* [PATCH RFC 0/3] hwmon: pwm-fan: Add RPM support @ 2019-01-30 15:07 Stefan Wahren 2019-01-30 15:07 ` [PATCH RFC 1/3] dt-bindings: hwmon: Add tachometer interrupt to pwm-fan Stefan Wahren ` (2 more replies) 0 siblings, 3 replies; 10+ messages in thread From: Stefan Wahren @ 2019-01-30 15:07 UTC (permalink / raw) To: Kamil Debski, Bartlomiej Zolnierkiewicz, Jean Delvare, Guenter Roeck, Rob Herring, Mark Rutland Cc: linux-hwmon, devicetree, linux-kernel, Stefan Wahren Contrary to the gpio-fan the pwm-fan driver isn't easy to setup with pwmconfig/fancontrol because of the missing hwmon sysfs entry for actual revolutions per minute. This series adds this feature. This series based on the recently submitted regulator support. Stefan Wahren (3): dt-bindings: hwmon: Add tachometer interrupt to pwm-fan Documentation: pwm-fan: Add description for RPM support hwmon: pwm-fan: Add RPM support via external interrupt .../devicetree/bindings/hwmon/pwm-fan.txt | 3 ++ Documentation/hwmon/pwm-fan | 4 ++ drivers/hwmon/pwm-fan.c | 55 ++++++++++++++++++++++ 3 files changed, 62 insertions(+) -- 2.7.4 ^ permalink raw reply [flat|nested] 10+ messages in thread
* [PATCH RFC 1/3] dt-bindings: hwmon: Add tachometer interrupt to pwm-fan 2019-01-30 15:07 [PATCH RFC 0/3] hwmon: pwm-fan: Add RPM support Stefan Wahren @ 2019-01-30 15:07 ` Stefan Wahren 2019-01-30 17:28 ` Guenter Roeck 2019-01-30 15:07 ` [PATCH RFC 2/3] Documentation: pwm-fan: Add description for RPM support Stefan Wahren 2019-01-30 15:07 ` [PATCH RFC 3/3] hwmon: pwm-fan: Add RPM support via external interrupt Stefan Wahren 2 siblings, 1 reply; 10+ messages in thread From: Stefan Wahren @ 2019-01-30 15:07 UTC (permalink / raw) To: Kamil Debski, Bartlomiej Zolnierkiewicz, Jean Delvare, Guenter Roeck, Rob Herring, Mark Rutland Cc: linux-hwmon, devicetree, linux-kernel, Stefan Wahren This adds the tachometer interrupt to the pwm-fan binding, which is necessary for RPM support. Signed-off-by: Stefan Wahren <stefan.wahren@i2se.com> --- Documentation/devicetree/bindings/hwmon/pwm-fan.txt | 3 +++ 1 file changed, 3 insertions(+) diff --git a/Documentation/devicetree/bindings/hwmon/pwm-fan.txt b/Documentation/devicetree/bindings/hwmon/pwm-fan.txt index 49ca5d8..7f69b0b 100644 --- a/Documentation/devicetree/bindings/hwmon/pwm-fan.txt +++ b/Documentation/devicetree/bindings/hwmon/pwm-fan.txt @@ -8,6 +8,9 @@ Required properties: Optional properties: - fan-supply : phandle to the regulator that provides power to the fan +- interrupts : contains a single interrupt specifier which describes the + tachometer pin output of a 2 pulse-per-revolution fan. + See interrupt-controller/interrupts.txt for the format. Example: fan0: pwm-fan { -- 2.7.4 ^ permalink raw reply related [flat|nested] 10+ messages in thread
* Re: [PATCH RFC 1/3] dt-bindings: hwmon: Add tachometer interrupt to pwm-fan 2019-01-30 15:07 ` [PATCH RFC 1/3] dt-bindings: hwmon: Add tachometer interrupt to pwm-fan Stefan Wahren @ 2019-01-30 17:28 ` Guenter Roeck 2019-01-30 20:23 ` Stefan Wahren 0 siblings, 1 reply; 10+ messages in thread From: Guenter Roeck @ 2019-01-30 17:28 UTC (permalink / raw) To: Stefan Wahren Cc: Kamil Debski, Bartlomiej Zolnierkiewicz, Jean Delvare, Rob Herring, Mark Rutland, linux-hwmon, devicetree, linux-kernel On Wed, Jan 30, 2019 at 04:07:05PM +0100, Stefan Wahren wrote: > This adds the tachometer interrupt to the pwm-fan binding, which is > necessary for RPM support. > > Signed-off-by: Stefan Wahren <stefan.wahren@i2se.com> > --- > Documentation/devicetree/bindings/hwmon/pwm-fan.txt | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/Documentation/devicetree/bindings/hwmon/pwm-fan.txt b/Documentation/devicetree/bindings/hwmon/pwm-fan.txt > index 49ca5d8..7f69b0b 100644 > --- a/Documentation/devicetree/bindings/hwmon/pwm-fan.txt > +++ b/Documentation/devicetree/bindings/hwmon/pwm-fan.txt > @@ -8,6 +8,9 @@ Required properties: > > Optional properties: > - fan-supply : phandle to the regulator that provides power to the fan > +- interrupts : contains a single interrupt specifier which describes the > + tachometer pin output of a 2 pulse-per-revolution fan. > + See interrupt-controller/interrupts.txt for the format. So a hypothetical {1,4} pulse-per-revolution fan would explicitly not be supported ? Why ? Guenter ^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [PATCH RFC 1/3] dt-bindings: hwmon: Add tachometer interrupt to pwm-fan 2019-01-30 17:28 ` Guenter Roeck @ 2019-01-30 20:23 ` Stefan Wahren 2019-01-30 20:35 ` Guenter Roeck 0 siblings, 1 reply; 10+ messages in thread From: Stefan Wahren @ 2019-01-30 20:23 UTC (permalink / raw) To: Guenter Roeck Cc: Kamil Debski, Bartlomiej Zolnierkiewicz, Jean Delvare, Rob Herring, Mark Rutland, linux-hwmon, devicetree, linux-kernel Hi Guenter, > Guenter Roeck <linux@roeck-us.net> hat am 30. Januar 2019 um 18:28 geschrieben: > > > On Wed, Jan 30, 2019 at 04:07:05PM +0100, Stefan Wahren wrote: > > This adds the tachometer interrupt to the pwm-fan binding, which is > > necessary for RPM support. > > > > Signed-off-by: Stefan Wahren <stefan.wahren@i2se.com> > > --- > > Documentation/devicetree/bindings/hwmon/pwm-fan.txt | 3 +++ > > 1 file changed, 3 insertions(+) > > > > diff --git a/Documentation/devicetree/bindings/hwmon/pwm-fan.txt b/Documentation/devicetree/bindings/hwmon/pwm-fan.txt > > index 49ca5d8..7f69b0b 100644 > > --- a/Documentation/devicetree/bindings/hwmon/pwm-fan.txt > > +++ b/Documentation/devicetree/bindings/hwmon/pwm-fan.txt > > @@ -8,6 +8,9 @@ Required properties: > > > > Optional properties: > > - fan-supply : phandle to the regulator that provides power to the fan > > +- interrupts : contains a single interrupt specifier which describes the > > + tachometer pin output of a 2 pulse-per-revolution fan. > > + See interrupt-controller/interrupts.txt for the format. > > So a hypothetical {1,4} pulse-per-revolution fan would explicitly not be > supported ? Why ? i could add an additional property to specify the pulse per revolution and use the 2 as default (according to the Intel spec for 4 pin pwm fan) which should fit in most cases. > > Guenter ^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [PATCH RFC 1/3] dt-bindings: hwmon: Add tachometer interrupt to pwm-fan 2019-01-30 20:23 ` Stefan Wahren @ 2019-01-30 20:35 ` Guenter Roeck 2019-01-31 8:02 ` Stefan Wahren 0 siblings, 1 reply; 10+ messages in thread From: Guenter Roeck @ 2019-01-30 20:35 UTC (permalink / raw) To: Stefan Wahren Cc: Kamil Debski, Bartlomiej Zolnierkiewicz, Jean Delvare, Rob Herring, Mark Rutland, linux-hwmon, devicetree, linux-kernel On Wed, Jan 30, 2019 at 09:23:31PM +0100, Stefan Wahren wrote: > Hi Guenter, > > > Guenter Roeck <linux@roeck-us.net> hat am 30. Januar 2019 um 18:28 geschrieben: > > > > > > On Wed, Jan 30, 2019 at 04:07:05PM +0100, Stefan Wahren wrote: > > > This adds the tachometer interrupt to the pwm-fan binding, which is > > > necessary for RPM support. > > > > > > Signed-off-by: