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iio: dac: driver for MCP4821
Adds driver for the MCP48xx series of DACs.
Device uses a simplex SPI channel. To set the value of an output channel,
a 16-bit data of following format must be written:
Bit field | Description
15 [MSB] | Channel selection bit
0 -> Channel A
1 -> Channel B
13 | Output Gain Selection bit
0 -> 2x Gain (Vref = 4.096V)
1 -> 1x Gain (Vref = 2.048V)
12 | Output Shutdown Control bit
0 -> Shutdown the selected channel
1 -> Active mode operation
11-0 [LSB]| DAC Input Data bits
Value's big endian representation is taken as input for the
selected DAC channel. For devices with a resolution of less
than 12-bits, only the x most significant bits are considered
where x is the resolution of the device.
Reference: Page#22 [MCP48x2 Datasheet]
Supported devices:
+---------+--------------+-------------+
| Device | Resolution | Channels |
|---------|--------------|-------------|
| MCP4801 | 8-bit | 1 |
| MCP4802 | 8-bit | 2 |
| MCP4811 | 10-bit | 1 |
| MCP4812 | 10-bit | 2 |
| MCP4821 | 12-bit | 1 |
| MCP4822 | 12-bit | 2 |
+---------+--------------+-------------+
Devices tested:
MCP4821 [12-bit single channel]
MCP4802 [8-bit dual channel]
Tested on Raspberry Pi Zero 2W
Datasheet: https://ww1.microchip.com/downloads/en/DeviceDoc/22244B.pdf #MCP48x1
Datasheet: https://ww1.microchip.com/downloads/en/DeviceDoc/20002249B.pdf #MCP48x2
Signed-off-by: Anshul Dalal <anshulusr@gmail.com>
Link: https://lore.kernel.org/r/20231220151954.154595-2-anshulusr@gmail.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
This commit is contained in:
Anshul Dalal
Jonathan Cameron
parent
6b626eee66
commit
cdf3ecb0d8
@ -13174,6 +13174,13 @@ F: Documentation/ABI/testing/sysfs-bus-iio-potentiometer-mcp4531
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F: drivers/iio/potentiometer/mcp4018.c
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F: drivers/iio/potentiometer/mcp4531.c
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MCP4821 DAC DRIVER
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M: Anshul Dalal <anshulusr@gmail.com>
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L: linux-iio@vger.kernel.org
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S: Maintained
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F: Documentation/devicetree/bindings/iio/dac/microchip,mcp4821.yaml
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F: drivers/iio/dac/mcp4821.c
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MCR20A IEEE-802.15.4 RADIO DRIVER
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M: Stefan Schmidt <stefan@datenfreihafen.org>
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L: linux-wpan@vger.kernel.org
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@ -400,6 +400,16 @@ config MCP4728
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To compile this driver as a module, choose M here: the module
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will be called mcp4728.
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config MCP4821
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tristate "MCP4801/02/11/12/21/22 DAC driver"
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depends on SPI
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help
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Say yes here to build the driver for the Microchip MCP4801
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MCP4802, MCP4811, MCP4812, MCP4821 and MCP4822 DAC devices.
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To compile this driver as a module, choose M here: the module
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will be called mcp4821.
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config MCP4922
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tristate "MCP4902, MCP4912, MCP4922 DAC driver"
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depends on SPI
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@ -42,6 +42,7 @@ obj-$(CONFIG_MAX5522) += max5522.o
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obj-$(CONFIG_MAX5821) += max5821.o
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obj-$(CONFIG_MCP4725) += mcp4725.o
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obj-$(CONFIG_MCP4728) += mcp4728.o
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obj-$(CONFIG_MCP4821) += mcp4821.o
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obj-$(CONFIG_MCP4922) += mcp4922.o
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obj-$(CONFIG_STM32_DAC_CORE) += stm32-dac-core.o
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obj-$(CONFIG_STM32_DAC) += stm32-dac.o
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236
drivers/iio/dac/mcp4821.c
Normal file
236
drivers/iio/dac/mcp4821.c
Normal file
@ -0,0 +1,236 @@
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// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* Copyright (C) 2023 Anshul Dalal <anshulusr@gmail.com>
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*
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* Driver for Microchip MCP4801, MCP4802, MCP4811, MCP4812, MCP4821 and MCP4822
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*
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* Based on the work of:
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* Michael Welling (MCP4922 Driver)
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*
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* Datasheet:
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* MCP48x1: https://ww1.microchip.com/downloads/en/DeviceDoc/22244B.pdf
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* MCP48x2: https://ww1.microchip.com/downloads/en/DeviceDoc/20002249B.pdf
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*
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* TODO:
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* - Configurable gain
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* - Regulator control
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*/
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#include <linux/module.h>
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#include <linux/of.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/types.h>
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#include <asm/unaligned.h>
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#define MCP4821_ACTIVE_MODE BIT(12)
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#define MCP4802_SECOND_CHAN BIT(15)
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/* DAC uses an internal Voltage reference of 4.096V at a gain of 2x */
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#define MCP4821_2X_GAIN_VREF_MV 4096
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enum mcp4821_supported_drvice_ids {
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ID_MCP4801,
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ID_MCP4802,
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ID_MCP4811,
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ID_MCP4812,
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ID_MCP4821,
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ID_MCP4822,
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};
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struct mcp4821_state {
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struct spi_device *spi;
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u16 dac_value[2];
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};
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struct mcp4821_chip_info {
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const char *name;
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int num_channels;
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const struct iio_chan_spec channels[2];
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};
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#define MCP4821_CHAN(channel_id, resolution) \
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{ \
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.type = IIO_VOLTAGE, .output = 1, .indexed = 1, \
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.channel = (channel_id), \
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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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.realbits = (resolution), \
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.shift = 12 - (resolution), \
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}, \
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}
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static const struct mcp4821_chip_info mcp4821_chip_info_table[6] = {
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[ID_MCP4801] = {
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.name = "mcp4801",
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.num_channels = 1,
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.channels = {
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MCP4821_CHAN(0, 8),
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},
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},
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[ID_MCP4802] = {
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.name = "mcp4802",
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.num_channels = 2,
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.channels = {
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MCP4821_CHAN(0, 8),
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MCP4821_CHAN(1, 8),
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},
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},
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[ID_MCP4811] = {
