[PATCH 14/14] i8k: Implement hwmon based fan speed control

Guenter Roeck
2013-12-14T17:31:35Z

Fan speed can be set to off, slow, and fast, which can be exported
to userspace through the hwmon ABI as pwm1 / pwm2.

Cc: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
---
drivers/char/i8k.c | 49 ++++++++++++++++++++++++++++++++++++++++++++-----
1 file changed, 44 insertions(+), 5 deletions(-)

diff --git a/drivers/char/i8k.c b/drivers/char/i8k.c
index ce826d9..70c8df2 100644
--- a/drivers/char/i8k.c
+++ b/drivers/char/i8k.c
@@ -509,6 +509,39 @@ static ssize_t i8k_hwmon_show_fan(struct device *dev,
return sprintf(buf, "%d\n", fan_speed);
}

+static ssize_t i8k_hwmon_show_pwm(struct device *dev,
+ struct device_attribute *devattr,
+ char *buf)
+{
+ int index = to_sensor_dev_attr(devattr)->index;
+ int status;
+
+ status = i8k_get_fan_status(index);
+ if (status < 0)
+ return -EIO;
+ return sprintf(buf, "%d\n", clamp_val(status * 128, 0, 255));
+}
+
+static ssize_t i8k_hwmon_set_pwm(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ int index = to_sensor_dev_attr(attr)->index;
+ unsigned long val;
+ int err;
+
+ err = kstrtoul(buf, 10, &val);
+ if (err)
+ return err;
+ val = clamp_val(DIV_ROUND_CLOSEST(val, 128), 0, 2);
+
+ mutex_lock(&i8k_mutex);
+ err = i8k_set_fan(index, val);
+ mutex_unlock(&i8k_mutex);
+
+ return err < 0 ? -EIO : count;
+}
+
static ssize_t i8k_hwmon_show_label(struct device *dev,
struct device_attribute *devattr,
char *buf)
@@ -529,8 +562,12 @@ static SENSOR_DEVICE_ATTR(temp3_input, S_IRUGO, i8k_hwmon_show_temp, NULL, 2);
static SENSOR_DEVICE_ATTR(temp4_input, S_IRUGO, i8k_hwmon_show_temp, NULL, 3);
static SENSOR_DEVICE_ATTR(fan1_input, S_IRUGO, i8k_hwmon_show_fan, NULL,
I8K_FAN_LEFT);
+static SENSOR_DEVICE_ATTR(pwm1, S_IRUGO | S_IWUSR, i8k_hwmon_show_pwm,
+ i8k_hwmon_set_pwm, I8K_FAN_LEFT);
static SENSOR_DEVICE_ATTR(fan2_input, S_IRUGO, i8k_hwmon_show_fan, NULL,
I8K_FAN_RIGHT);
+static SENSOR_DEVICE_ATTR(pwm2, S_IRUGO | S_IWUSR, i8k_hwmon_show_pwm,
+ i8k_hwmon_set_pwm, I8K_FAN_RIGHT);
static SENSOR_DEVICE_ATTR(temp1_label, S_IRUGO, i8k_hwmon_show_label, NULL, 0);
static SENSOR_DEVICE_ATTR(fan1_label, S_IRUGO, i8k_hwmon_show_label, NULL, 1);
static SENSOR_DEVICE_ATTR(fan2_label, S_IRUGO, i8k_hwmon_show_label, NULL, 2);
@@ -542,9 +579,11 @@ static struct attribute *i8k_attrs[] = {
&sensor_dev_attr_temp3_input.dev_attr.attr, /* 3 */
&sensor_dev_attr_temp4_input.dev_attr.attr, /* 4 */
&sensor_dev_attr_fan1_input.dev_attr.attr, /* 5 */
- &sensor_dev_attr_fan1_label.dev_attr.attr, /* 6 */
- &sensor_dev_attr_fan2_input.dev_attr.attr, /* 7 */
- &sensor_dev_attr_fan2_label.dev_attr.attr, /* 8 */
+ &sensor_dev_attr_pwm1.dev_attr.attr, /* 6 */
+ &sensor_dev_attr_fan1_label.dev_attr.attr, /* 7 */
+ &sensor_dev_attr_fan2_input.dev_attr.attr, /* 8 */
+ &sensor_dev_attr_pwm2.dev_attr.attr, /* 9 */
+ &sensor_dev_attr_fan2_label.dev_attr.attr, /* 10 */
NULL
};

@@ -560,10 +599,10 @@ static umode_t i8k_is_visible(struct kobject *kobj, struct attribute *attr,
return 0;
if (index == 4 && !(i8k_hwmon_flags & I8K_HWMON_HAVE_TEMP4))
return 0;
- if ((index == 5 || index == 6) &&
+ if (index >= 5 && index <= 7 &&
!(i8k_hwmon_flags & I8K_HWMON_HAVE_FAN1))
return 0;
- if ((index == 7 || index == 8) &&
+ if (index >= 8 && index <= 10 &&
!(i8k_hwmon_flags & I8K_HWMON_HAVE_FAN2))
return 0;

--
1.7.9.7