Stefan Wahren <stefan.wahren@i2se.com> > > > --- > > > Documentation/devicetree/bindings/hwmon/pwm-fan.txt | 3 +++ > > > 1 file changed, 3 insertions(+) > > > > > > diff --git a/Documentation/devicetree/bindings/hwmon/pwm-fan.txt b/Documentation/devicetree/bindings/hwmon/pwm-fan.txt > > > index 49ca5d8..7f69b0b 100644 > > > --- a/Documentation/devicetree/bindings/hwmon/pwm-fan.txt > > > +++ b/Documentation/devicetree/bindings/hwmon/pwm-fan.txt > > > @@ -8,6 +8,9 @@ Required properties: > > > > > > Optional properties: > > > - fan-supply : phandle to the regulator that provides power to the fan > > > +- interrupts : contains a single interrupt specifier which describes the > > > + tachometer pin output of a 2 pulse-per-revolution fan. > > > + See interrupt-controller/interrupts.txt for the format. > > > > So a hypothetical {1,4} pulse-per-revolution fan would explicitly not be > > supported ? Why ? > > i could add an additional property to specify the pulse per revolution and use the 2 as default (according to the Intel spec for 4 pin pwm fan) which should fit in most cases. > That would be a possibility and make sense, but that is not the point here. The "interrupts" property does not and should not care how many pulses per revolution the fan provides. Guenter ^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [PATCH RFC 1/3] dt-bindings: hwmon: Add tachometer interrupt to pwm-fan 2019-01-30 20:35 ` Guenter Roeck @ 2019-01-31 8:02 ` Stefan Wahren 2019-01-31 17:19 ` Guenter Roeck 0 siblings, 1 reply; 10+ messages in thread From: Stefan Wahren @ 2019-01-31 8:02 UTC (permalink / raw) To: Guenter Roeck Cc: Kamil Debski, Bartlomiej Zolnierkiewicz, Jean Delvare, Rob Herring, Mark Rutland, linux-hwmon, devicetree, linux-kernel Hi Guenter, Am 30.01.19 um 21:35 schrieb Guenter Roeck: > On Wed, Jan 30, 2019 at 09:23:31PM +0100, Stefan Wahren wrote: >> Hi Guenter, >> >>> Guenter Roeck <linux@roeck-us.net> hat am 30. Januar 2019 um 18:28 geschrieben: >>> >>> >>> On Wed, Jan 30, 2019 at 04:07:05PM +0100, Stefan Wahren wrote: >>>> This adds the tachometer interrupt to the pwm-fan binding, which is >>>> necessary for RPM support. >>>> >>>> Signed-off-by: Stefan Wahren <stefan.wahren@i2se.com> >>>> --- >>>> Documentation/devicetree/bindings/hwmon/pwm-fan.txt | 3 +++ >>>> 1 file changed, 3 insertions(+) >>>> >>>> diff --git a/Documentation/devicetree/bindings/hwmon/pwm-fan.txt b/Documentation/devicetree/bindings/hwmon/pwm-fan.txt >>>> index 49ca5d8..7f69b0b 100644 >>>> --- a/Documentation/devicetree/bindings/hwmon/pwm-fan.txt >>>> +++ b/Documentation/devicetree/bindings/hwmon/pwm-fan.txt >>>> @@ -8,6 +8,9 @@ Required properties: >>>> >>>> Optional properties: >>>> - fan-supply : phandle to the regulator that provides power to the fan >>>> +- interrupts : contains a single interrupt specifier which describes the >>>> + tachometer pin output of a 2 pulse-per-revolution fan. >>>> + See interrupt-controller/interrupts.txt for the format. >>> So a hypothetical {1,4} pulse-per-revolution fan would explicitly not be >>> supported ? Why ? >> i could add an additional property to specify the pulse per revolution and use the 2 as default (according to the Intel spec for 4 pin pwm fan) which should fit in most cases. >> > That would be a possibility and make sense, but that is not > the point here. The "interrupts" property does not and should > not care how many pulses per revolution the fan provides. sorry, i'm not sure