Adding gc9a01 Display device

README.md

@@ -40,6 +40,73 @@ Curious? Look at [supported devices](https://periph.io/device/) for more
 examples!
 
 
+## Supported Devices
+
+| Package | Description |
+|---------|-------------|
+| [ads1x15](ads1x15) | ADS1015/ADS1115 analog-to-digital converters via I²C |
+| [adxl345](adxl345) | ADXL345 3-axis accelerometer over SPI |
+| [aht20](aht20) | AHT20 temperature/humidity sensor over I²C |
+| [aip31068](aip31068) | AIP31068 HD44780-compatible I²C LCD driver |
+| [am2320](am2320) | AOSONG AM2320 temperature/humidity sensor |
+| [apa102](apa102) | APA102 LED strip over SPI |
+| [as7262](as7262) | AMS AS7262 6-channel visible spectral sensor via I²C |
+| [bh1750](bh1750) | ROHM BH1750 ambient light sensor over I²C |
+| [bitbang](bitbang) | Software bit-banging protocols (I²C, SPI, UART) via GPIO pins |
+| [bmxx80](bmxx80) | Bosch BMP180/BME280/BMP280 temperature/pressure/humidity sensor over I²C or SPI |
+| [cap1xxx](cap1xxx) | Microchip CAP1xxx capacitive touch sensors over I²C |
+| [ccs811](ccs811) | CCS811 volatile organic compound (VOC) sensor via I²C |
+| [common](common) | Shared utility functions used across multiple packages |
+| [dht22](dht22) | DHT22/AM2302 temperature/humidity sensor |
+| [ds18b20](ds18b20) | DS18B20/DS18S20/MAX31820 1-wire temperature sensors |
+| [ds248x](ds248x) | Maxim DS2483/DS2482-100 1-wire interface chip over I²C |
+| [ep0099](ep0099) | EP-0099 Raspberry Pi HAT with 4 relays via I²C |
+| [epd](epd) | Waveshare e-paper display series |
+| [gc9a01](gc9a01) | GC9A01 240x240 round RGB LCD display over SPI |
+| [hd44780](hd44780) | Hitachi HD44780 LCD display chipset |
+| [hdc302x](hdc302x) | Texas Instruments HDC3021/3022 temperature/humidity sensor over I²C |
+| [ht16k33](ht16k33) | Holtek HT16K33 16×8 LED driver |
+| [hx711](hx711) | HX711 24-bit analog-to-digital converter (load cells) |
+| [ina219](ina219) | Texas Instruments INA219 current/voltage/power monitor over I²C |
+| [inky](inky) | Pimoroni Inky pHAT/wHAT e-ink displays |
+| [lepton](lepton) | FLIR Lepton infrared (IR) camera |
+| [lirc](lirc) | Infrared receiver support via Linux LIRC |
+| [matrixorbital](matrixorbital) | MatrixOrbital character LCD displays |
+| [max7219](max7219) | MAX7219 7-segment and LED matrix displays |
+| [mcp23xxx](mcp23xxx) | Microchip MCP23xxx GPIO expanders |
+| [mcp472x](mcp472x) | Microchip MCP472x digital-to-analog converters |
+| [mcp9808](mcp9808) | Microchip MCP9808 temperature sensor |
+| [mfrc522](mfrc522) | MFRC522 Mifare RFID card reader |
+| [mpu9250](mpu9250) | MPU-9250 9-axis IMU (gyroscope, accelerometer, magnetometer) |
+| [nrzled](nrzled) | WS2811/WS2812/WS2812B and compatible NRZ-encoded LEDs (SK6812, UCS1903) |
+| [nxp74hc595](nxp74hc595) | 74HC595 serial-in parallel-out shift register |
+| [pca9548](pca9548) | PCA9548 8-port I²C multiplexer |
+| [pca9633](pca9633) | PCA9633 4-channel LED PWM controller |
+| [pca9685](pca9685) | PCA9685 16-channel PWM controller (servos, LEDs) |
+| [pcf857x](pcf857x) | TI/NXP PCF857x I²C I/O expander |
+| [piblaster](piblaster) | PWM via the pi-blaster daemon on Raspberry Pi |
+| [rainbowhat](rainbowhat) | Pimoroni Rainbow HAT |
+| [scd4x](scd4x) | Sensirion SCD4x CO₂ sensors |
+| [screen1d](screen1d) | 1D display output to terminal via ANSI color codes |
+| [serlcd](serlcd) | SparkFun SerLCD intelligent LCD display |
+| [sgp30](sgp30) | Sensirion SGP30 multi-gas sensor (TVOC and CO₂eq) |
+| [sht4x](sht4x) | Sensirion SHT-40/SHT-41/SHT-45 temperature/humidity sensors |
+| [sn3218](sn3218) | SN3218 18-channel LED driver over I²C |
+| [ssd1306](ssd1306) | SSD1306/SH1106/SH1107 monochrome OLED displays |
+| [st7567](st7567) | ST7567 single-chip dot matrix LCD |
+| [tca95xx](tca95xx) | Texas Instruments TCA95xx 8-bit I²C GPIO expanders |
+| [tic](tic) | Tic stepper motor controllers via I²C |
+| [tlv493d](tlv493d) | Infineon TLV493D 3D magnetic (Hall effect) sensor |
+| [tm1637](tm1637) | TM1637 LED display driver over GPIO |
+| [tmp102](tmp102) | Texas Instruments TMP102 temperature sensor over I²C |
+| [unicornhd](unicornhd) | Pimoroni Unicorn HD HAT (16×16 RGB LED matrix) |
+| [videosink](videosink) | Display driver serving frames over HTTP |
+| [waveshare1602](waveshare1602) | Waveshare 1602 LCD display |
+| [waveshare2in13v2](waveshare2in13v2) | Waveshare 2.13" v2 e-paper display |
+| [waveshare2in13v3](waveshare2in13v3) | Waveshare 2.13" v3 e-paper display |
+| [waveshare2in13v4](waveshare2in13v4) | Waveshare 2.13" v4 e-paper display |
+
+
 ## Authors
 
