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/drivers/extcon/extcon_class.c b/drivers/extcon/extcon_class.c
index 83a088f..403933b 100644
--- a/drivers/extcon/extcon_class.c
+++ b/drivers/extcon/extcon_class.c
@@ -31,6 +31,39 @@
#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 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 @@
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 @@
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 @@
* 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 @@
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 @@
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 @@
}
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 @@
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 @@
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 @@
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 @@
*/
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 @@
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 @@
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 @@
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;
}