Extcon: support multiple states at a device.
One switch device (e.g., MUIC(MAX8997, MAX77686, ...), and some 30-pin
devices) may have multiple cables attached. For example, one
30-pin port may inhabit a USB cable, an HDMI cable, and a mic.
Thus, one switch device requires multiple state bits each representing
a type of cable.
For such purpose, we use the 32bit state variable; thus, up to 32
different type of cables may be defined for a switch device. The list of
possible cables is defined by the array of cable names in the switch_dev
struct given to the class.
Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>
Signed-off-by: MyungJoo Ham <myungjoo.ham@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
--
Changes from V7
- Bugfixed in _call_per_cable() (incorrect nb) (Chanwoo Choi)
- Compiler error in header for !CONFIG_EXTCON (Chanwoo Choi)
Changes from V5
- Sysfs style reformed: subdirectory per cable.
- Updated standard cable names
- Removed unnecessary printf
- Bugfixes after testing
Changes from V4
- Bugfixes after more testing at Exynos4412 boards with userspace
processses.
Changes from V3
- Bugfixes after more testing at Exynos4412 boards.
Changes from V2
- State can be stored by user
- Documentation updated
Changes from RFC
- Switch is renamed to extcon
- Added kerneldoc comments
- Added APIs to support "standard" cable names
- Added helper APIs to support notifier block registration with cable
name.
- Regrouped function list in the header file.
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/include/linux/extcon.h b/include/linux/extcon.h
index c9c9afe..20e24b3 100644
--- a/include/linux/extcon.h
+++ b/include/linux/extcon.h
@@ -24,10 +24,60 @@
#define __LINUX_EXTCON_H__
#include <linux/notifier.h>
+
+#define SUPPORTED_CABLE_MAX 32
+#define CABLE_NAME_MAX 30
+
+/*
+ * The standard cable name is to help support general notifier
+ * and notifee device drivers to share the common names.
+ * Please use standard cable names unless your notifier device has
+ * a very unique and abnormal cable or
+ * the cable type is supposed to be used with only one unique
+ * pair of notifier/notifee devices.
+ *
+ * Please add any other "standard" cables used with extcon dev.
+ *
+ * You may add a dot and number to specify version or specification
+ * of the specific cable if it is required. (e.g., "Fast-charger.18"
+ * and "Fast-charger.10" for 1.8A and 1.0A chargers)
+ * However, the notifee and notifier should be able to handle such
+ * string and if the notifee can negotiate the protocol or idenify,
+ * you don't need such convention. This convention is helpful when
+ * notifier can distinguish but notifiee cannot.
+ */
+enum extcon_cable_name {
+ EXTCON_USB = 0,
+ EXTCON_USB_HOST,
+ EXTCON_TA, /* Travel Adaptor */
+ EXTCON_FAST_CHARGER,
+ EXTCON_SLOW_CHARGER,
+ EXTCON_CHARGE_DOWNSTREAM, /* Charging an external device */
+ EXTCON_HDMI,
+ EXTCON_MHL,
+ EXTCON_DVI,
+ EXTCON_VGA,
+ EXTCON_DOCK,
+ EXTCON_LINE_IN,
+ EXTCON_LINE_OUT,
+ EXTCON_MIC_IN,
+ EXTCON_HEADPHONE_OUT,
+ EXTCON_SPDIF_IN,
+ EXTCON_SPDIF_OUT,
+ EXTCON_VIDEO_IN,
+ EXTCON_VIDEO_OUT,
+};
+extern const char *extcon_cable_name[];
+
+struct extcon_cable;
+
/**
* struct extcon_dev - An extcon device represents one external connector.
* @name The name of this extcon device. Parent device name is used
* if NULL.
+ * @supported_cable Array of supported cable name ending with NULL.
+ * If supported_cable is NULL, cable name related APIs
+ * are disabled.
* @print_name An optional callback to override the method to print the
* name of the extcon device.
* @print_state An optional callback to override the method to print the
@@ -38,6 +88,11 @@
* @nh Notifier for the state change events from this extcon
* @entry To support list of extcon devices so that uses can search
* for extcon devices based on the extcon name.
+ * @lock
+ * @max_supported Internal value to store the number of cables.
+ * @extcon_dev_type Device_type struct to provide attribute_groups
+ * customized for each extcon device.
+ * @cables Sysfs subdirectories. Each represents one cable.
*
* In most cases, users only need to provide "User initializing data" of
* this struct when registering an extcon. In some exceptional cases,
@@ -47,6 +102,7 @@
struct extcon_dev {
/* --- Optional user initializing data --- */
const char *name;
+ const char **supported_cable;
/* --- Optional callbacks to override class functions --- */
ssize_t (*print_name)(struct extcon_dev *edev, char *buf);
@@ -57,6 +113,49 @@
u32 state;
struct raw_notifier_head nh;
struct list_head entry;
+ spinlock_t lock; /* could be called by irq handler */
+ int max_supported;
+
+ /* /sys/class/extcon/.../cable.n/... */
+ struct device_type extcon_dev_type;
+ struct extcon_cable *cables;
+};
+
+/**
+ * struct extcon_cable - An internal data for each cable of extcon device.
