From: Chanwoo Choi <cw00.choi@samsung.com>
To: linux-kernel@vger.kernel.org
Cc: rogerq@ti.com, r.baldyga@samsung.com, peter.chen@freescale.com,
        kishon@ti.com, balbi@ti.com, iivanov@mm-sol.com, cw00.choi@samsung.com,
        myungjoo.ham@samsung.com
Subject: [PATCH 1/2] extcon: Add extcon_set_cable_line_state() to inform the
 additional state of external connectors
Date: Fri, 22 May 2015 19:49:49 +0900
Message-id: <1432291790-4933-2-git-send-email-cw00.choi@samsung.com>
In-reply-to: <1432291790-4933-1-git-send-email-cw00.choi@samsung.com>
References: <1432291790-4933-1-git-send-email-cw00.choi@samsung.com>
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Sender: linux-kernel-owner@vger.kernel.org
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Lines: 193

This patch adds the extcon_set_cable_line_state() function to inform
the additional state of each external connector and 'enum extcon_line_state'
enumeration which include the specific states of each external connector.

The each external connector might need the different line state. So, current
'extcon_line_state' enumeration contains the specific state for USB as
following:

- Following the state mean the state of both ID and VBUS line for USB:
enum extcon_line_state {
	EXTCON_USB_ID_LOW	= BIT(1),	/* ID line is low. */
	EXTCON_USB_ID_HIGH	= BIT(2),	/* ID line is high. */
	EXTCON_USB_VBUS_LOW	= BIT(3),	/* VBUS line is low. */
	EXTCON_USB_VBUS_HIGH	= BIT(4),	/* VBUS line is high. */
};

Cc: Myungjoo Ham <cw00.choi@samsung.com>
Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>
---
 drivers/extcon/extcon.c | 74 ++++++++++++++++++++++++++++++++++++++++++++++++-
 include/linux/extcon.h  | 24 ++++++++++++++++
 2 files changed, 97 insertions(+), 1 deletion(-)

diff --git a/drivers/extcon/extcon.c b/drivers/extcon/extcon.c
index 5099c11..2f7db54 100644
--- a/drivers/extcon/extcon.c
+++ b/drivers/extcon/extcon.c
@@ -279,7 +279,9 @@ int extcon_update_state(struct extcon_dev *edev, u32 mask, u32 state)
 
 		for (index = 0; index < edev->max_supported; index++) {
 			if (is_extcon_changed(edev->state, state, index, &attached))
-				raw_notifier_call_chain(&edev->nh[index], attached, edev);
+				raw_notifier_call_chain(&edev->nh[index],
+					attached ? EXTCON_ATTACHED :
+					EXTCON_DETACHED, edev);
 		}
 
 		edev->state &= ~mask;
@@ -418,6 +420,69 @@ int extcon_set_cable_state(struct extcon_dev *edev,
 EXPORT_SYMBOL_GPL(extcon_set_cable_state);
 
 /**
+ * extcon_set_cable_line_state() - Set the line state of specific cable.
+ * @edev:		the extcon device that has the cable.
+ * @id:			the unique id of each external connector.
+ * @state:		the line state for specific cable.
+ *
+ * Note that this function support the only USB connector to inform the state
+ * of both ID and VBUS line until now. This function may be extended to support
+ * the additional external connectors.
+ *
+ * If the id is EXTCON_USB, it can support only following line states:
+ * - EXTCON_USB_ID_LOW
+ * - EXTCON_USB_ID_HIGH,
+ * - EXTCON_USB_VBUS_LOW
+ * - EXTCON_USB_VBUS_HIGH
+ */
+int extcon_set_cable_line_state(struct extcon_dev *edev, enum extcon id,
+				enum extcon_line_state state)
+{
+	unsigned long flags;
+	unsigned long line_state;
+	int ret = 0, index;
+
+	index = find_cable_index_by_id(edev, id);
+	if (index < 0)
+		return index;
+
+	spin_lock_irqsave(&edev->lock, flags);
+	line_state = edev->line_state[index];
+
+	switch (id) {
+	case EXTCON_USB:
+		if (line_state & state) {
+			dev_info(&edev->dev,
+				"0x%x state is already set for %s\n",
+				state, extcon_name[id]);
+			goto err;
+		}
+
+		if ((state & EXTCON_USB_ID_LOW) || (state & EXTCON_USB_ID_HIGH))
+			line_state &= ~(EXTCON_USB_ID_LOW | EXTCON_USB_ID_HIGH);
+
+		if ((state & EXTCON_USB_VBUS_LOW)
+			|| (state & EXTCON_USB_VBUS_HIGH))
+			line_state &=
+				~(EXTCON_USB_VBUS_LOW | EXTCON_USB_VBUS_HIGH);
+
+		line_state |= state;
+		break;
+	default:
+		ret = -EINVAL;
+		goto err;
+	}
+	edev->line_state[index] = line_state;
+
+	ret = raw_notifier_call_chain(&edev->nh[index], line_state, edev);
+err:
+	spin_unlock_irqrestore(&edev->lock, flags);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(extcon_set_cable_line_state);
+
+/**
  * extcon_get_extcon_dev() - Get the extcon device instance from the name
  * @extcon_name:	The extcon name provided with extcon_dev_register()
  */
@@ -897,6 +962,13 @@ int extcon_dev_register(struct extcon_dev *edev)
 		goto err_dev;
 	}
 
