[PATCH v2 2/2] iio: adc: add max11205 adc driver
From: Ramona Bolboaca
Date: Wed Aug 31 2022 - 09:30:58 EST
Adding support for max11205 16-bit single-channel ultra-low power
delta-sigma adc.
The MAX11205 is compatible with the 2-wire interface and uses
SCLK and RDY/DOUT for serial communications. In this mode, all
controls are implemented by timing the high or low phase of the SCLK.
The 2-wire serial interface only allows for data to be read out through
the RDY/DOUT output.
Datasheet: https://datasheets.maximintegrated.com/en/ds/MAX11205.pdf
Signed-off-by: Ramona Bolboaca <ramona.bolboaca@xxxxxxxxxx>
---
changes in v2:
- add chip_info null pointer check
- add support for probing with ACPI table
- remove function for module removal
- remove irq flag from max11205_sigma_delta_info
- add missing commas and missing spaces
- remove redundant blank line
- wrap text to 75-80 chars
- removed typos in commit message
drivers/iio/adc/Kconfig | 14 +++
drivers/iio/adc/Makefile | 1 +
drivers/iio/adc/max11205.c | 183 +++++++++++++++++++++++++++++++++++++
3 files changed, 198 insertions(+)
create mode 100644 drivers/iio/adc/max11205.c
diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
index 7fe5930891e0..0c8f376b65d8 100644
--- a/drivers/iio/adc/Kconfig
+++ b/drivers/iio/adc/Kconfig
@@ -653,6 +653,20 @@ config MAX1118
To compile this driver as a module, choose M here: the module will be
called max1118.
+config MAX11205
+ tristate "Maxim max11205 ADC driver"
+ depends on SPI
+ select AD_SIGMA_DELTA
+ select IIO_BUFFER
+ select IIO_TRIGGERED_BUFFER
+
+ help
+ Say yes here to build support for Maxim max11205 16-bit, single-channel
+ ultra-low power delta-sigma ADC.
+
+ To compile this driver as a module, choose M here: the module will be
+ called max11205.
+
config MAX1241
tristate "Maxim max1241 ADC driver"
depends on SPI_MASTER
diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile
index 1772a549a3c8..bb681844e497 100644
--- a/drivers/iio/adc/Makefile
+++ b/drivers/iio/adc/Makefile
@@ -61,6 +61,7 @@ obj-$(CONFIG_LTC2497) += ltc2497.o ltc2497-core.o
obj-$(CONFIG_MAX1027) += max1027.o
obj-$(CONFIG_MAX11100) += max11100.o
obj-$(CONFIG_MAX1118) += max1118.o
+obj-$(CONFIG_MAX11205) += max11205.o
obj-$(CONFIG_MAX1241) += max1241.o
obj-$(CONFIG_MAX1363) += max1363.o
obj-$(CONFIG_MAX9611) += max9611.o
diff --git a/drivers/iio/adc/max11205.c b/drivers/iio/adc/max11205.c
new file mode 100644
index 000000000000..68e6082e70e5
--- /dev/null
+++ b/drivers/iio/adc/max11205.c
@@ -0,0 +1,183 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * max11205 16-Bit Delta-Sigma ADC
+ *
+ * Datasheet: https://datasheets.maximintegrated.com/en/ds/MAX1240-max11205.pdf
+ * Copyright (C) 2022 Analog Devices, Inc.
