1// SPDX-License-Identifier: GPL-2.0-or-later 2/* 3 * mcp4922.c 4 * 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 2 20#define MCP4921_NUM_CHANNELS 1 21 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 struct regulator *vref_reg; 34 u8 mosi[2] __aligned(IIO_DMA_MINALIGN); 35}; 36 37#define MCP4922_CHAN(chan, bits) { \ 38 .type = IIO_VOLTAGE, \ 39 .output = 1, \ 40 .indexed = 1, \ 41 .channel = chan, \ 42 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \ 43 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \ 44 .scan_type = { \ 45 .sign = 'u', \ 46 .realbits = (bits), \ 47 .storagebits = 16, \ 48 .shift = 12 - (bits), \ 49 }, \ 50} 51 52static int mcp4922_spi_write(struct mcp4922_state *state, u8 addr, u32 val) 53{ 54 state->mosi[1] = val & 0xff; 55 state->mosi[0] = (addr == 0) ? 0x00 : 0x80; 56 state->mosi[0] |= 0x30 | ((val >> 8) & 0x0f); 57 58 return spi_write(state->spi, state->mosi, 2); 59} 60 61static int mcp4922_read_raw(struct iio_dev *indio_dev, 62 struct iio_chan_spec const *chan, 63 int *val, 64 int *val2, 65 long mask) 66{ 67 struct mcp4922_state *state = iio_priv(indio_dev); 68 69 switch (mask) { 70 case IIO_CHAN_INFO_RAW: 71 *val = state->value[chan->channel]; 72 return IIO_VAL_INT; 73 case IIO_CHAN_INFO_SCALE: 74 *val = state->vref_mv; 75 *val2 = chan->scan_type.realbits; 76 return IIO_VAL_FRACTIONAL_LOG2; 77 default: 78 return -EINVAL; 79 } 80} 81 82static int mcp4922_write_raw(struct iio_dev *indio_dev, 83 struct iio_chan_spec const *chan, 84 int val, 85 int val2, 86 long mask) 87{ 88 struct mcp4922_state *state = iio_priv(indio_dev); 89 int ret; 90 91 if (val2 != 0) 92 return -EINVAL; 93 94 switch (mask) { 95 case IIO_CHAN_INFO_RAW: 96 if (val < 0 || val > GENMASK(chan->scan_type.realbits - 1, 0)) 97 return -EINVAL; 98 val <<= chan->scan_type.shift; 99 100 ret = mcp4922_spi_write(state, chan->channel, val); 101 if (!ret) 102 state->value[chan->channel] = val; 103 return ret; 104 105 default: 106 return -EINVAL; 107 } 108} 109 110static const struct iio_chan_spec mcp4922_channels[4][MCP4922_NUM_CHANNELS] = { 111 [ID_MCP4902] = { MCP4922_CHAN(0, 8), MCP4922_CHAN(1, 8) }, 112 [ID_MCP4912] = { MCP4922_CHAN(0, 10), MCP4922_CHAN(1, 10) }, 113 [ID_MCP4921] = { MCP4922_CHAN(0, 12), {} }, 114 [ID_MCP4922] = { MCP4922_CHAN(0, 12), MCP4922_CHAN(1, 12) }, 115}; 116 117static const struct iio_info mcp4922_info = { 118 .read_raw = &mcp4922_read_raw, 119 .write_raw = &mcp4922_write_raw, 120}; 121 122static int mcp4922_probe(struct spi_device *spi) 123{ 124 struct iio_dev *indio_dev; 125 struct mcp4922_state *state; 126 const struct spi_device_id *id; 127 int ret; 128 129 indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*state)); 130 if (indio_dev == NULL) 131 return -ENOMEM; 132 133 state = iio_priv(indio_dev); 134 state->spi = spi; 135 state->vref_reg = devm_regulator_get(&spi->dev, "vref"); 136 if (IS_ERR(state->vref_reg)) 137 return dev_err_probe(&spi->dev, PTR_ERR(state->vref_reg), 138 "Vref regulator not specified\n"); 139 140 ret = regulator_enable(state->vref_reg); 141 if (ret) { 142 dev_err(&spi->dev, "Failed to enable vref regulator: %d\n", 143 ret); 144 return ret; 145 } 146 147 ret = regulator_get_voltage(state->vref_reg); 148 if (ret < 0) { 149 dev_err(&spi->dev, "Failed to read vref regulator: %d\n", 150 ret); 151 goto error_disable_reg; 152 } 153 state->vref_mv = ret / 1000; 154 155 spi_set_drvdata(spi, indio_dev); 156 id = spi_get_device_id(spi); 157 indio_dev->info = &mcp4922_info; 158 indio_dev->modes = INDIO_DIRECT_MODE; 159 indio_dev->channels = mcp4922_channels[id->driver_data]; 160 if (id->driver_data == ID_MCP4921) 161 indio_dev->num_channels = MCP4921_NUM_CHANNELS; 162 else 163 indio_dev->num_channels = MCP4922_NUM_CHANNELS; 164 indio_dev->name = id->name; 165 166 ret = iio_device_register(indio_dev); 167 if (ret) { 168 dev_err(&spi->dev, "Failed to register iio device: %d\n", 169 ret); 170 goto error_disable_reg; 171 } 172 173 return 0; 174 175error_disable_reg: 176 regulator_disable(state->vref_reg); 177 178 return ret; 179} 180 181static void mcp4922_remove(struct spi_device *spi) 182{ 183 struct iio_dev *indio_dev = spi_get_drvdata(spi); 184 struct mcp4922_state *state; 185 186 iio_device_unregister(indio_dev); 187 state = iio_priv(indio_dev); 188 regulator_disable(state->vref_reg); 189} 190 191static const struct spi_device_id mcp4922_id[] = { 192 {"mcp4902", ID_MCP4902}, 193 {"mcp4912", ID_MCP4912}, 194 {"mcp4921", ID_MCP4921}, 195 {"mcp4922", ID_MCP4922}, 196 {} 197}; 198MODULE_DEVICE_TABLE(spi, mcp4922_id); 199 200static struct spi_driver mcp4922_driver = { 201 .driver = { 202 .name = "mcp4922", 203 }, 204 .probe = mcp4922_probe, 205 .remove = mcp4922_remove, 206 .id_table = mcp4922_id, 207}; 208module_spi_driver(mcp4922_driver); 209 210MODULE_AUTHOR("Michael Welling <mwelling@ieee.org>"); 211MODULE_DESCRIPTION("Microchip MCP4902, MCP4912, MCP4922 DAC"); 212MODULE_LICENSE("GPL v2"); 213