On 3/17/20 1:50 PM, Michael Walle wrote:

This adds support for the hardware monitoring controller of the sl28cpld
board management controller. This driver is part of a multi-function
device.

Signed-off-by: Michael Walle <redacted>
---
 drivers/hwmon/Kconfig          |  10 +++
 drivers/hwmon/Makefile         |   1 +
 drivers/hwmon/sl28cpld-hwmon.c | 146 +++++++++++++++++++++++++++++++++

Please also provide Documentation/hwmon/sl28cpld.

Alphabetic order of include files, please.

+#define FAN_INPUT		0
+#define   FAN_SCALE_X8		BIT(7)
+#define   FAN_VALUE_MASK	GENMASK(6, 0)
+
+struct sl28cpld_hwmon {
+	struct regmap *regmap;
+	u32 offset;
+};
+
+static umode_t sl28cpld_hwmon_is_visible(const void *data,
+					 enum hwmon_sensor_types type,
+					 u32 attr, int channel)
+{
+	return 0444;
+}
+
+static int sl28cpld_hwmon_read(struct device *dev,
+			       enum hwmon_sensor_types type, u32 attr,
+			       int channel, long *input)
+{
+	struct sl28cpld_hwmon *hwmon = dev_get_drvdata(dev);
+	unsigned int value;
+	int ret;
+
+	switch (attr) {
+	case hwmon_fan_input:
+		ret = regmap_read(hwmon->regmap, hwmon->offset + FAN_INPUT,
+				  &value);
+		if (ret)
+			return ret;
+		/*
+		 * The register has a 7 bit value and 1 bit which indicates the
+		 * scale. If the MSB is set, then the lower 7 bit has to be
+		 * multiplied by 8, to get the correct reading.
+		 */
+		if (value & FAN_SCALE_X8)
+			value = FIELD_GET(FAN_VALUE_MASK, value) << 3;
+
+		/*
+		 * The counter period is 1000ms and the sysfs specification
+		 * says we should asssume 2 pulses per revolution.
+		 */
+		value *= 60 / 2;
+
+		break;
+	default:
+		return -EOPNOTSUPP;
+	}
+
+	*input = value;
+	return 0;
+}
+
+static const u32 sl28cpld_hwmon_fan_config[] = {
+	HWMON_F_INPUT,
+	0
+};
+
+static const struct hwmon_channel_info sl28cpld_hwmon_fan = {
+	.type = hwmon_fan,
+	.config = sl28cpld_hwmon_fan_config,
+};
+
+static const struct hwmon_channel_info *sl28cpld_hwmon_info[] = {
+	&sl28cpld_hwmon_fan,
+	NULL
+};
+
+static const struct hwmon_ops sl28cpld_hwmon_ops = {
+	.is_visible = sl28cpld_hwmon_is_visible,
+	.read = sl28cpld_hwmon_read,
+};
+
+static const struct hwmon_chip_info sl28cpld_hwmon_chip_info = {
+	.ops = &sl28cpld_hwmon_ops,
+	.info = sl28cpld_hwmon_info,
+};
+
+static int sl28cpld_hwmon_probe(struct platform_device *pdev)
+{
+	struct device *hwmon_dev;
+	struct sl28cpld_hwmon *hwmon;
+	struct resource *res;
+
+	hwmon = devm_kzalloc(&pdev->dev, sizeof(*hwmon), GFP_KERNEL);
+	if (!hwmon)
+		return -ENOMEM;
+
+	if (!pdev->dev.parent)
+		return -ENODEV;
+

Maybe do this first ?

+	hwmon->regmap = dev_get_regmap(pdev->dev.parent, NULL);
+	if (!hwmon->regmap)
+		return -ENODEV;
+
+	res = platform_get_resource(pdev, IORESOURCE_REG, 0);
+	if (!res)
+		return -EINVAL;
+	hwmon->offset = res->start;
+
+	hwmon_dev = devm_hwmon_device_register_with_info(&pdev->dev,
+							 "sl28cpld_hwmon",
+							 hwmon,
+							 &sl28cpld_hwmon_chip_info,
+							 NULL);
+	if (IS_ERR(hwmon_dev)) {
+		dev_err(&pdev->dev, "failed to register as hwmon device");
+		return PTR_ERR(hwmon_dev);
+	}
+
+	return 0;
+}
+
+static const struct platform_device_id sl28cpld_hwmon_id_table[] = {
+	{"sl28cpld-fan", 0},
+};
+MODULE_DEVICE_TABLE(platform, sl28cpld_hwmon_id_table);
+
+static struct platform_driver sl28cpld_hwmon_driver = {
+	.probe = sl28cpld_hwmon_probe,
+	.id_table = sl28cpld_hwmon_id_table,

I'd have expected an of_match_table.

+	.driver = {
+		.name = "sl28cpld-hwmon",
+	},
+};
+module_platform_driver(sl28cpld_hwmon_driver);
+
+MODULE_DESCRIPTION("sl28cpld Hardware Monitoring Driver");
+MODULE_LICENSE("GPL");

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