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Date: Wed, 29 Nov 2023 14:43:43 +0100
From: AngeloGioacchino Del Regno
<angelogioacchino.delregno@...labora.com>
To: rafael@...nel.org
Cc: daniel.lezcano@...aro.org, rui.zhang@...el.com,
lukasz.luba@....com, linux-pm@...r.kernel.org,
linux-kernel@...r.kernel.org, kernel@...labora.com,
wenst@...omium.org
Subject: Re: [PATCH v2] thermal: Add support for device tree thermal zones
consumers
Il 15/11/23 15:48, AngeloGioacchino Del Regno ha scritto:
> Add helpers to support retrieving thermal zones from device tree nodes:
> this will allow a device tree consumer to specify phandles to specific
> thermal zone(s), including support for specifying thermal-zone-names.
> This is useful, for example, for smart voltage scaling drivers that
> need to adjust CPU/GPU/other voltages based on temperature, and for
> battery charging drivers that need to scale current based on various
> aggregated temperature sensor readings which are board-dependant.
>
> Example:
> smart-scaling-driver@...00000 {
> [...]
>
> thermal-zones = <&cluster_big_tz>, <&gpu_tz>, <&vpu_tz>;
> thermal-zone-names = "cpu", "gpu", "vpu";
>
> [...]
> }
>
> battery-charger@...00000 {
> [...]
>
> thermal-zones = <&battery_temp>, <&device_skin_temp>;
> thermal-zone-names = "batt-ext-sensor", "skin";
>
> [...]
> }
>
> Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@...labora.com>
> ---
>
Hello,
just notifying that the dtschema for thermal consumers was merged[1], hence
totally unblocking this patch.
[1]:
https://github.com/devicetree-org/dt-schema/commit/414a9f792ff7ae20a54a560bd2e2160b70f7d566
Cheers,
Angelo
> Changes in v2:
> - Added missing static inline for !CONFIG_OF fallback functions
>
> Background story: while I was cleaning up the MediaTek Smart Voltage Scaling
> (SVS) driver, I've found out that there's a lot of commonization to be done.
> After a rewrite of "this and that" in that driver, I came across a barrier
> that didn't allow me to remove another ~100 lines of code, and that was also
> anyway breaking the driver, because the thermal zone names are different
> from what was originally intended.
>
> I've been looking for thermal zone handle retrieval around the kernel and
> found that there currently are at least four other drivers that could make
> use this as a cleanup: charger-manager, which is retrieving a thermal zone
> to look for with a "cm-thermal-zone" string property, gpu/drm/tiny/repaper.c
> that does the same by checking a "pervasive,thermal-zone" string property,
> and ab8500_temp and sdhci-omap which are simply hardcoding a "cpu_thermal"
> and "battery-thermal" thermal zone names respectively.
>
> There are a number of other devices (mostly embedded, mostly smartphones)
> that don't have an upstream driver and that could make use of this as well.
>
> Cheers!
>
>
> drivers/thermal/thermal_of.c | 91 ++++++++++++++++++++++++++++++++++++
> include/linux/thermal.h | 15 ++++++
> 2 files changed, 106 insertions(+)
>
> diff --git a/drivers/thermal/thermal_of.c b/drivers/thermal/thermal_of.c
> index 1e0655b63259..d8ead456993e 100644
> --- a/drivers/thermal/thermal_of.c
> +++ b/drivers/thermal/thermal_of.c
> @@ -538,6 +538,97 @@ static struct thermal_zone_device *thermal_of_zone_register(struct device_node *
> return ERR_PTR(ret);
> }
>
> +/**
> + * __thermal_of_get_zone_by_index() - Get thermal zone handle from the DT
> + * thermal-zones index
> + * @dev: Pointer to the consumer device
> + * @index: Index of thermal-zones
> + *
> + * This function will search for a thermal zone in the thermal-zones phandle
> + * array corresponding to the specified index, then will search for its name
> + * into the registered thermal zones through thermal_zone_get_zone_by_name()
> + *
> + * Please note that this function is for internal use only and expects that
> + * all of the sanity checks are performed by its caller.
> + *
> + * Return: thermal_zone_device pointer on success, ERR_PTR() on error or NULL
> + * when the API is disabled or the "thermal-zones" DT property is missing.
> + */
> +static struct thermal_zone_device
> +*__thermal_of_get_zone_by_index(struct device *dev, int index)
> +{
> + struct thermal_zone_device *tzd;
> + struct device_node *np;
> +
> + np = of_parse_phandle(dev->of_node, "thermal-zones", index);
> + if (!np)
> + return NULL;
> +
> + tzd = thermal_zone_get_zone_by_name(np->name);
> + of_node_put(np);
> +
> + return tzd;
> +}
> +
> +/**
> + * thermal_of_get_zone_by_index() - Get thermal zone handle from a DT node
> + * based on index
> + * @dev: Pointer to the consumer device
> + * @index: Index of thermal-zones
> + *
> + * Return: thermal_zone_device pointer on success, ERR_PTR() on error or NULL
> + * when the API is disabled or the "thermal-zones" DT property is missing.
> + */
> +struct thermal_zone_device *thermal_of_get_zone_by_index(struct device *dev, int index)
> +{
> + if (!dev || !dev->of_node)
> + return ERR_PTR(-ENODEV);
> +
> + if (!of_property_present(dev->of_node, "thermal-zones"))
> + return NULL;
> +
> + return __thermal_of_get_zone_by_index(dev, index);
> +}
> +
> +/**
> + * thermal_of_get_zone() - Get thermal zone handle from a DT node based
> + * on name, or the first handle in list
> + * @dev: Pointer to the consumer device
> + * @name: Name as found in thermal-zone-names or NULL
> + *
> + * This function will search for a thermal zone in the thermal-zones phandle
> + * array corresponding to the index of that in the thermal-zone-names array.
> + * If the name is not specified (NULL), it will return the first thermal zone
> + * in the thermal-zones phandle array.
> + *
> + * Return: thermal_zone_device pointer on success, ERR_PTR() on error or NULL
> + * when the API is disabled or the "thermal-zones" DT property is missing.
> + */
> +struct thermal_zone_device *thermal_of_get_zone(struct device *dev, const char *name)
> +{
> + int index;
> +
> + if (!dev || !dev->of_node)
> + return ERR_PTR(-ENODEV);
> +
> + if (!of_property_present(dev->of_node, "thermal-zones")) {
> + pr_err("thermal zones property not present\n");
> + return NULL;
> + }
> +
> + if (name) {
> + index = of_property_match_string(dev->of_node, "thermal-zone-names", name);
> + if (index < 0) {
> + pr_err("thermal zone names property not present\n");
> + return ERR_PTR(index);
> + }
> + } else {
> + index = 0;
> + }
> +
> + return __thermal_of_get_zone_by_index(dev, index);
> +}
> +
> static void devm_thermal_of_zone_release(struct device *dev, void *res)
> {
> thermal_of_zone_unregister(*(struct thermal_zone_device **)res);
> diff --git a/include/linux/thermal.h b/include/linux/thermal.h
> index cee814d5d1ac..0fceeb7ed08a 100644
> --- a/include/linux/thermal.h
> +++ b/include/linux/thermal.h
> @@ -261,6 +261,9 @@ struct thermal_zone_device *devm_thermal_of_zone_register(struct device *dev, in
>
> void devm_thermal_of_zone_unregister(struct device *dev, struct thermal_zone_device *tz);
>
> +struct thermal_zone_device *thermal_of_get_zone_by_index(struct device *dev, int index);
> +struct thermal_zone_device *thermal_of_get_zone(struct device *dev, const char *name);
> +
> #else
>
> static inline
> @@ -274,6 +277,18 @@ static inline void devm_thermal_of_zone_unregister(struct device *dev,
> struct thermal_zone_device *tz)
> {
> }
> +
> +static inline
> +struct thermal_zone_device *thermal_of_get_zone_by_index(struct device *dev, int index)
> +{
> + return ERR_PTR(-ENOTSUPP);
> +}
> +
> +static inline
> +struct thermal_zone_device *thermal_of_get_zone(struct device *dev, const char *name)
> +{
> + return ERR_PTR(-ENOTSUPP);
> +}
> #endif
>
> int __thermal_zone_get_trip(struct thermal_zone_device *tz, int trip_id,
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