| Message ID | 1548860827-29796-4-git-send-email-stefan.wahren@i2se.com (mailing list archive) |
|---|---|
| State | Changes Requested |
| Headers | show |
| Series | hwmon: pwm-fan: Add RPM support | expand |
On Wed, Jan 30, 2019 at 04:07:07PM +0100, Stefan Wahren wrote: > This adds RPM support to the pwm-fan driver in order to use with > fancontrol/pwmconfig. This feature is intended for 2 pulse-per-revolution > fans which provides a tachometer output signal. > > Signed-off-by: Stefan Wahren <stefan.wahren@i2se.com> > --- > drivers/hwmon/pwm-fan.c | 55 +++++++++++++++++++++++++++++++++++++++++++++++++ > 1 file changed, 55 insertions(+) > > diff --git a/drivers/hwmon/pwm-fan.c b/drivers/hwmon/pwm-fan.c > index 9e0591e..731fdc6 100644 > --- a/drivers/hwmon/pwm-fan.c > +++ b/drivers/hwmon/pwm-fan.c > @@ -18,6 +18,7 @@ > > #include <linux/hwmon.h> > #include <linux/hwmon-sysfs.h> > +#include <linux/interrupt.h> > #include <linux/module.h> > #include <linux/mutex.h> > #include <linux/of.h> > @@ -26,13 +27,22 @@ > #include <linux/regulator/consumer.h> > #include <linux/sysfs.h> > #include <linux/thermal.h> > +#include <linux/timer.h> > > #define MAX_PWM 255 > +#define SAMPLE_TIME 1 /* seconds */ > +#define PULSE_PER_REVOLUTION 2 > > struct pwm_fan_ctx { > struct mutex lock; > struct pwm_device *pwm; > struct regulator *reg_en; > + > + int irq; > + unsigned int pulses; > + unsigned int rpm; > + struct timer_list sample_timer; > + > unsigned int pwm_value; > unsigned int pwm_fan_state; > unsigned int pwm_fan_max_state; > @@ -40,6 +50,27 @@ struct pwm_fan_ctx { > struct thermal_cooling_device *cdev; > }; > > +static irqreturn_t pulse_handler(int irq, void *dev_id) > +{ > + struct pwm_fan_ctx *ctx = dev_id; > + > + if (ctx->pulses < INT_MAX / 2) > + ctx->pulses++; Please explain the limit. With this code, the maximum number for pulses is INT_MAX / 2. The calculation below multiplies that with 60, which is well above UINT_MAX. Either use a realistic limit or drop the if statement (it is kind of unlikely to get that many interrupts per second). > + > + return IRQ_HANDLED; This assumes a self resetting edge triggered interrupt ? You might want to mention that somewhere. > +} > + > +static void sample_timer(struct timer_list *t) > +{ > + struct pwm_fan_ctx *ctx = from_timer(ctx, t, sample_timer); > + unsigned int pulses; > + > + pulses = ctx->pulses; > + ctx->pulses -= pulses; This is racy; the substract operation is not atomic, and neither is the addition in the interrupt handler. > + ctx->rpm = pulses * 60 / SAMPLE_TIME / PULSE_PER_REVOLUTION; The calculation assumes that sample_timer is called exactly after one second. Have to tested how much variation this causes on a loaded system ? > + mod_timer(&ctx->sample_timer, jiffies + (HZ * SAMPLE_TIME)); > +} > + > static int __set_pwm(struct pwm_fan_ctx *ctx, unsigned long pwm) > { > unsigned long period; > @@ -100,11 +131,20 @@ static ssize_t pwm_show(struct device *dev, struct device_attribute *attr, > return sprintf(buf, "%u\n", ctx->pwm_value); > } > > +static ssize_t rpm_show(struct device *dev, > + struct device_attribute *attr, char *buf) > +{ > + struct pwm_fan_ctx *ctx = dev_get_drvdata(dev); > + > + return sprintf(buf, "%u\n", ctx->rpm); > +} > > static SENSOR_DEVICE_ATTR_RW(pwm1, pwm, 0); > +static SENSOR_DEVICE_ATTR_RO(fan1_input, rpm, 0); > > static struct attribute *pwm_fan_attrs[] = { > &sensor_dev_attr_pwm1.dev_attr.attr, > + &sensor_dev_attr_fan1_input.dev_attr.attr, This attribute is visible even if not supported, meaning it will report a fan speed of 0 rpm in that case. Please make the attribute conditional. > NULL, > }; > > @@ -263,6 +303,19 @@ static int pwm_fan_probe(struct platform_device *pdev) > } > } > > + timer_setup(&ctx->sample_timer, sample_timer, 0); > + > + ctx->irq = platform_get_irq(pdev, 0); > + if (ctx->irq >= 0) { > + ret = devm_request_irq(&pdev->dev, ctx->irq, pulse_handler, 0, > + pdev->name, ctx); > + if (ret) { > + dev_err(&pdev->dev, "Can't get interrupt working.