extcon: Use the unique id for external connector instead of string

This patch uses the unique id to identify the type of external connector instead
of string name. The string name have the many potential issues. So, this patch
defines the 'extcon' enumeration which includes all supported external connector
on EXTCON subsystem. If new external connector is necessary, the unique id of
new connector have to be added in 'extcon' enumeration. There are current
supported external connector in 'enum extcon' as following:

enum extcon {
	EXTCON_NONE		= 0x0,

	/* USB external connector */
	EXTCON_USB		= 0x1,
	EXTCON_USB_HOST		= 0x2,

	/* Charger external connector */
	EXTCON_TA		= 0x10,
	EXTCON_FAST_CHARGER	= 0x11,
	EXTCON_SLOW_CHARGER	= 0x12,
	EXTCON_CHARGE_DOWNSTREAM = 0x13,

	/* Audio and video external connector */
	EXTCON_LINE_IN		= 0x20,
	EXTCON_LINE_OUT		= 0x21,
	EXTCON_MICROPHONE	= 0x22,
	EXTCON_HEADPHONE	= 0x23,

	EXTCON_HDMI		= 0x30,
	EXTCON_MHL		= 0x31,
	EXTCON_DVI		= 0x32,
	EXTCON_VGA		= 0x33,
	EXTCON_SPDIF_IN		= 0x34,
	EXTCON_SPDIF_OUT	= 0x35,
	EXTCON_VIDEO_IN		= 0x36,
	EXTCON_VIDEO_OUT	= 0x37,

	/* Miscellaneous external connector */
	EXTCON_DOCK		= 0x50,
	EXTCON_JIG		= 0x51,
	EXTCON_MECHANICAL	= 0x52,

	EXTCON_END,
};

For example in extcon-arizona.c:
To use unique id removes the potential issue about handling
the inconsistent name of external connector with string.
- Previously, use the string to register the type of arizona jack connector
static const char *arizona_cable[] = {
	"Mechanical",
	"Microphone",
	"Headphone",
	"Line-out",
};
- Newly, use the unique id to register the type of arizona jack connector
static const enum extcon arizona_cable[] = {
	EXTCON_MECHANICAL,
	EXTCON_MICROPHONE,
	EXTCON_HEADPHONE,
	EXTCON_LINE_OUT,

	EXTCON_NONE,
};

And this patch modify the prototype of extcon_{get|set}_cable_state_() which
uses the 'enum extcon id' instead of 'cable_index'. Because although one more
extcon drivers support USB cable, each extcon driver might has the differnt
'cable_index' for USB cable. All extcon drivers can use the unique id number
for same external connector with modified extcon_{get|set}_cable_state_().

- Previously, use 'cable_index' on these functions:
extcon_get_cable_state_(struct extcon_dev*, int cable_index)
extcon_set_cable_state_(struct extcon_dev*, int cable_index, bool state)

-Newly, use 'enum extcon id' on these functions:
extcon_get_cable_state_(struct extcon_dev*, enum extcon id)
extcon_set_cable_state_(struct extcon_dev*, enum extcon id, bool state)

Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Felipe Balbi <balbi@ti.com>
Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>
Acked-by: Roger Quadros <rogerq@ti.com>
Acked-by: Charles Keepax <ckeepax@opensource.wolfsonmicro.com>
Acked-by: Ramakrishna Pallala <ramakrishna.pallala@intel.com>
Reviewed-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
[arnd: Report the build break about drivers/usb/phy/phy-tahvo.c after using the
unique id for external connector insteadf of string]
Reported-by: Arnd Bergmann <arnd@arndb.de>
[dan.carpenter: Report the build warning of extcon_{set|get}_cable_state_()]
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>

1 files changed, 91 insertions, 72 deletions

diff --git a/drivers/extcon/extcon.c b/drivers/extcon/extcon.c
index 2fb5f757e811..a57355fc8fea 100644
--- a/drivers/extcon/extcon.c
+++ b/drivers/extcon/extcon.c
@@ -3,6 +3,9 @@
  *
  *  External connector (extcon) class driver
  *
+ * Copyright (C) 2015 Samsung Electronics
+ * Author: Chanwoo Choi <cw00.choi@samsung.com>
+ *
  * Copyright (C) 2012 Samsung Electronics
  * Author: Donggeun Kim <dg77.kim@samsung.com>
  * Author: MyungJoo Ham <myungjoo.ham@samsung.com>
@@ -32,36 +35,32 @@
 #include <linux/slab.h>
 #include <linux/sysfs.h>
 
