drivers/hid/hid-appletb-bl.c

Source file repositories/reference/linux-study-clean/drivers/hid/hid-appletb-bl.c

File Facts

System
Linux kernel
Corpus path
drivers/hid/hid-appletb-bl.c
Extension
.c
Size
5182 bytes
Lines
205
Domain
Driver Families
Bucket
drivers/hid
Inferred role
Driver Families: implementation source
Status
source implementation candidate

Why This File Exists

Repeatable hardware-adapter layer. Deep compatibility for every driver is out of scope; this atlas records patterns, probe lifecycles, bus glue, IRQ/DMA usage, and links back to core abstractions.

Dependency Surface

Detected Declarations

Annotated Snippet

struct appletb_bl {
	struct hid_field *aux1_field, *brightness_field;
	struct backlight_device *bdev;

	bool full_on;
};

static const u8 appletb_bl_brightness_map[] = {
	APPLETB_BL_OFF,
	APPLETB_BL_DIM,
	APPLETB_BL_ON,
};

static int appletb_bl_set_brightness(struct appletb_bl *bl, u8 brightness)
{
	struct hid_report *report = bl->brightness_field->report;
	struct hid_device *hdev = report->device;
	int ret;

	ret = hid_set_field(bl->aux1_field, 0, 1);
	if (ret) {
		hid_err(hdev, "Failed to set auxiliary field (%pe)\n", ERR_PTR(ret));
		return ret;
	}

	ret = hid_set_field(bl->brightness_field, 0, brightness);
	if (ret) {
		hid_err(hdev, "Failed to set brightness field (%pe)\n", ERR_PTR(ret));
		return ret;
	}

	if (!bl->full_on) {
		ret = hid_hw_power(hdev, PM_HINT_FULLON);
		if (ret < 0) {
			hid_err(hdev, "Device didn't power on (%pe)\n", ERR_PTR(ret));
			return ret;
		}

		bl->full_on = true;
	}

	hid_hw_request(hdev, report, HID_REQ_SET_REPORT);

	if (brightness == APPLETB_BL_OFF) {
		hid_hw_power(hdev, PM_HINT_NORMAL);
		bl->full_on = false;
	}

	return 0;
}

static int appletb_bl_update_status(struct backlight_device *bdev)
{
	struct appletb_bl *bl = bl_get_data(bdev);
	u8 brightness;

	if (backlight_is_blank(bdev))
		brightness = APPLETB_BL_OFF;
	else
		brightness = appletb_bl_brightness_map[backlight_get_brightness(bdev)];

	return appletb_bl_set_brightness(bl, brightness);
}

static const struct backlight_ops appletb_bl_backlight_ops = {
	.options = BL_CORE_SUSPENDRESUME,
	.update_status = appletb_bl_update_status,
};

static int appletb_bl_probe(struct hid_device *hdev, const struct hid_device_id *id)
{
	struct hid_field *aux1_field, *brightness_field;
	struct backlight_properties bl_props = { 0 };
	struct device *dev = &hdev->dev;
	struct appletb_bl *bl;
	int ret;

	ret = hid_parse(hdev);
	if (ret)
		return dev_err_probe(dev, ret, "HID parse failed\n");

	aux1_field = hid_find_field(hdev, HID_FEATURE_REPORT,
				    HID_VD_APPLE_TB_BRIGHTNESS, HID_USAGE_AUX1);

	brightness_field = hid_find_field(hdev, HID_FEATURE_REPORT,
					  HID_VD_APPLE_TB_BRIGHTNESS, HID_USAGE_BRIGHTNESS);

	if (!aux1_field || !brightness_field)
		return -ENODEV;

Annotation

Implementation Notes