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feat: add ST7796 kernel module (fbtft)
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Add support for ST7796 based LCD module (connected via SPI interface). One of real device example is [MKS PI-TS35 display](https://github.com/makerbase-mks/MKS-TFT-Hardware/tree/master/MKS%20PI-TS35).
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@redrathnure @paolosabatino
redrathnure authored and paolosabatino committed Dec 8, 2024
1 parent 8e51750 commit 06c9c2d
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1 change: 1 addition & 0 deletions config/kernel/linux-rockchip64-current.config
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Expand Up @@ -7796,6 +7796,7 @@ CONFIG_FB_TFT_SSD1331=m
CONFIG_FB_TFT_SSD1351=m
CONFIG_FB_TFT_ST7735R=m
CONFIG_FB_TFT_ST7789V=m
CONFIG_FB_TFT_ST7796=m
CONFIG_FB_TFT_TINYLCD=m
CONFIG_FB_TFT_TLS8204=m
CONFIG_FB_TFT_UC1611=m
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1 change: 1 addition & 0 deletions config/kernel/linux-rockchip64-edge.config
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Expand Up @@ -8031,6 +8031,7 @@ CONFIG_FB_TFT_SSD1331=m
CONFIG_FB_TFT_SSD1351=m
CONFIG_FB_TFT_ST7735R=m
CONFIG_FB_TFT_ST7789V=m
CONFIG_FB_TFT_ST7796=m
CONFIG_FB_TFT_TINYLCD=m
CONFIG_FB_TFT_TLS8204=m
CONFIG_FB_TFT_UC1611=m
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196 changes: 196 additions & 0 deletions patch/kernel/archive/rockchip64-6.12/general-st7796-driver.patch
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@@ -0,0 +1,196 @@
From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Maxim Medvedev <redrathnure@gmail.com>
Date: Fri, 12 May 2023 22:30:14 +0000
Subject: Custom st7796 display module

---

diff --git a/drivers/staging/fbtft/Kconfig b/drivers/staging/fbtft/Kconfig
index 4d29e8c1014..265c7e3fe76 100644
--- a/drivers/staging/fbtft/Kconfig
+++ b/drivers/staging/fbtft/Kconfig
@@ -82,6 +82,12 @@ config FB_TFT_ILI9481
help
Generic Framebuffer support for ILI9481

