[PATCH v2 1/2] iio: max597x: Add support for max597x

From: Naresh Solanki
Date: Thu Mar 23 2023 - 15:46:01 EST

From: Patrick Rudolph <patrick.rudolph@xxxxxxxxxxxxx>

max597x has 10bit ADC for voltage & current monitoring.
Use iio framework to expose the same in sysfs.

Signed-off-by: Patrick Rudolph <patrick.rudolph@xxxxxxxxxxxxx>
Signed-off-by: Naresh Solanki <Naresh.Solanki@xxxxxxxxxxxxx>
...
Changes in V2:
- Remove fallthrough
- Use pdev->dev instead of i2c->dev
- Init indio_dev->name based on device type.
---
drivers/iio/adc/Kconfig | 15 ++++
drivers/iio/adc/Makefile | 1 +
drivers/iio/adc/max597x-iio.c | 152 ++++++++++++++++++++++++++++++++++
3 files changed, 168 insertions(+)
create mode 100644 drivers/iio/adc/max597x-iio.c

diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
index 45af2302be53..0d1a3dea0b7d 100644
--- a/drivers/iio/adc/Kconfig
+++ b/drivers/iio/adc/Kconfig
@@ -735,6 +735,21 @@ config MAX1363
To compile this driver as a module, choose M here: the module will be
called max1363.