-/*
- * extcon_cable_name suggests the standard cable names for commonly used
- * cable types.
- *
- * However, please do not use extcon_cable_name directly for extcon_dev
- * struct's supported_cable pointer unless your device really supports
- * every single port-type of the following cable names. Please choose cable
- * names that are actually used in your extcon device.
- */
-const char extcon_cable_name[][CABLE_NAME_MAX + 1] = {
+#define SUPPORTED_CABLE_MAX	32
+#define CABLE_NAME_MAX		30
+
+static const char *extcon_name[] =  {
 	[EXTCON_USB]		= "USB",
 	[EXTCON_USB_HOST]	= "USB-Host",
 	[EXTCON_TA]		= "TA",
 	[EXTCON_FAST_CHARGER]	= "Fast-charger",
 	[EXTCON_SLOW_CHARGER]	= "Slow-charger",
 	[EXTCON_CHARGE_DOWNSTREAM]	= "Charge-downstream",
+	[EXTCON_LINE_IN]	= "Line-in",
+	[EXTCON_LINE_OUT]	= "Line-out",
+	[EXTCON_MICROPHONE]	= "Microphone",
+	[EXTCON_HEADPHONE]	= "Headphone",
 	[EXTCON_HDMI]		= "HDMI",
 	[EXTCON_MHL]		= "MHL",
 	[EXTCON_DVI]		= "DVI",
 	[EXTCON_VGA]		= "VGA",
-	[EXTCON_DOCK]		= "Dock",
-	[EXTCON_LINE_IN]	= "Line-in",
-	[EXTCON_LINE_OUT]	= "Line-out",
-	[EXTCON_MIC_IN]		= "Microphone",
-	[EXTCON_HEADPHONE_OUT]	= "Headphone",
 	[EXTCON_SPDIF_IN]	= "SPDIF-in",
 	[EXTCON_SPDIF_OUT]	= "SPDIF-out",
 	[EXTCON_VIDEO_IN]	= "Video-in",
 	[EXTCON_VIDEO_OUT]	= "Video-out",
+	[EXTCON_DOCK]		= "Dock",
+	[EXTCON_JIG]		= "JIG",
 	[EXTCON_MECHANICAL]	= "Mechanical",
+	NULL,
 };
 
 static struct class *extcon_class;
@@ -101,6 +100,43 @@ static int check_mutually_exclusive(struct extcon_dev *edev, u32 new_state)
 	return 0;
 }
 
+static int find_cable_index_by_id(struct extcon_dev *edev, const enum extcon id)
+{
+	int i;
+
+	/* Find the the index of extcon cable in edev->supported_cable */
+	for (i = 0; i < edev->max_supported; i++) {
+		if (edev->supported_cable[i] == id)
+			return i;
+	}
+
+	return -EINVAL;
+}
+
+static int find_cable_index_by_name(struct extcon_dev *edev, const char *name)
+{
+	enum extcon id = EXTCON_NONE;
+	int i;
+
+	if (edev->max_supported == 0)
+		return -EINVAL;
+
+	/* Find the the number of extcon cable */
+	for (i = 0; i < EXTCON_END; i++) {
+		if (!extcon_name[i])
+			continue;
+		if (!strncmp(extcon_name[i], name, CABLE_NAME_MAX)) {
+			id = i;
+			break;
+		}
+	}
+
+	if (id == EXTCON_NONE)
+		return -EINVAL;
+
+	return find_cable_index_by_id(edev, id);
+}
+
 static ssize_t state_show(struct device *dev, struct device_attribute *attr,
 			  char *buf)
 {
@@ -118,11 +154,9 @@ static ssize_t state_show(struct device *dev, struct device_attribute *attr,
 	if (edev->max_supported == 0)
 		return sprintf(buf, "%u\n", edev->state);
 
-	for (i = 0; i < SUPPORTED_CABLE_MAX; i++) {
-		if (!edev->supported_cable[i])
-			break;
+	for (i = 0; i < edev->max_supported; i++) {
 		count += sprintf(buf + count, "%s=%d\n",
-				 edev->supported_cable[i],
+				extcon_name[edev->supported_cable[i]],
 				 !!(edev->state & (1 << i)));
 	}
 
