On 03/20/2018 09:40 PM, Rajkumar Rampelli wrote:
Add fan device attribute fan1_input in pwm-fan driver
to read speed of fan in rotations per minute.
Signed-off-by: Rajkumar Rampelli <rrajk@xxxxxxxxxx>
---
V2: Removed generic-pwm-tachometer driver and using pwm-fan driver as per suggestions
to read fan speed.
Added fan device attribute to report speed of fan in rpms through hwmon sysfs.
drivers/hwmon/pwm-fan.c | 23 +++++++++++++++++++++++
1 file changed, 23 insertions(+)
diff --git a/drivers/hwmon/pwm-fan.c b/drivers/hwmon/pwm-fan.c
index 70cc0d1..8dda209 100644
--- a/drivers/hwmon/pwm-fan.c
+++ b/drivers/hwmon/pwm-fan.c
@@ -98,11 +98,34 @@ static ssize_t show_pwm(struct device *dev,
return sprintf(buf, "%u\n", ctx->pwm_value);
}
+static ssize_t show_rpm(struct device *dev, struct device_attribute *attr,
+ char *buf)
+{
+ struct pwm_fan_ctx *ptt = dev_get_drvdata(dev);
+ struct pwm_device *pwm = ptt->pwm;
+ struct pwm_capture result;
+ unsigned int rpm = 0;
+ int ret;
+
+ ret = pwm_capture(pwm, &result, 0);
+ if (ret < 0) {
+ pr_err("Failed to capture PWM: %d\n", ret);
+ return ret;
+ }
+
+ if (result.period)
+ rpm = DIV_ROUND_CLOSEST_ULL(60ULL * NSEC_PER_SEC,
+ result.period);
+
+ return sprintf(buf, "%u\n", rpm);
+}
static SENSOR_DEVICE_ATTR(pwm1, S_IRUGO | S_IWUSR, show_pwm, set_pwm, 0);
+static SENSOR_DEVICE_ATTR(fan1_input, 0444, show_rpm, NULL, 0);
static struct attribute *pwm_fan_attrs[] = {
&sensor_dev_attr_pwm1.dev_attr.attr,
+ &sensor_dev_attr_fan1_input.dev_attr.attr,
This doesn't make sense. The same pwm can not both control the fan speed
and report it.
Guenter
NULL,
};
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