| Message ID | 1553243043-19486-4-git-send-email-stefan.wahren@i2se.com (mailing list archive) |
|---|---|
| State | Changes Requested |
| Headers | show |
| Series | hwmon: pwm-fan: Add RPM support | expand |
On 3/22/19 1:24 AM, Stefan Wahren wrote: > This adds RPM support to the pwm-fan driver in order to use with > fancontrol/pwmconfig. This feature is intended for fans with a tachometer > output signal, which generate a defined number of pulses per revolution. > > Signed-off-by: Stefan Wahren <stefan.wahren@i2se.com> > --- > drivers/hwmon/pwm-fan.c | 100 +++++++++++++++++++++++++++++++++++++++++++++++- > 1 file changed, 99 insertions(+), 1 deletion(-) > > diff --git a/drivers/hwmon/pwm-fan.c b/drivers/hwmon/pwm-fan.c > index 167221c..c8fb6a3 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> > @@ -26,6 +27,7 @@ > #include <linux/regulator/consumer.h> > #include <linux/sysfs.h> > #include <linux/thermal.h> > +#include <linux/timer.h> > > #define MAX_PWM 255 > > @@ -33,6 +35,14 @@ struct pwm_fan_ctx { > struct mutex lock; > struct pwm_device *pwm; > struct regulator *reg_en; > + > + int irq; > + atomic_t pulses; > + unsigned int rpm; > + u32 pulses_per_revolution; > + ktime_t sample_start; > + struct timer_list rpm_timer; > + > unsigned int pwm_value; > unsigned int pwm_fan_state; > unsigned int pwm_fan_max_state; > @@ -40,6 +50,32 @@ struct pwm_fan_ctx { > struct thermal_cooling_device *cdev; > }; > > +/* This handler assumes self resetting edge triggered interrupt. */ > +static irqreturn_t pulse_handler(int irq, void *dev_id) > +{ > + struct pwm_fan_ctx *ctx = dev_id; > + > + /* Avoid possible overflow */ > + if (atomic_read(&ctx->pulses) < 100000) > + atomic_inc(&ctx->pulses); > + 100000 * 60 * 1000 = 6,000,000,000, which is already above 32 bit, so you still get the overflow. Any limit would have to be below (0xffffffff / (60 * sample_ms)) for the maximum expected value of sample_ms. You could select a working limit, such as 32768 (that is just as arbitrary as 100,000, but at least it works up to sample_ms above 2,000), or check for overflow when calculating rpm. > + return IRQ_HANDLED; > +} > + > +static void sample_timer(struct timer_list *t) > +{ > + struct pwm_fan_ctx *ctx = from_timer(ctx, t, rpm_timer); > + int pulses, sample_ms; > + > + pulses = atomic_read(&ctx->pulses); > + atomic_sub(pulses, &ctx->pulses); > + sample_ms = ktime_ms_delta(ktime_get(), ctx->sample_start); > + ctx->rpm = pulses * 60 * sample_ms / 1000 / ctx->pulses_per_revolution; > + > + ctx->sample_start = ktime_get(); > + mod_timer(&ctx->rpm_timer, jiffies + HZ); > +} > + > static int __set_pwm(struct pwm_fan_ctx *ctx, unsigned long pwm) > { > unsigned long period; > @@ -100,15 +136,49 @@ 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, > }; > > -ATTRIBUTE_GROUPS(pwm_fan); > +static umode_t pwm_fan_attrs_visible(struct kobject *kobj, struct attribute *a, > + int n) > +{ > + struct device *dev = container_of(kobj, struct device, kobj); > + struct pwm_fan_ctx *ctx = dev_get_drvdata(dev); > + struct device_attribute *devattr; > + > + /* Hide fan_input in case no interrupt is available */ > + devattr = container_of(a, struct device_attribute, attr); > + if (devattr == &sensor_dev_attr_fan1_input.dev_attr) { > + if (ctx->irq < 0) > + return 0; > + } > + > + return a->mode; > +} > + > +static const struct attribute_group pwm_fan_group = { > + .attrs = pwm_fan_attrs, > + .is_visible = pwm_fan_attrs_visible, > +}; > + > +static const struct attribute_group *pwm_fan_groups[] = { > + &pwm_fan_group, > + NULL, > +}; > > /* thermal cooling device callbacks */ > static int pwm_fan_get_max_state(struct thermal_cooling_device *cdev, > @@ -261,6 +331,32 @@ static int pwm_fan_probe(struct platform_device *pdev) > goto err_reg_disable; > } > > + timer_setup(&ctx->rpm_timer, sample_timer, 0); > + > + if (of_property_read_u32(pdev->dev.of_node, "pulses-per-revolution", > + &ctx->pulses_per_revolution)) { > + ctx->pulses_per_revolution = 2; > + } > + > + if (!ctx->pulses_per_revolution) { > + dev_err(&pdev->dev, "pulses-per-revolution can't be zero.\n"); > + ret = -EINVAL; > + goto err_pwm_disable; > + } > + > + atomic_set(&ctx->pulses, 0); Already initialized with 0. > + ctx->irq = platform_get_irq(pdev, 0); > + if (ctx->irq >= 0) { I have seen other patches recently, changing this check to > 0. I never know what a valid irq is, but it may be prudent to change this to > 0 (and the check in is_visible to <= 0). Either case, the function can return -EPROBE_DEFER, which should be handled and not be ignored. > + 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"); > + goto err_pwm_disable; > + } > + ctx->sample_start = ktime_get(); > + mod_timer(&ctx->rpm_timer, jiffies + HZ); > + } > + > hwmon = devm_hwmon_device_register_with_groups(&pdev->dev, "pwmfan", > ctx, pwm_fan_groups); > if (IS_ERR(hwmon)) { del_timer_sync() here ? > @@ -306,6 +402,8 @@ 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->rpm_timer); > + > if (ctx->pwm_value) > pwm_disable(ctx->pwm); > >
On 22/03/2019 08:24, Stefan Wahren wrote: > This adds RPM support to the pwm-fan driver in order to use with > fancontrol/pwmconfig. This feature is intended for fans with a tachometer > output signal, which generate a defined number of pulses per revolution. Thanks for the CC - this is something I was planning to play with now that I have my fan set up, so it's nice to find it already done :) My board has a 3-wire fan connector driven by an unfiltered PWM output, so unfortunately what I end up measuring is actually the PWM frequency modulated by the rotation pulse frequency. I hacked up some crude low-pass filtering which subsequently got lost in a git reset incident, but I could recreate it if you think it's an idea worth considering (from a bit of research it does seem that 2 or 3-wire fans aren't really meant to be PWMed that way). > Signed-off-by: Stefan Wahren <stefan.wahren@i2se.com> > --- > drivers/hwmon/pwm-fan.c | 100 +++++++++++++++++++++++++++++++++++++++++++++++- > 1 file changed, 99 insertions(+), 1 deletion(-) > > diff --git a/drivers/hwmon/pwm-fan.c b/drivers/hwmon/pwm-fan.c > index 167221c..c8fb6a3 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> > @@ -26,6 +27,7 @@ > #include <linux/regulator/consumer.h> > #include <linux/sysfs.h> > #include <linux/thermal.h> > +#include <linux/timer.h> > > #define MAX_PWM 255 > > @@ -33,6 +35,14 @@ struct pwm_fan_ctx { > struct mutex lock; > struct pwm_device *pwm; > struct regulator *reg_en; > + > + int irq; > + atomic_t pulses; > + unsigned int rpm; > + u32 pulses_per_revolution; > + ktime_t sample_start; > + struct timer_list rpm_timer; > + > unsigned int pwm_value; > unsigned int pwm_fan_state; > unsigned int pwm_fan_max_state; > @@ -40,6 +50,32 @@ struct pwm_fan_ctx { > struct thermal_cooling_device *cdev; > }; > > +/* This handler assumes self resetting edge triggered interrupt. */ > +static irqreturn_t pulse_handler(int irq, void *dev_id) > +{ > + struct pwm_fan_ctx *ctx = dev_id; > + > + /* Avoid possible overflow */ > + if (atomic_read(&ctx->pulses) < 100000) I agree with Guenter that this seems a bit misplaced - since the raw count itself is unlikely to overflow in practice, it certainly feels more sensible to handle calculation overflow in the calculation itself... > + atomic_inc(&ctx->pulses); > + > + return IRQ_HANDLED; > +} > + > +static void sample_timer(struct timer_list *t) > +{ > + struct pwm_fan_ctx *ctx = from_timer(ctx, t, rpm_timer); > + int pulses, sample_ms; > + > + pulses = atomic_read(&ctx->pulses); > + atomic_sub(pulses, &ctx->pulses); > + sample_ms = ktime_ms_delta(ktime_get(), ctx->sample_start); > + ctx->rpm = pulses * 60 * sample_ms / 1000 / ctx->pulses_per_revolution; ...for which maybe mult_frac() could help here, although it might be easier just to do the intermediate calculations in u64 and arrange them to rule out non-constant division. Robin. > + > + ctx->sample_start = ktime_get(); > + mod_timer(&ctx->rpm_timer, jiffies + HZ); > +} > + > static int __set_pwm(struct pwm_fan_ctx *ctx, unsigned long pwm) > { > unsigned long period; > @@ -100,15 +136,49 @@ 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, > }; > > -ATTRIBUTE_GROUPS(pwm_fan); > +static umode_t pwm_fan_attrs_visible(struct kobject *kobj, struct attribute *a, > + int n) > +{ > + struct device *dev = container_of(kobj, struct device, kobj); > + struct pwm_fan_ctx *ctx = dev_get_drvdata(dev); > + struct device_attribute *devattr; > + > + /* Hide fan_input in case no interrupt is available */ > + devattr = container_of(a, struct device_attribute, attr); > + if (devattr == &sensor_dev_attr_fan1_input.dev_attr) { > + if (ctx->irq < 0) > + return 0; > + } > + > + return a->mode; > +} > + > +static const struct attribute_group pwm_fan_group = { > + .attrs = pwm_fan_attrs, > + .is_visible = pwm_fan_attrs_visible, > +}; > + > +static const struct attribute_group *pwm_fan_groups[] = { > + &pwm_fan_group, > + NULL, > +}; > > /* thermal cooling device callbacks */ > static int pwm_fan_get_max_state(struct thermal_cooling_device *cdev, > @@ -261,6 +331,32 @@ static int pwm_fan_probe(struct platform_device *pdev) > goto err_reg_disable; > } > > + timer_setup(&ctx->rpm_timer, sample_timer, 0); > + > + if (of_property_read_u32(pdev->dev.of_node, "pulses-per-revolution", > + &ctx->pulses_per_revolution)) { > + ctx->pulses_per_revolution = 2; > + } > + > + if (!ctx->pulses_per_revolution) { > + dev_err(&pdev->dev, "pulses-per-revolution can't be zero.\n"); > + ret = -EINVAL; > + goto err_pwm_disable; > + } > + > + atomic_set(&ctx->pulses, 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"); > + goto err_pwm_disable; > + } > + ctx->sample_start = ktime_get(); > + mod_timer(&ctx->rpm_timer, jiffies + HZ); > + } > + > hwmon = devm_hwmon_device_register_with_groups(&pdev->dev, "pwmfan", > ctx, pwm_fan_groups); > if (IS_ERR(hwmon)) { > @@ -306,6 +402,8 @@ 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->rpm_timer); > + > if (ctx->pwm_value) > pwm_disable(ctx->pwm); > >
