Extcon: support multiple states at a device.
Syed Rafiuddin [Mon, 3 Sep 2012 10:00:58 +0000 (15:00 +0530)]
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.

(cherry picked from commit 806d9dd71ff52ef09764585baaeec23afbb98560)

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>

Change-Id: Ic77273f660d528f0f53fa38a005e61f4a9ad422f
Signed-off-by: Syed Rafiuddin <srafiuddin@nvidia.com>
Reviewed-on: http://git-master/r/130610
Reviewed-by: Laxman Dewangan <ldewangan@nvidia.com>

Documentation/ABI/testing/sysfs-class-extcon
drivers/extcon/extcon_class.c
include/linux/extcon.h

index 59a4b1c..19b18e9 100644 (file)
@@ -1,5 +1,5 @@
 What:          /sys/class/extcon/.../
-Date:          December 2011
+Date:          February 2012
 Contact:       MyungJoo Ham <myungjoo.ham@samsung.com>
 Description:
                Provide a place in sysfs for the extcon objects.
@@ -7,8 +7,16 @@ Description:
                The name of extcon object denoted as ... is the name given
                with extcon_dev_register.
 
+               One extcon device denotes a single external connector
+               port. An external connector may have multiple cables
+               attached simultaneously. Many of docks, cradles, and
+               accessory cables have such capability. For example,
+               the 30-pin port of Nuri board (/arch/arm/mach-exynos)
+               may have both HDMI and Charger attached, or analog audio,
+               video, and USB cables attached simulteneously.
+
 What:          /sys/class/extcon/.../name
-Date:          December 2011
+Date:          February 2012
 Contact:       MyungJoo Ham <myungjoo.ham@samsung.com>
 Description:
                The /sys/class/extcon/.../name shows the name of the extcon
@@ -17,10 +25,51 @@ Description:
                this sysfs node.
 
 What:          /sys/class/extcon/.../state
-Date:          December 2011
+Date:          February 2012
+Contact:       MyungJoo Ham <myungjoo.ham@samsung.com>
+Description:
+               The /sys/class/extcon/.../state shows and stores the cable
+               attach/detach information of the corresponding extcon object.
+               If the extcon object has an optional callback "show_state"
+               defined, the showing function is overriden with the optional
+               callback.
+
+               If the default callback for showing function is used, the
+               format is like this:
+               # cat state
+               USB_OTG=1
+               HDMI=0
+               TA=1
+               EAR_JACK=0
+               #
+               In this example, the extcon device have USB_OTG and TA
+               cables attached and HDMI and EAR_JACK cables detached.
+
+               In order to update the state of an extcon device, enter a hex
+               state number starting with 0x.
+                echo 0xHEX > state
+
+               This updates the whole state of the extcon dev.
+               Inputs of all the methods are required to meet the
+               mutually_exclusive contidions if they exist.
+
+               It is recommended to use this "global" state interface if
+               you need to enter the value atomically. The later state
+               interface associated with each cable cannot update
+               multiple cable states of an extcon device simultaneously.
+
+What:          /sys/class/extcon/.../cable.x/name
+Date:          February 2012
+Contact:       MyungJoo Ham <myungjoo.ham@samsung.com>
+Description:
+               The /sys/class/extcon/.../cable.x/name shows the name of cable
+               "x" (integer between 0 and 31) of an extcon device.
+
+What:          /sys/class/extcon/.../cable.x/state
+Date:          February 2012
 Contact:       MyungJoo Ham <myungjoo.ham@samsung.com>
 Description:
-               The /sys/class/extcon/.../state shows the cable attach/detach
-               information of the corresponding extcon object. If the extcon
-               objecct has an optional callback "show_state" defined, the
-               callback will provide the name with this sysfs node.
+               The /sys/class/extcon/.../cable.x/name shows and stores the
+               state of cable "x" (integer between 0 and 31) of an extcon
+               device. The state value is either 0 (detached) or 1
+               (attached).
index 83a088f..403933b 100644 (file)
 #include <linux/extcon.h>
 #include <linux/slab.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[] = {
+       [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_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",
+
+       NULL,
+};
+
 struct class *extcon_class;
 #if defined(CONFIG_ANDROID) && !defined(CONFIG_ANDROID_SWITCH)
 static struct class_compat *switch_class;
@@ -42,6 +75,7 @@ static DEFINE_MUTEX(extcon_dev_list_lock);
 static ssize_t state_show(struct device *dev, struct device_attribute *attr,
                          char *buf)
 {
+       int i, count = 0;
        struct extcon_dev *edev = (struct extcon_dev *) dev_get_drvdata(dev);
 
