diff options
Diffstat (limited to 'kernel/drivers/staging/fbtft/fb_st7789v.c')
-rw-r--r-- | kernel/drivers/staging/fbtft/fb_st7789v.c | 265 |
1 files changed, 265 insertions, 0 deletions
diff --git a/kernel/drivers/staging/fbtft/fb_st7789v.c b/kernel/drivers/staging/fbtft/fb_st7789v.c new file mode 100644 index 000000000..085e9872c --- /dev/null +++ b/kernel/drivers/staging/fbtft/fb_st7789v.c @@ -0,0 +1,265 @@ +/* + * 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/delay.h> +#include <linux/init.h> +#include <linux/kernel.h> +#include <linux/module.h> +#include <video/mipi_display.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 + * + * @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. + * Furthermore, commands that are compliant with the MIPI DCS have been left + * out as well to avoid duplicate entries. + */ +enum st7789v_command { + 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 */ + +/** + * init_display() - initialize the display controller + * + * @par: FBTFT parameter object + * + * Most of the commands in this init function 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. + * + * Return: 0 on success, < 0 if error occurred. + */ +static int init_display(struct fbtft_par *par) +{ + /* turn off sleep mode */ + write_reg(par, MIPI_DCS_EXIT_SLEEP_MODE); + mdelay(120); + + /* set pixel format to RGB-565 */ + write_reg(par, MIPI_DCS_SET_PIXEL_FORMAT, MIPI_DCS_PIXEL_FMT_16BIT); + + write_reg(par, PORCTRL, 0x08, 0x08, 0x00, 0x22, 0x22); + + /* + * VGH = 13.26V + * VGL = -10.43V + */ + write_reg(par, GCTRL, 0x35); + + /* + * VDV and VRH register values come from command write + * (instead of NVM) + */ + write_reg(par, VDVVRHEN, 0x01, 0xFF); + + /* + * VAP = 4.1V + (VCOM + VCOM offset + 0.5 * VDV) + * VAN = -4.1V + (VCOM + VCOM offset + 0.5 * VDV) + */ + write_reg(par, VRHS, 0x0B); + + /* VDV = 0V */ + write_reg(par, VDVS, 0x20); + + /* VCOM = 0.9V */ + write_reg(par, VCOMS, 0x20); + + /* VCOM offset = 0V */ + write_reg(par, VCMOFSET, 0x20); + + /* + * AVDD = 6.8V + * AVCL = -4.8V + * VDS = 2.3V + */ + write_reg(par, PWCTRL1, 0xA4, 0xA1); + + write_reg(par, MIPI_DCS_SET_DISPLAY_ON); + return 0; +} + +/** + * 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, MIPI_DCS_SET_ADDRESS_MODE, 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, MIPI_DCS_SET_DISPLAY_OFF); + else + write_reg(par, MIPI_DCS_SET_DISPLAY_ON); + return 0; +} + +static struct fbtft_display display = { + .regwidth = 8, + .width = 240, + .height = 320, + .gamma_num = 2, + .gamma_len = 14, + .gamma = DEFAULT_GAMMA, + .fbtftops = { + .init_display = init_display, + .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"); |