[PATCH V2 6/7] platform/x86: lg-laptop.c: Expose reader mode as a LED, rather than a sysfs file for 2018 and newer models

[Matan Ziv-Av <matan@xxxxxxxxxxx>]

On 2018 and newer models, setting reader mode does not change display
Gamma, so treat reader mode as a LED, instead of a switch.

Signed-off-by: Matan Ziv-Av <matan@xxxxxxxxxxx>
---
 drivers/platform/x86/lg-laptop.c | 30 +++++++++++++++++++++++++++++-
 1 file changed, 29 insertions(+), 1 deletion(-)

diff --git a/drivers/platform/x86/lg-laptop.c b/drivers/platform/x86/lg-laptop.c
index ccdc93be2a9b..fd802e9f6556 100644
--- a/drivers/platform/x86/lg-laptop.c
+++ b/drivers/platform/x86/lg-laptop.c
@@ -73,6 +73,7 @@ static u32 inited;
 #define INIT_INPUT_ACPI         0x04
 #define INIT_TPAD_LED           0x08
 #define INIT_KBD_LED            0x10
+#define INIT_RDMODE_LED         0x20
 #define INIT_SPARSE_KEYMAP      0x80
 
 static int battery_limit_use_wmbb;
@@ -529,9 +530,9 @@ static DEVICE_ATTR_RW(battery_care_limit);
 static struct attribute *dev_attributes[] = {
 	&dev_attr_fan_mode.attr,
 	&dev_attr_usb_charge.attr,
-	&dev_attr_reader_mode.attr,
 	&dev_attr_fn_lock.attr,
 	&dev_attr_battery_care_limit.attr,
+	&dev_attr_reader_mode.attr, // This is last, to be easily removed
 	NULL
 };
 
@@ -555,6 +556,22 @@ static enum led_brightness tpad_led_get(struct led_classdev *cdev)
 
 static LED_DEVICE(tpad_led, 1);
 
+static void reader_mode_led_set(struct led_classdev *cdev,
+				enum led_brightness brightness)
+{
+	reader_mode_store(NULL, NULL, brightness == LED_OFF ? "0" : "1", 1);
+}
+
+static enum led_brightness reader_mode_led_get(struct led_classdev *cdev)
+{
+	char buf[BUFFER_SIZE];
+
+	reader_mode_show(NULL, NULL, buf);
+	return buf[0] != '0';
+}
+
+static LED_DEVICE(reader_mode_led, 1);
+
 static void kbd_backlight_set(struct led_classdev *cdev,
 			      enum led_brightness brightness)
 {
@@ -670,6 +687,9 @@ static int acpi_add(struct acpi_device *device)
 	if (year >= 2019)
 		battery_limit_use_wmbb = 1;
 
+	if (year >= 2018)
+		dev_attributes[4] = NULL; // Remove reader mode special file.
+
 	ret = sysfs_create_group(&pf_device->dev.kobj, &dev_attribute_group);
 	if (ret)
 		goto out_platform_device;
@@ -680,6 +700,11 @@ static int acpi_add(struct acpi_device *device)
 	if (!led_classdev_register(&pf_device->dev, &tpad_led))
 		inited |= INIT_TPAD_LED;
 
+	// For 2018 and 2019 models, reader mode only controls the LED
+	if (year >= 2018)
+		if (!led_classdev_register(&pf_device->dev, &reader_mode_led))
+			inited |= INIT_RDMODE_LED;
+
 	wmi_input_setup();
 
 	return 0;
@@ -700,6 +725,9 @@ static int acpi_remove(struct acpi_device *device)
 	if (inited & INIT_TPAD_LED)
 		led_classdev_unregister(&tpad_led);
 
+	if (inited & INIT_RDMODE_LED)
+		led_classdev_unregister(&reader_mode_led);
+
 	wmi_input_destroy();
 	platform_device_unregister(pf_device);
 	pf_device = NULL;
-- 
2.21.0