        if (edev->print_state) {
@@ -51,7 +85,39 @@ static ssize_t state_show(struct device *dev, struct device_attribute *attr,
                        return ret;
                /* Use default if failed */
        }
-       return sprintf(buf, "%u\n", edev->state);
+
+       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;
+               count += sprintf(buf + count, "%s=%d\n",
+                                edev->supported_cable[i],
+                                !!(edev->state & (1 << i)));
+       }
+
+       return count;
+}
+
+void extcon_set_state(struct extcon_dev *edev, u32 state);
+static ssize_t state_store(struct device *dev, struct device_attribute *attr,
+                          const char *buf, size_t count)
+{
+       u32 state;
+       ssize_t ret = 0;
+       struct extcon_dev *edev = (struct extcon_dev *) dev_get_drvdata(dev);
+
+       ret = sscanf(buf, "0x%x", &state);
+       if (ret == 0)
+               ret = -EINVAL;
+       else
+               extcon_set_state(edev, state);
+
+       if (ret < 0)
+               return ret;
+
+       return count;
 }
 
 static ssize_t name_show(struct device *dev, struct device_attribute *attr,
@@ -69,9 +135,52 @@ static ssize_t name_show(struct device *dev, struct device_attribute *attr,
        return sprintf(buf, "%s\n", dev_name(edev->dev));
 }
 
+static ssize_t cable_name_show(struct device *dev,
+                              struct device_attribute *attr, char *buf)
+{
+       struct extcon_cable *cable = container_of(attr, struct extcon_cable,
+                                                 attr_name);
+
+       return sprintf(buf, "%s\n",
+                      cable->edev->supported_cable[cable->cable_index]);
+}
+
+static ssize_t cable_state_show(struct device *dev,
+                               struct device_attribute *attr, char *buf)
+{
+       struct extcon_cable *cable = container_of(attr, struct extcon_cable,
+                                                 attr_state);
+
+       return sprintf(buf, "%d\n",
+                      extcon_get_cable_state_(cable->edev,
+                                              cable->cable_index));
+}
+
+static ssize_t cable_state_store(struct device *dev,
+                                struct device_attribute *attr, const char *buf,
+                                size_t count)
+{
+       struct extcon_cable *cable = container_of(attr, struct extcon_cable,
+                                                 attr_state);
+       int ret, state;
+
+       ret = sscanf(buf, "%d", &state);
+       if (ret == 0)
+               ret = -EINVAL;
+       else
+               ret = extcon_set_cable_state_(cable->edev, cable->cable_index,
+                                             state);
+
+       if (ret < 0)
+               return ret;
+       return count;
+}
+
 /**
- * extcon_set_state() - Set the cable attach states of the extcon device.
+ * extcon_update_state() - Update the cable attach states of the extcon device
+ *                     only for the masked bits.
  * @edev:      the extcon device
+ * @mask:      the bit mask to designate updated bits.
  * @state:     new cable attach status for @edev
  *
  * Changing the state sends uevent with environment variable containing
@@ -79,10 +188,10 @@ static ssize_t name_show(struct device *dev, struct device_attribute *attr,
  * Tizen uses this format for extcon device to get events from ports.
  * Android uses this format as well.
  *
- * Note that notifier provides the which bits are changes in the state
- * variable with "val" to the callback.
+ * Note that the notifier provides which bits are changed in the state
+ * variable with the val parameter (second) to the callback.
  */
-void extcon_set_state(struct extcon_dev *edev, u32 state)
+void extcon_update_state(struct extcon_dev *edev, u32 mask, u32 state)
 {
        char name_buf[120];
        char state_buf[120];
@@ -90,15 +199,20 @@ void extcon_set_state(struct extcon_dev *edev, u32 state)
        char *envp[3];
        int env_offset = 0;
        int length;
-       u32 old_state = edev->state;
+       unsigned long flags;
 
-       if (edev->state != state) {
-               edev->state = state;
+       spin_lock_irqsave(&edev->lock, flags);
 
-               raw_notifier_call_chain(&edev->nh, old_state ^ edev->state,
-                                       edev);
+       if (edev->state != ((edev->state & ~mask) | (state & mask))) {
+               u32 old_state = edev->state;
 
