[PATCH v2 5/5] drivers: iio: adc: Add MAX77541 ADC Support

From: Okan Sahin
Date: Mon Dec 26 2022 - 17:42:03 EST

The MAX77541 has an 8-bit Successive Approximation Register (SAR) ADC
with four multiplexers for supporting the telemetry feature

Signed-off-by: Okan Sahin <okan.sahin@xxxxxxxxxx>
---
MAINTAINERS | 1 +
drivers/iio/adc/Kconfig | 11 ++
drivers/iio/adc/Makefile | 1 +
drivers/iio/adc/max77541-adc.c | 199 +++++++++++++++++++++++++++++++++
4 files changed, 212 insertions(+)
create mode 100644 drivers/iio/adc/max77541-adc.c

diff --git a/MAINTAINERS b/MAINTAINERS
index 8e5572b28a8c..18ce4644cc75 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -12503,6 +12503,7 @@ L: linux-kernel@xxxxxxxxxxxxxxx
S: Maintained
F: Documentation/devicetree/bindings/mfd/adi,max77541.yaml
F: Documentation/devicetree/bindings/regulator/adi,max77541.yaml
+F: drivers/iio/adc/max77541-adc.c
F: drivers/mfd/max77541.c
F: drivers/regulator/max77541-regulator.c
F: include/linux/mfd/max77541.h
diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
index 791612ca6012..9716225b50da 100644
--- a/drivers/iio/adc/Kconfig
+++ b/drivers/iio/adc/Kconfig
@@ -696,6 +696,17 @@ config MAX1363
To compile this driver as a module, choose M here: the module will be
called max1363.