+	edev->line_state = devm_kzalloc(&edev->dev,
+		sizeof(*edev->line_state) * edev->max_supported, GFP_KERNEL);
+	if (!edev->line_state) {
+		ret = -ENOMEM;
+		goto err_dev;
+	}
+
 	for (index = 0; index < edev->max_supported; index++)
 		RAW_INIT_NOTIFIER_HEAD(&edev->nh[index]);
 
diff --git a/include/linux/extcon.h b/include/linux/extcon.h
index be9652b..79e5073 100644
--- a/include/linux/extcon.h
+++ b/include/linux/extcon.h
@@ -66,6 +66,19 @@ enum extcon {
 	EXTCON_END,
 };
 
+enum extcon_line_state {
+	/* Following two definition are used for whether external connectors
+	 * is attached or detached. */
+	EXTCON_DETACHED		= 0x0,
+	EXTCON_ATTACHED		= 0x1,
+
+	/* Following states are only used for EXTCON_USB. */
+	EXTCON_USB_ID_LOW	= BIT(1),	/* ID line is low. */
+	EXTCON_USB_ID_HIGH	= BIT(2),	/* ID line is high. */
+	EXTCON_USB_VBUS_LOW	= BIT(3),	/* VBUS line is low. */
+	EXTCON_USB_VBUS_HIGH	= BIT(4),	/* VBUS line is high. */
+};
+
 struct extcon_cable;
 
 /**
@@ -90,6 +103,8 @@ struct extcon_cable;
  * @dev:		Device of this extcon.
  * @state:		Attach/detach state of this extcon. Do not provide at
  *			register-time.
+ * @line_state:		Line state for each external connecotrs are included in
+ *			this extcon device.
  * @nh:			Notifier for the state change events from this extcon
  * @entry:		To support list of extcon devices so that users can
  *			search for extcon devices based on the extcon name.
@@ -121,6 +136,7 @@ struct extcon_dev {
 	int max_supported;
 	spinlock_t lock;	/* could be called by irq handler */
 	u32 state;
+	unsigned long *line_state;
 
 	/* /sys/class/extcon/.../cable.n/... */
 	struct device_type extcon_dev_type;
@@ -217,6 +233,8 @@ extern int extcon_get_cable_state(struct extcon_dev *edev,
 				  const char *cable_name);
 extern int extcon_set_cable_state(struct extcon_dev *edev,
 				  const char *cable_name, bool cable_state);
+extern int extcon_set_cable_line_state(struct extcon_dev *edev, enum extcon id,
+					enum extcon_line_state state);
 
 /*
  * Following APIs are for notifiees (those who want to be notified)
@@ -324,6 +342,12 @@ static inline int extcon_set_cable_state(struct extcon_dev *edev,
 	return 0;
 }
 
+static inline int extcon_set_cable_line_state(struct extcon_dev *edev,
+			enum extcon id, enum extcon_line_state state)
+{
+	return 0;
+}
+
 static inline struct extcon_dev *extcon_get_extcon_dev(const char *extcon_name)
 {
 	return NULL;
-- 
1.8.5.5

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