diff mbox series

[1/2] power: supply: cros_usbpd-charger: extend as a thermal of cooling device

Message ID 20241122-extend_power_limit-v1-1-a3ecd87afa76@chromium.org (mailing list archive)
State New
Headers show
Series Extend the cros_usbpd-charger to make it a passive thermal cooling device | expand

Commit Message

Sung-Chi Li Nov. 22, 2024, 3:47 a.m. UTC
cros_usbpd-charger is the driver that takes care the system input power
from the pd charger. This driver also exposes the functionality to limit
input current.

We can extend this driver to make it as a passive thermal cooling
device by limiting the input current. As such, this commit implements
the required cooling methods and OF style registration.

Signed-off-by: Sung-Chi Li <lschyi@chromium.org>
---
 drivers/power/supply/cros_usbpd-charger.c | 98 +++++++++++++++++++++++++++++--
 1 file changed, 93 insertions(+), 5 deletions(-)

Comments

Thomas Weißschuh Nov. 22, 2024, 10:21 a.m. UTC | #1
On 2024-11-22 11:47:21+0800, Sung-Chi Li wrote:
> cros_usbpd-charger is the driver that takes care the system input power
> from the pd charger. This driver also exposes the functionality to limit
> input current.
> 
> We can extend this driver to make it as a passive thermal cooling
> device by limiting the input current. As such, this commit implements
> the required cooling methods and OF style registration.
> 
> Signed-off-by: Sung-Chi Li <lschyi@chromium.org>
> ---
>  drivers/power/supply/cros_usbpd-charger.c | 98 +++++++++++++++++++++++++++++--
>  1 file changed, 93 insertions(+), 5 deletions(-)

A dependency from CHARGER_CROS_PCHG to THERMAL needs to be added to
drivers/power/supply/Kconfig.

> 
> diff --git a/drivers/power/supply/cros_usbpd-charger.c b/drivers/power/supply/cros_usbpd-charger.c
> index 47d3f58aa15c..a0451630cdd7 100644
> --- a/drivers/power/supply/cros_usbpd-charger.c
> +++ b/drivers/power/supply/cros_usbpd-charger.c
> @@ -13,6 +13,9 @@
>  #include <linux/platform_device.h>
>  #include <linux/power_supply.h>
>  #include <linux/slab.h>
> +#ifdef CONFIG_THERMAL_OF

Remove this ifdef. The header is perfectly usable in any case.

Actually the CONFIG_THERMAL_OF dependency is not needed at all.
It is only necessary for devm_thermal_of_zone_register() but not 
devm_thermal_of_cooling_device_register() which you are using.
I am confused.

OTOH you are adding the #cooling-cells OF property which itself seems to
be only used by devm_thermal_of_zone_register(), so I'm now even more
confused.

In general, try to also test the driver configurations
!CONFIG_THERMAL_OF and !CONFIG_THERMAL.

> +#include <linux/thermal.h>
> +#endif /* CONFIG_THERMAL_OF */
>  
>  #define CHARGER_USBPD_DIR_NAME			"CROS_USBPD_CHARGER%d"
>  #define CHARGER_DEDICATED_DIR_NAME		"CROS_DEDICATED_CHARGER"
> @@ -22,6 +25,7 @@
>  					 sizeof(CHARGER_DEDICATED_DIR_NAME))
>  #define CHARGER_CACHE_UPDATE_DELAY		msecs_to_jiffies(500)
>  #define CHARGER_MANUFACTURER_MODEL_LENGTH	32
> +#define CHARGER_COOLING_INTERVALS		10
>  
>  #define DRV_NAME "cros-usbpd-charger"
>  
> @@ -76,6 +80,8 @@ static enum power_supply_property cros_usbpd_dedicated_charger_props[] = {
>  /* Input voltage/current limit in mV/mA. Default to none. */
>  static u16 input_voltage_limit = EC_POWER_LIMIT_NONE;
>  static u16 input_current_limit = EC_POWER_LIMIT_NONE;
> +/* Cooling level interns of current limit */
> +static u16 input_current_cooling_level;
>  
>  static bool cros_usbpd_charger_port_is_dedicated(struct port_data *port)
>  {
> @@ -459,13 +465,20 @@ static int cros_usbpd_charger_set_prop(struct power_supply *psy,
>  			break;
>  
>  		input_current_limit = intval;
> -		if (input_current_limit == EC_POWER_LIMIT_NONE)
> +		if (input_current_limit == EC_POWER_LIMIT_NONE) {
>  			dev_info(dev,
>  			  "External Current Limit cleared for all ports\n");
> -		else
> -			dev_info(dev,
> -			  "External Current Limit set to %dmA for all ports\n",
> -			  input_current_limit);
> +			input_current_cooling_level = 0;
> +		} else {
> +			dev_info(
> +				dev,
> +				"External Current Limit set to %dmA for all ports\n",
> +				input_current_limit);
> +			input_current_cooling_level =
> +				input_current_limit *
> +				CHARGER_COOLING_INTERVALS /
> +				port->psy_current_max;

