| // SPDX-License-Identifier: GPL-2.0-or-later |
| /* |
| * mcp4922.c |
| * |
| * Driver for Microchip Digital to Analog Converters. |
| * Supports MCP4902, MCP4912, and MCP4922. |
| * |
| * Copyright (c) 2014 EMAC Inc. |
| */ |
| |
| #include <linux/module.h> |
| #include <linux/init.h> |
| #include <linux/spi/spi.h> |
| #include <linux/iio/iio.h> |
| #include <linux/iio/sysfs.h> |
| #include <linux/regulator/consumer.h> |
| #include <linux/bitops.h> |
| |
| #define MCP4922_NUM_CHANNELS 2 |
| |
| enum mcp4922_supported_device_ids { |
| ID_MCP4902, |
| ID_MCP4912, |
| ID_MCP4922, |
| }; |
| |
| struct mcp4922_state { |
| struct spi_device *spi; |
| unsigned int value[MCP4922_NUM_CHANNELS]; |
| unsigned int vref_mv; |
| struct regulator *vref_reg; |
| u8 mosi[2] ____cacheline_aligned; |
| }; |
| |
| #define MCP4922_CHAN(chan, bits) { \ |
| .type = IIO_VOLTAGE, \ |
| .output = 1, \ |
| .indexed = 1, \ |
| .channel = chan, \ |
| .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \ |
| .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \ |
| .scan_type = { \ |
| .sign = 'u', \ |
| .realbits = (bits), \ |
| .storagebits = 16, \ |
| .shift = 12 - (bits), \ |
| }, \ |
| } |
| |
| static int mcp4922_spi_write(struct mcp4922_state *state, u8 addr, u32 val) |
| { |
| state->mosi[1] = val & 0xff; |
| state->mosi[0] = (addr == 0) ? 0x00 : 0x80; |
| state->mosi[0] |= 0x30 | ((val >> 8) & 0x0f); |
| |
| return spi_write(state->spi, state->mosi, 2); |
| } |
| |
| static int mcp4922_read_raw(struct iio_dev *indio_dev, |
| struct iio_chan_spec const *chan, |
| int *val, |
| int *val2, |
| long mask) |
| { |
| struct mcp4922_state *state = iio_priv(indio_dev); |
| |
| switch (mask) { |
| case IIO_CHAN_INFO_RAW: |
| *val = state->value[chan->channel]; |
| return IIO_VAL_INT; |
| case IIO_CHAN_INFO_SCALE: |
| *val = state->vref_mv; |
| *val2 = chan->scan_type.realbits; |
| return IIO_VAL_FRACTIONAL_LOG2; |
| default: |
| return -EINVAL; |
| } |
| } |
| |
| static int mcp4922_write_raw(struct iio_dev *indio_dev, |
| struct iio_chan_spec const *chan, |
| int val, |
| int val2, |
| long mask) |
| { |
| struct mcp4922_state *state = iio_priv(indio_dev); |
| int ret; |
| |
| if (val2 != 0) |
| return -EINVAL; |
| |
| switch (mask) { |
| case IIO_CHAN_INFO_RAW: |
| if (val < 0 || val > GENMASK(chan->scan_type.realbits - 1, 0)) |
| return -EINVAL; |
| val <<= chan->scan_type.shift; |
| |
| ret = mcp4922_spi_write(state, chan->channel, val); |
| if (!ret) |
| state->value[chan->channel] = val; |
| return ret; |
| |
| default: |
| return -EINVAL; |
| } |
| } |
| |
| static const struct iio_chan_spec mcp4922_channels[3][MCP4922_NUM_CHANNELS] = { |
| [ID_MCP4902] = { MCP4922_CHAN(0, 8), MCP4922_CHAN(1, 8) }, |
| [ID_MCP4912] = { MCP4922_CHAN(0, 10), MCP4922_CHAN(1, 10) }, |
| [ID_MCP4922] = { MCP4922_CHAN(0, 12), MCP4922_CHAN(1, 12) }, |
| }; |
| |
| static const struct iio_info mcp4922_info = { |
| .read_raw = &mcp4922_read_raw, |
| .write_raw = &mcp4922_write_raw, |
| }; |
| |
| static int mcp4922_probe(struct spi_device *spi) |
| { |
| struct iio_dev *indio_dev; |
| struct mcp4922_state *state; |
| const struct spi_device_id *id; |
| int ret; |
| |
| indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*state)); |
| if (indio_dev == NULL) |
| return -ENOMEM; |
| |
| state = iio_priv(indio_dev); |
| state->spi = spi; |
| state->vref_reg = devm_regulator_get(&spi->dev, "vref"); |
| if (IS_ERR(state->vref_reg)) { |
| dev_err(&spi->dev, "Vref regulator not specified\n"); |
| return PTR_ERR(state->vref_reg); |
| } |
| |
| ret = regulator_enable(state->vref_reg); |
| if (ret) { |
| dev_err(&spi->dev, "Failed to enable vref regulator: %d\n", |
| ret); |
| return ret; |
| } |
| |
| ret = regulator_get_voltage(state->vref_reg); |
| if (ret < 0) { |
| dev_err(&spi->dev, "Failed to read vref regulator: %d\n", |
| ret); |
| goto error_disable_reg; |
| } |
| state->vref_mv = ret / 1000; |
| |
| spi_set_drvdata(spi, indio_dev); |
| id = spi_get_device_id(spi); |
| indio_dev->dev.parent = &spi->dev; |
| indio_dev->info = &mcp4922_info; |
| indio_dev->modes = INDIO_DIRECT_MODE; |
| indio_dev->channels = mcp4922_channels[id->driver_data]; |
| indio_dev->num_channels = MCP4922_NUM_CHANNELS; |
| indio_dev->name = id->name; |
| |
| ret = iio_device_register(indio_dev); |
| if (ret) { |
| dev_err(&spi->dev, "Failed to register iio device: %d\n", |
| ret); |
| goto error_disable_reg; |
| } |
| |
| return 0; |
| |
| error_disable_reg: |
| regulator_disable(state->vref_reg); |
| |
| return ret; |
| } |
| |
| static int mcp4922_remove(struct spi_device *spi) |
| { |
| struct iio_dev *indio_dev = spi_get_drvdata(spi); |
| struct mcp4922_state *state; |
| |
| iio_device_unregister(indio_dev); |
| state = iio_priv(indio_dev); |
| regulator_disable(state->vref_reg); |
| |
| return 0; |
| } |
| |
| static const struct spi_device_id mcp4922_id[] = { |
| {"mcp4902", ID_MCP4902}, |
| {"mcp4912", ID_MCP4912}, |
| {"mcp4922", ID_MCP4922}, |
| {} |
| }; |
| MODULE_DEVICE_TABLE(spi, mcp4922_id); |
| |
| static struct spi_driver mcp4922_driver = { |
| .driver = { |
| .name = "mcp4922", |
| }, |
| .probe = mcp4922_probe, |
| .remove = mcp4922_remove, |
| .id_table = mcp4922_id, |
| }; |
| module_spi_driver(mcp4922_driver); |
| |
| MODULE_AUTHOR("Michael Welling <mwelling@ieee.org>"); |
| MODULE_DESCRIPTION("Microchip MCP4902, MCP4912, MCP4922 DAC"); |
| MODULE_LICENSE("GPL v2"); |