On Sun, 6 Nov 2022 17:59:28 +0100
Angelo Dureghello <angelo.dureghello@xxxxxxxxxxx> wrote:
> Add initial support for DAC max5522.
>
> Tested writing DAC A and B with some values,
> from 0 to 1023, measured output voltages, driver works properly.
>
> Additions for max5523/24/25 will follow.
>
> Signed-off-by: Angelo Dureghello <angelo.dureghello@xxxxxxxxxxx>
I've been dozy up to now. This needs a (fairly simple)
device tree binding doc in Documentation/devicetree/bindings/iio/dac/
Make sure to include the device tree binding maintainers on that
and to follow the instructions to test the binding.
Feel free to send as a separate patch but refer back to this one.
I'll hold off applying this just in case it needs any changes
resulting form the binding review.
>
> ---
> Changes for v.2
> - fix commit message
> - Kconfig, fix depends and select
> - Kconfig, fix typo
> - fix include alphabetical order
> - remove sysfs includes
> - fix MAX5522_REG_DATA macro
> - use devm_ as much as possible
> - add regulator_enable
> - remove useless code
> - remove commas after structure initializers and null terminators
> - change to use simplier module_spi_driver
> - get id->name from device info structure
> - regulator voltage read always from read_raw (no cache)
>
> Changes for v.3
> - move signed-off to be before the changelog
> - re-fix include alphabetical order
> - remove vrefin_mv references
> - align function params with opening bracket
> - try to get chip_info from firmware
> - name always read from max5522_chip_info_tbl
> - remove line break before MODULE_DEVICE_TABLE
> ---
> drivers/iio/dac/Kconfig | 13 +++
> drivers/iio/dac/Makefile | 1 +
> drivers/iio/dac/max5522.c | 207 ++++++++++++++++++++++++++++++++++++++
> 3 files changed, 221 insertions(+)
> create mode 100644 drivers/iio/dac/max5522.c
>
> diff --git a/drivers/iio/dac/Kconfig b/drivers/iio/dac/Kconfig
> index 80521bd28d0f..6c49523fe357 100644
> --- a/drivers/iio/dac/Kconfig
> +++ b/drivers/iio/dac/Kconfig
> @@ -357,6 +357,19 @@ config MAX517
> This driver can also be built as a module. If so, the module
> will be called max517.
>
> +config MAX5522
> + tristate "Maxim MAX5522 DAC driver"
> + depends on SPI_MASTER
> + select REGMAP_SPI
> + help
> + Say Y here if you want to build a driver for the Maxim MAX5522.
> +
> + MAX5522 is a dual, ultra-low-power, 10-Bit, voltage-output
> + digital to analog converter (DAC) offering rail-to-rail buffered
> + voltage outputs.
> +
> + If compiled as a module, it will be called max5522.
> +
> config MAX5821
> tristate "Maxim MAX5821 DAC driver"
> depends on I2C
> diff --git a/drivers/iio/dac/Makefile b/drivers/iio/dac/Makefile
> index ec3e42713f00..6c74fea21736 100644
> --- a/drivers/iio/dac/Makefile
> +++ b/drivers/iio/dac/Makefile
> @@ -38,6 +38,7 @@ obj-$(CONFIG_LTC2632) += ltc2632.o
> obj-$(CONFIG_LTC2688) += ltc2688.o
> obj-$(CONFIG_M62332) += m62332.o
> obj-$(CONFIG_MAX517) += max517.o
> +obj-$(CONFIG_MAX5522) += max5522.o
> obj-$(CONFIG_MAX5821) += max5821.o
> obj-$(CONFIG_MCP4725) += mcp4725.o
> obj-$(CONFIG_MCP4922) += mcp4922.o
> diff --git a/drivers/iio/dac/max5522.c b/drivers/iio/dac/max5522.c
> new file mode 100644
> index 000000000000..00ba4e98fb9c
> --- /dev/null
> +++ b/drivers/iio/dac/max5522.c
> @@ -0,0 +1,207 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * Maxim MAX5522
> + * Dual, Ultra-Low-Power 10-Bit, Voltage-Output DACs
> + *
> + * Copyright 2022 Timesys Corp.
