extcon: max8997: Use workqueue to check cable state after completing boot of platform

This patch use delayed workqueue to check cable state after a certain
time. If extcon-max8997 driver check cable state during booting of
platform, this couldn't send the correct notification of cable state
to extcon consumer. Alwasys, this driver should check cable state
after the completion of platform initialization

Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>
Signed-off-by: Myungjoo Ham <myungjoo.ham@samsung.com>

drivers/extcon/extcon-max8997.c

@@ -29,6 +29,7 @@
 #include <linux/irqdomain.h>
 
 #define	DEV_NAME			"max8997-muic"
+#define	DELAY_MS_DEFAULT		20000		/* unit: millisecond */
 
 enum max8997_muic_adc_debounce_time {
 	ADC_DEBOUNCE_TIME_0_5MS = 0,	/* 0.5ms */
@@ -128,6 +129,14 @@ struct max8997_muic_info {
 	struct max8997_muic_platform_data *muic_pdata;
 	enum max8997_muic_charger_type pre_charger_type;
 
+	/*
+	 * Use delayed workqueue to detect cable state and then
+	 * notify cable state to notifiee/platform through uevent.
+	 * After completing the booting of platform, the extcon provider
+	 * driver should notify cable state to upper layer.
+	 */
+	struct delayed_work wq_detcable;
+
 	/*
 	 * Default usb/uart path whether UART/USB or AUX_UART/AUX_USB
 	 * h/w path of COMP2/COMN1 on CONTROL1 register.
@@ -629,11 +638,23 @@ static int max8997_muic_detect_dev(struct max8997_muic_info *info)
 	return 0;
 }
 
+static void max8997_muic_detect_cable_wq(struct work_struct *work)
+{
+	struct max8997_muic_info *info = container_of(to_delayed_work(work),
+				struct max8997_muic_info, wq_detcable);
+	int ret;
+
+	ret = max8997_muic_detect_dev(info);
+	if (ret < 0)
+		pr_err("failed to detect cable type\n");
+}
+
 static int max8997_muic_probe(struct platform_device *pdev)
 {
 	struct max8997_dev *max8997 = dev_get_drvdata(pdev->dev.parent);
 	struct max8997_platform_data *pdata = dev_get_platdata(max8997->dev);
 	struct max8997_muic_info *info;
+	int delay_jiffies;
 	int ret, i;
 
 	info = devm_kzalloc(&pdev->dev, sizeof(struct max8997_muic_info),
@@ -721,17 +742,23 @@ static int max8997_muic_probe(struct platform_device *pdev)
 	/* Set ADC debounce time */
 	max8997_muic_set_debounce_time(info, ADC_DEBOUNCE_TIME_25MS);
 
-	/* Initial device detection */
-	ret = max8997_muic_detect_dev(info);
-	if (ret < 0) {
-		dev_err(&pdev->dev, "failed to detect cable type\n");
-		goto err_extcon;
-	}
+	/*
+	 * Detect accessory after completing the initialization of platform
+	 *
+	 * - Use delayed workqueue to detect cable state and then
+	 * notify cable state to notifiee/platform through uevent.
+	 * After completing the booting of platform, the extcon provider
+	 * driver should notify cable state to upper layer.
+	 */
+	INIT_DELAYED_WORK(&info->wq_detcable, max8997_muic_detect_cable_wq);
+	if (pdata->muic_pdata->detcable_delay_ms)
+		delay_jiffies = msecs_to_jiffies(pdata->muic_pdata->detcable_delay_ms);
+	else
+		delay_jiffies = msecs_to_jiffies(DELAY_MS_DEFAULT);
+	schedule_delayed_work(&info->wq_detcable, delay_jiffies);
 
-	return ret;
+	return 0;
 
-err_extcon:
-	extcon_dev_unregister(info->edev);
 err_irq:
 	while (--i >= 0)
 		free_irq(muic_irqs[i].virq, info);

include/linux/mfd/max8997.h

@@ -93,6 +93,9 @@ struct max8997_muic_platform_data {
 	struct max8997_muic_reg_data *init_data;
 	int num_init_data;
 
+	/* Check cable state after certain delay */
+	int detcable_delay_ms;
+
 	/*
 	 * Default usb/uart path whether UART/USB or AUX_UART/AUX_USB
 	 * h/w path of COMP2/COMN1 on CONTROL1 register.