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authorMatan Ziv-Av <matan@svgalib.org>2018-09-28 17:34:06 +0300
committerAndy Shevchenko <andriy.shevchenko@linux.intel.com>2018-10-19 19:21:57 +0300
commitdbf0c5a6b1f8e7bec5e17baa60a1e04c28d90f9b (patch)
treebeb9d919d4707d7c7fe3cbbea34aae20b7fbd651 /Documentation/laptops
parent9fe44fc98ce45fe42004be9fd282775030c6b147 (diff)
downloadlinux-dbf0c5a6b1f8e7bec5e17baa60a1e04c28d90f9b.tar.xz
platform/x86: Add LG Gram laptop special features driver
A driver for LG Gram laptop supporting features not available through the standard interfaces: - Support for the 5 Fn keys that generate ACPI or WMI events. - Two software controlled LEDs: keyboard backlight (also controlled by hardware) and touchpad LED. - Extra features: reader mode, Fn lock, cooling mode, USB charge mode, and maximal battery charging level. Signed-off-by: Matan Ziv-Av <matan@svgalib.org> Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
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+.. SPDX-License-Identifier: GPL-2.0+
+LG Gram laptop extra features
+=============================
+
+By Matan Ziv-Av <matan@svgalib.org>
+
+
+Hotkeys
+-------
+
+The following FN keys are ignored by the kernel without this driver:
+- FN-F1 (LG control panel) - Generates F15
+- FN-F5 (Touchpad toggle) - Generates F13
+- FN-F6 (Airplane mode) - Generates RFKILL
+- FN-F8 (Keyboard backlight) - Generates F16.
+ This key also changes keyboard backlight mode.
+- FN-F9 (Reader mode) - Generates F14
+
+The rest of the FN key work without a need for a special driver.
+
+
+Reader mode
+-----------
+
+Writing 0/1 to /sys/devices/platform/lg-laptop/reader_mode disables/enables
+reader mode. In this mode the screen colors change (blue color reduced),
+and the reader mode indicator LED (on F9 key) turns on.
+
+
+FN Lock
+-------
+
+Writing 0/1 to /sys/devices/platform/lg-laptop/fn_lock disables/enables
+FN lock.
+
+
+Battery care limit
+------------------
+
+Writing 80/100 to /sys/devices/platform/lg-laptop/battery_care_limit
+sets the maximum capacity to charge the battery. Limiting the charge
+reduces battery capacity loss over time.
+
+This value is reset to 100 when the kernel boots.
+
+
+Fan mode
+--------
+
+Writing 1/0 to /sys/devices/platform/lg-laptop/fan_mode disables/enables
+the fan silent mode.
+
+
+USB charge
+----------
+
+Writing 0/1 to /sys/devices/platform/lg-laptop/usb_charge disables/enables
+charging another device from the USB port while the device is turned off.
+
+This value is reset to 0 when the kernel boots.
+
+
+LEDs
+~~~~
+
+The are two LED devices supported by the driver:
+
+Keyboard backlight
+------------------
+
+A led device named kbd_led controls the keyboard backlight. There are three
+lighting level: off (0), low (127) and high (255).
+
+The keyboard backlight is also controlled by the key combination FN-F8
+which cycles through those levels.
+
+
+Touchpad indicator LED
+----------------------
+
+On the F5 key. Controlled by led device names tpad_led.