+ * Author: Ramona Bolboaca <ramona.bolboaca@xxxxxxxxxx>
+ */
+
+#include <linux/device.h>
+#include <linux/module.h>
+#include <linux/regulator/consumer.h>
+#include <linux/spi/spi.h>
+
+#include <linux/iio/iio.h>
+#include <linux/iio/adc/ad_sigma_delta.h>
+
+#define MAX11205_BIT_SCALE 15
+#define MAX11205A_OUT_DATA_RATE 116
+#define MAX11205B_OUT_DATA_RATE 13
+
+enum chip_type {
+ TYPE_MAX11205A,
+ TYPE_MAX11205B,
+};
+
+struct chip_info {
+ unsigned int out_data_rate;
+ const char *name;
+};
+
+struct max11205_state {
+ const struct chip_info *chip_info;
+ struct regulator *vref;
+ struct ad_sigma_delta sd;
+};
+
+static const struct ad_sigma_delta_info max11205_sigma_delta_info = {
+ .has_registers = false,
+};
+
+static int max11205_read_raw(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *chan,
+ int *val, int *val2, long mask)
+{
+ struct max11205_state *st = iio_priv(indio_dev);
+ int reg_mv;
+
+ switch (mask) {
+ case IIO_CHAN_INFO_RAW:
+ return ad_sigma_delta_single_conversion(indio_dev, chan, val);
+ case IIO_CHAN_INFO_SCALE:
+ reg_mv = regulator_get_voltage(st->vref);
+ if (reg_mv < 0)
+ return reg_mv;
+ reg_mv /= 1000;
+ *val = reg_mv;
+ *val2 = MAX11205_BIT_SCALE;
+ return IIO_VAL_FRACTIONAL_LOG2;
+ case IIO_CHAN_INFO_SAMP_FREQ:
+ *val = st->chip_info->out_data_rate;
+ return IIO_VAL_INT;
+ default:
+ return -EINVAL;
+ }
+}
+
+static const struct iio_info max11205_iio_info = {
+ .read_raw = max11205_read_raw,
+ .validate_trigger = ad_sd_validate_trigger,
+};
+
+static const struct iio_chan_spec max11205_channels[] = {
+ {
+ .type = IIO_VOLTAGE,
+ .indexed = 1,
+ .scan_type = {
+ .sign = 's',
+ .realbits = 16,
+ .storagebits = 16,
+ .endianness = IIO_BE
+ },
+ .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
+ BIT(IIO_CHAN_INFO_SAMP_FREQ) |
+ BIT(IIO_CHAN_INFO_SCALE),
+ },
+};
+
+static const struct chip_info max11205_chip_info[] = {
+ [TYPE_MAX11205A] = {
+ .out_data_rate = MAX11205A_OUT_DATA_RATE,
+ .name = "max11205a",
+ },
+ [TYPE_MAX11205B] = {
+ .out_data_rate = MAX11205B_OUT_DATA_RATE,
+ .name = "max11205b",
+ },
+};
+
+static void max11205_reg_disable(void *reg)
+{
+ regulator_disable(reg);
+}
+
+static int max11205_probe(struct spi_device *spi)
+{
+ struct max11205_state *st;
+ struct iio_dev *indio_dev;
+ int ret;
+
+ indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
+ if (!indio_dev)
+ return -ENOMEM;
+
+ st = iio_priv(indio_dev);
+
+ ad_sd_init(&st->sd, indio_dev, spi, &max11205_sigma_delta_info);
+
+ st->chip_info = device_get_match_data(&spi->dev);
+
+ if (!st->chip_info)
+ st->chip_info = (const struct chip_info *)spi_get_device_id(spi)->driver_data;
+
+ indio_dev->name = st->chip_info->name;
+ indio_dev->modes = INDIO_DIRECT_MODE;
+ indio_dev->channels = max11205_channels;
+ indio_dev->num_channels = 1;
+ indio_dev->info = &max11205_iio_info;
+
+ st->vref = devm_regulator_get(&spi->dev, "vref");
+ if (IS_ERR(st->vref))
+ return dev_err_probe(&spi->dev, PTR_ERR(st->vref),
+ "Failed to get vref regulator\n");
+
+ ret = regulator_enable(st->vref);
+ if (ret)
+ return ret;
+
+ ret = devm_add_action_or_reset(&spi->dev, max11205_reg_disable, st->vref);
+ if (ret)
+ return ret;
+
+ ret = devm_ad_sd_setup_buffer_and_trigger(&spi->dev, indio_dev);
+ if (ret)
+ return ret;
+
+ return devm_iio_device_register(&spi->dev, indio_dev);
+}
+
+static const struct spi_device_id max11205_spi_ids[] = {
+ { "max11205a", (kernel_ulong_t)&max11205_chip_info[TYPE_MAX11205A] },
+ { "max11205b", (kernel_ulong_t)&max11205_chip_info[TYPE_MAX11205B] },
+ { }
+};
+MODULE_DEVICE_TABLE(spi, max11205_spi_ids);
+
+static const struct of_device_id max11205_dt_ids[] = {
+ {
+ .compatible = "maxim,max11205a",
+ .data = &max11205_chip_info[TYPE_MAX11205A],
+ },
+ {
+ .compatible = "maxim,max11205b",
+ .data = &max11205_chip_info[TYPE_MAX11205B],
+ },
+ { }
+};
+MODULE_DEVICE_TABLE(of, max11205_dt_ids);
+
+static struct spi_driver max11205_spi_driver = {
+ .driver = {
+ .name = "max11205",
+ .of_match_table = max11205_dt_ids,
+ },
+ .probe = max11205_probe,
+ .id_table = max11205_spi_ids,
+};
+module_spi_driver(max11205_spi_driver);
+
+MODULE_AUTHOR("Ramona Bolboaca <ramona.bolboaca@xxxxxxxxxx>");
+MODULE_DESCRIPTION("MAX11205 ADC driver");
+MODULE_LICENSE("GPL v2");
+MODULE_IMPORT_NS(IIO_AD_SIGMA_DELTA);
--
2.25.1