A charge chip is connected to the ChromeOS Embedded Controller (EC).
When external power input into the system, current would go through the
charger chip, generating heat in the system. The EC supports limiting
the input current, thus reducing the generated heat.
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. As a result, extend this driver to make it as a passive
thermal cooling device by limiting the input current. This commit
implements the required cooling methods and OF style registration.
Signed-off-by: Sung-Chi Li <lschyi@xxxxxxxxxxxx>
---
drivers/power/supply/cros_usbpd-charger.c | 84 ++++++++++++++++++++++++++++++-
1 file changed, 82 insertions(+), 2 deletions(-)
diff --git a/drivers/power/supply/cros_usbpd-charger.c b/drivers/power/supply/cros_usbpd-charger.c
index 47d3f58aa15c..a080090898c0 100644
--- a/drivers/power/supply/cros_usbpd-charger.c
+++ b/drivers/power/supply/cros_usbpd-charger.c
@@ -13,6 +13,7 @@
#include <linux/platform_device.h>
#include <linux/power_supply.h>
#include <linux/slab.h>
+#include <linux/thermal.h>
#define CHARGER_USBPD_DIR_NAME "CROS_USBPD_CHARGER%d"
#define CHARGER_DEDICATED_DIR_NAME "CROS_DEDICATED_CHARGER"
@@ -22,6 +23,7 @@
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 +78,8 @@ 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 +463,19 @@ 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
+ 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 +535,64 @@ static void cros_usbpd_charger_unregister_notifier(void *data)
cros_usbpd_unregister_notify(&charger->notifier);
}
+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 const 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,
+};
+
static int cros_usbpd_charger_probe(struct platform_device *pd)
{
struct cros_ec_dev *ec_dev = dev_get_drvdata(pd->dev.parent);
@@ -534,6 +602,7 @@ static int cros_usbpd_charger_probe(struct platform_device *pd)
struct charger_data *charger;
struct power_supply *psy;
struct port_data *port;
+ struct thermal_cooling_device *cdev;
int ret = -EINVAL;
int i;
@@ -674,6 +743,17 @@ static int cros_usbpd_charger_probe(struct platform_device *pd)
goto fail;
}
+ if (IS_ENABLED(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_warn_probe(
+ dev, PTR_ERR(cdev),
+ "Failing register thermal cooling device\n");
+ }
+ }
+
return 0;
fail:
--
2.47.0.371.ga323438b13-goog