This seems to be a very spammy driver...

> +		}
>  		break;
>  	case POWER_SUPPLY_PROP_INPUT_VOLTAGE_LIMIT:
>  		ret = cros_usbpd_charger_set_ext_power_limit(charger,
> @@ -525,6 +538,66 @@ static void cros_usbpd_charger_unregister_notifier(void *data)
>  	cros_usbpd_unregister_notify(&charger->notifier);
>  }
>  
> +#ifdef CONFIG_THERMAL_OF
> +static int
> +cros_usbpd_charger_get_max_cooling_state(struct thermal_cooling_device *cdev,
> +					 unsigned long *cooling_level)
> +{
> +	*cooling_level = CHARGER_COOLING_INTERVALS;
> +	return 0;
> +}
> +
> +static int
> +cros_usbpd_charger_get_cur_cooling_state(struct thermal_cooling_device *cdev,
> +					 unsigned long *cooling_level)
> +{
> +	*cooling_level = input_current_cooling_level;
> +	return 0;
> +}
> +
> +static int
> +cros_usbpd_charger_set_cur_cooling_state(struct thermal_cooling_device *cdev,
> +					 unsigned long cooling_level)
> +{
> +	struct charger_data *charger = cdev->devdata;
> +	struct port_data *port;
> +	int current_limit;
> +	int idx = -1;
> +	int ret;
> +
> +	for (int i = 0; i < charger->num_registered_psy; i++) {
> +		port = charger->ports[i];
> +		if (port->psy_status == POWER_SUPPLY_STATUS_CHARGING) {
> +			idx = i;
> +			break;
> +		}
> +	}

Why not register one cooling device per charger?
It would make things more predictable.
I have no experience with the thermal subsystem, so this is just a
guess.

> +
> +	if (idx == -1)
> +		return -EINVAL;
> +
> +	current_limit =
> +		port->psy_current_max - (cooling_level * port->psy_current_max /
> +					 CHARGER_COOLING_INTERVALS);
> +	ret = cros_usbpd_charger_set_ext_power_limit(charger, current_limit,
> +						     input_voltage_limit);
> +	if (ret < 0)
> +		return ret;
> +
> +	input_current_limit = (current_limit == port->psy_current_max) ?
> +				      EC_POWER_LIMIT_NONE :
> +				      current_limit;
> +	input_current_cooling_level = cooling_level;
> +	return 0;
> +}
> +
> +static struct thermal_cooling_device_ops cros_usbpd_charger_cooling_ops = {

