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Subject[PATCH v2 1/2] extcon: Add extcon_set_cable_line_state() to inform the additional state of external connectors
Date
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..142bf0f 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_warn(&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;
--
2.2.0.GIT


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