\n"); > + return ret; > + } > + mod_timer(&ctx->sample_timer, jiffies + (HZ * SAMPLE_TIME)); > + } > + > hwmon = devm_hwmon_device_register_with_groups(&pdev->dev, "pwmfan", > ctx, pwm_fan_groups); > if (IS_ERR(hwmon)) { > @@ -304,6 +357,8 @@ static int pwm_fan_remove(struct platform_device *pdev) > struct pwm_fan_ctx *ctx = platform_get_drvdata(pdev); > > thermal_cooling_device_unregister(ctx->cdev); > + del_timer_sync(&ctx->sample_timer); > + > if (ctx->pwm_value) > pwm_disable(ctx->pwm); >
diff --git a/drivers/hwmon/pwm-fan.c b/drivers/hwmon/pwm-fan.c index 9e0591e..731fdc6 100644 --- a/drivers/hwmon/pwm-fan.c +++ b/drivers/hwmon/pwm-fan.c @@ -18,6 +18,7 @@ #include <linux/hwmon.h> #include <linux/hwmon-sysfs.h> +#include <linux/interrupt.h> #include <linux/module.h> #include <linux/mutex.h> #include <linux/of.h> @@ -26,13 +27,22 @@ #include <linux/regulator/consumer.h> #include <linux/sysfs.h> #include <linux/thermal.h> +#include <linux/timer.h> #define MAX_PWM 255 +#define SAMPLE_TIME 1 /* seconds */ +#define PULSE_PER_REVOLUTION 2 struct pwm_fan_ctx { struct mutex lock; struct pwm_device *pwm; struct regulator *reg_en; + + int irq; + unsigned int pulses; + unsigned int rpm; + struct timer_list sample_timer; + unsigned int pwm_value; unsigned int pwm_fan_state; unsigned int pwm_fan_max_state; @@ -40,6 +50,27 @@ struct pwm_fan_ctx { struct thermal_cooling_device *cdev; }; +static irqreturn_t pulse_handler(int irq, void *dev_id) +{ + struct pwm_fan_ctx *ctx = dev_id; + + if (ctx->pulses < INT_MAX / 2) + ctx->pulses++; + + return IRQ_HANDLED; +} + +static void sample_timer(struct timer_list *t) +{ + struct pwm_fan_ctx *ctx = from_timer(ctx, t, sample_timer); + unsigned int pulses; + + pulses = ctx->pulses; + ctx->pulses -= pulses; + ctx->rpm = pulses * 60 / SAMPLE_TIME / PULSE_PER_REVOLUTION; + mod_timer(&ctx->sample_timer, jiffies + (HZ * SAMPLE_TIME)); +} + static int __set_pwm(struct pwm_fan_ctx *ctx, unsigned long pwm) { unsigned long period; @@ -100,11 +131,20 @@ static ssize_t pwm_show(struct device *dev, struct device_attribute *attr, return sprintf(buf, "%u\n", ctx->pwm_value); } +static ssize_t rpm_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct pwm_fan_ctx *ctx = dev_get_drvdata(dev); + + return sprintf(buf, "%u\n", ctx->rpm); +} static SENSOR_DEVICE_ATTR_RW(pwm1, pwm, 0); +static SENSOR_DEVICE_ATTR_RO(fan1_input, rpm, 0); static struct attribute *pwm_fan_attrs[] = { &sensor_dev_attr_pwm1.dev_attr.attr, + &sensor_dev_attr_fan1_input.dev_attr.attr, NULL, }; @@ -263,6 +303,19 @@ static int pwm_fan_probe(struct platform_device *pdev) } } + timer_setup(&ctx->sample_timer, sample_timer, 0); + + ctx->irq = platform_get_irq(pdev, 0); + if (ctx->irq >= 0) { + ret = devm_request_irq(&pdev->dev, ctx->irq, pulse_handler, 0, + pdev->name, ctx); + if (ret) { + dev_err(&pdev->dev, "Can't get interrupt working.\n"); + return ret; + } + mod_timer(&ctx->sample_timer, jiffies + (HZ * SAMPLE_TIME)); + } + hwmon = devm_hwmon_device_register_with_groups(&pdev->dev, "pwmfan", ctx, pwm_fan_groups); if (IS_ERR(hwmon)) { @@ -304,6 +357,8 @@ static int pwm_fan_remove(struct platform_device *pdev) struct pwm_fan_ctx *ctx = platform_get_drvdata(pdev); thermal_cooling_device_unregister(ctx->cdev); + del_timer_sync(&ctx->sample_timer); + if (ctx->pwm_value) pwm_disable(ctx->pwm);
This adds RPM support to the pwm-fan driver in order to use with fancontrol/pwmconfig. This feature is intended for 2 pulse-per-revolution fans which provides a tachometer output signal. Signed-off-by: Stefan Wahren <stefan.wahren@i2se.com> --- drivers/hwmon/pwm-fan.c | 55 +++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 55 insertions(+)