This simple charger driver uses the USB role switch framework to detect
the presence of a charger. The USB charger will report as online when
the USB role is set to device, and offline otherwise.
Signed-off-by: Paul Cercueil <paul@xxxxxxxxxxxxxxx>
---
Notes:
v2: Instead of detecting charger state from USB PHY, we detect it from the
USB role in use.
drivers/power/supply/Kconfig | 8 ++
drivers/power/supply/Makefile | 1 +
drivers/power/supply/generic-usb-charger.c | 124 +++++++++++++++++++++
3 files changed, 133 insertions(+)
create mode 100644 drivers/power/supply/generic-usb-charger.c
diff --git a/drivers/power/supply/Kconfig b/drivers/power/supply/Kconfig
index 27164a1d3c7c..c4221bcabee4 100644
--- a/drivers/power/supply/Kconfig
+++ b/drivers/power/supply/Kconfig
@@ -51,6 +51,14 @@ config GENERIC_ADC_BATTERY
Say Y here to enable support for the generic battery driver
which uses IIO framework to read adc.
+config GENERIC_USB_CHARGER
+ tristate "Generic USB charger"
+ depends on USB_SUPPORT
+ select USB_ROLE_SWITCH
+ help
+ Say Y here to enable a generic USB charger driver which uses
+ the USB role switch framework to detect the presence of the charger.
+
config MAX8925_POWER
tristate "MAX8925 battery charger support"
depends on MFD_MAX8925
diff --git a/drivers/power/supply/Makefile b/drivers/power/supply/Makefile
index 6c7da920ea83..03f9b553bdfc 100644
--- a/drivers/power/supply/Makefile
+++ b/drivers/power/supply/Makefile
@@ -8,6 +8,7 @@ power_supply-$(CONFIG_LEDS_TRIGGERS) += power_supply_leds.o
obj-$(CONFIG_POWER_SUPPLY) += power_supply.o
obj-$(CONFIG_POWER_SUPPLY_HWMON) += power_supply_hwmon.o
obj-$(CONFIG_GENERIC_ADC_BATTERY) += generic-adc-battery.o
+obj-$(CONFIG_GENERIC_USB_CHARGER) += generic-usb-charger.o
obj-$(CONFIG_PDA_POWER) += pda_power.o
obj-$(CONFIG_APM_POWER) += apm_power.o
diff --git a/drivers/power/supply/generic-usb-charger.c b/drivers/power/supply/generic-usb-charger.c
new file mode 100644
index 000000000000..0493fafbd4c0
--- /dev/null
+++ b/drivers/power/supply/generic-usb-charger.c
@@ -0,0 +1,124 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Simple USB charger driver
+ * Copyright (c) 2019 Paul Cercueil <paul@xxxxxxxxxxxxxxx>
+ */
+
+#include <linux/device.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/power_supply.h>
+#include <linux/usb/role.h>
+
+struct usb_charger {
+ struct notifier_block nb;
+ struct usb_role_switch *role;
+ struct power_supply_desc desc;
+ struct power_supply *charger;
+};
+
+static enum power_supply_property usb_charger_properties[] = {
+ POWER_SUPPLY_PROP_ONLINE,
+};
+
+static int usb_charger_get_property(struct power_supply *psy,
+ enum power_supply_property psp,
+ union power_supply_propval *val)
+{
+ struct usb_charger *charger = power_supply_get_drvdata(psy);
+ enum usb_role role;
+
+ switch (psp) {
+ case POWER_SUPPLY_PROP_ONLINE:
+ role = usb_role_switch_get_role(charger->role);
+ val->intval = role == USB_ROLE_DEVICE;
+ break;
+ default:
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+static int usb_charger_event(struct notifier_block *nb,
+ unsigned long event, void *d)
+{
+ struct usb_charger *charger = container_of(nb, struct usb_charger, nb);
+
+ power_supply_changed(charger->charger);
+
+ return 0;
+}
+
+static void usb_charger_unregister(void *data)
+{
+ struct usb_charger *charger = data;
+
+ usb_role_switch_unregister_notifier(charger->role, &charger->nb);
+}
+
+static int usb_charger_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct power_supply_desc *desc;
+ struct usb_charger *charger;
+ struct power_supply_config cfg = {
+ .of_node = dev->of_node,
+ };
+ int err;
+
+ charger = devm_kzalloc(dev, sizeof(*charger), GFP_KERNEL);
+ if (!charger)
+ return -ENOMEM;
+
+ cfg.drv_data = charger;
+ charger->nb.notifier_call = usb_charger_event;
+
+ charger->role = usb_role_switch_get(dev);
+ if (IS_ERR(charger->role)) {
+ if (PTR_ERR(charger->role) != -EPROBE_DEFER)
+ dev_err(dev, "Unable to get USB role");
+ return PTR_ERR(charger->role);
+ }
+
+ desc = &charger->desc;
+ desc->name = "usb-charger";
+ desc->properties = usb_charger_properties;
+ desc->num_properties = ARRAY_SIZE(usb_charger_properties);
+ desc->get_property = usb_charger_get_property;
+ desc->type = POWER_SUPPLY_TYPE_USB;
+
+ charger->charger = devm_power_supply_register(dev, desc, &cfg);
+ if (IS_ERR(charger->charger)) {
+ dev_err(dev, "Unable to register charger");
+ return PTR_ERR(charger->charger);
+ }
+
+ err = usb_role_switch_register_notifier(charger->role, &charger->nb);
+ if (err) {
+ dev_err(dev, "Unable to register USB role switch notifier");
+ return err;
+ }
+
+ return devm_add_action_or_reset(dev, usb_charger_unregister, charger);
+}
+
+static const struct of_device_id usb_charger_of_match[] = {
+ { .compatible = "usb-charger" },
+ { /* sentinel */ },
+};
+MODULE_DEVICE_TABLE(of, usb_charger_of_match);
+
+static struct platform_driver usb_charger_driver = {
+ .driver = {
+ .name = "usb-charger",
+ .of_match_table = of_match_ptr(usb_charger_of_match),
+ },
+ .probe = usb_charger_probe,
+};
+module_platform_driver(usb_charger_driver);
+
+MODULE_DESCRIPTION("Simple USB charger driver");
+MODULE_AUTHOR("Paul Cercueil <paul@xxxxxxxxxxxxxxx>");
+MODULE_LICENSE("GPL");
--
2.24.0