+ * @edev The extcon device
+ * @cable_index Index of this cable in the edev
+ * @attr_g Attribute group for the cable
+ * @attr_name "name" sysfs entry
+ * @attr_state "state" sysfs entry
+ * @attrs Array pointing to attr_name and attr_state for attr_g
+ */
+struct extcon_cable {
+ struct extcon_dev *edev;
+ int cable_index;
+
+ struct attribute_group attr_g;
+ struct device_attribute attr_name;
+ struct device_attribute attr_state;
+
+ struct attribute *attrs[3]; /* to be fed to attr_g.attrs */
+};
+
+/**
+ * struct extcon_specific_cable_nb - An internal data for
+ * extcon_register_interest().
+ * @internal_nb a notifier block bridging extcon notifier and cable notifier.
+ * @user_nb user provided notifier block for events from a specific cable.
+ * @cable_index the target cable.
+ * @edev the target extcon device.
+ * @previous_value the saved previous event value.
+ */
+struct extcon_specific_cable_nb {
+ struct notifier_block internal_nb;
+ struct notifier_block *user_nb;
+ int cable_index;
+ struct extcon_dev *edev;
+ unsigned long previous_value;
};
#if IS_ENABLED(CONFIG_EXTCON)
@@ -69,16 +168,54 @@
extern void extcon_dev_unregister(struct extcon_dev *edev);
extern struct extcon_dev *extcon_get_extcon_dev(const char *extcon_name);
+/*
+ * get/set/update_state access the 32b encoded state value, which represents
+ * states of all possible cables of the multistate port. For example, if one
+ * calls extcon_set_state(edev, 0x7), it may mean that all the three cables
+ * are attached to the port.
+ */
static inline u32 extcon_get_state(struct extcon_dev *edev)
{
return edev->state;
}
extern void extcon_set_state(struct extcon_dev *edev, u32 state);
+extern void extcon_update_state(struct extcon_dev *edev, u32 mask, u32 state);
+
+/*
+ * get/set_cable_state access each bit of the 32b encoded state value.
+ * They are used to access the status of each cable based on the cable_name
+ * or cable_index, which is retrived by extcon_find_cable_index
+ */
+extern int extcon_find_cable_index(struct extcon_dev *sdev,
+ const char *cable_name);
+extern int extcon_get_cable_state_(struct extcon_dev *edev, int cable_index);
+extern int extcon_set_cable_state_(struct extcon_dev *edev, int cable_index,
+ bool cable_state);
+
+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);
+
+/*
+ * Following APIs are for notifiees (those who want to be notified)
+ * to register a callback for events from a specific cable of the extcon.
+ * Notifiees are the connected device drivers wanting to get notified by
+ * a specific external port of a connection device.
+ */
+extern int extcon_register_interest(struct extcon_specific_cable_nb *obj,
+ const char *extcon_name,
+ const char *cable_name,
+ struct notifier_block *nb);
+extern int extcon_unregister_interest(struct extcon_specific_cable_nb *nb);
/*
* Following APIs are to monitor every action of a notifier.
* Registerer gets notified for every external port of a connection device.
+ * Probably this could be used to debug an action of notifier; however,
+ * we do not recommend to use this at normal 'notifiee' device drivers who
+ * want to be notified by a specific external port of the notifier.
*/
extern int extcon_register_notifier(struct extcon_dev *edev,
struct notifier_block *nb);
@@ -99,6 +236,41 @@
}
static inline void extcon_set_state(struct extcon_dev *edev, u32 state) { }
+
+static inline void extcon_update_state(struct extcon_dev *edev, u32 mask,
+ u32 state)
+{ }
+
+static inline int extcon_find_cable_index(struct extcon_dev *edev,
+ const char *cable_name)
+{
+ return 0;
+}
+
+static inline int extcon_get_cable_state_(struct extcon_dev *edev,
+ int cable_index)
+{
+ return 0;
+}
+
+static inline int extcon_set_cable_state_(struct extcon_dev *edev,
+ int cable_index, bool cable_state)
+{
+ return 0;
+}
+
+static inline int extcon_get_cable_state(struct extcon_dev *edev,
+ const char *cable_name)
+{
+ return 0;
+}
+
+static inline int extcon_set_cable_state(struct extcon_dev *edev,
+ const char *cable_name, int state)
+{
+ return 0;
+}
+
static inline struct extcon_dev *extcon_get_extcon_dev(const char *extcon_name)
{
return NULL;
@@ -116,5 +288,18 @@
return 0;
}
+static inline int extcon_register_interest(struct extcon_specific_cable_nb *obj,
+ const char *extcon_name,
+ const char *cable_name,
+ struct notifier_block *nb)
+{
+ return 0;
+}
+
+static inline int extcon_unregister_interest(struct extcon_specific_cable_nb
+ *obj)
+{
+ return 0;
+}
#endif /* CONFIG_EXTCON */
#endif /* __LINUX_EXTCON_H__ */