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Date: Tue, 28 Mar 2017 20:26:18 +0900
From: Chanwoo Choi <cw00.choi@...sung.com>
To: linux-kernel@...r.kernel.org
Cc: cw00.choi@...sung.com, chanwoo@...nel.org, myungjoo.ham@...sung.com
Subject: [PATCH] extcon: Remove porting compatibility of swich class
This patch removes the porting compatibility for switch class
because there is no any usage and requirement of swich class
over a couple of years.
Signed-off-by: Chanwoo Choi <cw00.choi@...sung.com>
---
Documentation/extcon/porting-android-switch-class | 123 ----------------------
drivers/extcon/extcon.c | 20 ----
2 files changed, 143 deletions(-)
delete mode 100644 Documentation/extcon/porting-android-switch-class
diff --git a/Documentation/extcon/porting-android-switch-class b/Documentation/extcon/porting-android-switch-class
deleted file mode 100644
index 49c81caef84d..000000000000
--- a/Documentation/extcon/porting-android-switch-class
+++ /dev/null
@@ -1,123 +0,0 @@
-
- Staging/Android Switch Class Porting Guide
- (linux/drivers/staging/android/switch)
- (c) Copyright 2012 Samsung Electronics
-
-AUTHORS
-MyungJoo Ham <myungjoo.ham@...sung.com>
-
-/*****************************************************************
- * CHAPTER 1. *
- * PORTING SWITCH CLASS DEVICE DRIVERS *
- *****************************************************************/
-
-****** STEP 1. Basic Functionality
- No extcon extended feature, but switch features only.
-
-- struct switch_dev (fed to switch_dev_register/unregister)
- @name: no change
- @dev: no change
- @index: drop (not used in switch device driver side anyway)
- @state: no change
- If you have used @state with magic numbers, keep it
- at this step.
- @print_name: no change but type change (switch_dev->extcon_dev)
- @print_state: no change but type change (switch_dev->extcon_dev)
-
-- switch_dev_register(sdev, dev)
- => extcon_dev_register(edev)
- : type change (sdev->edev)
- : remove second param('dev'). if edev has parent device, should store
- 'dev' to 'edev.dev.parent' before registering extcon device
-- switch_dev_unregister(sdev)
- => extcon_dev_unregister(edev)
- : no change but type change (sdev->edev)
-- switch_get_state(sdev)
- => extcon_get_state(edev)
- : no change but type change (sdev->edev) and (return: int->u32)
-- switch_set_state(sdev, state)
- => extcon_set_state(edev, state)
- : no change but type change (sdev->edev) and (state: int->u32)
-
-With this changes, the ex-switch extcon class device works as it once
-worked as switch class device. However, it will now have additional
-interfaces (both ABI and in-kernel API) and different ABI locations.
-However, if CONFIG_ANDROID is enabled without CONFIG_ANDROID_SWITCH,
-/sys/class/switch/* will be symbolically linked to /sys/class/extcon/
-so that they are still compatible with legacy userspace processes.
-
-****** STEP 2. Multistate (no more magic numbers in state value)
- Extcon's extended features for switch device drivers with
- complex features usually required magic numbers in state
- value of switch_dev. With extcon, such magic numbers that
- support multiple cables are no more required or supported.
-
- 1. Define cable names at edev->supported_cable.
- 2. (Recommended) remove print_state callback.
- 3. Use extcon_get_cable_state_(edev, index) or
- extcon_get_cable_state(edev, cable_name) instead of
- extcon_get_state(edev) if you intend to get a state of a specific
- cable. Same for set_state. This way, you can remove the usage of
- magic numbers in state value.
- 4. Use extcon_update_state() if you are updating specific bits of
- the state value.
-
-Example: a switch device driver w/ magic numbers for two cables.
- "0x00": no cables connected.
- "0x01": cable 1 connected
- "0x02": cable 2 connected
- "0x03": cable 1 and 2 connected
- 1. edev->supported_cable = {"1", "2", NULL};
- 2. edev->print_state = NULL;
- 3. extcon_get_cable_state_(edev, 0) shows cable 1's state.
- extcon_get_cable_state(edev, "1") shows cable 1's state.
