iio: dac: add support for max5522

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@timesys.com>
Link: https://lore.kernel.org/r/20221106165928.223318-1-angelo.dureghello@timesys.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

diff --git a/drivers/iio/dac/Kconfig b/drivers/iio/dac/Kconfig
index e83eb75..d3f90cf 100644 (file)
--- 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 ec3e427..6c74fea 100644 (file)
--- 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 (file)
index 0000000..00ba4e9
--- /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@timesys.com");
+MODULE_DESCRIPTION("MAX5522 DAC driver");
+MODULE_LICENSE("GPL");