From: Cryolitia PukNgae <cryolitia@uniontech.com>

Add GPD fan driver document

Signed-off-by: Cryolitia PukNgae <cryolitia@uniontech.com>
---
 Documentation/hwmon/gpd-fan.rst | 79 +++++++++++++++++++++++++++++++++++++++++
 Documentation/hwmon/index.rst   |  1 +
 MAINTAINERS                     |  1 +
 3 files changed, 81 insertions(+)

diff --git a/Documentation/hwmon/gpd-fan.rst b/Documentation/hwmon/gpd-fan.rst
new file mode 100644
index 0000000000000000000000000000000000000000..a8541049d680beef93c5f7623de77e759242ffac
--- /dev/null
+++ b/Documentation/hwmon/gpd-fan.rst
@@ -0,0 +1,79 @@
+.. SPDX-License-Identifier: GPL-2.0-or-later
+
+Kernel driver gpd-fan
+=========================
+
+Author:
+    - Cryolitia PukNgae <cryolitia@uniontech.com>
+
+Description
+------------
+
+Handheld devices from Shenzhen GPD Technology Co., Ltd. provide fan readings
+and fan control through their embedded controllers.
+
+Supported devices
+-----------------
+
+Currently the driver supports the following handhelds:
+
+ - GPD Win Mini (7840U)
+ - GPD Win Mini (8840U)
+ - GPD Win Mini (HX370)
+ - GPD Pocket 4
+ - GPD Duo
+ - GPD Win Max 2 (6800U)
+ - GPD Win Max 2 2023 (7840U)
+ - GPD Win Max 2 2024 (8840U)
+ - GPD Win Max 2 2025 (HX370)
+ - GPD Win 4 (6800U)
+ - GPD Win 4 (7840U)
+
+Module parameters
+-----------------
+
+gpd_fan_board
+  Force specific which module quirk should be used.
+  Use it like "gpd_fan_board=wm2".
+
+   - wm2
+       - GPD Win 4 (7840U)
+       - GPD Win Max 2 (6800U)
+       - GPD Win Max 2 2023 (7840U)
+       - GPD Win Max 2 2024 (8840U)
+       - GPD Win Max 2 2025 (HX370)
+   - win4
+       - GPD Win 4 (6800U)
+   - win_mini
+       - GPD Win Mini (7840U)
+       - GPD Win Mini (8840U)
+       - GPD Win Mini (HX370)
+       - GPD Pocket 4
+       - GPD Duo
+
+Sysfs entries
+-------------
+
+The following attributes are supported:
+
+fan1_input
+  Read Only. Reads current fan RPM.
+
+pwm1_enable
+  Read/Write. Enable manual fan control. Write "0" to disable control and run
+  at full speed. Write "1" to set to manual, write "2" to let the EC control
+  decide fan speed. Read this attribute to see current status.
+
+  NB：In consideration of the safety of the device, when setting to manual mode,
+  the pwm speed will be set to the maximum value (255) by default. You can set
+  a different value by writing pwm1 later.
+
+pwm1
+  Read/Write. Read this attribute to see current duty cycle in the range
+  [0-255]. When pwm1_enable is set to "1" (manual) write any value in the
+  range [0-255] to set fan speed.
+
+  NB: Many boards (except listed under wm2 above) don't support reading the
+  current pwm value in auto mode. That will just return 255 as default on
+  those boards, or a previously written value. In manual mode it will always
+  return the real value.
diff --git a/Documentation/hwmon/index.rst b/Documentation/hwmon/index.rst
index d292a86ac5da902cad02c1965c90f5de530489df..ce4419f064e1368740387af70af38a85cadd952d 100644
--- a/Documentation/hwmon/index.rst
+++ b/Documentation/hwmon/index.rst
@@ -82,6 +82,7 @@ Hardware Monitoring Kernel Drivers
    gigabyte_waterforce
    gsc-hwmon
    gl518sm
+   gpd-fan
    gxp-fan-ctrl
    hih6130
    hp-wmi-sensors
diff --git a/MAINTAINERS b/MAINTAINERS
index 14a616be5ff08aaeee52436dff54a86c4a81e5fb..0b6ae95c2007f0737bc4a4e1f2bac52f71628f78 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -10425,6 +10425,7 @@ GPD FAN DRIVER
 M:	Cryolitia PukNgae <cryolitia@uniontech.com>
 L:	linux-hwmon@vger.kernel.org
 S:	Maintained
+F:	Documentation/hwmon/gpd-fan.rst
 F:	drivers/hwmon/gpd-fan.c
 
 GPD POCKET FAN DRIVER

-- 
2.51.0