- extcon_set_cable_state_(edev, 1) sets cable 2's state.
- extcon_set_cable_state(edev, "2") sets cable 2's state
- 4. extcon_update_state(edev, 0x01, 0) sets the least bit's 0.
-
-****** STEP 3. Notify other device drivers
-
- You can notify others of the cable attach/detach events with
-notifier chains.
-
- At the side of other device drivers (the extcon device itself
-does not need to get notified of its own events), there are two
-methods to register notifier_block for cable events:
-(a) for a specific cable or (b) for every cable.
-
- (a) extcon_register_interest(obj, extcon_name, cable_name, nb)
- Example: want to get news of "MAX8997_MUIC"'s "USB" cable
-
- obj = kzalloc(sizeof(struct extcon_specific_cable_nb),
- GFP_KERNEL);
- nb->notifier_call = the_callback_to_handle_usb;
-
- extcon_register_intereset(obj, "MAX8997_MUIC", "USB", nb);
-
- (b) extcon_register_notifier(edev, nb)
- Call nb for any changes in edev.
-
- Please note that in order to properly behave with method (a),
-the extcon device driver should support multistate feature (STEP 2).
-
-****** STEP 4. Inter-cable relation (mutually exclusive)
-
- You can provide inter-cable mutually exclusiveness information
-for an extcon device. When cables A and B are declared to be mutually
-exclusive, the two cables cannot be in ATTACHED state simulteneously.
-
-
-/*****************************************************************
- * CHAPTER 2. *
- * PORTING USERSPACE w/ SWITCH CLASS DEVICE SUPPORT *
- *****************************************************************/
-
-****** ABI Location
-
- If "CONFIG_ANDROID" is enabled, /sys/class/switch/* are created
-as symbolic links to /sys/class/extcon/*.
-
- The two files of switch class, name and state, are provided with
-extcon, too. When the multistate support (STEP 2 of CHAPTER 1.) is
-not enabled or print_state callback is supplied, the output of
-state ABI is same with switch class.
diff --git a/drivers/extcon/extcon.c b/drivers/extcon/extcon.c
index 09ac5e70c2f3..e85704eda645 100644
--- a/drivers/extcon/extcon.c
+++ b/drivers/extcon/extcon.c
@@ -230,9 +230,6 @@ struct extcon_cable {
};
static struct class *extcon_class;
-#if defined(CONFIG_ANDROID)
-static struct class_compat *switch_class;
-#endif /* CONFIG_ANDROID */
static LIST_HEAD(extcon_dev_list);
static DEFINE_MUTEX(extcon_dev_list_lock);
@@ -968,12 +965,6 @@ static int create_extcon_class(void)
if (IS_ERR(extcon_class))
return PTR_ERR(extcon_class);
extcon_class->dev_groups = extcon_groups;
-
-#if defined(CONFIG_ANDROID)
- switch_class = class_compat_register("switch");
- if (WARN(!switch_class, "cannot allocate"))
- return -ENOMEM;
-#endif /* CONFIG_ANDROID */
}
return 0;
@@ -1195,10 +1186,6 @@ int extcon_dev_register(struct extcon_dev *edev)
put_device(&edev->dev);
goto err_dev;
}
-#if defined(CONFIG_ANDROID)
- if (switch_class)
- ret = class_compat_create_link(switch_class, &edev->dev, NULL);
-#endif /* CONFIG_ANDROID */
spin_lock_init(&edev->lock);
@@ -1284,10 +1271,6 @@ void extcon_dev_unregister(struct extcon_dev *edev)
kfree(edev->cables);
}
-#if defined(CONFIG_ANDROID)
- if (switch_class)
- class_compat_remove_link(switch_class, &edev->dev, NULL);
-#endif
put_device(&edev->dev);
}
EXPORT_SYMBOL_GPL(extcon_dev_unregister);
@@ -1358,9 +1341,6 @@ static int __init extcon_class_init(void)
static void __exit extcon_class_exit(void)
{
-#if defined(CONFIG_ANDROID)
- class_compat_unregister(switch_class);
-#endif
class_destroy(extcon_class);
}
module_exit(extcon_class_exit);
--
1.9.1
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