[RFC PATCH v6 4/5] ACPI: button: extract input creation/destruction helpers

[Lv Zheng]

From: Benjamin Tissoires <benjamin.tissoi...@redhat.com>

When the LID switch ACPI implementation is unreliable, we might want
to remove the device when we are not sure about the state. This should
prevent any suspend/resume loops given that in that case, there will be
no more LID switch input node.

This patch prepares the dynamic creation/destruction of the input node.

Signed-off-by: Benjamin Tissoires <benjamin.tissoi...@redhat.com>
Signed-off-by: Lv Zheng <lv.zh...@intel.com>
---
 drivers/acpi/button.c | 86 +++++++++++++++++++++++++++++++--------------------
 1 file changed, 53 insertions(+), 33 deletions(-)

diff --git a/drivers/acpi/button.c b/drivers/acpi/button.c
index 1256a8c..91c9989 100644
--- a/drivers/acpi/button.c
+++ b/drivers/acpi/button.c
@@ -302,6 +302,54 @@ int acpi_lid_open(void)
 }
 EXPORT_SYMBOL(acpi_lid_open);
 
+static void acpi_button_remove_input(struct acpi_device *device)
+{
+       struct acpi_button *button = acpi_driver_data(device);
+
+       input_unregister_device(button->input);
+       button->input = NULL;
+}
+
+static int acpi_button_add_input(struct acpi_device *device)
+{
+       struct acpi_button *button = acpi_driver_data(device);
+       struct input_dev *input;
+       int error;
+
+       input = input_allocate_device();
+       if (!input) {
+               error = -ENOMEM;
+               goto err;
+       }
+
+       input->name = acpi_device_name(device);
+       input->phys = button->phys;
+       input->id.bustype = BUS_HOST;
+       input->id.product = button->type;
+       input->dev.parent = &device->dev;
+       switch (button->type) {
+       case ACPI_BUTTON_TYPE_POWER:
+               input_set_capability(input, EV_KEY, KEY_POWER);
+               break;
+       case ACPI_BUTTON_TYPE_SLEEP:
+               input_set_capability(input, EV_KEY, KEY_SLEEP);
+               break;
+       case ACPI_BUTTON_TYPE_LID:
+               input_set_capability(input, EV_SW, SW_LID);
+               break;
+       }
+
+       error = input_register_device(input);
+       if (error)
+               goto err;
+
+       button->input = input;
+       return 0;
+ err:
+       input_free_device(input);
+       return error;
+}
+
 static int acpi_lid_update_state(struct acpi_device *device)
 {
        int state;
@@ -414,7 +462,6 @@ static int acpi_button_resume(struct device *dev)
 static int acpi_button_add(struct acpi_device *device)
 {
        struct acpi_button *button;
-       struct input_dev *input;
        const char *hid = acpi_device_hid(device);
        char *name, *class;
        int error;
@@ -425,12 +472,6 @@ static int acpi_button_add(struct acpi_device *device)
 
        device->driver_data = button;
 
-       button->input = input = input_allocate_device();
-       if (!input) {
-               error = -ENOMEM;
-               goto err_free_button;
-       }
-
        name = acpi_device_name(device);
        class = acpi_device_class(device);
 
@@ -457,38 +498,19 @@ static int acpi_button_add(struct acpi_device *device)
        } else {
                printk(KERN_ERR PREFIX "Unsupported hid [%s]\n", hid);
                error = -ENODEV;
-               goto err_free_input;
+               goto err_free_button;
        }
 
        error = acpi_button_add_fs(device);
        if (error)
-               goto err_free_input;
+               goto err_free_button;
 
        snprintf(button->phys, sizeof(button->phys), "%s/button/input0", hid);
 
-       input->name = name;
-       input->phys = button->phys;
-       input->id.bustype = BUS_HOST;
-       input->id.product = button->type;
-       input->dev.parent = &device->dev;
-
-       switch (button->type) {
-       case ACPI_BUTTON_TYPE_POWER:
-               input_set_capability(input, EV_KEY, KEY_POWER);
-               break;
-
-       case ACPI_BUTTON_TYPE_SLEEP:
-               input_set_capability(input, EV_KEY, KEY_SLEEP);
-               break;
-
-       case ACPI_BUTTON_TYPE_LID:
-               input_set_capability(input, EV_SW, SW_LID);
-               break;
-       }
-
-       error = input_register_device(input);
+       error = acpi_button_add_input(device);
        if (error)
                goto err_remove_fs;
+
        if (button->type == ACPI_BUTTON_TYPE_LID) {
                /*
                 * This assumes there's only one lid device, or if there are
@@ -507,8 +529,6 @@ static int acpi_button_add(struct acpi_device *device)
 
  err_remove_fs:
        acpi_button_remove_fs(device);
- err_free_input:
-       input_free_device(input);
  err_free_button:
        kfree(button);
        return error;
@@ -521,7 +541,7 @@ static int acpi_button_remove(struct acpi_device *device)
        acpi_button_remove_fs(device);
        if (button->type == ACPI_BUTTON_TYPE_LID)
                del_timer_sync(&button->lid_timer);
-       input_unregister_device(button->input);
+       acpi_button_remove_input(device);
        kfree(button);
        return 0;
 }
-- 
2.7.4