2022-01-22 00:41:43

by Aditya Garg

[permalink] [raw]
Subject: [PATCH 1/3] Add support for keyboard backlight on certain T2 Macs.

From: Paul Pawlowski <[email protected]>

This patch introduces the requisite plumbing for supporting keyboard
backlight on T2-attached, USB exposed models. The quirk mechanism was
used to reuse the existing hid-apple driver.

Signed-off-by: Paul Pawlowski <[email protected]>
Signed-off-by: Aun-Ali Zaidi <[email protected]>
Signed-off-by: Aditya Garg <[email protected]>
---
drivers/hid/hid-apple.c | 125 ++++++++++++++++++++++++++++++++++++++++
1 file changed, 125 insertions(+)

diff --git a/drivers/hid/hid-apple.c b/drivers/hid/hid-apple.c
index 24802a4a6..c22d445a9 100644
--- a/drivers/hid/hid-apple.c
+++ b/drivers/hid/hid-apple.c
@@ -7,6 +7,7 @@
* Copyright (c) 2005 Michael Haboustak <[email protected]> for Concept2, Inc
* Copyright (c) 2006-2007 Jiri Kosina
* Copyright (c) 2008 Jiri Slaby <[email protected]>
+ * Copyright (c) 2019 Paul Pawlowski <[email protected]>
*/

/*
@@ -33,6 +34,7 @@
/* BIT(7) reserved, was: APPLE_IGNORE_HIDINPUT */
#define APPLE_NUMLOCK_EMULATION BIT(8)
#define APPLE_RDESC_BATTERY BIT(9)
+#define APPLE_BACKLIGHT_CTL 0x0200

#define APPLE_FLAG_FKEY 0x01

@@ -61,6 +63,12 @@ MODULE_PARM_DESC(swap_fn_leftctrl, "Swap the Fn and left Control keys. "
"(For people who want to keep PC keyboard muscle memory. "
"[0] = as-is, Mac layout, 1 = swapped, PC layout)");

+struct apple_sc_backlight {
+ struct led_classdev cdev;
+ struct hid_device *hdev;
+ unsigned short backlight_off, backlight_on_min, backlight_on_max;
+};
+
struct apple_sc {
struct hid_device *hdev;
unsigned long quirks;
@@ -68,6 +76,7 @@ struct apple_sc {
unsigned int fn_found;
DECLARE_BITMAP(pressed_numlock, KEY_CNT);
struct timer_list battery_timer;
+ struct apple_sc_backlight *backlight;
};

struct apple_key_translation {
@@ -76,6 +85,20 @@ struct apple_key_translation {
u8 flags;
};

+struct apple_backlight_config_report {
+ u8 report_id;
+ u8 version;
+ u16 backlight_off, backlight_on_min, backlight_on_max;
+};
+
+struct apple_backlight_set_report {
+ u8 report_id;
+ u8 version;
+ u16 backlight;
+ u16 rate;
+};
+
+
static const struct apple_key_translation apple2021_fn_keys[] = {
{ KEY_BACKSPACE, KEY_DELETE },
{ KEY_ENTER, KEY_INSERT },
@@ -530,6 +553,105 @@ static int apple_input_configured(struct hid_device *hdev,
return 0;
}

+static bool apple_backlight_check_support(struct hid_device *hdev)
+{
+ int i;
+ unsigned int hid;
+ struct hid_report *report;
+
+ list_for_each_entry(report, &hdev->report_enum[HID_INPUT_REPORT].report_list, list) {
+ for (i = 0; i < report->maxfield; i++) {
+ hid = report->field[i]->usage->hid;
+ if ((hid & HID_USAGE_PAGE) == HID_UP_MSVENDOR && (hid & HID_USAGE) == 0xf)
+ return true;
+ }
+ }
+
+ return false;
+}
+
+static int apple_backlight_set(struct hid_device *hdev, u16 value, u16 rate)
+{
+ int ret = 0;
+ struct apple_backlight_set_report *rep;
+
+ rep = kmalloc(sizeof(*rep), GFP_KERNEL);
+ if (rep == NULL)
+ return -ENOMEM;
+
+ rep->report_id = 0xB0;
+ rep->version = 1;
+ rep->backlight = value;
+ rep->rate = rate;
+
+ ret = hid_hw_raw_request(hdev, 0xB0u, (u8 *) rep, sizeof(*rep),
+ HID_OUTPUT_REPORT, HID_REQ_SET_REPORT);
+
+ kfree(rep);
+ return ret;
+}
+
+static int apple_backlight_led_set(struct led_classdev *led_cdev,
+ enum led_brightness brightness)
+{
+ struct apple_sc_backlight *backlight = container_of(led_cdev,
+ struct apple_sc_backlight, cdev);
+
+ return apple_backlight_set(backlight->hdev, brightness, 0);
+}
+
+static int apple_backlight_init(struct hid_device *hdev)
+{
+ int ret;
+ struct apple_sc *asc = hid_get_drvdata(hdev);
+ struct apple_backlight_config_report *rep;
+
+ if (!apple_backlight_check_support(hdev))
+ return -EINVAL;
+
+ rep = kmalloc(0x200, GFP_KERNEL);
+ if (rep == NULL)
+ return -ENOMEM;
+
+ ret = hid_hw_raw_request(hdev, 0xBFu, (u8 *) rep, sizeof(*rep),
+ HID_FEATURE_REPORT, HID_REQ_GET_REPORT);
+ if (ret < 0) {
+ hid_err(hdev, "backlight request failed: %d\n", ret);
+ goto cleanup_and_exit;
+ }
+ if (ret < 8 || rep->version != 1) {
+ hid_err(hdev, "backlight config struct: bad version %i\n", rep->version);
+ ret = -EINVAL;
+ goto cleanup_and_exit;
+ }
+
+ hid_dbg(hdev, "backlight config: off=%u, on_min=%u, on_max=%u\n",
+ rep->backlight_off, rep->backlight_on_min, rep->backlight_on_max);
+
+ asc->backlight = devm_kzalloc(&hdev->dev, sizeof(*asc->backlight), GFP_KERNEL);
+ if (!asc->backlight) {
+ ret = -ENOMEM;
+ goto cleanup_and_exit;
+ }
+
+ asc->backlight->hdev = hdev;
+ asc->backlight->cdev.name = "apple::kbd_backlight";
+ asc->backlight->cdev.max_brightness = rep->backlight_on_max;
+ asc->backlight->cdev.brightness_set_blocking = apple_backlight_led_set;
+
+ ret = apple_backlight_set(hdev, 0, 0);
+ if (ret < 0) {
+ hid_err(hdev, "backlight set request failed: %d\n", ret);
+ goto cleanup_and_exit;
+ }
+
+ ret = devm_led_classdev_register(&hdev->dev, &asc->backlight->cdev);
+
+cleanup_and_exit:
+ kfree(rep);
+ return ret;
+}
+
static int apple_probe(struct hid_device *hdev,
const struct hid_device_id *id)
{
@@ -565,6 +687,9 @@ static int apple_probe(struct hid_device *hdev,
jiffies + msecs_to_jiffies(APPLE_BATTERY_TIMEOUT_MS));
apple_fetch_battery(hdev);

+ if (quirks & APPLE_BACKLIGHT_CTL)
+ apple_backlight_init(hdev);
+
return 0;
}

--
2.25.1