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.name = "mcp4811",
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.num_channels = 1,
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.channels = {
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MCP4821_CHAN(0, 10),
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},
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},
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[ID_MCP4812] = {
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.name = "mcp4812",
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.num_channels = 2,
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.channels = {
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MCP4821_CHAN(0, 10),
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MCP4821_CHAN(1, 10),
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},
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},
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[ID_MCP4821] = {
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.name = "mcp4821",
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.num_channels = 1,
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.channels = {
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MCP4821_CHAN(0, 12),
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},
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},
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[ID_MCP4822] = {
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.name = "mcp4822",
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.num_channels = 2,
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.channels = {
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MCP4821_CHAN(0, 12),
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MCP4821_CHAN(1, 12),
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},
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},
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};
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static int mcp4821_read_raw(struct iio_dev *indio_dev,
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struct iio_chan_spec const *chan, int *val,
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int *val2, long mask)
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{
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struct mcp4821_state *state;
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switch (mask) {
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case IIO_CHAN_INFO_RAW:
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state = iio_priv(indio_dev);
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*val = state->dac_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 = MCP4821_2X_GAIN_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 mcp4821_write_raw(struct iio_dev *indio_dev,
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struct iio_chan_spec const *chan, int val,
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int val2, long mask)
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{
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struct mcp4821_state *state = iio_priv(indio_dev);
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u16 write_val;
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__be16 write_buffer;
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int ret;
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if (val2 != 0)
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return -EINVAL;
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if (val < 0 || val >= BIT(chan->scan_type.realbits))
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return -EINVAL;
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if (mask != IIO_CHAN_INFO_RAW)
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return -EINVAL;
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write_val = MCP4821_ACTIVE_MODE | val << chan->scan_type.shift;
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if (chan->channel)
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write_val |= MCP4802_SECOND_CHAN;
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write_buffer = cpu_to_be16(write_val);
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ret = spi_write(state->spi, &write_buffer, sizeof(write_buffer));
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if (ret) {
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dev_err(&state->spi->dev, "Failed to write to device: %d", ret);
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return ret;
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}
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state->dac_value[chan->channel] = val;
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return 0;
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}
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static const struct iio_info mcp4821_info = {
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.read_raw = &mcp4821_read_raw,
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.write_raw = &mcp4821_write_raw,
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};
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static int mcp4821_probe(struct spi_device *spi)
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{
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struct iio_dev *indio_dev;
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struct mcp4821_state *state;
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const struct mcp4821_chip_info *info;
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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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info = spi_get_device_match_data(spi);
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indio_dev->name = info->name;
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indio_dev->info = &mcp4821_info;
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indio_dev->modes = INDIO_DIRECT_MODE;
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indio_dev->channels = info->channels;
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indio_dev->num_channels = info->num_channels;
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return devm_iio_device_register(&spi->dev, indio_dev);
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}
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#define MCP4821_COMPATIBLE(of_compatible, id) \
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{ \
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.compatible = of_compatible, \
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.data = &mcp4821_chip_info_table[id] \
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}
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static const struct of_device_id mcp4821_of_table[] = {
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MCP4821_COMPATIBLE("microchip,mcp4801", ID_MCP4801),
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MCP4821_COMPATIBLE("microchip,mcp4802", ID_MCP4802),
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MCP4821_COMPATIBLE("microchip,mcp4811", ID_MCP4811),
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MCP4821_COMPATIBLE("microchip,mcp4812", ID_MCP4812),
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MCP4821_COMPATIBLE("microchip,mcp4821", ID_MCP4821),
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MCP4821_COMPATIBLE("microchip,mcp4822", ID_MCP4822),
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{ /* Sentinel */ }
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};
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MODULE_DEVICE_TABLE(of, mcp4821_of_table);
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static const struct spi_device_id mcp4821_id_table[] = {
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{ "mcp4801", (kernel_ulong_t)&mcp4821_chip_info_table[ID_MCP4801]},
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{ "mcp4802", (kernel_ulong_t)&mcp4821_chip_info_table[ID_MCP4802]},
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{ "mcp4811", (kernel_ulong_t)&mcp4821_chip_info_table[ID_MCP4811]},
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{ "mcp4812", (kernel_ulong_t)&mcp4821_chip_info_table[ID_MCP4812]},
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{ "mcp4821", (kernel_ulong_t)&mcp4821_chip_info_table[ID_MCP4821]},
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{ "mcp4822", (kernel_ulong_t)&mcp4821_chip_info_table[ID_MCP4822]},
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{ /* Sentinel */ }
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};
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MODULE_DEVICE_TABLE(spi, mcp4821_id_table);
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static struct spi_driver mcp4821_driver = {
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.driver = {
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.name = "mcp4821",
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.of_match_table = mcp4821_of_table,
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},
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.probe = mcp4821_probe,
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.id_table = mcp4821_id_table,
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};
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module_spi_driver(mcp4821_driver);
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MODULE_AUTHOR("Anshul Dalal <anshulusr@gmail.com>");
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MODULE_DESCRIPTION("Microchip MCP4821 DAC Driver");
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MODULE_LICENSE("GPL");
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