@@ -171,9 +205,10 @@ static ssize_t cable_name_show(struct device *dev,
 {
 	struct extcon_cable *cable = container_of(attr, struct extcon_cable,
 						  attr_name);
+	int i = cable->cable_index;
 
 	return sprintf(buf, "%s\n",
-		       cable->edev->supported_cable[cable->cable_index]);
+			extcon_name[cable->edev->supported_cable[i]]);
 }
 
 static ssize_t cable_state_show(struct device *dev,
@@ -283,39 +318,19 @@ int extcon_set_state(struct extcon_dev *edev, u32 state)
 EXPORT_SYMBOL_GPL(extcon_set_state);
 
 /**
- * extcon_find_cable_index() - Get the cable index based on the cable name.
+ * extcon_get_cable_state_() - Get the status of a specific cable.
  * @edev:	the extcon device that has the cable.
- * @cable_name:	cable name to be searched.
- *
- * Note that accessing a cable state based on cable_index is faster than
- * cable_name because using cable_name induces a loop with strncmp().
- * Thus, when get/set_cable_state is repeatedly used, using cable_index
- * is recommended.
+ * @id:		the unique id of each external connector in extcon enumeration.
  */
-int extcon_find_cable_index(struct extcon_dev *edev, const char *cable_name)
+int extcon_get_cable_state_(struct extcon_dev *edev, const enum extcon id)
 {
-	int i;
-
-	if (edev->supported_cable) {
-		for (i = 0; edev->supported_cable[i]; i++) {
-			if (!strncmp(edev->supported_cable[i],
-				cable_name, CABLE_NAME_MAX))
-				return i;
-		}
-	}
+	int index;
 
-	return -EINVAL;
-}
-EXPORT_SYMBOL_GPL(extcon_find_cable_index);
+	index = find_cable_index_by_id(edev, id);
+	if (index < 0)
+		return index;
 
-/**
- * extcon_get_cable_state_() - Get the status of a specific cable.
- * @edev:	the extcon device that has the cable.
- * @index:	cable index that can be retrieved by extcon_find_cable_index().
- */
-int extcon_get_cable_state_(struct extcon_dev *edev, int index)
-{
-	if (index < 0 || (edev->max_supported && edev->max_supported <= index))
+	if (edev->max_supported && edev->max_supported <= index)
 		return -EINVAL;
 
 	return !!(edev->state & (1 << index));
@@ -331,7 +346,7 @@ EXPORT_SYMBOL_GPL(extcon_get_cable_state_);
  */
 int extcon_get_cable_state(struct extcon_dev *edev, const char *cable_name)
 {
-	return extcon_get_cable_state_(edev, extcon_find_cable_index
+	return extcon_get_cable_state_(edev, find_cable_index_by_name
 						(edev, cable_name));
 }
 EXPORT_SYMBOL_GPL(extcon_get_cable_state);
@@ -339,17 +354,22 @@ EXPORT_SYMBOL_GPL(extcon_get_cable_state);
 /**
  * extcon_set_cable_state_() - Set the status of a specific cable.
  * @edev:		the extcon device that has the cable.
- * @index:		cable index that can be retrieved by
- *			extcon_find_cable_index().
- * @cable_state:	the new cable status. The default semantics is
+ * @id:			the unique id of each external connector
+ *			in extcon enumeration.
+ * @state:		the new cable status. The default semantics is
  *			true: attached / false: detached.
  */
-int extcon_set_cable_state_(struct extcon_dev *edev,
-			int index, bool cable_state)
+int extcon_set_cable_state_(struct extcon_dev *edev, enum extcon id,
+				bool cable_state)
 {
 	u32 state;
+	int index;
 