+config MAX597X_IIO
+ tristate "Maxim 597x power switch and monitor"
+ depends on I2C && OF
+ select MFD_MAX597X
+ help
+ This driver enables support for the Maxim 597x smart switch and
+ voltage/current monitoring interface using the Industrial I/O (IIO)
+ framework. The Maxim 597x is a power switch and monitor that can
+ provide voltage and current measurements via the I2C bus. Enabling
+ this driver will allow user space applications to read the voltage
+ and current measurements using IIO interfaces.
+
+ To compile this driver as a module, choose M here: the module will be
+ called max597x-iio.
+
config MAX9611
tristate "Maxim max9611/max9612 ADC driver"
depends on I2C
diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile
index 36c18177322a..7ec0c2cf7bbb 100644
--- a/drivers/iio/adc/Makefile
+++ b/drivers/iio/adc/Makefile
@@ -67,6 +67,7 @@ obj-$(CONFIG_MAX11205) += max11205.o
obj-$(CONFIG_MAX11410) += max11410.o
obj-$(CONFIG_MAX1241) += max1241.o
obj-$(CONFIG_MAX1363) += max1363.o
+obj-$(CONFIG_MAX597X_IIO) += max597x-iio.o
obj-$(CONFIG_MAX9611) += max9611.o
obj-$(CONFIG_MCP320X) += mcp320x.o
obj-$(CONFIG_MCP3422) += mcp3422.o
diff --git a/drivers/iio/adc/max597x-iio.c b/drivers/iio/adc/max597x-iio.c
new file mode 100644
index 000000000000..8a9fc27ff71e
--- /dev/null
+++ b/drivers/iio/adc/max597x-iio.c
@@ -0,0 +1,152 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Device driver for IIO in MAX5970 and MAX5978 IC
+ *
+ * Copyright (c) 2022 9elements GmbH
+ *
+ * Author: Patrick Rudolph <patrick.rudolph@xxxxxxxxxxxxx>
+ */
+
+#include <linux/iio/iio.h>
+#include <linux/mfd/max597x.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+
+struct max597x_iio {
+ struct regmap *regmap;
+ int shunt_micro_ohms[MAX5970_NUM_SWITCHES];
+ unsigned int irng[MAX5970_NUM_SWITCHES];
+ unsigned int mon_rng[MAX5970_NUM_SWITCHES];
+};
+
+#define MAX597X_ADC_CHANNEL(_idx, _type) { \
+ .type = IIO_ ## _type, \
+ .indexed = 1, \
+ .channel = (_idx), \
+ .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | \
+ BIT(IIO_CHAN_INFO_SCALE), \
+ .address = MAX5970_REG_ ## _type ## _L(_idx), \
+}
+
+static const struct iio_chan_spec max5978_adc_iio_channels[] = {
+ MAX597X_ADC_CHANNEL(0, VOLTAGE),
+ MAX597X_ADC_CHANNEL(0, CURRENT),
+};
+
+static const struct iio_chan_spec max5970_adc_iio_channels[] = {
+ MAX597X_ADC_CHANNEL(0, VOLTAGE),
+ MAX597X_ADC_CHANNEL(0, CURRENT),
+ MAX597X_ADC_CHANNEL(1, VOLTAGE),
+ MAX597X_ADC_CHANNEL(1, CURRENT),
+};
+
+static int max597x_iio_read_raw(struct iio_dev *iio_dev,
+ struct iio_chan_spec const *chan,
+ int *val, int *val2, long info)
+{
+ int ret;
+ struct max597x_iio *data = iio_priv(iio_dev);
+ unsigned int reg_l, reg_h;
+
+ switch (info) {
+ case IIO_CHAN_INFO_RAW:
+ ret = regmap_read(data->regmap, chan->address, &reg_l);
+ if (ret < 0)
+ return ret;
+ ret = regmap_read(data->regmap, chan->address - 1, &reg_h);
+ if (ret < 0)
+ return ret;
+ *val = (reg_h << 2) | (reg_l & 3);
+
+ return IIO_VAL_INT;
+ case IIO_CHAN_INFO_SCALE:
+
+ switch (chan->address) {
+ case MAX5970_REG_CURRENT_L(0):
+ case MAX5970_REG_CURRENT_L(1):
+ /* in A, convert to mA */
+ *val = data->irng[chan->channel] * 1000;
+ *val2 =
+ data->shunt_micro_ohms[chan->channel] * ADC_MASK;
+ return IIO_VAL_FRACTIONAL;
+
+ case MAX5970_REG_VOLTAGE_L(0):
+ case MAX5970_REG_VOLTAGE_L(1):
+ /* in uV, convert to mV */
+ *val = data->mon_rng[chan->channel];
+ *val2 = ADC_MASK * 1000;
+ return IIO_VAL_FRACTIONAL;
+ }
+
+ break;
+ }
+ return -EINVAL;
+}
+
+static const struct iio_info max597x_adc_iio_info = {
+ .read_raw = &max597x_iio_read_raw,
+};
+
+static int max597x_iio_probe(struct platform_device *pdev)
+{
+ struct max597x_data *max597x = dev_get_drvdata(pdev->dev.parent);
+ struct regmap *regmap = dev_get_regmap(pdev->dev.parent, NULL);
+ struct iio_dev *indio_dev;
+ struct max597x_iio *priv;
+ int ret, i;
+
+ if (!regmap)
+ return -EPROBE_DEFER;
+
+ if (!max597x || !max597x->num_switches)
+ return -EPROBE_DEFER;
+
+ /* registering iio */
+ indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*priv));
+ if (!indio_dev)
+ return dev_err_probe(&pdev->dev, -ENOMEM,
+ "failed to allocate iio device\n");
+
+ indio_dev->info = &max597x_adc_iio_info;
+ indio_dev->modes = INDIO_DIRECT_MODE;
+
+ switch (max597x->num_switches) {
+ case MAX597x_TYPE_MAX5970:
+ indio_dev->channels = max5970_adc_iio_channels;
+ indio_dev->num_channels = ARRAY_SIZE(max5970_adc_iio_channels);
+ indio_dev->name = "max5970";
+ break;
+ case MAX597x_TYPE_MAX5978:
+ indio_dev->channels = max5978_adc_iio_channels;
+ indio_dev->num_channels = ARRAY_SIZE(max5978_adc_iio_channels);
+ indio_dev->name = "max5978";
+ break;
+ }
+
+ priv = iio_priv(indio_dev);
+ priv->regmap = regmap;
+ for (i = 0; i < indio_dev->num_channels; i++) {
+ priv->irng[i] = max597x->irng[i];
+ priv->mon_rng[i] = max597x->mon_rng[i];
+ priv->shunt_micro_ohms[i] = max597x->shunt_micro_ohms[i];
+ }
+
+ ret = devm_iio_device_register(&pdev->dev, indio_dev);
+ if (ret)
+ dev_err_probe(&pdev->dev, ret, "could not register iio device");
+
+ return ret;
+}
+
+static struct platform_driver max597x_iio_driver = {
+ .driver = {
+ .name = "max597x-iio",
+ },
+ .probe = max597x_iio_probe,
+};
+
+module_platform_driver(max597x_iio_driver);
+
+MODULE_AUTHOR("Patrick Rudolph <patrick.rudolph@xxxxxxxxxxxxx>");
+MODULE_DESCRIPTION("MAX5970_hot-swap controller driver");
+MODULE_LICENSE("GPL");

base-commit: 368eb79f738a21e16c2bdbcac2444dfa96b01aaa
--
2.39.1