what's the problem about. Do you want me to use a GPIO instead of interrupt? Or is it the wording here? Suggestion: contains a single interrupt specifier which is describes the tachometer output of the fan as an input Stefan > > Guenter ^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: [PATCH RFC 1/3] dt-bindings: hwmon: Add tachometer interrupt to pwm-fan 2019-01-31 8:02 ` Stefan Wahren @ 2019-01-31 17:19 ` Guenter Roeck 0 siblings, 0 replies; 10+ messages in thread From: Guenter Roeck @ 2019-01-31 17:19 UTC (permalink / raw) To: Stefan Wahren Cc: Kamil Debski, Bartlomiej Zolnierkiewicz, Jean Delvare, Rob Herring, Mark Rutland, linux-hwmon, devicetree, linux-kernel On Thu, Jan 31, 2019 at 09:02:33AM +0100, Stefan Wahren wrote: > Hi Guenter, > > Am 30.01.19 um 21:35 schrieb Guenter Roeck: > > On Wed, Jan 30, 2019 at 09:23:31PM +0100, Stefan Wahren wrote: > >> Hi Guenter, > >> > >>> Guenter Roeck <linux@roeck-us.net> hat am 30. Januar 2019 um 18:28 geschrieben: > >>> > >>> > >>> On Wed, Jan 30, 2019 at 04:07:05PM +0100, Stefan Wahren wrote: > >>>> This adds the tachometer interrupt to the pwm-fan binding, which is > >>>> necessary for RPM support. > >>>> > >>>> Signed-off-by: Stefan Wahren <stefan.wahren@i2se.com> > >>>> --- > >>>> Documentation/devicetree/bindings/hwmon/pwm-fan.txt | 3 +++ > >>>> 1 file changed, 3 insertions(+) > >>>> > >>>> diff --git a/Documentation/devicetree/bindings/hwmon/pwm-fan.txt b/Documentation/devicetree/bindings/hwmon/pwm-fan.txt > >>>> index 49ca5d8..7f69b0b 100644 > >>>> --- a/Documentation/devicetree/bindings/hwmon/pwm-fan.txt > >>>> +++ b/Documentation/devicetree/bindings/hwmon/pwm-fan.txt > >>>> @@ -8,6 +8,9 @@ Required properties: > >>>> > >>>> Optional properties: > >>>> - fan-supply : phandle to the regulator that provides power to the fan > >>>> +- interrupts : contains a single interrupt specifier which describes the > >>>> + tachometer pin output of a 2 pulse-per-revolution fan. > >>>> + See interrupt-controller/interrupts.txt for the format. > >>> So a hypothetical {1,4} pulse-per-revolution fan would explicitly not be > >>> supported ? Why ? > >> i could add an additional property to specify the pulse per revolution and use the 2 as default (according to the Intel spec for 4 pin pwm fan) which should fit in most cases. > >> > > That would be a possibility and make sense, but that is not > > the point here. The "interrupts" property does not and should > > not care how many pulses per revolution the fan provides. > > sorry, i'm not sure what's the problem about. Do you want me to use a > GPIO instead of interrupt? > > Or is it the wording here? > You wording limits the use of interrupts with pwm fans to fans with 2 pulses per revolution. You do not explain why that restriction would be required or even make sense, or why it should be associated with the 'interrupts' property. Logically I assume that is because you expect an interrupt per pulse, but that is not explained (or what the interrupt is expected to be used for in the first place - it might, after all, be some kind of error interrupt). Guenter ^ permalink raw reply [flat|nested] 10+ messages in thread
