Messages in this thread | | | Subject | Re: [PATCH V2 7/9] hwmon: pwm-fan: add sysfs node to read rpm of fan | From | Guenter Roeck <> | Date | Tue, 20 Mar 2018 23:09:52 -0700 |
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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@nvidia.com> > --- > > 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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