1 /* 2 * FB driver for the ST7789V LCD Controller 3 * 4 * Copyright (C) 2015 Dennis Menschel 5 * 6 * This program is free software; you can redistribute it and/or modify 7 * it under the terms of the GNU General Public License as published by 8 * the Free Software Foundation; either version 2 of the License, or 9 * (at your option) any later version. 10 * 11 * This program is distributed in the hope that it will be useful, 12 * but WITHOUT ANY WARRANTY; without even the implied warranty of 13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 14 * GNU General Public License for more details. 15 */ 16 17 #include <linux/bitops.h> 18 #include <linux/delay.h> 19 #include <linux/init.h> 20 #include <linux/kernel.h> 21 #include <linux/module.h> 22 #include <video/mipi_display.h> 23 24 #include "fbtft.h" 25 26 #define DRVNAME "fb_st7789v" 27 28 #define DEFAULT_GAMMA \ 29 "70 2C 2E 15 10 09 48 33 53 0B 19 18 20 25\n" \ 30 "70 2C 2E 15 10 09 48 33 53 0B 19 18 20 25" 31 32 /** 33 * enum st7789v_command - ST7789V display controller commands 34 * 35 * @PORCTRL: porch setting 36 * @GCTRL: gate control 37 * @VCOMS: VCOM setting 38 * @VDVVRHEN: VDV and VRH command enable 39 * @VRHS: VRH set 40 * @VDVS: VDV set 41 * @VCMOFSET: VCOM offset set 42 * @PWCTRL1: power control 1 43 * @PVGAMCTRL: positive voltage gamma control 44 * @NVGAMCTRL: negative voltage gamma control 45 * 46 * The command names are the same as those found in the datasheet to ease 47 * looking up their semantics and usage. 48 * 49 * Note that the ST7789V display controller offers quite a few more commands 50 * which have been omitted from this list as they are not used at the moment. 51 * Furthermore, commands that are compliant with the MIPI DCS have been left 52 * out as well to avoid duplicate entries. 53 */ 54 enum st7789v_command { 55 PORCTRL = 0xB2, 56 GCTRL = 0xB7, 57 VCOMS = 0xBB, 58 VDVVRHEN = 0xC2, 59 VRHS = 0xC3, 60 VDVS = 0xC4, 61 VCMOFSET = 0xC5, 62 PWCTRL1 = 0xD0, 63 PVGAMCTRL = 0xE0, 64 NVGAMCTRL = 0xE1, 65 }; 66 67 #define MADCTL_BGR BIT(3) /* bitmask for RGB/BGR order */ 68 #define MADCTL_MV BIT(5) /* bitmask for page/column order */ 69 #define MADCTL_MX BIT(6) /* bitmask for column address order */ 70 #define MADCTL_MY BIT(7) /* bitmask for page address order */ 71 72 /** 73 * init_display() - initialize the display controller 74 * 75 * @par: FBTFT parameter object 76 * 77 * Most of the commands in this init function set their parameters to the 78 * same default values which are already in place after the display has been 79 * powered up. (The main exception to this rule is the pixel format which 80 * would default to 18 instead of 16 bit per pixel.) 81 * Nonetheless, this sequence can be used as a template for concrete 82 * displays which usually need some adjustments. 83 * 84 * Return: 0 on success, < 0 if error occurred. 85 */ 86 static int init_display(struct fbtft_par *par) 87 { 88 /* turn off sleep mode */ 89 write_reg(par, MIPI_DCS_EXIT_SLEEP_MODE); 90 mdelay(120); 91 92 /* set pixel format to RGB-565 */ 93 write_reg(par, MIPI_DCS_SET_PIXEL_FORMAT, MIPI_DCS_PIXEL_FMT_16BIT); 94 95 write_reg(par, PORCTRL, 0x08, 0x08, 0x00, 0x22, 0x22); 96 97 /* 98 * VGH = 13.26V 99 * VGL = -10.43V 100 */ 101 write_reg(par, GCTRL, 0x35); 102 103 /* 104 * VDV and VRH register values come from command write 105 * (instead of NVM) 106 */ 107 write_reg(par, VDVVRHEN, 0x01, 0xFF); 108 109 /* 110 * VAP = 4.1V + (VCOM + VCOM offset + 0.5 * VDV) 111 * VAN = -4.1V + (VCOM + VCOM offset + 0.5 * VDV) 112 */ 113 write_reg(par, VRHS, 0x0B); 114 115 /* VDV = 0V */ 116 write_reg(par, VDVS, 0x20); 117 118 /* VCOM = 0.9V */ 119 write_reg(par, VCOMS, 0x20); 120 121 /* VCOM offset = 0V */ 122 write_reg(par, VCMOFSET, 0x20); 123 124 /* 125 * AVDD = 6.8V 126 * AVCL = -4.8V 127 * VDS = 2.3V 128 */ 129 write_reg(par, PWCTRL1, 0xA4, 0xA1); 130 131 write_reg(par, MIPI_DCS_SET_DISPLAY_ON); 132 return 0; 133 } 134 135 /** 136 * set_var() - apply LCD properties like rotation and BGR mode 137 * 138 * @par: FBTFT parameter object 139 * 140 * Return: 0 on success, < 0 if error occurred. 