extcon: palmas: Support GPIO based USB ID detection

Some palmas based chip variants do not have OTG based ID logic.
For these variants we rely on GPIO based USB ID detection.

These chips do have VBUS comparator for VBUS detection so we
continue to use the old way of detecting VBUS.

Signed-off-by: Roger Quadros <[e-mail]>
Acked-by: Chanwoo Choi <[e-mail]>
Acked-by: Lee Jones <[e-mail]>
Signed-off-by: Chanwoo Choi <[e-mail]>

Documentation/devicetree/bindings/extcon/extcon-palmas.txt

···
 
 Optional Properties:
  - ti,wakeup : To enable the wakeup comparator in probe
- - ti,enable-id-detection: Perform ID detection.
+ - ti,enable-id-detection: Perform ID detection. If id-gpio is specified
+		it performs id-detection using GPIO else using OTG core.
  - ti,enable-vbus-detection: Perform VBUS detection.
+ - id-gpio: gpio for GPIO ID detection. See gpio binding.
+ - debounce-delay-ms: debounce delay for GPIO ID pin in milliseconds.
 
 palmas-usb {
        compatible = "ti,twl6035-usb", "ti,palmas-usb";

drivers/extcon/extcon-palmas.c

···
 #include <linux/mfd/palmas.h>
 #include <linux/of.h>
 #include <linux/of_platform.h>
+#include <linux/of_gpio.h>
+#include <linux/workqueue.h>
+
+#define USB_GPIO_DEBOUNCE_MS	20	/* ms */
 
 static const unsigned int palmas_extcon_cable[] = {
 	EXTCON_USB,
···
 	return IRQ_HANDLED;
 }
 
+static void palmas_gpio_id_detect(struct work_struct *work)
+{
+	int id;
+	struct palmas_usb *palmas_usb = container_of(to_delayed_work(work),
+						     struct palmas_usb,
+						     wq_detectid);
+	struct extcon_dev *edev = palmas_usb->edev;
+
+	if (!palmas_usb->id_gpiod)
+		return;
+
+	id = gpiod_get_value_cansleep(palmas_usb->id_gpiod);
+
+	if (id) {
+		extcon_set_cable_state_(edev, EXTCON_USB_HOST, false);
+		dev_info(palmas_usb->dev, "USB-HOST cable is detached\n");
+	} else {
+		extcon_set_cable_state_(edev, EXTCON_USB_HOST, true);
+		dev_info(palmas_usb->dev, "USB-HOST cable is attached\n");
+	}
+}
+
+static irqreturn_t palmas_gpio_id_irq_handler(int irq, void *_palmas_usb)
+{
+	struct palmas_usb *palmas_usb = _palmas_usb;
+
+	queue_delayed_work(system_power_efficient_wq, &palmas_usb->wq_detectid,
+			   palmas_usb->sw_debounce_jiffies);
+
+	return IRQ_HANDLED;
+}
+
 static void palmas_enable_irq(struct palmas_usb *palmas_usb)
 {
 	palmas_write(palmas_usb->palmas, PALMAS_USB_OTG_BASE,
 		PALMAS_USB_VBUS_CTRL_SET,
 		PALMAS_USB_VBUS_CTRL_SET_VBUS_ACT_COMP);
 
-	palmas_write(palmas_usb->palmas, PALMAS_USB_OTG_BASE,
-		PALMAS_USB_ID_CTRL_SET, PALMAS_USB_ID_CTRL_SET_ID_ACT_COMP);
+	if (palmas_usb->enable_id_detection) {
+		palmas_write(palmas_usb->palmas, PALMAS_USB_OTG_BASE,
+			     PALMAS_USB_ID_CTRL_SET,
+			     PALMAS_USB_ID_CTRL_SET_ID_ACT_COMP);
 
-	palmas_write(palmas_usb->palmas, PALMAS_USB_OTG_BASE,
-		PALMAS_USB_ID_INT_EN_HI_SET,
-		PALMAS_USB_ID_INT_EN_HI_SET_ID_GND |
-		PALMAS_USB_ID_INT_EN_HI_SET_ID_FLOAT);
+		palmas_write(palmas_usb->palmas, PALMAS_USB_OTG_BASE,
+			     PALMAS_USB_ID_INT_EN_HI_SET,
+			     PALMAS_USB_ID_INT_EN_HI_SET_ID_GND |
+			     PALMAS_USB_ID_INT_EN_HI_SET_ID_FLOAT);
+	}
 
 	if (palmas_usb->enable_vbus_detection)
 		palmas_vbus_irq_handler(palmas_usb->vbus_irq, palmas_usb);
···
 			palmas_usb->wakeup = pdata->wakeup;
 	}
 
+	palmas_usb->id_gpiod = devm_gpiod_get_optional(&pdev->dev, "id");
+	if (IS_ERR(palmas_usb->id_gpiod)) {
+		dev_err(&pdev->dev, "failed to get id gpio\n");
+		return PTR_ERR(palmas_usb->id_gpiod);
+	}
+
+	if (palmas_usb->enable_id_detection && palmas_usb->id_gpiod) {
+		palmas_usb->enable_id_detection = false;
+		palmas_usb->enable_gpio_id_detection = true;
+	}
+
+	if (palmas_usb->enable_gpio_id_detection) {
+		u32 debounce;
+
+		if (of_property_read_u32(node, "debounce-delay-ms", &debounce))
+			debounce = USB_GPIO_DEBOUNCE_MS;
+
+		status = gpiod_set_debounce(palmas_usb->id_gpiod,
+					    debounce * 1000);
+		if (status < 0)
+			palmas_usb->sw_debounce_jiffies = msecs_to_jiffies(debounce);
+	}
+
+	INIT_DELAYED_WORK(&palmas_usb->wq_detectid, palmas_gpio_id_detect);
+
 	palmas->usb = palmas_usb;
 	palmas_usb->palmas = palmas;
 