const

> +	.get_max_state = cros_usbpd_charger_get_max_cooling_state,
> +	.get_cur_state = cros_usbpd_charger_get_cur_cooling_state,
> +	.set_cur_state = cros_usbpd_charger_set_cur_cooling_state,
> +};
> +#endif /* CONFIG_THERMAL_OF */
> +
>  static int cros_usbpd_charger_probe(struct platform_device *pd)
>  {
>  	struct cros_ec_dev *ec_dev = dev_get_drvdata(pd->dev.parent);
> @@ -534,6 +607,9 @@ static int cros_usbpd_charger_probe(struct platform_device *pd)
>  	struct charger_data *charger;
>  	struct power_supply *psy;
>  	struct port_data *port;
> +#ifdef CONFIG_THERMAL_OF
> +	struct thermal_cooling_device *cdev;
> +#endif /* CONFIG_THERMAL_OF */
>  	int ret = -EINVAL;
>  	int i;
>  
> @@ -674,6 +750,18 @@ static int cros_usbpd_charger_probe(struct platform_device *pd)
>  			goto fail;
>  	}
>  
> +#ifdef CONFIG_THERMAL_OF

Avoid ifdef in .c files.
Use if (IS_ENABLED(CONFIG_THERMAL_OF)) in the normal code flow.
The compiler will optimize away all the unreachable code.

> +	cdev = devm_thermal_of_cooling_device_register(
> +		dev, ec_device->dev->of_node, DRV_NAME, charger,
> +		&cros_usbpd_charger_cooling_ops);
> +	if (IS_ERR(cdev)) {
> +		dev_err(dev,
> +			"Failing register thermal cooling device (err:%pe)\n",
> +			cdev);

dev_err_probe().

> +		goto fail;

Does the call to devm_thermal_of_cooling_device_register() work if there
is no OF configuration?

> +	}
> +#endif /* CONFIG_THERMAL_OF */
> +
>  	return 0;
>  
>  fail:
> 
> -- 
> 2.47.0.371.ga323438b13-goog
>
diff mbox series

Patch

diff --git a/drivers/power/supply/cros_usbpd-charger.c b/drivers/power/supply/cros_usbpd-charger.c
index 47d3f58aa15c..a0451630cdd7 100644
--- a/drivers/power/supply/cros_usbpd-charger.c
+++ b/drivers/power/supply/cros_usbpd-charger.c
@@ -13,6 +13,9 @@ 
 #include <linux/platform_device.h>
 #include <linux/power_supply.h>
 #include <linux/slab.h>
+#ifdef CONFIG_THERMAL_OF
+#include <linux/thermal.h>
+#endif /* CONFIG_THERMAL_OF */
 
 #define CHARGER_USBPD_DIR_NAME			"CROS_USBPD_CHARGER%d"
 #define CHARGER_DEDICATED_DIR_NAME		"CROS_DEDICATED_CHARGER"
@@ -22,6 +25,7 @@ 
 					 sizeof(CHARGER_DEDICATED_DIR_NAME))
 #define CHARGER_CACHE_UPDATE_DELAY		msecs_to_jiffies(500)
 #define CHARGER_MANUFACTURER_MODEL_LENGTH	32
+#define CHARGER_COOLING_INTERVALS		10
 
 #define DRV_NAME "cros-usbpd-charger"
 
@@ -76,6 +80,8 @@  static enum power_supply_property cros_usbpd_dedicated_charger_props[] = {
 /* Input voltage/current limit in mV/mA. Default to none. */
 static u16 input_voltage_limit = EC_POWER_LIMIT_NONE;
 static u16 input_current_limit = EC_POWER_LIMIT_NONE;
+/* Cooling level interns of current limit */
+static u16 input_current_cooling_level;
 
 static bool cros_usbpd_charger_port_is_dedicated(struct port_data *port)
 {
@@ -459,13 +465,20 @@  static int cros_usbpd_charger_set_prop(struct power_supply *psy,
 			break;
 
