[gsl3670] Add touchscreen docs

src/content/docs/components/index.mdx

@@ -1076,6 +1076,7 @@ Used for creating infrared (IR) remote control transmitters and/or receivers.
   ["CST816", "/components/touchscreen/cst816/", "cst816.jpg"],
   ["EKTF2232", "/components/touchscreen/ektf2232/", "ektf2232.svg", "Inkplate 6 Plus"],
   ["FT63X6", "/components/touchscreen/ft63x6/", "wt32-sc01.png"],
+  ["GSL3670", "/components/touchscreen/gsl3670/", "touchscreen.svg", "dark-invert"],
   ["GT911", "/components/touchscreen/gt911/", "esp32_s3_box_3.png"],
   ["Lilygo T5 4.7", "/components/touchscreen/lilygo_t5_47/", "lilygo_t5_47_touch.jpg"],
   ["TT21100", "/components/touchscreen/tt21100/", "esp32-s3-korvo-2-lcd.png"],

src/content/docs/components/touchscreen/gsl3670.mdx

@@ -0,0 +1,88 @@
+---
+description: "Instructions for setting up GSL3670 touch screen controller with ESPHome"
+title: "GSL3670 Touch Screen Controller"
+---
+
+import APIRef from '@components/APIRef.astro';
+
+The `gsl3670` touchscreen platform allows using the touch screen controllers based on the GSL3670 chip with ESPHome.
+An [I²C](/components/i2c) bus is required to be set up in your configuration for this touchscreen to work.
+
+This controller is used in the Seeed Studio reTerminal D1001.
+
+The component requires a binary firmware file to be loaded into the controller during initialization. When using a built-in model, this firmware is downloaded automatically from the [esphome-libs/gsl3670-firmware](https://github.com/esphome-libs/gsl3670-firmware) release and cached locally, so it does not need to be supplied manually. The download is verified against a known SHA-256 checksum. Alternatively, a firmware file can be supplied from a custom URL or from a local file.
+
+## Base Touchscreen Configuration
+
+```yaml
+# Example configuration entry using the built-in Seeed reTerminal D1001 model
+touchscreen:
+  platform: gsl3670
+  id: my_touchscreen
+  model: SEEED-RETERMINAL-D1001
+```
+
+```yaml
+# Example configuration entry for a custom touchscreen, firmware from a URL
+touchscreen:
+  platform: gsl3670
+  id: my_touchscreen
+  interrupt_pin: GPIOXX
+  reset_pin: GPIOXX
+  firmware:
+    url: https://example.com/my_gsl3670_firmware.bin
+    sha256: 2e50501ad83656fb6fa3d92591f9f31add4d442c8e8a79f29f5c4d335bd127a4
+```
+
+```yaml
+# Example configuration entry using a local firmware file
+touchscreen:
+  platform: gsl3670
+  id: my_touchscreen
+  interrupt_pin: GPIOXX
+  reset_pin: GPIOXX
+  firmware:
+    file: my_gsl3670_firmware.bin
+```
+
+### Configuration variables
+
+- **id** (*Optional*, [ID](/guides/configuration-types#id)): Manually set the ID of this touchscreen.
+- **model** (*Optional*, string): A predefined model that sets default values for pin assignments, calibration, and firmware. Currently supported:
+  - `SEEED-RETERMINAL-D1001`: Seeed Studio reTerminal D1001. Sets appropriate defaults for interrupt pin, reset pin, calibration, axis mirroring/swapping, and the firmware download URL and checksum.
+  - `CUSTOM`: No defaults are applied; all options must be configured manually. This is the default.
+- **interrupt_pin** (*Optional*, [Pin Schema](/guides/configuration-types#pin-schema)): The touch detection pin.
+- **reset_pin** (*Optional*, [Pin Schema](/guides/configuration-types#pin-schema)): The chip reset pin.
+- **firmware** (**Required**, dict): The source of the GSL3670 binary firmware file. When using a built-in model, this is set automatically. Exactly one of `url` or `file` must be provided:
+  - **url** (*Optional*, string): URL of the firmware file. The file is downloaded and cached locally at build time.
+  - **sha256** (*Optional*, string): The expected SHA-256 checksum of the downloaded firmware file. When set, the download is rejected if the checksum does not match.
+  - **file** (*Optional*, string): Path to a local firmware file, used instead of downloading from `url`. If the file is not found at the given path, the component will also look for it in its own directory.
+
+The firmware is validated for correct format and integrity at config validation time.
+
+- All other options from [Touchscreen](/components/touchscreen#config-touchscreen).
+
+### Sample config for the Seeed reTerminal D1001
+
+```yaml
+i2c:
+  - id: lcd_i2c
+    sda:
+      ignore_strapping_warning: true
+      number: GPIO37
+    scl:
+      ignore_strapping_warning: true
+      number: GPIO38
+    scan: true
+    frequency: 400kHz
+
+touchscreen:
+  - platform: gsl3670
+    i2c_id: lcd_i2c
+    model: SEEED-RETERMINAL-D1001
+```
+
+## See Also
+
+- [Touchscreen Components](/components/touchscreen/)
+- <APIRef text="gsl3670_touchscreen.h" path="gsl3670/gsl3670_touchscreen.h" />

src/content/docs/components/touchscreen/index.mdx

@@ -293,6 +293,7 @@ binary_sensor:
 - [EKTF2232 Touchscreen Controller](/components/touchscreen/ektf2232/)
 - [XPT2046 Touch Screen Controller (Updated version)](/components/touchscreen/xpt2046/)
 - [TT21100 Touch Screen Controller](/components/touchscreen/tt21100/)
+- [GSL3670 Touch Screen Controller](/components/touchscreen/gsl3670/)
 - [gt911 Touch Screen Controller](/components/touchscreen/gt911/)
 - <APIRef text="touchscreen.h" path="touchscreen/touchscreen.h" />
 - <APIRef text="touchscreen_binary_sensor.h" path="touchscreen/binary_sensor/touchscreen_binary_sensor.h" />