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.
Changes in V3:
- rename property interrupt-ratio to pulses-per-revolution
to avoid confusion with interrupt binding
- handle error case pulses-per-revolution = 0
- bail out properly in case we are unable to request the irq
Changes in V2:
- address Guenter's comments:
- improve description of interrupts
- use atomic_t to avoid races of the pulse counter
- measure sample time to make rpm more reliable under load
- make sysfs entry fan1_input conditional
- add dt-property to define interrupts per fan revolution
- example for fan with RPM 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 | 22 ++++-
Documentation/hwmon/pwm-fan | 3 +
drivers/hwmon/pwm-fan.c | 100 ++++++++++++++++++++-
3 files changed, 123 insertions(+), 2 deletions(-)
--
2.7.4
This adds the tachometer interrupt to the pwm-fan binding, which is
necessary for RPM support.
Signed-off-by: Stefan Wahren <[email protected]>
---
.../devicetree/bindings/hwmon/pwm-fan.txt | 22 +++++++++++++++++++++-
1 file changed, 21 insertions(+), 1 deletion(-)
diff --git a/Documentation/devicetree/bindings/hwmon/pwm-fan.txt b/Documentation/devicetree/bindings/hwmon/pwm-fan.txt
index 49ca5d8..722005f 100644
--- a/Documentation/devicetree/bindings/hwmon/pwm-fan.txt
+++ b/Documentation/devicetree/bindings/hwmon/pwm-fan.txt
@@ -7,7 +7,16 @@ Required properties:
which correspond to thermal cooling states
Optional properties:
-- fan-supply : phandle to the regulator that provides power to the fan
+- fan-supply : phandle to the regulator that provides power to the fan
+- interrupts : This contains a single interrupt specifier which
+ describes the tachometer output of the fan as an
+ interrupt source. The output signal must generate a
+ defined number of interrupts per fan revolution, which
+ require that it must be self resetting edge interrupts.
+ See interrupt-controller/interrupts.txt for the format.
+- pulses-per-revolution : define the tachometer pulses per fan revolution as
+ an integer (default is 2 interrupts per revolution).
+ The value must be greater than zero.
Example:
fan0: pwm-fan {
@@ -38,3 +47,14 @@ Example:
};
};
};
+
+Example 2:
+ fan0: pwm-fan {
+ fan0: pwm-fan {
+ compatible = "pwm-fan";
+ pwms = <&pwm 0 40000 0>;
+ fan-supply = <®_fan>;
+ interrupt-parent = <&gpio5>;
+ interrupts = <1 IRQ_TYPE_EDGE_FALLING>;
+ pulses-per-revolution = <2>;
+ };
--
2.7.4
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 <[email protected]>
---
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);
+
+ 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);
--
2.7.4
This adds a short description for the new RPM support of the pwm-fan
driver.
Signed-off-by: Stefan Wahren <[email protected]>
---
Documentation/hwmon/pwm-fan | 3 +++
1 file changed, 3 insertions(+)
diff --git a/Documentation/hwmon/pwm-fan b/Documentation/hwmon/pwm-fan
index 18529d2..82fe967 100644
--- a/Documentation/hwmon/pwm-fan
+++ b/Documentation/hwmon/pwm-fan
@@ -15,3 +15,6 @@ 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 fan rotation speed returned via the optional 'fan1_input' is extrapolated
+from the sampled interrupts from the tachometer signal within 1 second.
--
2.7.4
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 <[email protected]>
> ---
> 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 Fri, Mar 22, 2019 at 09:24:01AM +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 <[email protected]>
> ---
> .../devicetree/bindings/hwmon/pwm-fan.txt | 22 +++++++++++++++++++++-
> 1 file changed, 21 insertions(+), 1 deletion(-)
>
> diff --git a/Documentation/devicetree/bindings/hwmon/pwm-fan.txt b/Documentation/devicetree/bindings/hwmon/pwm-fan.txt
> index 49ca5d8..722005f 100644
> --- a/Documentation/devicetree/bindings/hwmon/pwm-fan.txt
> +++ b/Documentation/devicetree/bindings/hwmon/pwm-fan.txt
> @@ -7,7 +7,16 @@ Required properties:
> which correspond to thermal cooling states
>
> Optional properties:
> -- fan-supply : phandle to the regulator that provides power to the fan
> +- fan-supply : phandle to the regulator that provides power to the fan
> +- interrupts : This contains a single interrupt specifier which
> + describes the tachometer output of the fan as an
> + interrupt source. The output signal must generate a
> + defined number of interrupts per fan revolution, which
> + require that it must be self resetting edge interrupts.
> + See interrupt-controller/interrupts.txt for the format.
> +- pulses-per-revolution : define the tachometer pulses per fan revolution as
> + an integer (default is 2 interrupts per revolution).
> + The value must be greater than zero.
>
> Example:
> fan0: pwm-fan {
> @@ -38,3 +47,14 @@ Example:
> };
> };
> };
> +
> +Example 2:
> + fan0: pwm-fan {
> + fan0: pwm-fan {
This line should go.
Otherwise,
Reviewed-by: Rob Herring <[email protected]>
> + compatible = "pwm-fan";
> + pwms = <&pwm 0 40000 0>;
> + fan-supply = <®_fan>;
> + interrupt-parent = <&gpio5>;
> + interrupts = <1 IRQ_TYPE_EDGE_FALLING>;
> + pulses-per-revolution = <2>;
> + };
> --
> 2.7.4
>
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 <[email protected]>
> ---
> 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);
>
>