 		input_current_limit = intval;
-		if (input_current_limit == EC_POWER_LIMIT_NONE)
+		if (input_current_limit == EC_POWER_LIMIT_NONE) {
 			dev_info(dev,
 			  "External Current Limit cleared for all ports\n");
-		else
-			dev_info(dev,
-			  "External Current Limit set to %dmA for all ports\n",
-			  input_current_limit);
+			input_current_cooling_level = 0;
+		} else {
+			dev_info(
+				dev,
+				"External Current Limit set to %dmA for all ports\n",
+				input_current_limit);
+			input_current_cooling_level =
+				input_current_limit *
+				CHARGER_COOLING_INTERVALS /
+				port->psy_current_max;
+		}
 		break;
 	case POWER_SUPPLY_PROP_INPUT_VOLTAGE_LIMIT:
 		ret = cros_usbpd_charger_set_ext_power_limit(charger,
@@ -525,6 +538,66 @@  static void cros_usbpd_charger_unregister_notifier(void *data)
 	cros_usbpd_unregister_notify(&charger->notifier);
 }
 
+#ifdef CONFIG_THERMAL_OF
+static int
+cros_usbpd_charger_get_max_cooling_state(struct thermal_cooling_device *cdev,
+					 unsigned long *cooling_level)
+{
+	*cooling_level = CHARGER_COOLING_INTERVALS;
+	return 0;
+}
+
+static int
+cros_usbpd_charger_get_cur_cooling_state(struct thermal_cooling_device *cdev,
+					 unsigned long *cooling_level)
+{
+	*cooling_level = input_current_cooling_level;
+	return 0;
+}
+
+static int
+cros_usbpd_charger_set_cur_cooling_state(struct thermal_cooling_device *cdev,
+					 unsigned long cooling_level)
+{
+	struct charger_data *charger = cdev->devdata;
+	struct port_data *port;
+	int current_limit;
+	int idx = -1;
+	int ret;
+
+	for (int i = 0; i < charger->num_registered_psy; i++) {
+		port = charger->ports[i];
+		if (port->psy_status == POWER_SUPPLY_STATUS_CHARGING) {
+			idx = i;
+			break;
+		}
+	}
+
+	if (idx == -1)
+		return -EINVAL;
+
+	current_limit =
+		port->psy_current_max - (cooling_level * port->psy_current_max /
+					 CHARGER_COOLING_INTERVALS);
+	ret = cros_usbpd_charger_set_ext_power_limit(charger, current_limit,
+						     input_voltage_limit);
+	if (ret < 0)
+		return ret;
+
+	input_current_limit = (current_limit == port->psy_current_max) ?
+				      EC_POWER_LIMIT_NONE :
+				      current_limit;
+	input_current_cooling_level = cooling_level;
+	return 0;
+}
+
+static struct thermal_cooling_device_ops cros_usbpd_charger_cooling_ops = {
+	.get_max_state = cros_usbpd_charger_get_max_cooling_state,
+	.get_cur_state = cros_usbpd_charger_get_cur_cooling_state,
+	.set_cur_state = cros_usbpd_charger_set_cur_cooling_state,
+};
+#endif /* CONFIG_THERMAL_OF */
+
 static int cros_usbpd_charger_probe(struct platform_device *pd)
 {
 	struct cros_ec_dev *ec_dev = dev_get_drvdata(pd->dev.parent);
@@ -534,6 +607,9 @@  static int cros_usbpd_charger_probe(struct platform_device *pd)
 	struct charger_data *charger;
 	struct power_supply *psy;
 	struct port_data *port;
+#ifdef CONFIG_THERMAL_OF
+	struct thermal_cooling_device *cdev;
+#endif /* CONFIG_THERMAL_OF */
 	int ret = -EINVAL;
 	int i;
 
@@ -674,6 +750,18 @@  static int cros_usbpd_charger_probe(struct platform_device *pd)
 			goto fail;
 	}
 
+#ifdef CONFIG_THERMAL_OF
+	cdev = devm_thermal_of_cooling_device_register(
+		dev, ec_device->dev->of_node, DRV_NAME, charger,
+		&cros_usbpd_charger_cooling_ops);
+	if (IS_ERR(cdev)) {
+		dev_err(dev,
+			"Failing register thermal cooling device (err:%pe)\n",
+			cdev);
+		goto fail;
+	}
+#endif /* CONFIG_THERMAL_OF */
+
 	return 0;
 
 fail: