staging: fbtft: add support for C-Berry28 display

This patch adds support for the C-Berry28, a small 2.8" color display
with a resolution of 320x240 pixels from admatec for the Raspberry Pi.
It uses the Sitronix ST7789V display controller along with a custom
init sequence and custom gamma curves.

Signed-off-by: Dennis Menschel <menschel-d@posteo.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/staging/fbtft/fbtft_device.c b/drivers/staging/fbtft/fbtft_device.c
index a60f389..0e501d0 100644 (file)
--- a/drivers/staging/fbtft/fbtft_device.c
+++ b/drivers/staging/fbtft/fbtft_device.c
@@ -126,6 +126,59 @@ static void adafruit18_green_tab_set_addr_win(struct fbtft_par *par,
                "02 1c 07 12 37 32 29 2d 29 25 2B 39 00 01 03 10\n" \
                "03 1d 07 06 2E 2C 29 2D 2E 2E 37 3F 00 00 02 10"
 
+#define CBERRY28_GAMMA \
+               "D0 00 14 15 13 2C 42 43 4E 09 16 14 18 21\n" \
+               "D0 00 14 15 13 0B 43 55 53 0C 17 14 23 20"
+
+static int cberry28_init_sequence[] = {
+       /* turn off sleep mode */
+       -1, 0x11,
+       -2, 120,
+
+       /* set pixel format to RGB-565 */
+       -1, 0x3A, 0x05,
+
+       -1, 0xB2, 0x0C, 0x0C, 0x00, 0x33, 0x33,
+
+       /*
+        * VGH = 13.26V
+        * VGL = -10.43V
+        */
+       -1, 0xB7, 0x35,
+
+       /*
+        * VDV and VRH register values come from command write
+        * (instead of NVM)
+        */
+       -1, 0xC2, 0x01, 0xFF,
+
+       /*
+        * VAP =  4.7V + (VCOM + VCOM offset + 0.5 * VDV)
+        * VAN = -4.7V + (VCOM + VCOM offset + 0.5 * VDV)
+        */
+       -1, 0xC3, 0x17,
+
+       /* VDV = 0V */
+       -1, 0xC4, 0x20,
+
+       /* VCOM = 0.875V */
+       -1, 0xBB, 0x1F,
+
+       /* VCOM offset = 0V */
+       -1, 0xC5, 0x20,
+
+       /*
+        * AVDD = 6.6V
+        * AVCL = -4.8V
+        * VDS = 2.3V
+        */
+       -1, 0xD0, 0xA4, 0x61,
+
+       -1, 0x29,
+
+       -3,
+};
+
 static int hy28b_init_sequence[] = {
        -1, 0x00e7, 0x0010, -1, 0x0000, 0x0001,
        -1, 0x0001, 0x0100, -1, 0x0002, 0x0700,
@@ -313,6 +366,27 @@ static struct fbtft_device_display displays[] = {
                        }
                }
        }, {
+               .name = "admatec_c-berry28",
+               .spi = &(struct spi_board_info) {
+                       .modalias = "fb_st7789v",
+                       .max_speed_hz = 48000000,
+                       .mode = SPI_MODE_0,
+                       .platform_data = &(struct fbtft_platform_data) {
+                               .display = {
+                                       .buswidth = 8,
+                                       .backlight = 1,
+                                       .init_sequence = cberry28_init_sequence,
+                               },
+                               .gpios = (const struct fbtft_gpio []) {
+                                       { "reset", 25 },
+                                       { "dc", 22 },
+                                       { "led", 18 },
+                                       {},
+                               },
+                               .gamma = CBERRY28_GAMMA,
+                       }
+               }
+       }, {
                .name = "agm1264k-fl",
                .pdev = &(struct platform_device) {
                        .name = "fb_agm1264k-fl",