217 строки
5.2 KiB
C
217 строки
5.2 KiB
C
/*
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* mcp4922.c
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*
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* Driver for Microchip Digital to Analog Converters.
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* Supports MCP4902, MCP4912, and MCP4922.
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*
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* Copyright (c) 2014 EMAC Inc.
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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 as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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*/
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#include <linux/module.h>
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#include <linux/init.h>
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#include <linux/spi/spi.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/regulator/consumer.h>
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#include <linux/bitops.h>
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#define MCP4922_NUM_CHANNELS 2
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enum mcp4922_supported_device_ids {
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ID_MCP4902,
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ID_MCP4912,
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ID_MCP4922,
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};
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struct mcp4922_state {
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struct spi_device *spi;
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unsigned int value[MCP4922_NUM_CHANNELS];
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unsigned int vref_mv;
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struct regulator *vref_reg;
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u8 mosi[2] ____cacheline_aligned;
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};
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#define MCP4922_CHAN(chan, bits) { \
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.type = IIO_VOLTAGE, \
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.output = 1, \
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.indexed = 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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.scan_type = { \
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.sign = 'u', \
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.realbits = (bits), \
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.storagebits = 16, \
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.shift = 12 - (bits), \
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}, \
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}
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static int mcp4922_spi_write(struct mcp4922_state *state, u8 addr, u32 val)
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{
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state->mosi[1] = val & 0xff;
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state->mosi[0] = (addr == 0) ? 0x00 : 0x80;
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state->mosi[0] |= 0x30 | ((val >> 8) & 0x0f);
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return spi_write(state->spi, state->mosi, 2);
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}
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static int mcp4922_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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struct mcp4922_state *state = iio_priv(indio_dev);
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switch (mask) {
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case IIO_CHAN_INFO_RAW:
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*val = state->value[chan->channel];
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return IIO_VAL_INT;
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case IIO_CHAN_INFO_SCALE:
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*val = state->vref_mv;
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*val2 = chan->scan_type.realbits;
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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 mcp4922_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 mcp4922_state *state = iio_priv(indio_dev);
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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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if (val > GENMASK(chan->scan_type.realbits-1, 0))
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return -EINVAL;
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val <<= chan->scan_type.shift;
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state->value[chan->channel] = val;
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return mcp4922_spi_write(state, chan->channel, val);
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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_chan_spec mcp4922_channels[3][MCP4922_NUM_CHANNELS] = {
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[ID_MCP4902] = { MCP4922_CHAN(0, 8), MCP4922_CHAN(1, 8) },
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[ID_MCP4912] = { MCP4922_CHAN(0, 10), MCP4922_CHAN(1, 10) },
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[ID_MCP4922] = { MCP4922_CHAN(0, 12), MCP4922_CHAN(1, 12) },
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};
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static const struct iio_info mcp4922_info = {
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.read_raw = &mcp4922_read_raw,
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.write_raw = &mcp4922_write_raw,
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.driver_module = THIS_MODULE,
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};
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static int mcp4922_probe(struct spi_device *spi)
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{
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struct iio_dev *indio_dev;
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struct mcp4922_state *state;
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const struct spi_device_id *id;
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int ret;
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indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*state));
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if (indio_dev == NULL)
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return -ENOMEM;
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state = iio_priv(indio_dev);
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state->spi = spi;
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state->vref_reg = devm_regulator_get(&spi->dev, "vref");
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if (IS_ERR(state->vref_reg)) {
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dev_err(&spi->dev, "Vref regulator not specified\n");
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return PTR_ERR(state->vref_reg);
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}
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ret = regulator_enable(state->vref_reg);
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if (ret) {
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dev_err(&spi->dev, "Failed to enable vref regulator: %d\n",
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ret);
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return ret;
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}
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ret = regulator_get_voltage(state->vref_reg);
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if (ret < 0) {
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dev_err(&spi->dev, "Failed to read vref regulator: %d\n",
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ret);
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goto error_disable_reg;
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}
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state->vref_mv = ret / 1000;
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spi_set_drvdata(spi, indio_dev);
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id = spi_get_device_id(spi);
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indio_dev->dev.parent = &spi->dev;
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indio_dev->info = &mcp4922_info;
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indio_dev->modes = INDIO_DIRECT_MODE;
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indio_dev->channels = mcp4922_channels[id->driver_data];
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indio_dev->num_channels = MCP4922_NUM_CHANNELS;
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indio_dev->name = id->name;
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ret = iio_device_register(indio_dev);
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if (ret) {
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dev_err(&spi->dev, "Failed to register iio device: %d\n",
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ret);
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goto error_disable_reg;
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}
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return 0;
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error_disable_reg:
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regulator_disable(state->vref_reg);
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return ret;
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}
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static int mcp4922_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 mcp4922_state *state;
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iio_device_unregister(indio_dev);
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state = iio_priv(indio_dev);
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regulator_disable(state->vref_reg);
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return 0;
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}
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static const struct spi_device_id mcp4922_id[] = {
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{"mcp4902", ID_MCP4902},
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{"mcp4912", ID_MCP4912},
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{"mcp4922", ID_MCP4922},
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{}
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};
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MODULE_DEVICE_TABLE(spi, mcp4922_id);
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static struct spi_driver mcp4922_driver = {
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.driver = {
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.name = "mcp4922",
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.owner = THIS_MODULE,
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},
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.probe = mcp4922_probe,
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.remove = mcp4922_remove,
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.id_table = mcp4922_id,
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};
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module_spi_driver(mcp4922_driver);
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MODULE_AUTHOR("Michael Welling <mwelling@ieee.org>");
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MODULE_DESCRIPTION("Microchip MCP4902, MCP4912, MCP4922 DAC");
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MODULE_LICENSE("GPL v2");
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