-	if (index < 0 || (edev->max_supported && edev->max_supported <= index))
+	index = find_cable_index_by_id(edev, id);
+	if (index < 0)
+		return index;
+
+	if (edev->max_supported && edev->max_supported <= index)
 		return -EINVAL;
 
 	state = cable_state ? (1 << index) : 0;
@@ -369,7 +389,7 @@ EXPORT_SYMBOL_GPL(extcon_set_cable_state_);
 int extcon_set_cable_state(struct extcon_dev *edev,
 			const char *cable_name, bool cable_state)
 {
-	return extcon_set_cable_state_(edev, extcon_find_cable_index
+	return extcon_set_cable_state_(edev, find_cable_index_by_name
 					(edev, cable_name), cable_state);
 }
 EXPORT_SYMBOL_GPL(extcon_set_cable_state);
@@ -455,8 +475,8 @@ int extcon_register_interest(struct extcon_specific_cable_nb *obj,
 		if (!obj->edev)
 			return -ENODEV;
 
-		obj->cable_index = extcon_find_cable_index(obj->edev,
-							  cable_name);
+		obj->cable_index = find_cable_index_by_name(obj->edev,
+							cable_name);
 		if (obj->cable_index < 0)
 			return obj->cable_index;
 
@@ -479,7 +499,7 @@ int extcon_register_interest(struct extcon_specific_cable_nb *obj,
 		while ((dev = class_dev_iter_next(&iter))) {
 			extd = dev_get_drvdata(dev);
 
-			if (extcon_find_cable_index(extd, cable_name) < 0)
+			if (find_cable_index_by_name(extd, cable_name) < 0)
 				continue;
 
 			class_dev_iter_exit(&iter);
@@ -595,7 +615,7 @@ static void dummy_sysfs_dev_release(struct device *dev)
 
 /*
  * extcon_dev_allocate() - Allocate the memory of extcon device.
- * @supported_cable:	Array of supported cable names ending with NULL.
+ * @supported_cable:	Array of supported extcon ending with EXTCON_NONE.
  *			If supported_cable is NULL, cable name related APIs
  *			are disabled.
  *
@@ -605,7 +625,7 @@ static void dummy_sysfs_dev_release(struct device *dev)
  *
  * Return the pointer of extcon device if success or ERR_PTR(err) if fail
  */
-struct extcon_dev *extcon_dev_allocate(const char **supported_cable)
+struct extcon_dev *extcon_dev_allocate(const enum extcon *supported_cable)
 {
 	struct extcon_dev *edev;
 
@@ -647,7 +667,7 @@ static void devm_extcon_dev_release(struct device *dev, void *res)
 /**
  * devm_extcon_dev_allocate - Allocate managed extcon device
  * @dev:		device owning the extcon device being created
- * @supported_cable:	Array of supported cable names ending with NULL.
+ * @supported_cable:	Array of supported extcon ending with EXTCON_NONE.
  *			If supported_cable is NULL, cable name related APIs
  *			are disabled.
  *
@@ -659,7 +679,7 @@ static void devm_extcon_dev_release(struct device *dev, void *res)
  * or ERR_PTR(err) if fail
  */
 struct extcon_dev *devm_extcon_dev_allocate(struct device *dev,
-					    const char **supported_cable)
+					const enum extcon *supported_cable)
 {
 	struct extcon_dev **ptr, *edev;
 
@@ -709,17 +729,15 @@ int extcon_dev_register(struct extcon_dev *edev)
 			return ret;
 	}
 
-	if (edev->supported_cable) {
-		/* Get size of array */
-		for (index = 0; edev->supported_cable[index]; index++)
-			;
-		edev->max_supported = index;
-	} else {
-		edev->max_supported = 0;
-	}
+	if (!edev->supported_cable)
+		return -EINVAL;
+
+	for (; edev->supported_cable[index] != EXTCON_NONE; index++);
 
+	edev->max_supported = index;
 	if (index > SUPPORTED_CABLE_MAX) {
-		dev_err(&edev->dev, "extcon: maximum number of supported cables exceeded.\n");
+		dev_err(&edev->dev,
+			"exceed the maximum number of supported cables\n");
 		return -EINVAL;
 	}
 
@@ -1070,6 +1088,7 @@ static void __exit extcon_class_exit(void)
 }
 module_exit(extcon_class_exit);
 
+MODULE_AUTHOR("Chanwoo Choi <cw00.choi@samsung.com>");
 MODULE_AUTHOR("Mike Lockwood <lockwood@android.com>");
 MODULE_AUTHOR("Donggeun Kim <dg77.kim@samsung.com>");
 MODULE_AUTHOR("MyungJoo Ham <myungjoo.ham@samsung.com>");