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Date: Fri, 01 Feb 2013 16:27:40 +0800
From: Zhang Rui <rui.zhang@...el.com>
To: Amit Daniel Kachhap <amit.daniel@...sung.com>
Cc: linux-pm@...r.kernel.org, jonghwa3.lee@...sung.com,
linux-samsung-soc@...r.kernel.org, linux-kernel@...r.kernel.org,
durgadoss.r@...el.com
Subject: Re: [PATCH V2 1/2] thermal: sysfs: Add a new sysfs node emul_temp
for thermal emulation
On Sun, 2013-01-27 at 19:28 -0800, Amit Daniel Kachhap wrote:
> This patch adds support to set the emulated temperature method in
> thermal zone (sensor). After setting this feature thermal zone may
> report this temperature and not the actual temperature. The emulation
> implementation may be based on sensor capability through platform
> specific handler or pure software emulation if no platform handler defined.
>
> This is useful in debugging different temperature threshold and its
> associated cooling action. Critical threshold's cannot be emulated.
> Writing 0 on this node should disable emulation.
>
> Signed-off-by: Amit Daniel Kachhap <amit.daniel@...sung.com>
> Acked-by: Kukjin Kim <kgene.kim@...sung.com>
> ---
>
> Changes in V2:
> * Added config option for enabling emulation support.
> * Added s/w emulation if no platform handler registered.
> * skip the critical trip point emulation
>
> This patchset is based on thermal maintainer next tree.
> git://git.kernel.org/pub/scm/linux/kernel/git/rzhang/linux.git next
>
> Documentation/thermal/sysfs-api.txt | 13 ++++++
> drivers/thermal/Kconfig | 8 +++
> drivers/thermal/thermal_sys.c | 82 ++++++++++++++++++++++++++++++-----
> include/linux/thermal.h | 2 +
> 4 files changed, 94 insertions(+), 11 deletions(-)
>
> diff --git a/Documentation/thermal/sysfs-api.txt b/Documentation/thermal/sysfs-api.txt
> index 526d4b9..6859661 100644
> --- a/Documentation/thermal/sysfs-api.txt
> +++ b/Documentation/thermal/sysfs-api.txt
> @@ -55,6 +55,8 @@ temperature) and throttle appropriate devices.
> .get_trip_type: get the type of certain trip point.
> .get_trip_temp: get the temperature above which the certain trip point
> will be fired.
> + .set_emul_temp: set the emulation temperature which helps in debugging
> + different threshold temperature points.
>
> 1.1.2 void thermal_zone_device_unregister(struct thermal_zone_device *tz)
>
> @@ -153,6 +155,7 @@ Thermal zone device sys I/F, created once it's registered:
> |---trip_point_[0-*]_temp: Trip point temperature
> |---trip_point_[0-*]_type: Trip point type
> |---trip_point_[0-*]_hyst: Hysteresis value for this trip point
> + |---emul_temp: Emulated temperature set node
>
> Thermal cooling device sys I/F, created once it's registered:
> /sys/class/thermal/cooling_device[0-*]:
> @@ -252,6 +255,16 @@ passive
> Valid values: 0 (disabled) or greater than 1000
> RW, Optional
>
> +emul_temp
> + Interface to set the emulated temperature method in thermal zone
> + (sensor). After setting this temperature, the thermal zone may pass
> + this temperature to platform emulation function if registered or
> + cache it locally. This is useful in debugging different temperature
> + threshold and its associated cooling action. This is write only node
> + and writing 0 on this node should disable emulation.
> + Unit: millidegree Celsius
> + WO, Optional
> +
> *****************************
> * Cooling device attributes *
> *****************************
> diff --git a/drivers/thermal/Kconfig b/drivers/thermal/Kconfig
> index faf38c5..e4cf7fb 100644
> --- a/drivers/thermal/Kconfig
> +++ b/drivers/thermal/Kconfig
> @@ -78,6 +78,14 @@ config CPU_THERMAL
> and not the ACPI interface.
> If you want this support, you should say Y here.
>
> +config THERMAL_EMULATION
> + bool "Thermal emulation mode support"
> + help
> + Enable this option to make a emul_temp sysfs node in thermal zone
> + directory to support temperature emulation. With emulation sysfs node,
> + user can manually input temperature and test the different trip
> + threshold behaviour for simulation purpose.
> +
> config SPEAR_THERMAL
> bool "SPEAr thermal sensor driver"
> depends on PLAT_SPEAR
> diff --git a/drivers/thermal/thermal_sys.c b/drivers/thermal/thermal_sys.c
> index 0a1bf6b..59ba709 100644
> --- a/drivers/thermal/thermal_sys.c
> +++ b/drivers/thermal/thermal_sys.c
> @@ -378,24 +378,57 @@ static void handle_thermal_trip(struct thermal_zone_device *tz, int trip)
> monitor_thermal_zone(tz);
> }
>
> +static int thermal_zone_get_temp(struct thermal_zone_device *tz,
> + unsigned long *temp)
> +{
> + int ret = 0, count;
> + unsigned long crit_temp = -1UL;
> + enum thermal_trip_type type;
> +
> + mutex_lock(&tz->lock);
> +
> + if (tz->ops->get_temp)
> + ret = tz->ops->get_temp(tz, temp);
we do not need to do this check, .get_temp() should always be available.