 	palmas_usb->dev	 = &pdev->dev;
-
-	palmas_usb->id_otg_irq = regmap_irq_get_virq(palmas->irq_data,
-						PALMAS_ID_OTG_IRQ);
-	palmas_usb->id_irq = regmap_irq_get_virq(palmas->irq_data,
-						PALMAS_ID_IRQ);
-	palmas_usb->vbus_otg_irq = regmap_irq_get_virq(palmas->irq_data,
-						PALMAS_VBUS_OTG_IRQ);
-	palmas_usb->vbus_irq = regmap_irq_get_virq(palmas->irq_data,
-						PALMAS_VBUS_IRQ);
 
 	palmas_usb_wakeup(palmas, palmas_usb->wakeup);
 
···
 	}
 
 	if (palmas_usb->enable_id_detection) {
+		palmas_usb->id_otg_irq = regmap_irq_get_virq(palmas->irq_data,
+							     PALMAS_ID_OTG_IRQ);
+		palmas_usb->id_irq = regmap_irq_get_virq(palmas->irq_data,
+							 PALMAS_ID_IRQ);
 		status = devm_request_threaded_irq(palmas_usb->dev,
 				palmas_usb->id_irq,
 				NULL, palmas_id_irq_handler,
···
 					palmas_usb->id_irq, status);
 			return status;
 		}
+	} else if (palmas_usb->enable_gpio_id_detection) {
+		palmas_usb->gpio_id_irq = gpiod_to_irq(palmas_usb->id_gpiod);
+		if (palmas_usb->gpio_id_irq < 0) {
+			dev_err(&pdev->dev, "failed to get id irq\n");
+			return palmas_usb->gpio_id_irq;
+		}
+		status = devm_request_threaded_irq(&pdev->dev,
+						   palmas_usb->gpio_id_irq,
+						   NULL,
+						   palmas_gpio_id_irq_handler,
+						   IRQF_TRIGGER_RISING |
+						   IRQF_TRIGGER_FALLING |
+						   IRQF_ONESHOT,
+						   "palmas_usb_id",
+						   palmas_usb);
+		if (status < 0) {
+			dev_err(&pdev->dev,
+				"failed to request handler for id irq\n");
+			return status;
+		}
 	}
 
 	if (palmas_usb->enable_vbus_detection) {
+		palmas_usb->vbus_otg_irq = regmap_irq_get_virq(palmas->irq_data,
+						       PALMAS_VBUS_OTG_IRQ);
+		palmas_usb->vbus_irq = regmap_irq_get_virq(palmas->irq_data,
+							   PALMAS_VBUS_IRQ);
 		status = devm_request_threaded_irq(palmas_usb->dev,
 				palmas_usb->vbus_irq, NULL,
 				palmas_vbus_irq_handler,
···
 	}
 
 	palmas_enable_irq(palmas_usb);
+	/* perform initial detection */
+	palmas_gpio_id_detect(&palmas_usb->wq_detectid.work);
 	device_set_wakeup_capable(&pdev->dev, true);
+	return 0;
+}
+
+static int palmas_usb_remove(struct platform_device *pdev)
+{
+	struct palmas_usb *palmas_usb = platform_get_drvdata(pdev);
+
+	cancel_delayed_work_sync(&palmas_usb->wq_detectid);
+
 	return 0;
 }
 
···
 			enable_irq_wake(palmas_usb->vbus_irq);
 		if (palmas_usb->enable_id_detection)
 			enable_irq_wake(palmas_usb->id_irq);
+		if (palmas_usb->enable_gpio_id_detection)
+			enable_irq_wake(palmas_usb->gpio_id_irq);
 	}
 	return 0;
 }
···
 			disable_irq_wake(palmas_usb->vbus_irq);
 		if (palmas_usb->enable_id_detection)
 			disable_irq_wake(palmas_usb->id_irq);
+		if (palmas_usb->enable_gpio_id_detection)
+			disable_irq_wake(palmas_usb->gpio_id_irq);
 	}
 	return 0;
 };
···
 
 static struct platform_driver palmas_usb_driver = {
 	.probe = palmas_usb_probe,
+	.remove = palmas_usb_remove,
 	.driver = {
 		.name = "palmas-usb",
 		.of_match_table = of_palmas_match_tbl,

drivers/extcon/extcon-usb-gpio.c

···
  */
 
 #include <linux/extcon.h>
+#include <linux/gpio.h>
 #include <linux/gpio/consumer.h>
 #include <linux/init.h>
 #include <linux/interrupt.h>

include/linux/mfd/palmas.h

···
 #include <linux/regmap.h>
 #include <linux/regulator/driver.h>
 #include <linux/extcon.h>
+#include <linux/of_gpio.h>
 #include <linux/usb/phy_companion.h>
 
 #define PALMAS_NUM_CLIENTS		3
···
 	int vbus_otg_irq;
 	int vbus_irq;
 
+	int gpio_id_irq;
+	struct gpio_desc *id_gpiod;
+	unsigned long sw_debounce_jiffies;
+	struct delayed_work wq_detectid;
+
 	enum palmas_usb_state linkstat;
 	int wakeup;
 	bool enable_vbus_detection;
 	bool enable_id_detection;
+	bool enable_gpio_id_detection;
 };
 
 #define comparator_to_palmas(x) container_of((x), struct palmas_usb, comparator)