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Commit d4c402ff authored by Dennis Menschel's avatar Dennis Menschel Committed by Greg Kroah-Hartman
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staging: fbtft: add support for ST7789V display controller



This patch adds support for the Sitronix ST7789V display controller.
The controller is intended for small color displays with a resolution
of up to 320x240 pixels.

Signed-off-by: default avatarDennis Menschel <menschel-d@posteo.de>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 56b3152e
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@@ -141,6 +141,16 @@ config FB_TFT_ST7735R
	help
	  Generic Framebuffer support for ST7735R

config FB_TFT_ST7789V
	tristate "FB driver for the ST7789V LCD Controller"
	depends on FB_TFT
	help
	  This enables generic framebuffer support for the Sitronix ST7789V
	  display controller. The controller is intended for small color
	  displays with a resolution of up to 320x240 pixels.

	  Say Y if you have such a display that utilizes this controller.

config FB_TFT_TINYLCD
	tristate "FB driver for tinylcd.com display"
	depends on FB_TFT
+1 −0
Original line number Diff line number Diff line
@@ -25,6 +25,7 @@ obj-$(CONFIG_FB_TFT_SSD1306) += fb_ssd1306.o
obj-$(CONFIG_FB_TFT_SSD1331)     += fb_ssd1331.o
obj-$(CONFIG_FB_TFT_SSD1351)     += fb_ssd1351.o
obj-$(CONFIG_FB_TFT_ST7735R)     += fb_st7735r.o
obj-$(CONFIG_FB_TFT_ST7789V)     += fb_st7789v.o
obj-$(CONFIG_FB_TFT_TINYLCD)     += fb_tinylcd.o
obj-$(CONFIG_FB_TFT_TLS8204)     += fb_tls8204.o
obj-$(CONFIG_FB_TFT_UC1611)      += fb_uc1611.o
+290 −0
Original line number Diff line number Diff line
/*
 * FB driver for the ST7789V LCD Controller
 *
 * Copyright (C) 2015 Dennis Menschel
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 */

#include <linux/bitops.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>

#include "fbtft.h"

#define DRVNAME "fb_st7789v"

#define DEFAULT_GAMMA \
	"70 2C 2E 15 10 09 48 33 53 0B 19 18 20 25\n" \
	"70 2C 2E 15 10 09 48 33 53 0B 19 18 20 25"

/**
 * enum st7789v_command - ST7789V display controller commands
 *
 * @SLPOUT: sleep out
 * @DISPOFF: display off
 * @DISPON: display on
 * @CASET: column address set
 * @RASET: row address set
 * @RAMRW: memory write
 * @MADCTL: memory data access control
 * @COLMOD: interface pixel format
 * @PORCTRL: porch setting
 * @GCTRL: gate control
 * @VCOMS: VCOM setting
 * @VDVVRHEN: VDV and VRH command enable
 * @VRHS: VRH set
 * @VDVS: VDV set
 * @VCMOFSET: VCOM offset set
 * @PWCTRL1: power control 1
 * @PVGAMCTRL: positive voltage gamma control
 * @NVGAMCTRL: negative voltage gamma control
 *
 * The command names are the same as those found in the datasheet to ease
 * looking up their semantics and usage.
 *
 * Note that the ST7789V display controller offers quite a few more commands
 * which have been omitted from this list as they are not used at the moment.
 */
enum st7789v_command {
	SLPOUT = 0x11,
	DISPOFF = 0x28,
	DISPON = 0x29,
	CASET = 0x2A,
	RASET = 0x2B,
	RAMRW = 0x2C,
	MADCTL = 0x36,
	COLMOD = 0x3A,
	PORCTRL = 0xB2,
	GCTRL = 0xB7,
	VCOMS = 0xBB,
	VDVVRHEN = 0xC2,
	VRHS = 0xC3,
	VDVS = 0xC4,
	VCMOFSET = 0xC5,
	PWCTRL1 = 0xD0,
	PVGAMCTRL = 0xE0,
	NVGAMCTRL = 0xE1,
};

#define MADCTL_BGR BIT(3) /* bitmask for RGB/BGR order */
#define MADCTL_MV BIT(5) /* bitmask for page/column order */
#define MADCTL_MX BIT(6) /* bitmask for column address order */
#define MADCTL_MY BIT(7) /* bitmask for page address order */

/**
 * default_init_sequence - default initialization sequence for ST7789V
 *
 * Most of the commands in this init sequence set their parameters to the
 * same default values which are already in place after the display has been
 * powered up. (The main exception to this rule is the pixel format which
 * would default to 18 instead of 16 bit per pixel.)
 * Nonetheless, this sequence can be used as a template for concrete
 * displays which usually need some adjustments.
 */
static int default_init_sequence[] = {
	/* turn off sleep mode */
	-1, SLPOUT,
	-2, 120,

	/* set pixel format to RGB-565 */
	-1, COLMOD, 0x05,

	-1, PORCTRL, 0x08, 0x08, 0x00, 0x22, 0x22,

	/*
	 * VGH = 13.26V
	 * VGL = -10.43V
	 */
	-1, GCTRL, 0x35,

	/*
	 * VDV and VRH register values come from command write
	 * (instead of NVM)
	 */
	-1, VDVVRHEN, 0x01, 0xFF,

