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1// SPDX-License-Identifier: GPL-2.0-or-later2/*3 * mcp4922.c4 *5 * Driver for Microchip Digital to Analog Converters.6 * Supports MCP4902, MCP4912, and MCP4922.7 *8 * Copyright (c) 2014 EMAC Inc.9 */10 11#include <linux/module.h>12#include <linux/init.h>13#include <linux/spi/spi.h>14#include <linux/iio/iio.h>15#include <linux/iio/sysfs.h>16#include <linux/regulator/consumer.h>17#include <linux/bitops.h>18 19#define MCP4922_NUM_CHANNELS 220#define MCP4921_NUM_CHANNELS 121 22enum mcp4922_supported_device_ids {23 ID_MCP4902,24 ID_MCP4912,25 ID_MCP4921,26 ID_MCP4922,27};28 29struct mcp4922_state {30 struct spi_device *spi;31 unsigned int value[MCP4922_NUM_CHANNELS];32 unsigned int vref_mv;33 u8 mosi[2] __aligned(IIO_DMA_MINALIGN);34};35 36#define MCP4922_CHAN(chan, bits) { \37 .type = IIO_VOLTAGE, \38 .output = 1, \39 .indexed = 1, \40 .channel = chan, \41 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \42 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \43 .scan_type = { \44 .sign = 'u', \45 .realbits = (bits), \46 .storagebits = 16, \47 .shift = 12 - (bits), \48 }, \49}50 51static int mcp4922_spi_write(struct mcp4922_state *state, u8 addr, u32 val)52{53 state->mosi[1] = val & 0xff;54 state->mosi[0] = (addr == 0) ? 0x00 : 0x80;55 state->mosi[0] |= 0x30 | ((val >> 8) & 0x0f);56 57 return spi_write(state->spi, state->mosi, 2);58}59 60static int mcp4922_read_raw(struct iio_dev *indio_dev,61 struct iio_chan_spec const *chan,62 int *val,63 int *val2,64 long mask)65{66 struct mcp4922_state *state = iio_priv(indio_dev);67 68 switch (mask) {69 case IIO_CHAN_INFO_RAW:70 *val = state->value[chan->channel];71 return IIO_VAL_INT;72 case IIO_CHAN_INFO_SCALE:73 *val = state->vref_mv;74 *val2 = chan->scan_type.realbits;75 return IIO_VAL_FRACTIONAL_LOG2;76 default:77 return -EINVAL;78 }79}80 81static int mcp4922_write_raw(struct iio_dev *indio_dev,82 struct iio_chan_spec const *chan,83 int val,84 int val2,85 long mask)86{87 struct mcp4922_state *state = iio_priv(indio_dev);88 int ret;89 90 if (val2 != 0)91 return -EINVAL;92 93 switch (mask) {94 case IIO_CHAN_INFO_RAW:95 if (val < 0 || val > GENMASK(chan->scan_type.realbits - 1, 0))96 return -EINVAL;97 val <<= chan->scan_type.shift;98 99 ret = mcp4922_spi_write(state, chan->channel, val);100 if (!ret)101 state->value[chan->channel] = val;102 return ret;103 104 default:105 return -EINVAL;106 }107}108 109static const struct iio_chan_spec mcp4922_channels[4][MCP4922_NUM_CHANNELS] = {110 [ID_MCP4902] = { MCP4922_CHAN(0, 8), MCP4922_CHAN(1, 8) },111 [ID_MCP4912] = { MCP4922_CHAN(0, 10), MCP4922_CHAN(1, 10) },112 [ID_MCP4921] = { MCP4922_CHAN(0, 12), {} },113 [ID_MCP4922] = { MCP4922_CHAN(0, 12), MCP4922_CHAN(1, 12) },114};115 116static const struct iio_info mcp4922_info = {117 .read_raw = &mcp4922_read_raw,118 .write_raw = &mcp4922_write_raw,119};120 121static int mcp4922_probe(struct spi_device *spi)122{123 struct iio_dev *indio_dev;124 struct mcp4922_state *state;125 const struct spi_device_id *id;126 int ret;127 128 indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*state));129 if (indio_dev == NULL)130 return -ENOMEM;131 132 state = iio_priv(indio_dev);133 state->spi = spi;134 135 ret = devm_regulator_get_enable_read_voltage(&spi->dev, "vref");136 if (ret < 0)137 return dev_err_probe(&spi->dev, ret, "Failed to get vref voltage\n");138 139 state->vref_mv = ret / 1000;140 141 id = spi_get_device_id(spi);142 indio_dev->info = &mcp4922_info;143 indio_dev->modes = INDIO_DIRECT_MODE;144 indio_dev->channels = mcp4922_channels[id->driver_data];145 if (id->driver_data == ID_MCP4921)146 indio_dev->num_channels = MCP4921_NUM_CHANNELS;147 else148 indio_dev->num_channels = MCP4922_NUM_CHANNELS;149 indio_dev->name = id->name;150 151 ret = devm_iio_device_register(&spi->dev, indio_dev);152 if (ret)153 return dev_err_probe(&spi->dev, ret, "Failed to register iio device\n");154 155 return 0;156}157 158 159static const struct spi_device_id mcp4922_id[] = {160 {"mcp4902", ID_MCP4902},161 {"mcp4912", ID_MCP4912},162 {"mcp4921", ID_MCP4921},163 {"mcp4922", ID_MCP4922},164 {}165};166MODULE_DEVICE_TABLE(spi, mcp4922_id);167 168static struct spi_driver mcp4922_driver = {169 .driver = {170 .name = "mcp4922",171 },172 .probe = mcp4922_probe,173 .id_table = mcp4922_id,174};175module_spi_driver(mcp4922_driver);176 177MODULE_AUTHOR("Michael Welling <mwelling@ieee.org>");178MODULE_DESCRIPTION("Microchip MCP4902, MCP4912, MCP4922 DAC");179MODULE_LICENSE("GPL v2");180