linux-kernel - [PATCH 2/4] extcon: sm5502: Detect cable state after completing platform booting

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Date:	Wed, 28 May 2014 18:39:34 +0900
From:	Chanwoo Choi <cw00.choi@...sung.com>
To:	linux-kernel@...r.kernel.org
Cc:	myungjoo.ham@...sung.com, kyungmin.park@...sung.com,
	Chanwoo Choi <cw00.choi@...sung.com>
Subject: [PATCH 2/4] extcon: sm5502: Detect cable state after completing
 platform booting

This patch detect whether cable is connected or not and the cable type
after completing kernel/platform booting using system_power_efficient_wq.

Signed-off-by: Chanwoo Choi <cw00.choi@...sung.com>
---
 drivers/extcon/extcon-sm5502.c | 36 ++++++++++++++++++++++++++++++++++++
 1 file changed, 36 insertions(+)

diff --git a/drivers/extcon/extcon-sm5502.c b/drivers/extcon/extcon-sm5502.c
index ebf3d5c..3588df0 100644
--- a/drivers/extcon/extcon-sm5502.c
+++ b/drivers/extcon/extcon-sm5502.c
@@ -28,6 +28,8 @@
 #include <linux/extcon.h>
 #include <linux/extcon/sm5502.h>
 
+#define	DELAY_MS_DEFAULT		17000	/* unit: millisecond */
+
 struct muic_irq {
 	unsigned int irq;
 	const char *name;
@@ -59,6 +61,14 @@ struct sm5502_muic_info {
 	unsigned int num_reg_data;
 
 	struct mutex mutex;
+
+	/*
+	 * 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 value of SM5502 register to bring up MUIC device. */
@@ -341,6 +351,8 @@ static int sm5502_muic_cable_handler(struct sm5502_muic_info *info,
 	case SM5502_MUIC_ADC_OPEN_USB_OTG:
 		idx = EXTCON_CABLE_USB_HOST;
 		break;
+	case SM5502_MUIC_ADC_GROUND:
+		break;
 	default:
 		dev_dbg(info->dev,
 			"cannot handle this cable_type (0x%x)\n", cable_type);
@@ -433,6 +445,18 @@ static irqreturn_t sm5502_muic_irq_handler(int irq, void *data)
 	return IRQ_HANDLED;
 }
 
+static void sm5502_muic_detect_cable_wq(struct work_struct *work)
+{
+	struct sm5502_muic_info *info = container_of(to_delayed_work(work),
+				struct sm5502_muic_info, wq_detcable);
+	int ret;
+
+	/* Notify the state of connector cable or not  */
+	ret = sm5502_muic_cable_handler(info, true);
+	if (ret < 0)
+		dev_warn(info->dev, "failed to detect cable state\n");
+}
+
 static void sm5502_init_dev_type(struct sm5502_muic_info *info)
 {
 	unsigned int reg_data, vendor_id, version_id;
@@ -548,6 +572,18 @@ static int sm5022_muic_i2c_probe(struct i2c_client *i2c,
 		return ret;
 	}
 
+	/*
+	 * 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, sm5502_muic_detect_cable_wq);
+	queue_delayed_work(system_power_efficient_wq, &info->wq_detcable,
+			msecs_to_jiffies(DELAY_MS_DEFAULT));
+
 	/* Initialize SM5502 device and print vendor id and version id */
 	sm5502_init_dev_type(info);
 
-- 
1.8.0

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