	/*
	 * VAP =  4.1V + (VCOM + VCOM offset + 0.5 * VDV)
	 * VAN = -4.1V + (VCOM + VCOM offset + 0.5 * VDV)
	 */
	-1, VRHS, 0x0B,

	/* VDV = 0V */
	-1, VDVS, 0x20,

	/* VCOM = 0.9V */
	-1, VCOMS, 0x20,

	/* VCOM offset = 0V */
	-1, VCMOFSET, 0x20,

	/*
	 * AVDD = 6.8V
	 * AVCL = -4.8V
	 * VDS = 2.3V
	 */
	-1, PWCTRL1, 0xA4, 0xA1,

	-1, DISPON,

	-3,
};

/**
 * set_addr_win() - configure display area to use
 *
 * @par: FBTFT parameter object
 * @xs: first active pixel of x-axis
 * @ys: first active pixel of y-axis
 * @xe: last active pixel of x-axis
 * @ye: last active pixel of y-axis
 */
static void set_addr_win(struct fbtft_par *par, int xs, int ys, int xe, int ye)
{
	write_reg(par, CASET, xs >> 8, xs & 0xFF, xe >> 8, xe & 0xFF);
	write_reg(par, RASET, ys >> 8, ys & 0xFF, ye >> 8, ye & 0xFF);
	write_reg(par, RAMRW);
}

/**
 * set_var() - apply LCD properties like rotation and BGR mode
 *
 * @par: FBTFT parameter object
 *
 * Return: 0 on success, < 0 if error occurred.
 */
static int set_var(struct fbtft_par *par)
{
	u8 madctl_par = 0;

	if (par->bgr)
		madctl_par |= MADCTL_BGR;
	switch (par->info->var.rotate) {
	case 0:
		break;
	case 90:
		madctl_par |= (MADCTL_MV | MADCTL_MY);
		break;
	case 180:
		madctl_par |= (MADCTL_MX | MADCTL_MY);
		break;
	case 270:
		madctl_par |= (MADCTL_MV | MADCTL_MX);
		break;
	default:
		return -EINVAL;
	}
	write_reg(par, MADCTL, madctl_par);
	return 0;
}

/**
 * set_gamma() - set gamma curves
 *
 * @par: FBTFT parameter object
 * @curves: gamma curves
 *
 * Before the gamma curves are applied, they are preprocessed with a bitmask
 * to ensure syntactically correct input for the display controller.
 * This implies that the curves input parameter might be changed by this
 * function and that illegal gamma values are auto-corrected and not
 * reported as errors.
 *
 * Return: 0 on success, < 0 if error occurred.
 */
static int set_gamma(struct fbtft_par *par, unsigned long *curves)
{
	int i;
	int j;
	int c; /* curve index offset */

	/*
	 * Bitmasks for gamma curve command parameters.
	 * The masks are the same for both positive and negative voltage
	 * gamma curves.
	 */
	const u8 gamma_par_mask[] = {
		0xFF, /* V63[3:0], V0[3:0]*/
		0x3F, /* V1[5:0] */
		0x3F, /* V2[5:0] */
		0x1F, /* V4[4:0] */
		0x1F, /* V6[4:0] */
		0x3F, /* J0[1:0], V13[3:0] */
		0x7F, /* V20[6:0] */
		0x77, /* V36[2:0], V27[2:0] */
		0x7F, /* V43[6:0] */
		0x3F, /* J1[1:0], V50[3:0] */
		0x1F, /* V57[4:0] */
		0x1F, /* V59[4:0] */
		0x3F, /* V61[5:0] */
		0x3F, /* V62[5:0] */
	};

	for (i = 0; i < par->gamma.num_curves; i++) {
		c = i * par->gamma.num_values;
		for (j = 0; j < par->gamma.num_values; j++)
			curves[c + j] &= gamma_par_mask[j];
		write_reg(
			par, PVGAMCTRL + i,
			curves[c + 0], curves[c + 1], curves[c + 2],
			curves[c + 3], curves[c + 4], curves[c + 5],
			curves[c + 6], curves[c + 7], curves[c + 8],
			curves[c + 9], curves[c + 10], curves[c + 11],
			curves[c + 12], curves[c + 13]);
	}
	return 0;
}

/**
 * blank() - blank the display
 *
 * @par: FBTFT parameter object
 * @on: whether to enable or disable blanking the display
 *
 * Return: 0 on success, < 0 if error occurred.
 */
static int blank(struct fbtft_par *par, bool on)
{
	if (on)
		write_reg(par, DISPOFF);
	else
		write_reg(par, DISPON);
	return 0;
}

static struct fbtft_display display = {
	.regwidth = 8,
	.width = 240,
	.height = 320,
	.init_sequence = default_init_sequence,
	.gamma_num = 2,
	.gamma_len = 14,
	.gamma = DEFAULT_GAMMA,
	.fbtftops = {
		.set_addr_win = set_addr_win,
		.set_var = set_var,
		.set_gamma = set_gamma,
		.blank = blank,
	},
};

FBTFT_REGISTER_DRIVER(DRVNAME, "sitronix,st7789v", &display);

MODULE_ALIAS("spi:" DRVNAME);
MODULE_ALIAS("platform:" DRVNAME);
MODULE_ALIAS("spi:st7789v");
MODULE_ALIAS("platform:st7789v");

MODULE_DESCRIPTION("FB driver for the ST7789V LCD Controller");
MODULE_AUTHOR("Dennis Menschel");
MODULE_LICENSE("GPL");