141 */ 142 static int set_var(struct fbtft_par *par) 143 { 144 u8 madctl_par = 0; 145 146 if (par->bgr) 147 madctl_par |= MADCTL_BGR; 148 switch (par->info->var.rotate) { 149 case 0: 150 break; 151 case 90: 152 madctl_par |= (MADCTL_MV | MADCTL_MY); 153 break; 154 case 180: 155 madctl_par |= (MADCTL_MX | MADCTL_MY); 156 break; 157 case 270: 158 madctl_par |= (MADCTL_MV | MADCTL_MX); 159 break; 160 default: 161 return -EINVAL; 162 } 163 write_reg(par, MIPI_DCS_SET_ADDRESS_MODE, madctl_par); 164 return 0; 165 } 166 167 /** 168 * set_gamma() - set gamma curves 169 * 170 * @par: FBTFT parameter object 171 * @curves: gamma curves 172 * 173 * Before the gamma curves are applied, they are preprocessed with a bitmask 174 * to ensure syntactically correct input for the display controller. 175 * This implies that the curves input parameter might be changed by this 176 * function and that illegal gamma values are auto-corrected and not 177 * reported as errors. 178 * 179 * Return: 0 on success, < 0 if error occurred. 180 */ 181 static int set_gamma(struct fbtft_par *par, unsigned long *curves) 182 { 183 int i; 184 int j; 185 int c; /* curve index offset */ 186 187 /* 188 * Bitmasks for gamma curve command parameters. 189 * The masks are the same for both positive and negative voltage 190 * gamma curves. 191 */ 192 const u8 gamma_par_mask[] = { 193 0xFF, /* V63[3:0], V0[3:0]*/ 194 0x3F, /* V1[5:0] */ 195 0x3F, /* V2[5:0] */ 196 0x1F, /* V4[4:0] */ 197 0x1F, /* V6[4:0] */ 198 0x3F, /* J0[1:0], V13[3:0] */ 199 0x7F, /* V20[6:0] */ 200 0x77, /* V36[2:0], V27[2:0] */ 201 0x7F, /* V43[6:0] */ 202 0x3F, /* J1[1:0], V50[3:0] */ 203 0x1F, /* V57[4:0] */ 204 0x1F, /* V59[4:0] */ 205 0x3F, /* V61[5:0] */ 206 0x3F, /* V62[5:0] */ 207 }; 208 209 for (i = 0; i < par->gamma.num_curves; i++) { 210 c = i * par->gamma.num_values; 211 for (j = 0; j < par->gamma.num_values; j++) 212 curves[c + j] &= gamma_par_mask[j]; 213 write_reg( 214 par, PVGAMCTRL + i, 215 curves[c + 0], curves[c + 1], curves[c + 2], 216 curves[c + 3], curves[c + 4], curves[c + 5], 217 curves[c + 6], curves[c + 7], curves[c + 8], 218 curves[c + 9], curves[c + 10], curves[c + 11], 219 curves[c + 12], curves[c + 13]); 220 } 221 return 0; 222 } 223 224 /** 225 * blank() - blank the display 226 * 227 * @par: FBTFT parameter object 228 * @on: whether to enable or disable blanking the display 229 * 230 * Return: 0 on success, < 0 if error occurred. 231 */ 232 static int blank(struct fbtft_par *par, bool on) 233 { 234 if (on) 235 write_reg(par, MIPI_DCS_SET_DISPLAY_OFF); 236 else 237 write_reg(par, MIPI_DCS_SET_DISPLAY_ON); 238 return 0; 239 } 240 241 static struct fbtft_display display = { 242 .regwidth = 8, 243 .width = 240, 244 .height = 320, 245 .gamma_num = 2, 246 .gamma_len = 14, 247 .gamma = DEFAULT_GAMMA, 248 .fbtftops = { 249 .init_display = init_display, 250 .set_var = set_var, 251 .set_gamma = set_gamma, 252 .blank = blank, 253 }, 254 }; 255 256 FBTFT_REGISTER_DRIVER(DRVNAME, "sitronix,st7789v", &display); 257 258 MODULE_ALIAS("spi:" DRVNAME); 259 MODULE_ALIAS("platform:" DRVNAME); 260 MODULE_ALIAS("spi:st7789v"); 261 MODULE_ALIAS("platform:st7789v"); 262 263 MODULE_DESCRIPTION("FB driver for the ST7789V LCD Controller"); 264 MODULE_AUTHOR("Dennis Menschel"); 265 MODULE_LICENSE("GPL"); 266