* [PATCH RFC 2/3] Documentation: pwm-fan: Add description for RPM support 2019-01-30 15:07 [PATCH RFC 0/3] hwmon: pwm-fan: Add RPM support Stefan Wahren 2019-01-30 15:07 ` [PATCH RFC 1/3] dt-bindings: hwmon: Add tachometer interrupt to pwm-fan Stefan Wahren @ 2019-01-30 15:07 ` Stefan Wahren 2019-01-30 15:07 ` [PATCH RFC 3/3] hwmon: pwm-fan: Add RPM support via external interrupt Stefan Wahren 2 siblings, 0 replies; 10+ messages in thread From: Stefan Wahren @ 2019-01-30 15:07 UTC (permalink / raw) To: Kamil Debski, Bartlomiej Zolnierkiewicz, Jean Delvare, Guenter Roeck, Rob Herring, Mark Rutland Cc: linux-hwmon, devicetree, linux-kernel, Stefan Wahren This adds a short description for the new RPM support of the pwm-fan driver. Signed-off-by: Stefan Wahren <stefan.wahren@i2se.com> --- Documentation/hwmon/pwm-fan | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/Documentation/hwmon/pwm-fan b/Documentation/hwmon/pwm-fan index 18529d2..a1ba34c 100644 --- a/Documentation/hwmon/pwm-fan +++ b/Documentation/hwmon/pwm-fan @@ -15,3 +15,7 @@ The driver implements a simple interface for driving a fan connected to a PWM output. It uses the generic PWM interface, thus it can be used with a range of SoCs. The driver exposes the fan to the user space through the hwmon's sysfs interface. + +The measured fan rotation speed returned via 'fan1_input' is derived +from the sampled interrupts from the tachometer signal by assuming +a 2 pulse-per-revolution fan. -- 2.7.4 ^ permalink raw reply related [flat|nested] 10+ messages in thread
* [PATCH RFC 3/3] hwmon: pwm-fan: Add RPM support via external interrupt 2019-01-30 15:07 [PATCH RFC 0/3] hwmon: pwm-fan: Add RPM support Stefan Wahren 2019-01-30 15:07 ` [PATCH RFC 1/3] dt-bindings: hwmon: Add tachometer interrupt to pwm-fan Stefan Wahren 2019-01-30 15:07 ` [PATCH RFC 2/3] Documentation: pwm-fan: Add description for RPM support Stefan Wahren @ 2019-01-30 15:07 ` Stefan Wahren 2019-01-31 17:40 ` Guenter Roeck 2 siblings, 1 reply; 10+ messages in thread From: Stefan Wahren @ 2019-01-30 15:07 UTC (permalink / raw) To: Kamil Debski, Bartlomiej Zolnierkiewicz, Jean Delvare, Guenter Roeck, Rob Herring, Mark Rutland Cc: linux-hwmon, devicetree, linux-kernel, Stefan Wahren 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++; + + 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); -- 2.7.4 ^ permalink raw reply related [flat|nested] 10+ messages in thread
* Re: [PATCH RFC 3/3] hwmon: pwm-fan: Add RPM support via external interrupt 2019-01-30 15:07 ` [PATCH RFC 3/3] hwmon: pwm-fan: Add RPM support via external interrupt Stefan Wahren @ 2019-01-31 17:40 ` Guenter Roeck 0 siblings, 0 replies; 10+ messages in thread From: Guenter Roeck @ 2019-01-31 17:40 UTC (permalink / raw) To: Stefan Wahren Cc: Kamil Debski, Bartlomiej Zolnierkiewicz, Jean Delvare, Rob Herring, Mark Rutland, linux-hwmon, devicetree, linux-kernel 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); > ^ permalink raw reply [flat|nested] 10+ messages in thread
end of thread, other threads:[~2019-01-31 17:40 UTC | newest] Thread overview: 10+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2019-01-30 15:07 [PATCH RFC 0/3] hwmon: pwm-fan: Add RPM support Stefan Wahren 2019-01-30 15:07 ` [PATCH RFC 1/3] dt-bindings: hwmon: Add tachometer interrupt to pwm-fan Stefan Wahren 2019-01-30 17:28 ` Guenter Roeck 2019-01-30 20:23 ` Stefan Wahren 2019-01-30 20:35 ` Guenter Roeck 2019-01-31 8:02 ` Stefan Wahren 2019-01-31 17:19 ` Guenter Roeck 2019-01-30 15:07 ` [PATCH RFC 2/3] Documentation: pwm-fan: Add description for RPM support Stefan Wahren 2019-01-30 15:07 ` [PATCH RFC 3/3] hwmon: pwm-fan: Add RPM support via external interrupt Stefan Wahren 2019-01-31 17:40 ` Guenter Roeck
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