+config FB_TFT_ST7796
+ tristate "FB driver for the ST7796 LCD Controller"
+ depends on FB_TFT
+ help
+ Generic Framebuffer support for ST7796
+
config FB_TFT_ILI9486
tristate "FB driver for the ILI9486 LCD Controller"
depends on FB_TFT
diff --git a/drivers/staging/fbtft/Makefile b/drivers/staging/fbtft/Makefile
index e9cdf0f0a7d..3c62b33e596 100644
--- a/drivers/staging/fbtft/Makefile
+++ b/drivers/staging/fbtft/Makefile
@@ -16,6 +16,7 @@ obj-$(CONFIG_FB_TFT_ILI9325) += fb_ili9325.o
obj-$(CONFIG_FB_TFT_ILI9340) += fb_ili9340.o
obj-$(CONFIG_FB_TFT_ILI9341) += fb_ili9341.o
obj-$(CONFIG_FB_TFT_ILI9481) += fb_ili9481.o
+obj-$(CONFIG_FB_TFT_ST7796) += fb_st7796.o
obj-$(CONFIG_FB_TFT_ILI9486) += fb_ili9486.o
obj-$(CONFIG_FB_TFT_PCD8544) += fb_pcd8544.o
obj-$(CONFIG_FB_TFT_RA8875) += fb_ra8875.o
diff --git a/drivers/staging/fbtft/fb_st7796.c b/drivers/staging/fbtft/fb_st7796.c
new file mode 100755
index 00000000000..c7deedbea69
--- /dev/null
+++ b/drivers/staging/fbtft/fb_st7796.c
@@ -0,0 +1,160 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * FB driver for the ST7796 LCD display controller
+ *
+ * Based on ILI9486 from Christian Vogelgsang and adafruit22fb.c by Noralf Tronnes.
+ */
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/delay.h>
+#include <video/mipi_display.h>
+
+#include "fbtft.h"
+
+// Patch from MKS - start
+
+#define DRVNAME "fb_st7796"
+#define WIDTH 320
+#define HEIGHT 480
+#define TXBUFLEN 0xfffe // (4 * PAGE_SIZE)
+
+ // Patch from MKS - end
+
+#define DEFAULT_GAMMA "1F 1A 18 0A 0F 06 45 87 32 0A 07 02 07 05 00\n" \
+ "00 25 27 05 10 09 3A 78 4D 05 18 0D 38 3A 1F"
+
+static int init_display(struct fbtft_par *par)
+{
+ par->fbtftops.reset(par);
+
+ /* startup sequence for MI0283QT-9A */
+ write_reg(par, MIPI_DCS_SOFT_RESET);
+ mdelay(5);
+ write_reg(par, MIPI_DCS_SET_DISPLAY_OFF);
+
+ // Patch from MKS - start
+
+ /*these are for st7796*/
+ /* --------------------------------------------------------- */
+ write_reg(par, 0xf0, 0xc3);
+ write_reg(par, 0xf0, 0x96);
+ write_reg(par, 0x36, 0x28);
+ write_reg(par, 0x3A, 0x55);
+ write_reg(par, 0xB4, 0x01);
+ write_reg(par, 0xB7, 0xc6);
+ write_reg(par, 0xE8, 0x40, 0x8a, 0x00, 0x00, 0x29, 0x19, 0xa5, 0x33);
+ write_reg(par, 0xc1, 0x06);
+ write_reg(par, 0xc2, 0xa7);
+ write_reg(par, 0xc5, 0x18);
+ write_reg(par, 0xE0, 0xf0, 0x09, 0x0b, 0x06, 0x04, 0x15, 0x2f, 0x54, 0x42, 0x3c, 0x17, 0x14, 0x18, 0x1b);
+ write_reg(par, 0xE1, 0xf0, 0x09, 0x0b, 0x06, 0x04, 0x03, 0x2d, 0x43, 0x42, 0x3b, 0x16, 0x14, 0x17, 0x1b);
+ write_reg(par, 0xf0, 0x3c);
+ write_reg(par, 0xf0, 0x69);
+ write_reg(par, 0x11);
+ mdelay(100);
+ write_reg(par, 0x29);
+ mdelay(20);
+
+ // Patch from MKS - end
+
+ return 0;
+}
+
+static void set_addr_win(struct fbtft_par *par, int xs, int ys, int xe, int ye)
+{
+ write_reg(par, MIPI_DCS_SET_COLUMN_ADDRESS,
+ (xs >> 8) & 0xFF, xs & 0xFF, (xe >> 8) & 0xFF, xe & 0xFF);
+
+ write_reg(par, MIPI_DCS_SET_PAGE_ADDRESS,
+ (ys >> 8) & 0xFF, ys & 0xFF, (ye >> 8) & 0xFF, ye & 0xFF);
+
+ write_reg(par, MIPI_DCS_WRITE_MEMORY_START);
+}
+
+#define MEM_Y BIT(7) /* MY row address order */
+#define MEM_X BIT(6) /* MX column address order */
+#define MEM_V BIT(5) /* MV row / column exchange */
+#define MEM_L BIT(4) /* ML vertical refresh order */
+#define MEM_H BIT(2) /* MH horizontal refresh order */
+#define MEM_BGR (3) /* RGB-BGR Order */
+static int set_var(struct fbtft_par *par)
+{
+ switch (par->info->var.rotate) {
+ case 0:
+ write_reg(par, MIPI_DCS_SET_ADDRESS_MODE,
+ MEM_X | (par->bgr << MEM_BGR));
+ break;
+ case 270:
+ write_reg(par, MIPI_DCS_SET_ADDRESS_MODE,
+ MEM_V | MEM_L | (par->bgr << MEM_BGR));
+ break;
+ case 180:
+ write_reg(par, MIPI_DCS_SET_ADDRESS_MODE,
+ MEM_Y | (par->bgr << MEM_BGR));
+ break;
+ case 90:
+ write_reg(par, MIPI_DCS_SET_ADDRESS_MODE,
+ MEM_Y | MEM_X | MEM_V | (par->bgr << MEM_BGR));
+ break;
+ }
+
+ return 0;
+}
+
+/*
+ * Gamma string format:
+ * Positive: Par1 Par2 [...] Par15
+ * Negative: Par1 Par2 [...] Par15
+ */
+#define CURVE(num, idx) curves[(num) * par->gamma.num_values + (idx)]
+static int set_gamma(struct fbtft_par *par, u32 *curves)
+{
+ int i;
+
+ for (i = 0; i < par->gamma.num_curves; i++)
+ write_reg(par, 0xE0 + i,
+ CURVE(i, 0), CURVE(i, 1), CURVE(i, 2),
+ CURVE(i, 3), CURVE(i, 4), CURVE(i, 5),
+ CURVE(i, 6), CURVE(i, 7), CURVE(i, 8),
+ CURVE(i, 9), CURVE(i, 10), CURVE(i, 11),
+ CURVE(i, 12), CURVE(i, 13), CURVE(i, 14));
+
+ return 0;
+}
+
+#undef CURVE
+
+static struct fbtft_display display = {
+ .regwidth = 8,
+ .width = WIDTH,
+ .height = HEIGHT,
+ .txbuflen = TXBUFLEN,
+ .gamma_num = 2,
+ .gamma_len = 15,
+ .gamma = DEFAULT_GAMMA,
+ .fbtftops = {
+ .init_display = init_display,
+ .set_addr_win = set_addr_win,
+ .set_var = set_var,
+ .set_gamma = set_gamma,
+ },
+};
+
+FBTFT_REGISTER_DRIVER(DRVNAME, "ilitek,st7796", &display);
+
+MODULE_ALIAS("spi:" DRVNAME);
+MODULE_ALIAS("platform:" DRVNAME);
+MODULE_ALIAS("spi:st7796");
+MODULE_ALIAS("platform:st7796");
+
+MODULE_DESCRIPTION("FB driver for the ST7796 LCD display controller");
+MODULE_AUTHOR("Christian Vogelgsang + somebody from makerbase");
+MODULE_LICENSE("GPL");
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