-               prop_buf = (char *)get_zeroed_page(GFP_KERNEL);
+               edev->state &= ~mask;
+               edev->state |= state & mask;
+
+               raw_notifier_call_chain(&edev->nh, old_state, edev);
+
+               /* This could be in interrupt handler */
+               prop_buf = (char *)get_zeroed_page(GFP_ATOMIC);
                if (prop_buf) {
                        length = name_show(edev->dev, NULL, prop_buf);
                        if (length > 0) {
@@ -117,17 +231,132 @@ void extcon_set_state(struct extcon_dev *edev, u32 state)
                                envp[env_offset++] = state_buf;
                        }
                        envp[env_offset] = NULL;
+                       /* Unlock early before uevent */
+                       spin_unlock_irqrestore(&edev->lock, flags);
+
                        kobject_uevent_env(&edev->dev->kobj, KOBJ_CHANGE, envp);
                        free_page((unsigned long)prop_buf);
                } else {
+                       /* Unlock early before uevent */
+                       spin_unlock_irqrestore(&edev->lock, flags);
+
                        dev_err(edev->dev, "out of memory in extcon_set_state\n");
                        kobject_uevent(&edev->dev->kobj, KOBJ_CHANGE);
                }
+       } else {
+               /* No changes */
+               spin_unlock_irqrestore(&edev->lock, flags);
        }
 }
+EXPORT_SYMBOL_GPL(extcon_update_state);
+
+/**
+ * extcon_set_state() - Set the cable attach states of the extcon device.
+ * @edev:      the extcon device
+ * @state:     new cable attach status for @edev
+ *
+ * Note that notifier provides which bits are changed in the state
+ * variable with the val parameter (second) to the callback.
+ */
+void extcon_set_state(struct extcon_dev *edev, u32 state)
+{
+       extcon_update_state(edev, 0xffffffff, state);
+}
 EXPORT_SYMBOL_GPL(extcon_set_state);
 
 /**
+ * extcon_find_cable_index() - Get the cable index based on the cable name.
+ * @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.
+ */
+int extcon_find_cable_index(struct extcon_dev *edev, const char *cable_name)
+{
+       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;
+               }
+       }
+
+       return -EINVAL;
+}
+EXPORT_SYMBOL_GPL(extcon_find_cable_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))
+               return -EINVAL;
+
+       return !!(edev->state & (1 << index));
+}
+EXPORT_SYMBOL_GPL(extcon_get_cable_state_);
+
+/**
+ * extcon_get_cable_state() - Get the status of a specific cable.
+ * @edev:      the extcon device that has the cable.
+ * @cable_name:        cable name.
+ *
+ * Note that this is slower than 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
+                                               (edev, cable_name));
+}
+EXPORT_SYMBOL_GPL(extcon_get_cable_state);
+
+/**
+ * extcon_get_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
+ *                     true: attached / false: detached.
+ */
+int extcon_set_cable_state_(struct extcon_dev *edev,
+                       int index, bool cable_state)
+{
+       u32 state;
+
+       if (index < 0 || (edev->max_supported && edev->max_supported <= index))
+               return -EINVAL;
+
+       state = cable_state ? (1 << index) : 0;
+       extcon_update_state(edev, 1 << index, state);
+       return 0;
+}
+EXPORT_SYMBOL_GPL(extcon_set_cable_state_);
+
+/**
+ * extcon_get_cable_state() - Set the status of a specific cable.
+ * @edev:      the extcon device that has the cable.
+ * @cable_name:        cable name.
+ * @cable_state:       the new cable status. The default semantics is
+ *                     true: attached / false: detached.
+ *
+ * Note that this is slower than 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
+                                       (edev, cable_name), cable_state);
+}
+EXPORT_SYMBOL_GPL(extcon_set_cable_state);
+
+/**
  * extcon_get_extcon_dev() - Get the extcon device instance from the name
  * @extcon_name:       The extcon name provided with extcon_dev_register()
  */
@@ -147,11 +376,88 @@ out:
 }
 EXPORT_SYMBOL_GPL(extcon_get_extcon_dev);
 