+config MAX77541_ADC
+ tristate "Analog Devices MAX77541 ADC driver"
+ depends on MFD_MAX77541
+ help
+ This driver controls a Analog Devices MAX77541 ADC
+ via I2C bus. This device has one adc. Say yes here to build
+ support for Analog Devices MAX77541 ADC interface.
+
+ To compile this driver as a module, choose M here:
+ the module will be called max77541-adc.
+
config MAX9611
tristate "Maxim max9611/max9612 ADC driver"
depends on I2C
diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile
index 46caba7a010c..03774cccbb4b 100644
--- a/drivers/iio/adc/Makefile
+++ b/drivers/iio/adc/Makefile
@@ -64,6 +64,7 @@ obj-$(CONFIG_MAX1118) += max1118.o
obj-$(CONFIG_MAX11205) += max11205.o
obj-$(CONFIG_MAX1241) += max1241.o
obj-$(CONFIG_MAX1363) += max1363.o
+obj-$(CONFIG_MAX77541_ADC) += max77541-adc.o
obj-$(CONFIG_MAX9611) += max9611.o
obj-$(CONFIG_MCP320X) += mcp320x.o
obj-$(CONFIG_MCP3422) += mcp3422.o
diff --git a/drivers/iio/adc/max77541-adc.c b/drivers/iio/adc/max77541-adc.c
new file mode 100644
index 000000000000..29adcdbd96ae
--- /dev/null
+++ b/drivers/iio/adc/max77541-adc.c
@@ -0,0 +1,199 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (c) 2022 Analog Devices, Inc.
+ * ADI MAX77541 ADC Driver with IIO interface
+ */
+
+#include <linux/bitfield.h>
+#include <linux/iio/iio.h>
+#include <linux/mfd/max77541.h>
+#include <linux/mod_devicetable.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+#include <linux/regulator/driver.h>
+#include <linux/regulator/of_regulator.h>
+#include <linux/units.h>
+
+#define MAX77541_ADC_CHANNEL(_channel, _name, _type, _reg) \
+ { \
+ .type = _type, \
+ .indexed = 1, \
+ .channel = _channel, \
+ .address = _reg, \
+ .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | \
+ BIT(IIO_CHAN_INFO_SCALE) |\
+ BIT(IIO_CHAN_INFO_OFFSET),\
+ .datasheet_name = _name, \
+ }
+
+enum max77541_adc_range {
+ LOW_RANGE,
+ MID_RANGE,
+ HIGH_RANGE,
+};
+
+struct max77541_adc_iio {
+ struct regmap *regmap;
+};
+
+enum max77541_adc_channel {
+ MAX77541_ADC_VSYS_V = 0,
+ MAX77541_ADC_VOUT1_V,
+ MAX77541_ADC_VOUT2_V,
+ MAX77541_ADC_TEMP,
+};
+
+static int max77541_adc_offset(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *chan,
+ int *val, int *val2)
+{
+ switch (chan->channel) {
+ case MAX77541_ADC_VSYS_V:
+ case MAX77541_ADC_VOUT1_V:
+ case MAX77541_ADC_VOUT2_V:
+ *val = 0;
+ *val2 = 0;
+ return IIO_VAL_INT_PLUS_MICRO;
+ case MAX77541_ADC_TEMP:
+ *val = DIV_ROUND_CLOSEST(ABSOLUTE_ZERO_MILLICELSIUS,
+ MILLIDEGREE_PER_DEGREE);
+ *val2 = 0;
+ return IIO_VAL_INT_PLUS_MICRO;
+ default:
+ return -EINVAL;
+ }
+}
+
+static int max77541_adc_scale(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *chan,
+ int *val, int *val2)
+{
+ struct max77541_adc_iio *info = iio_priv(indio_dev);
+ unsigned int reg_val;
+ int ret;
+
+ switch (chan->channel) {
+ case MAX77541_ADC_VSYS_V:
+ *val = 0;
+ *val2 = 25000;
+ return IIO_VAL_INT_PLUS_MICRO;
+ case MAX77541_ADC_VOUT1_V:
+ case MAX77541_ADC_VOUT2_V:
+ ret = regmap_read(info->regmap, MAX77541_REG_M2_CFG1, &reg_val);
+ if (ret)
+ return ret;
+ reg_val = FIELD_GET(MAX77541_BITS_MX_CFG1_RNG, reg_val);
+
+ *val = 0;
+
+ switch (reg_val) {
+ case LOW_RANGE:
+ *val2 = 6250;
+ break;
+ case MID_RANGE:
+ *val2 = 12500;
+ break;
+ case HIGH_RANGE:
+ *val2 = 25000;
+ break;
+ default:
+ return -EINVAL;
+ }
+
+ return IIO_VAL_INT_PLUS_MICRO;
+ case MAX77541_ADC_TEMP:
+ *val = 1;
+ *val2 = 725000;
+ return IIO_VAL_INT_PLUS_MICRO;
+ default:
+ return -EINVAL;
+ }
+}
+
+static int max77541_adc_raw(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *chan,
+ int *val)
+{
+ struct max77541_adc_iio *info = iio_priv(indio_dev);
+ int ret;
+
+ ret = regmap_read(info->regmap, chan->address, val);
+ if (ret)
+ return ret;
+
+ return IIO_VAL_INT;
+}
+
+static const struct iio_chan_spec max77541_adc_channels[] = {
+ MAX77541_ADC_CHANNEL(MAX77541_ADC_VSYS_V, "vsys_v", IIO_VOLTAGE,
+ MAX77541_REG_ADC_DATA_CH1),
+ MAX77541_ADC_CHANNEL(MAX77541_ADC_VOUT1_V, "vout1_v", IIO_VOLTAGE,
+ MAX77541_REG_ADC_DATA_CH2),
+ MAX77541_ADC_CHANNEL(MAX77541_ADC_VOUT2_V, "vout2_v", IIO_VOLTAGE,
+ MAX77541_REG_ADC_DATA_CH3),
+ MAX77541_ADC_CHANNEL(MAX77541_ADC_TEMP, "temp", IIO_TEMP,
+ MAX77541_REG_ADC_DATA_CH6),
+};
+
+static int max77541_adc_read_raw(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *chan,
+ int *val, int *val2, long mask)
+{
+ switch (mask) {
+ case IIO_CHAN_INFO_OFFSET:
+ return max77541_adc_offset(indio_dev, chan, val, val2);
+ case IIO_CHAN_INFO_SCALE:
+ return max77541_adc_scale(indio_dev, chan, val, val2);
+ case IIO_CHAN_INFO_RAW:
+ return max77541_adc_raw(indio_dev, chan, val);
+ default:
+ return -EINVAL;
+ }
+}
+
+static const struct iio_info max77541_adc_info = {
+ .read_raw = max77541_adc_read_raw,
+};
+
+static int max77541_adc_probe(struct platform_device *pdev)
+{
+ struct max77541_dev *max77541 = dev_get_drvdata(pdev->dev.parent);
+ struct device *dev = &pdev->dev;
+ struct max77541_adc_iio *info;
+ struct iio_dev *indio_dev;
+
+ indio_dev = devm_iio_device_alloc(dev, sizeof(*info));
+ if (!indio_dev)
+ return -ENOMEM;
+
+ info = iio_priv(indio_dev);
+
+ info->regmap = max77541->regmap;
+ indio_dev->modes = INDIO_DIRECT_MODE;
+
+ indio_dev->name = platform_get_device_id(pdev)->name;
+ indio_dev->info = &max77541_adc_info;
+ indio_dev->channels = max77541_adc_channels;
+ indio_dev->num_channels = ARRAY_SIZE(max77541_adc_channels);
+
+ return devm_iio_device_register(dev, indio_dev);
+}
+
+static const struct platform_device_id max77541_adc_platform_id[] = {
+ { "max77541-adc", },
+ { /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(platform, max77541_adc_platform_id);
+
+static struct platform_driver max77541_adc_driver = {
+ .driver = {
+ .name = "max77541-adc",
+ },
+ .probe = max77541_adc_probe,
+ .id_table = max77541_adc_platform_id,
+};
+module_platform_driver(max77541_adc_driver);
+
+MODULE_AUTHOR("Okan Sahin <Okan.Sahin@xxxxxxxxxx>");
+MODULE_DESCRIPTION("MAX77541 ADC driver");
+MODULE_LICENSE("GPL");
--
2.30.2