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

Naresh Solanki <naresh.solanki@xxxxxxxxxxxxx> · Fri, 24 Mar 2023 15:40:50 +0530

Hi,

On 24-03-2023 01:36 am, Christophe JAILLET wrote:
Le 23/03/2023 à 20:45, Naresh Solanki a écrit :
From: Patrick Rudolph 
<patrick.rudolph-cWEv32IpryCakBO8gow8eQ@xxxxxxxxxxxxxxxx>

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

Signed-off-by: Patrick Rudolph 
<patrick.rudolph-cWEv32IpryCakBO8gow8eQ@xxxxxxxxxxxxxxxx>
Signed-off-by: Naresh Solanki 
<Naresh.Solanki-cWEv32IpryCakBO8gow8eQ@xxxxxxxxxxxxxxxx>

Hi, a few nits below, should there be a v3.

CJ

...
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-cWEv32IpryCakBO8gow8eQ@xxxxxxxxxxxxxxxx>
+ */
+
+#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:
+

Nit: This blank line would look nicer if above the case:
Oh yes. Will do that in V3

+        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");

Nit: \n missing

Sure will make it like this:
	if (ret)
		return dev_err_probe(&pdev->dev, ret, "could not register iio device\n");
+
+    return ret;

Nit: return 0;
Sure

+}
+
+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-cWEv32IpryCakBO8gow8eQ@xxxxxxxxxxxxxxxx>");
+MODULE_DESCRIPTION("MAX5970_hot-swap controller driver");
+MODULE_LICENSE("GPL");

base-commit: 368eb79f738a21e16c2bdbcac2444dfa96b01aaa