+static int _call_per_cable(struct notifier_block *nb, unsigned long val,
+                          void *ptr)
+{
+       struct extcon_specific_cable_nb *obj = container_of(nb,
+                       struct extcon_specific_cable_nb, internal_nb);
+       struct extcon_dev *edev = ptr;
+
+       if ((val & (1 << obj->cable_index)) !=
+           (edev->state & (1 << obj->cable_index))) {
+               obj->previous_value = val;
+               return obj->user_nb->notifier_call(obj->user_nb, val, ptr);
+       }
+
+       return NOTIFY_OK;
+}
+
+/**
+ * extcon_register_interest() - Register a notifier for a state change of a
+ *                           specific cable, not a entier set of cables of a
+ *                           extcon device.
+ * @obj:       an empty extcon_specific_cable_nb object to be returned.
+ * @extcon_name:       the name of extcon device.
+ * @cable_name:                the target cable name.
+ * @nb:                the notifier block to get notified.
+ *
+ * Provide an empty extcon_specific_cable_nb. extcon_register_interest() sets
+ * the struct for you.
+ *
+ * extcon_register_interest is a helper function for those who want to get
+ * notification for a single specific cable's status change. If a user wants
+ * to get notification for any changes of all cables of a extcon device,
+ * he/she should use the general extcon_register_notifier().
+ *
+ * Note that the second parameter given to the callback of nb (val) is
+ * "old_state", not the current state. The current state can be retrieved
+ * by looking at the third pameter (edev pointer)'s state value.
+ */
+int extcon_register_interest(struct extcon_specific_cable_nb *obj,
+                            const char *extcon_name, const char *cable_name,
+                            struct notifier_block *nb)
+{
+       if (!obj || !extcon_name || !cable_name || !nb)
+               return -EINVAL;
+
+       obj->edev = extcon_get_extcon_dev(extcon_name);
+       if (!obj->edev)
+               return -ENODEV;
+
+       obj->cable_index = extcon_find_cable_index(obj->edev, cable_name);
+       if (obj->cable_index < 0)
+               return -ENODEV;
+
+       obj->user_nb = nb;
+
+       obj->internal_nb.notifier_call = _call_per_cable;
+
+       return raw_notifier_chain_register(&obj->edev->nh, &obj->internal_nb);
+}
+
+/**
+ * extcon_unregister_interest() - Unregister the notifier registered by
+ *                             extcon_register_interest().
+ * @obj:       the extcon_specific_cable_nb object returned by
+ *             extcon_register_interest().
+ */
+int extcon_unregister_interest(struct extcon_specific_cable_nb *obj)
+{
+       if (!obj)
+               return -EINVAL;
+
+       return raw_notifier_chain_unregister(&obj->edev->nh, &obj->internal_nb);
+}
+
 /**
  * extcon_register_notifier() - Register a notifee to get notified by
  *                           any attach status changes from the extcon.
  * @edev:      the extcon device.
  * @nb:                a notifier block to be registered.
+ *
+ * Note that the second parameter given to the callback of nb (val) is
+ * "old_state", not the current state. The current state can be retrieved
+ * by looking at the third pameter (edev pointer)'s state value.
  */
 int extcon_register_notifier(struct extcon_dev *edev,
                        struct notifier_block *nb)
@@ -173,8 +479,9 @@ int extcon_unregister_notifier(struct extcon_dev *edev,
 EXPORT_SYMBOL_GPL(extcon_unregister_notifier);
 
 static struct device_attribute extcon_attrs[] = {
-       __ATTR_RO(state),
+       __ATTR(state, S_IRUGO | S_IWUSR, state_show, state_store),
        __ATTR_RO(name),
+       __ATTR_NULL,
 };
 
 static int create_extcon_class(void)
@@ -202,6 +509,16 @@ static void extcon_cleanup(struct extcon_dev *edev, bool skip)
        mutex_unlock(&extcon_dev_list_lock);
 
        if (!skip && get_device(edev->dev)) {
+               int index;
+
+               for (index = 0; index < edev->max_supported; index++)
+                       kfree(edev->cables[index].attr_g.name);
+
+               if (edev->max_supported) {
+                       kfree(edev->extcon_dev_type.groups);
+                       kfree(edev->cables);
+               }
+
                device_unregister(edev->dev);
                put_device(edev->dev);
        }
@@ -216,6 +533,10 @@ static void extcon_dev_release(struct device *dev)
        extcon_cleanup(edev, true);
 }
 