> + */
> +
> +#include <linux/device.h>
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/mod_devicetable.h>
> +#include <linux/regmap.h>
> +#include <linux/regulator/consumer.h>
> +#include <linux/slab.h>
> +#include <linux/spi/spi.h>
> +
> +#include <linux/iio/iio.h>
> +
> +#define MAX5522_MAX_ADDR 15
> +#define MAX5522_CTRL_NONE 0
> +#define MAX5522_CTRL_LOAD_IN_A 9
> +#define MAX5522_CTRL_LOAD_IN_B 10
> +
> +#define MAX5522_REG_DATA(x) ((x) + MAX5522_CTRL_LOAD_IN_A)
> +
> +struct max5522_chip_info {
> + const char *name;
> + const struct iio_chan_spec *channels;
> + unsigned int num_channels;
> +};
> +
> +struct max5522_state {
> + struct regmap *regmap;
> + const struct max5522_chip_info *chip_info;
> + unsigned short dac_cache[2];
> + struct regulator *vrefin_reg;
> +};
> +
> +#define MAX5522_CHANNEL(chan) { \
> + .type = IIO_VOLTAGE, \
> + .indexed = 1, \
> + .output = 1, \
> + .channel = chan, \
> + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | \
> + BIT(IIO_CHAN_INFO_SCALE), \
> + .scan_type = { \
> + .sign = 'u', \
> + .realbits = 10, \
> + .storagebits = 16, \
> + .shift = 2, \
> + } \
> +}
> +
> +const struct iio_chan_spec max5522_channels[] = {
> + MAX5522_CHANNEL(0),
> + MAX5522_CHANNEL(1),
> +};
> +
> +enum max5522_type {
> + ID_MAX5522,
> +};
> +
> +static const struct max5522_chip_info max5522_chip_info_tbl[] = {
> + [ID_MAX5522] = {
> + .name = "max5522",
> + .channels = max5522_channels,
> + .num_channels = 2,
> + },
> +};
> +
> +static inline int max5522_info_to_reg(struct iio_chan_spec const *chan)
> +{
> + return MAX5522_REG_DATA(chan->channel);
> +}
> +
> +static int max5522_read_raw(struct iio_dev *indio_dev,
> + struct iio_chan_spec const *chan,
> + int *val, int *val2, long info)
> +{
> + struct max5522_state *state = iio_priv(indio_dev);
> + int ret;
> +
> + switch (info) {
> + case IIO_CHAN_INFO_RAW:
> + *val = state->dac_cache[chan->channel];
> + return IIO_VAL_INT;
> + case IIO_CHAN_INFO_SCALE:
> + ret = regulator_get_voltage(state->vrefin_reg);
> + if (ret < 0)
> + return -EINVAL;
> + *val = ret / 1000;
> + *val2 = 10;
> + return IIO_VAL_FRACTIONAL_LOG2;
> + default:
> + return -EINVAL;
> + }
> +
> + return -EINVAL;
> +}
> +
> +static int max5522_write_raw(struct iio_dev *indio_dev,
> + struct iio_chan_spec const *chan,
> + int val, int val2, long info)
> +{
> + struct max5522_state *state = iio_priv(indio_dev);
> + int rval;
> +
> + if (val > 1023 || val < 0)
> + return -EINVAL;
> +
> + rval = regmap_write(state->regmap, max5522_info_to_reg(chan),
> + val << chan->scan_type.shift);
> + if (rval < 0)
> + return rval;
> +
> + state->dac_cache[chan->channel] = val;
> +
> + return 0;
> +}
> +
> +static const struct iio_info max5522_info = {
> + .read_raw = max5522_read_raw,
> + .write_raw = max5522_write_raw,
> +};
> +
> +static const struct regmap_config max5522_regmap_config = {
> + .reg_bits = 4,
> + .val_bits = 12,
> + .max_register = MAX5522_MAX_ADDR,
> +};
> +
> +static int max5522_spi_probe(struct spi_device *spi)
> +{
> + const struct spi_device_id *id = spi_get_device_id(spi);
> + struct iio_dev *indio_dev;
> + struct max5522_state *state;
> + int ret;
> +
> + indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*state));
> + if (indio_dev == NULL) {
> + dev_err(&spi->dev, "failed to allocate iio device\n");
> + return -ENOMEM;
> + }
> +
> + state = iio_priv(indio_dev);
> + state->chip_info = device_get_match_data(&spi->dev);
> + if (!state->chip_info) {
> + state->chip_info =
> + (struct max5522_chip_info *)(id->driver_data);
> + if (!state->chip_info)
> + return -EINVAL;
> + }
> +
> + state->vrefin_reg = devm_regulator_get(&spi->dev, "vrefin");
> + if (IS_ERR(state->vrefin_reg))
> + return dev_err_probe(&spi->dev, PTR_ERR(state->vrefin_reg),
> + "Vrefin regulator not specified\n");
> +
> + ret = regulator_enable(state->vrefin_reg);
> + if (ret) {
> + return dev_err_probe(&spi->dev, ret,
> + "Failed to enable vref regulators\n");
> + }
> +
> + state->regmap = devm_regmap_init_spi(spi, &max5522_regmap_config);
> +
> + if (IS_ERR(state->regmap))
> + return PTR_ERR(state->regmap);
> +
> + indio_dev->info = &max5522_info;
> + indio_dev->modes = INDIO_DIRECT_MODE;
> + indio_dev->channels = max5522_channels;
> + indio_dev->num_channels = ARRAY_SIZE(max5522_channels);
> + indio_dev->name = max5522_chip_info_tbl[ID_MAX5522].name;
> +
> + return devm_iio_device_register(&spi->dev, indio_dev);
> +}
> +
> +static const struct spi_device_id max5522_ids[] = {
> + { "max5522", (kernel_ulong_t)&max5522_chip_info_tbl[ID_MAX5522] },
> + {}
> +};
> +MODULE_DEVICE_TABLE(spi, max5522_ids);
> +
> +static const struct of_device_id max5522_of_match[] = {
> + {
> + .compatible = "maxim,max5522",
> + .data = &max5522_chip_info_tbl[ID_MAX5522],
> + },
> + {}
> +};
> +MODULE_DEVICE_TABLE(of, max5522_of_match);
> +
> +static struct spi_driver max5522_spi_driver = {
> + .driver = {
> + .name = "max5522",
> + .of_match_table = max5522_of_match,
> + },
> + .probe = max5522_spi_probe,
> + .id_table = max5522_ids,
> +};
> +module_spi_driver(max5522_spi_driver);
> +
> +MODULE_AUTHOR("Angelo Dureghello <angelo.dureghello@xxxxxxxxxxx");
> +MODULE_DESCRIPTION("MAX5522 DAC driver");
> +MODULE_LICENSE("GPL");
