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Message-ID: <1544022595.2841.45.camel@intel.com>
Subject: Re: [PATCH v2 02/11] thermal: add irq-mode configuration for trip
 point
From:   Zhang Rui <rui.zhang@intel.com>
To:     Lukasz Luba <l.luba@partner.samsung.com>,
        devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
        linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-pm@vger.kernel.org
Cc:     edubezval@gmail.com, daniel.lezcano@linaro.org, robh+dt@kernel.org,
        mark.rutland@arm.com, corbet@lwn.net, b.zolnierkie@samsung.com,
        krzk@kernel.org
Date:   Wed, 05 Dec 2018 23:09:55 +0800
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On 三, 2018-11-07 at 18:09 +0100, Lukasz Luba wrote:
> This patch adds support irq mode in trip point.
> When that flag is set in DT, there is no need for polling
> in thermal framework. Crossing the trip point will rise an IRQ.
> The naming convention for tip point 'type' can be confussing
> and 'passive' (whic is passive cooling) might be interpretted
> wrongly.
> 
> This mechanism prevents from missue and adds explicit setting
> for hardware which support interrupts for pre-configured temperature
> threshold.
> 
> Cc: Zhang Rui <rui.zhang@intel.com>
> Cc: Eduardo Valentin <edubezval@gmail.com>
> Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
> Signed-off-by: Lukasz Luba <l.luba@partner.samsung.com>
> ---
>  drivers/thermal/of-thermal.c   | 17 +++++++++++++++++
>  drivers/thermal/thermal_core.c | 10 ++++++++--
>  include/linux/thermal.h        |  5 +++++
>  3 files changed, 30 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/thermal/of-thermal.c b/drivers/thermal/of-
> thermal.c
> index 4bfdb4a..1a75946a 100644
> --- a/drivers/thermal/of-thermal.c
> +++ b/drivers/thermal/of-thermal.c
> @@ -312,6 +312,20 @@ static int of_thermal_get_trip_type(struct
> thermal_zone_device *tz, int trip,
>  	return 0;
>  }
>  
> +static int
> +of_thermal_get_trip_irq_mode(struct thermal_zone_device *tz, int
> trip,
> +			     bool *mode)
> +{
> +	struct __thermal_zone *data = tz->devdata;
> +
> +	if (trip >= data->ntrips || trip < 0)
> +		return -EDOM;
> +
> +	*mode = data->trips[trip].irq_mode;
> +
> +	return 0;
> +}
> +
>  static int of_thermal_get_trip_temp(struct thermal_zone_device *tz,
> int trip,
>  				    int *temp)
>  {
> @@ -394,6 +408,7 @@ static struct thermal_zone_device_ops
> of_thermal_ops = {
>  	.set_mode = of_thermal_set_mode,
>  
>  	.get_trip_type = of_thermal_get_trip_type,
> +	.get_trip_irq_mode = of_thermal_get_trip_irq_mode,
>  	.get_trip_temp = of_thermal_get_trip_temp,
>  	.set_trip_temp = of_thermal_set_trip_temp,
>  	.get_trip_hyst = of_thermal_get_trip_hyst,
> @@ -827,6 +842,8 @@ static int thermal_of_populate_trip(struct
> device_node *np,
>  		return ret;
>  	}
>  
> +	trip->irq_mode = of_property_read_bool(np, "irq-mode");
> +
>  	/* Required for cooling map matching */
>  	trip->np = np;
>  	of_node_get(np);
> diff --git a/drivers/thermal/thermal_core.c
> b/drivers/thermal/thermal_core.c
> index 39fc812..6d41e08 100644
> --- a/drivers/thermal/thermal_core.c
> +++ b/drivers/thermal/thermal_core.c
> @@ -406,6 +406,7 @@ static void handle_critical_trips(struct
> thermal_zone_device *tz,
>  static void handle_thermal_trip(struct thermal_zone_device *tz, int
> trip)
>  {
>  	enum thermal_trip_type type;
> +	bool irq_mode = false;
>  
>  	/* Ignore disabled trip points */
>  	if (test_bit(trip, &tz->trips_disabled))
> @@ -419,9 +420,14 @@ static void handle_thermal_trip(struct
> thermal_zone_device *tz, int trip)
>  		handle_non_critical_trips(tz, trip);
>  	/*
>  	 * Alright, we handled this trip successfully.
> -	 * So, start monitoring again.
> +	 * So, start monitoring in polling mode if
> +	 * trip is not using irq HW support.
>  	 */
> -	monitor_thermal_zone(tz);
> +	if (tz->ops->get_trip_irq_mode)
> +		tz->ops->get_trip_irq_mode(tz, trip, &irq_mode);
> +
> +	if (!irq_mode)
> +		monitor_thermal_zone(tz);
>  }
>  
handle_thermal_trip() is called from thermal_zone_device_update(), and
it is invoked for every trip points.
say, you have a passive trip point 1 that supports irq_mode, and
another passive trip point 2 that does not support irq_mode,
monitor_thermal_zone() is still called in handle_thermal_trip(tz, 2),
and the passive timer will be activated anyway, do I miss something?

thanks,
rui

>  static void update_temperature(struct thermal_zone_device *tz)
> diff --git a/include/linux/thermal.h b/include/linux/thermal.h
> index 5f4705f..b064565 100644
> --- a/include/linux/thermal.h
> +++ b/include/linux/thermal.h
> @@ -103,6 +103,7 @@ struct thermal_zone_device_ops {
>  		enum thermal_device_mode);
>  	int (*get_trip_type) (struct thermal_zone_device *, int,
>  		enum thermal_trip_type *);
> +	int (*get_trip_irq_mode) (struct thermal_zone_device *, int,
> bool *);
>  	int (*get_trip_temp) (struct thermal_zone_device *, int, int
> *);
>  	int (*set_trip_temp) (struct thermal_zone_device *, int,
> int);
>  	int (*get_trip_hyst) (struct thermal_zone_device *, int, int
> *);
> @@ -196,6 +197,7 @@ struct thermal_zone_device {
>  	struct thermal_attr *trip_temp_attrs;
>  	struct thermal_attr *trip_type_attrs;
>  	struct thermal_attr *trip_hyst_attrs;
> +	struct thermal_attr *trip_irq_mode_attrs;
>  	void *devdata;
>  	int trips;
>  	unsigned long trips_disabled;	/* bitmap for disabled
> trips */
> @@ -364,6 +366,8 @@ struct thermal_zone_of_device_ops {
>   * @temperature: temperature value in miliCelsius
>   * @hysteresis: relative hysteresis in miliCelsius
>   * @type: trip point type
> + * @irq_mode: to not use polling in framework set support of HW irq
> (which will
> + *	      be triggered when temperature reaches this level).
>   */
>  
>  struct thermal_trip {
> @@ -371,6 +375,7 @@ struct thermal_trip {
>  	int temperature;
>  	int hysteresis;
>  	enum thermal_trip_type type;
> +	bool irq_mode;
>  };
>  
>  /* Function declarations */