[PATCH] hwmon: (nct7802) Add fan output control

[Constantine Shulyupin]

Notes:

Some lines intentionally more than 80 characters because wrapping
this lines decreases readability.
The patch was checked with scripts/checkpatch.pl --max-line-length=88

Following code is not typecasting.
It is inline struct attribute_group definition using compound literal.
(See https://gcc.gnu.org/onlinedocs/gcc-3.2.2/gcc/Compound-Literals.html)

static const struct attribute_group *nct7802_groups[] = {
	...
	&(const struct attribute_group){ .attrs = fan_output_attributes },
	...

Reference:

Nuvoton Hardware Monitoring IC NCT7802Y
7.2.91 Fan Control 1 Output Value
Location : Index 60h

7.2.92 Fan Control 2 Output Value
Location : Index 61h

7.2.93 Fan Control 3 Output Value
Location : Index 62h

Signed-off-by: Constantine Shulyupin <const@xxxxxxxxxxxxx>
---
 drivers/hwmon/nct7802.c | 45 +++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 45 insertions(+)

diff --git a/drivers/hwmon/nct7802.c b/drivers/hwmon/nct7802.c
index afa242d..56d3547 100644
--- a/drivers/hwmon/nct7802.c
+++ b/drivers/hwmon/nct7802.c
@@ -102,6 +102,38 @@ static ssize_t store_temp_type(struct device *dev,
 	return err ? : count;
 }
 
+static ssize_t show_dec(struct device *dev, struct device_attribute *devattr, char *buf)
+{
+	int ret = -1;
+	struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
+	struct nct7802_data *data = dev_get_drvdata(dev);
+	unsigned int val = 0;
+
+	ret = regmap_read(data->regmap, attr->index, &val);
+	if (ret < 0)
+		return ret;
+
+	ret = sprintf(buf, "%d\n", val);
+	return ret;
+}
+
+static ssize_t store_u8(struct device *dev, struct device_attribute *devattr,
+			const char *buf, size_t count)
+{
+	struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
+	struct nct7802_data *data = dev_get_drvdata(dev);
+	int err;
+	unsigned int val;
+
+	err = kstrtouint(buf, 0, &val);
+	if (err < 0)
+		return err;
+	if (val > 0xFF)
+		return -EINVAL;
+
+	err = regmap_write(data->regmap, attr->index, val);
+	return err ? : count;
+}
 
 static int nct7802_read_temp(struct nct7802_data *data,
 			     u8 reg_temp, u8 reg_temp_low, int *temp)
@@ -735,6 +767,11 @@ static SENSOR_DEVICE_ATTR_2(fan3_alarm, S_IRUGO, show_alarm, NULL, 0x1a, 2);
 static SENSOR_DEVICE_ATTR_2(fan3_beep, S_IRUGO | S_IWUSR, show_beep, store_beep,
 			    0x5b, 2);
 
+/* 7.2.91... Fan Control Output Value */
+static SENSOR_DEVICE_ATTR(fan1_output, S_IRUGO | S_IWUSR, show_dec, store_u8, 0x60);
+static SENSOR_DEVICE_ATTR(fan2_output, S_IRUGO | S_IWUSR, show_dec, store_u8, 0x61);
+static SENSOR_DEVICE_ATTR(fan3_output, S_IRUGO | S_IWUSR, show_dec, store_u8, 0x62);
+
 static struct attribute *nct7802_fan_attrs[] = {
 	&sensor_dev_attr_fan1_input.dev_attr.attr,
 	&sensor_dev_attr_fan1_min.dev_attr.attr,
@@ -773,10 +810,18 @@ static struct attribute_group nct7802_fan_group = {
 	.is_visible = nct7802_fan_is_visible,
 };
 
+static struct attribute *fan_output_attributes[] = {
+	&sensor_dev_attr_fan1_output.dev_attr.attr,
+	&sensor_dev_attr_fan2_output.dev_attr.attr,
+	&sensor_dev_attr_fan3_output.dev_attr.attr,
+	NULL
+};
+
 static const struct attribute_group *nct7802_groups[] = {
 	&nct7802_temp_group,
 	&nct7802_in_group,
 	&nct7802_fan_group,
+	&(const struct attribute_group){ .attrs = fan_output_attributes },
 	NULL
 };
 
-- 
1.9.1

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