+static void dummy_sysfs_dev_release(struct device *dev)
+{
+}
+
 /**
  * extcon_dev_register() - Register a new extcon device
  * @edev       : the new extcon device (should be allocated before calling)
@@ -228,7 +549,7 @@ static void extcon_dev_release(struct device *dev)
  */
 int extcon_dev_register(struct extcon_dev *edev, struct device *dev)
 {
-       int ret;
+       int ret, index = 0;
 
        if (!extcon_class) {
                ret = create_extcon_class();
@@ -236,12 +557,93 @@ int extcon_dev_register(struct extcon_dev *edev, struct device *dev)
                        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 (index > SUPPORTED_CABLE_MAX) {
+               dev_err(edev->dev, "extcon: maximum number of supported cables exceeded.\n");
+               return -EINVAL;
+       }
+
        edev->dev = kzalloc(sizeof(struct device), GFP_KERNEL);
        edev->dev->parent = dev;
        edev->dev->class = extcon_class;
        edev->dev->release = extcon_dev_release;
 
        dev_set_name(edev->dev, edev->name ? edev->name : dev_name(dev));
+
+       if (edev->max_supported) {
+               char buf[10];
+               char *str;
+               struct extcon_cable *cable;
+
+               edev->cables = kzalloc(sizeof(struct extcon_cable) *
+                                      edev->max_supported, GFP_KERNEL);
+               if (!edev->cables) {
+                       ret = -ENOMEM;
+                       goto err_sysfs_alloc;
+               }
+               for (index = 0; index < edev->max_supported; index++) {
+                       cable = &edev->cables[index];
+
+                       snprintf(buf, 10, "cable.%d", index);
+                       str = kzalloc(sizeof(char) * (strlen(buf) + 1),
+                                     GFP_KERNEL);
+                       if (!str) {
+                               for (index--; index >= 0; index--) {
+                                       cable = &edev->cables[index];
+                                       kfree(cable->attr_g.name);
+                               }
+                               ret = -ENOMEM;
+
+                               goto err_alloc_cables;
+                       }
+                       strcpy(str, buf);
+
+                       cable->edev = edev;
+                       cable->cable_index = index;
+                       cable->attrs[0] = &cable->attr_name.attr;
+                       cable->attrs[1] = &cable->attr_state.attr;
+                       cable->attrs[2] = NULL;
+                       cable->attr_g.name = str;
+                       cable->attr_g.attrs = cable->attrs;
+
+                       cable->attr_name.attr.name = "name";
+                       cable->attr_name.attr.mode = 0444;
+                       cable->attr_name.show = cable_name_show;
+
+                       cable->attr_state.attr.name = "state";
+                       cable->attr_state.attr.mode = 0644;
+                       cable->attr_state.show = cable_state_show;
+                       cable->attr_state.store = cable_state_store;
+               }
+       }
+
+       if (edev->max_supported) {
+               edev->extcon_dev_type.groups =
+                       kzalloc(sizeof(struct attribute_group *) *
+                               (edev->max_supported + 1), GFP_KERNEL);
+               if (!edev->extcon_dev_type.groups) {
+                       ret = -ENOMEM;
+                       goto err_alloc_groups;
+               }
+
+               edev->extcon_dev_type.name = dev_name(edev->dev);
+               edev->extcon_dev_type.release = dummy_sysfs_dev_release;
+
+               for (index = 0; index < edev->max_supported; index++)
+                       edev->extcon_dev_type.groups[index] =
+                               &edev->cables[index].attr_g;
+
+               edev->dev->type = &edev->extcon_dev_type;
+       }
+
        ret = device_register(edev->dev);
        if (ret) {
                put_device(edev->dev);
@@ -253,6 +655,8 @@ int extcon_dev_register(struct extcon_dev *edev, struct device *dev)
                                               dev);
 #endif /* CONFIG_ANDROID && !defined(CONFIG_ANDROID_SWITCH) */
 
+       spin_lock_init(&edev->lock);
+
        RAW_INIT_NOTIFIER_HEAD(&edev->nh);
 
        dev_set_drvdata(edev->dev, edev);
@@ -265,6 +669,15 @@ int extcon_dev_register(struct extcon_dev *edev, struct device *dev)
        return 0;
 
 err_dev:
+       if (edev->max_supported)
+               kfree(edev->extcon_dev_type.groups);
+err_alloc_groups:
+       for (index = 0; index < edev->max_supported; index++)
+               kfree(edev->cables[index].attr_g.name);
+err_alloc_cables:
+       if (edev->max_supported)
+               kfree(edev->cables);
+err_sysfs_alloc:
        kfree(edev->dev);
        return ret;
 }
index c9c9afe..20e24b3 100644 (file)
 #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
  * @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,
 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 @@ struct extcon_dev {
        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 int extcon_dev_register(struct extcon_dev *edev, struct device *dev);
 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 u32 extcon_get_state(struct extcon_dev *edev)
 }
 
 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 @@ static inline int extcon_unregister_notifier(struct extcon_dev *edev,
        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__ */