->dev,
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"Error getting voltage reference regulator\n");
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return PTR_ERR(st->vref_reg);
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} else {
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/* use external reference voltage */
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ret = regulator_enable(st->vref_reg);
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if (ret) {
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dev_err(&spi->dev,
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"enable reference regulator failed, %d\n",
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ret);
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return ret;
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}
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st->vref_mv = regulator_get_voltage(st->vref_reg) / 1000;
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ret = ltc2632_spi_write(spi, LTC2632_CMD_EXTERNAL_REFER,
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0, 0, 0);
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if (ret) {
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dev_err(&spi->dev,
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"Set external reference command failed, %d\n",
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ret);
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return ret;
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}
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}
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indio_dev->dev.parent = &spi->dev;
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indio_dev->name = dev_of_node(&spi->dev) ? dev_of_node(&spi->dev)->name
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: spi_get_device_id(spi)->name;
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indio_dev->info = <c2632_info;
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indio_dev->modes = INDIO_DIRECT_MODE;
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indio_dev->channels = chip_info->channels;
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indio_dev->num_channels = LTC2632_DAC_CHANNELS;
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return iio_device_register(indio_dev);
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}
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static int ltc2632_remove(struct spi_device *spi)
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{
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struct iio_dev *indio_dev = spi_get_drvdata(spi);
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struct ltc2632_state *st = iio_priv(indio_dev);
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iio_device_unregister(indio_dev);
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if (st->vref_reg)
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regulator_disable(st->vref_reg);
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return 0;
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}
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static const struct spi_device_id ltc2632_id[] = {
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{ "ltc2632-l12", (kernel_ulong_t)<c2632_chip_info_tbl[ID_LTC2632L12] },
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{ "ltc2632-l10", (kernel_ulong_t)<c2632_chip_info_tbl[ID_LTC2632L10] },
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{ "ltc2632-l8", (kernel_ulong_t)<c2632_chip_info_tbl[ID_LTC2632L8] },
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{ "ltc2632-h12", (kernel_ulong_t)<c2632_chip_info_tbl[ID_LTC2632H12] },
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{ "ltc2632-h10", (kernel_ulong_t)<c2632_chip_info_tbl[ID_LTC2632H10] },
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{ "ltc2632-h8", (kernel_ulong_t)<c2632_chip_info_tbl[ID_LTC2632H8] },
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{}
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};
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MODULE_DEVICE_TABLE(spi, ltc2632_id);
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static const struct of_device_id ltc2632_of_match[] = {
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{
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.compatible = "lltc,ltc2632-l12",
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.data = <c2632_chip_info_tbl[ID_LTC2632L12]
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}, {
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.compatible = "lltc,ltc2632-l10",
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.data = <c2632_chip_info_tbl[ID_LTC2632L10]
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}, {
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.compatible = "lltc,ltc2632-l8",
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.data = <c2632_chip_info_tbl[ID_LTC2632L8]
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}, {
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.compatible = "lltc,ltc2632-h12",
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.data = <c2632_chip_info_tbl[ID_LTC2632H12]
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}, {
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.compatible = "lltc,ltc2632-h10",
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.data = <c2632_chip_info_tbl[ID_LTC2632H10]
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}, {
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.compatible = "lltc,ltc2632-h8",
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.data = <c2632_chip_info_tbl[ID_LTC2632H8]
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},
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{}
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};
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MODULE_DEVICE_TABLE(of, ltc2632_of_match);
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static struct spi_driver ltc2632_driver = {
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.driver = {
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.name = "ltc2632",
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.of_match_table = of_match_ptr(ltc2632_of_match),
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},
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.probe = ltc2632_probe,
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.remove = ltc2632_remove,
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.id_table = ltc2632_id,
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};
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module_spi_driver(ltc2632_driver);
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MODULE_AUTHOR("Maxime Roussin-Belanger <maxime.roussinbelanger@gmail.com>");
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MODULE_DESCRIPTION("LTC2632 DAC SPI driver");
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MODULE_LICENSE("GPL v2");
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