#ifdef CONFIG_THERMAL_EMUL
> + else
> + ret = -EPERM;
> +
> + if (!tz->emul_temperature)
> + goto skip_emul;
> +
> + for (count = 0; count < tz->trips; count++) {
> + ret = tz->ops->get_trip_type(tz, count, &type);
> + if (!ret && type == THERMAL_TRIP_CRITICAL) {
> + ret = tz->ops->get_trip_temp(tz, count, &crit_temp);
> + break;
> + }
> + }
> +
> + if (ret)
> + goto skip_emul;
> +
> + if (*temp < crit_temp)
> + *temp = tz->emul_temperature;
> +
> +skip_emul:
#endif
or you can introduce get_emul_temp() instead.
> + mutex_unlock(&tz->lock);
> + return ret;
> +}
> +
> static void update_temperature(struct thermal_zone_device *tz)
> {
> long temp;
> int ret;
>
> - mutex_lock(&tz->lock);
> -
> - ret = tz->ops->get_temp(tz, &temp);
> + ret = thermal_zone_get_temp(tz, &temp);
> if (ret) {
> dev_warn(&tz->device, "failed to read out thermal zone %d\n",
> tz->id);
> - goto exit;
> + return;
> }
>
> + mutex_lock(&tz->lock);
> tz->last_temperature = tz->temperature;
> tz->temperature = temp;
> -
> -exit:
> mutex_unlock(&tz->lock);
> }
>
> @@ -438,10 +471,7 @@ temp_show(struct device *dev, struct device_attribute *attr, char *buf)
> long temperature;
> int ret;
>
> - if (!tz->ops->get_temp)
> - return -EPERM;
> -
> - ret = tz->ops->get_temp(tz, &temperature);
> + ret = thermal_zone_get_temp(tz, &temperature);
>
> if (ret)
> return ret;
> @@ -701,6 +731,31 @@ policy_show(struct device *dev, struct device_attribute *devattr, char *buf)
> return sprintf(buf, "%s\n", tz->governor->name);
> }
>
> +#ifdef CONFIG_THERMAL_EMULATION
> +static ssize_t
> +emul_temp_store(struct device *dev, struct device_attribute *attr,
> + const char *buf, size_t count)
> +{
> + struct thermal_zone_device *tz = to_thermal_zone(dev);
> + int ret = 0;
> + unsigned long temperature;
> +
> + if (kstrtoul(buf, 10, &temperature))
> + return -EINVAL;
> +
> + if (!tz->ops->set_emul_temp) {
> + mutex_lock(&tz->lock);
> + tz->emul_temperature = temperature;
> + mutex_unlock(&tz->lock);
> + } else {
> + ret = tz->ops->set_emul_temp(tz, temperature);
> + }
> +
> + return ret ? ret : count;
> +}
> +static DEVICE_ATTR(emul_temp, S_IWUSR, NULL, emul_temp_store);
> +#endif/*CONFIG_THERMAL_EMULATION*/
> +
> static DEVICE_ATTR(type, 0444, type_show, NULL);
> static DEVICE_ATTR(temp, 0444, temp_show, NULL);
> static DEVICE_ATTR(mode, 0644, mode_show, mode_store);
> @@ -843,7 +898,7 @@ temp_input_show(struct device *dev, struct device_attribute *attr, char *buf)
> temp_input);
> struct thermal_zone_device *tz = temp->tz;
>
> - ret = tz->ops->get_temp(tz, &temperature);
> + ret = thermal_zone_get_temp(tz, &temperature);
>
> if (ret)
> return ret;
> @@ -1596,6 +1651,11 @@ struct thermal_zone_device *thermal_zone_device_register(const char *type,
> goto unregister;
> }
>
> +#ifdef CONFIG_THERMAL_EMULATION
> + result = device_create_file(&tz->device, &dev_attr_emul_temp);
> + if (result)
> + goto unregister;
> +#endif
> /* Create policy attribute */
> result = device_create_file(&tz->device, &dev_attr_policy);
> if (result)
> diff --git a/include/linux/thermal.h b/include/linux/thermal.h
> index 9b78f8c..f0bd7f9 100644
> --- a/include/linux/thermal.h
> +++ b/include/linux/thermal.h
> @@ -123,6 +123,7 @@ struct thermal_zone_device_ops {
> int (*set_trip_hyst) (struct thermal_zone_device *, int,
> unsigned long);
> int (*get_crit_temp) (struct thermal_zone_device *, unsigned long *);
> + int (*set_emul_temp) (struct thermal_zone_device *, unsigned long);
> int (*get_trend) (struct thermal_zone_device *, int,
> enum thermal_trend *);
> int (*notify) (struct thermal_zone_device *, int,
> @@ -165,6 +166,7 @@ struct thermal_zone_device {
> int polling_delay;
> int temperature;
> int last_temperature;
> + int emul_temperature;
> int passive;
> unsigned int forced_passive;
> const struct thermal_zone_device_ops *ops;
others look okay to me.
thanks,
rui
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