diff --git a/drivers/hwmon/pwm-fan.c b/drivers/hwmon/pwm-fan.c index 167221c..c8fb6a3 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> @@ -26,6 +27,7 @@ #include <linux/regulator/consumer.h> #include <linux/sysfs.h> #include <linux/thermal.h> +#include <linux/timer.h> #define MAX_PWM 255 @@ -33,6 +35,14 @@ struct pwm_fan_ctx { struct mutex lock; struct pwm_device *pwm; struct regulator *reg_en; + + int irq; + atomic_t pulses; + unsigned int rpm; + u32 pulses_per_revolution; + ktime_t sample_start; + struct timer_list rpm_timer; + unsigned int pwm_value; unsigned int pwm_fan_state; unsigned int pwm_fan_max_state; @@ -40,6 +50,32 @@ struct pwm_fan_ctx { struct thermal_cooling_device *cdev; }; +/* This handler assumes self resetting edge triggered interrupt. */ +static irqreturn_t pulse_handler(int irq, void *dev_id) +{ + struct pwm_fan_ctx *ctx = dev_id; + + /* Avoid possible overflow */ + if (atomic_read(&ctx->pulses) < 100000) + atomic_inc(&ctx->pulses); + + return IRQ_HANDLED; +} + +static void sample_timer(struct timer_list *t) +{ + struct pwm_fan_ctx *ctx = from_timer(ctx, t, rpm_timer); + int pulses, sample_ms; + + pulses = atomic_read(&ctx->pulses); + atomic_sub(pulses, &ctx->pulses); + sample_ms = ktime_ms_delta(ktime_get(), ctx->sample_start); + ctx->rpm = pulses * 60 * sample_ms / 1000 / ctx->pulses_per_revolution; + + ctx->sample_start = ktime_get(); + mod_timer(&ctx->rpm_timer, jiffies + HZ); +} + static int __set_pwm(struct pwm_fan_ctx *ctx, unsigned long pwm) { unsigned long period; @@ -100,15 +136,49 @@ 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, }; -ATTRIBUTE_GROUPS(pwm_fan); +static umode_t pwm_fan_attrs_visible(struct kobject *kobj, struct attribute *a, + int n) +{ + struct device *dev = container_of(kobj, struct device, kobj); + struct pwm_fan_ctx *ctx = dev_get_drvdata(dev); + struct device_attribute *devattr; + + /* Hide fan_input in case no interrupt is available */ + devattr = container_of(a, struct device_attribute, attr); + if (devattr == &sensor_dev_attr_fan1_input.dev_attr) { + if (ctx->irq < 0) + return 0; + } + + return a->mode; +} + +static const struct attribute_group pwm_fan_group = { + .attrs = pwm_fan_attrs, + .is_visible = pwm_fan_attrs_visible, +}; + +static const struct attribute_group *pwm_fan_groups[] = { + &pwm_fan_group, + NULL, +}; /* thermal cooling device callbacks */ static int pwm_fan_get_max_state(struct thermal_cooling_device *cdev, @@ -261,6 +331,32 @@ static int pwm_fan_probe(struct platform_device *pdev) goto err_reg_disable; } + timer_setup(&ctx->rpm_timer, sample_timer, 0); + + if (of_property_read_u32(pdev->dev.of_node, "pulses-per-revolution", + &ctx->pulses_per_revolution)) { + ctx->pulses_per_revolution = 2; + } + + if (!ctx->pulses_per_revolution) { + dev_err(&pdev->dev, "pulses-per-revolution can't be zero.\n"); + ret = -EINVAL; + goto err_pwm_disable; + } + + atomic_set(&ctx->pulses, 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"); + goto err_pwm_disable; + } + ctx->sample_start = ktime_get(); + mod_timer(&ctx->rpm_timer, jiffies + HZ); + } + hwmon = devm_hwmon_device_register_with_groups(&pdev->dev, "pwmfan", ctx, pwm_fan_groups); if (IS_ERR(hwmon)) { @@ -306,6 +402,8 @@ 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->rpm_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 fans with a tachometer output signal, which generate a defined number of pulses per revolution. Signed-off-by: Stefan Wahren <stefan.wahren@i2se.com> --- drivers/hwmon/pwm-fan.c | 100 +++++++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 99 insertions(+), 1 deletion(-)