 `periph` was initiated with ❤️️ and passion by [Marc-Antoine

gc9a01/doc.go

@@ -0,0 +1,18 @@
+// Copyright 2025 The Periph Authors. All rights reserved.
+// Use of this source code is governed under the Apache License, Version 2.0
+// that can be found in the LICENSE file.
+
+// Package gc9a01 controls a GC9A01 240x240 round RGB LCD display over SPI.
+//
+// The GC9A01 is a single-chip driver for 240x240 resolution TFT LCD displays
+// with 65K colors (RGB565). It communicates via 4-wire SPI.
+//
+// # Datasheet
+//
+// https://www.buydisplay.com/download/ic/GC9A01A.pdf
+//
+// # Wiring
+//
+// Connect SDA to SPI_MOSI, SCL to SPI_CLK, CS to SPI_CS, DC to a GPIO pin.
+// Optionally connect RST to a GPIO pin for hardware reset.
+package gc9a01

gc9a01/example_test.go

@@ -0,0 +1,119 @@
+// Copyright 2025 The Periph Authors. All rights reserved.
+// Use of this source code is governed under the Apache License, Version 2.0
+// that can be found in the LICENSE file.
+
+package gc9a01_test
+
+import (
+	"fmt"
+	"image"
+	"image/color"
+	"image/draw"
+	"log"
+	"math"
+	"time"
+
+	"periph.io/x/conn/v3/gpio/gpioreg"
+	"periph.io/x/conn/v3/spi/spireg"
+	"periph.io/x/devices/v3/gc9a01"
+	"periph.io/x/host/v3"
+)
+
+func Example() {
+	// Make sure periph is initialized.
+	if _, err := host.Init(); err != nil {
+		log.Fatal(err)
+	}
+
+	// Use spireg SPI bus registry to find the first available SPI bus.
+	p, err := spireg.Open("")
+	if err != nil {
+		log.Fatal(err)
+	}
+	defer p.Close()
+
+	// Data/Command pin.
+	dc := gpioreg.ByName("GPIO25")
+	if dc == nil {
+		log.Fatal("failed to find DC pin")
+	}
+
+	// Optional reset pin.
+	rst := gpioreg.ByName("GPIO27")
+
+	dev, err := gc9a01.New(p, dc, rst, &gc9a01.DefaultOpts)
+	if err != nil {
+		log.Fatal(err)
+	}
+	fmt.Printf("device=%s\n", dev.String())
+
+	// Draw a colorful bullseye pattern.
+	img := image.NewNRGBA(dev.Bounds())
+	colors := []color.NRGBA{
+		{0xFF, 0x00, 0x00, 0xFF}, // Red
+		{0xFF, 0xA5, 0x00, 0xFF}, // Orange
+		{0xFF, 0xFF, 0x00, 0xFF}, // Yellow
+		{0x00, 0xFF, 0x00, 0xFF}, // Green
+		{0x00, 0x00, 0xFF, 0xFF}, // Blue
+		{0x4B, 0x00, 0x82, 0xFF}, // Indigo
+		{0xEE, 0x82, 0xEE, 0xFF}, // Violet
+	}
+	cx, cy := 120, 120
+	for y := 0; y < 240; y++ {
+		for x := 0; x < 240; x++ {
+			dx := float64(x - cx)
+			dy := float64(y - cy)
+			dist := math.Sqrt(dx*dx + dy*dy)
+			ring := int(dist / 18)
+			if ring < len(colors) {
+				img.SetNRGBA(x, y, colors[ring])
+			}
+		}
+	}
+	if err := dev.Draw(dev.Bounds(), img, image.Point{}); err != nil {
+		log.Fatal(err)
+	}
+	time.Sleep(3 * time.Second)
+
+	// Draw a gradient.
+	for y := 0; y < 240; y++ {
+		for x := 0; x < 240; x++ {
+			img.SetNRGBA(x, y, color.NRGBA{
+				R: uint8(x * 255 / 239),
+				G: uint8(y * 255 / 239),
+				B: 128,
+				A: 255,
+			})
+		}
+	}
+	if err := dev.Draw(dev.Bounds(), img, image.Point{}); err != nil {
+		log.Fatal(err)
+	}
+	time.Sleep(3 * time.Second)
+
+	// Clear to white using image.Uniform.
+	white := &image.Uniform{color.NRGBA{0xFF, 0xFF, 0xFF, 0xFF}}
+	if err := dev.Draw(dev.Bounds(), white, image.Point{}); err != nil {
+		log.Fatal(err)
+	}
+
+	// Draw a filled red circle in the center using draw.Draw.
+	red := &image.Uniform{color.NRGBA{0xFF, 0x00, 0x00, 0xFF}}
+	circle := image.NewNRGBA(dev.Bounds())
+	draw.Draw(circle, circle.Bounds(), white, image.Point{}, draw.Src)
+	for y := 0; y < 240; y++ {
+		for x := 0; x < 240; x++ {
+			dx := float64(x - cx)
+			dy := float64(y - cy)
+			if dx*dx+dy*dy <= 80*80 {
+				circle.Set(x, y, red)
+			}
+		}
+	}
+	if err := dev.Draw(dev.Bounds(), circle, image.Point{}); err != nil {
+		log.Fatal(err)
+	}
+	time.Sleep(3 * time.Second)
+
+	_ = dev.Halt()
+}