1 // SPDX-License-Identifier: GPL-2.0+ 2 /* 3 * FB driver for the ST7789V LCD Controller 4 * 5 * Copyright (C) 2015 Dennis Menschel 6 */ 7 8 #include <linux/bitops.h> 9 #include <linux/delay.h> 10 #include <linux/init.h> 11 #include <linux/kernel.h> 12 #include <linux/module.h> 13 #include <video/mipi_display.h> 14 15 #include "fbtft.h" 16 17 #define DRVNAME "fb_st7789v" 18 19 #define DEFAULT_GAMMA \ 20 "70 2C 2E 15 10 09 48 33 53 0B 19 18 20 25\n" \ 21 "70 2C 2E 15 10 09 48 33 53 0B 19 18 20 25" 22 23 #define HSD20_IPS_GAMMA \ 24 "D0 05 0A 09 08 05 2E 44 45 0F 17 16 2B 33\n" \ 25 "D0 05 0A 09 08 05 2E 43 45 0F 16 16 2B 33" 26 27 #define HSD20_IPS 1 28 29 /** 30 * enum st7789v_command - ST7789V display controller commands 31 * 32 * @PORCTRL: porch setting 33 * @GCTRL: gate control 34 * @VCOMS: VCOM setting 35 * @VDVVRHEN: VDV and VRH command enable 36 * @VRHS: VRH set 37 * @VDVS: VDV set 38 * @VCMOFSET: VCOM offset set 39 * @PWCTRL1: power control 1 40 * @PVGAMCTRL: positive voltage gamma control 41 * @NVGAMCTRL: negative voltage gamma control 42 * 43 * The command names are the same as those found in the datasheet to ease 44 * looking up their semantics and usage. 45 * 46 * Note that the ST7789V display controller offers quite a few more commands 47 * which have been omitted from this list as they are not used at the moment. 48 * Furthermore, commands that are compliant with the MIPI DCS have been left 49 * out as well to avoid duplicate entries. 50 */ 51 enum st7789v_command { 52 PORCTRL = 0xB2, 53 GCTRL = 0xB7, 54 VCOMS = 0xBB, 55 VDVVRHEN = 0xC2, 56 VRHS = 0xC3, 57 VDVS = 0xC4, 58 VCMOFSET = 0xC5, 59 PWCTRL1 = 0xD0, 60 PVGAMCTRL = 0xE0, 61 NVGAMCTRL = 0xE1, 62 }; 63 64 #define MADCTL_BGR BIT(3) /* bitmask for RGB/BGR order */ 65 #define MADCTL_MV BIT(5) /* bitmask for page/column order */ 66 #define MADCTL_MX BIT(6) /* bitmask for column address order */ 67 #define MADCTL_MY BIT(7) /* bitmask for page address order */ 68 69 /** 70 * init_display() - initialize the display controller 71 * 72 * @par: FBTFT parameter object 73 * 74 * Most of the commands in this init function set their parameters to the 75 * same default values which are already in place after the display has been 76 * powered up. (The main exception to this rule is the pixel format which 77 * would default to 18 instead of 16 bit per pixel.) 78 * Nonetheless, this sequence can be used as a template for concrete 79 * displays which usually need some adjustments. 80 * 81 * Return: 0 on success, < 0 if error occurred. 82 */ 83 static int init_display(struct fbtft_par *par) 84 { 85 /* turn off sleep mode */ 86 write_reg(par, MIPI_DCS_EXIT_SLEEP_MODE); 87 mdelay(120); 88 89 /* set pixel format to RGB-565 */ 90 write_reg(par, MIPI_DCS_SET_PIXEL_FORMAT, MIPI_DCS_PIXEL_FMT_16BIT); 91 if (HSD20_IPS) 92 write_reg(par, PORCTRL, 0x05, 0x05, 0x00, 0x33, 0x33); 93 94 else 95 write_reg(par, PORCTRL, 0x08, 0x08, 0x00, 0x22, 0x22); 96 97 /* 98 * VGH = 13.26V 99 * VGL = -10.43V 100 */ 101 if (HSD20_IPS) 102 write_reg(par, GCTRL, 0x75); 103 else 104 write_reg(par, GCTRL, 0x35); 105 106 /* 107 * VDV and VRH register values come from command write 108 * (instead of NVM) 109 */ 110 write_reg(par, VDVVRHEN, 0x01, 0xFF); 111 112 /* 113 * VAP = 4.1V + (VCOM + VCOM offset + 0.5 * VDV) 114 * VAN = -4.1V + (VCOM + VCOM offset + 0.5 * VDV) 115 */ 116 if (HSD20_IPS) 117 write_reg(par, VRHS, 0x13); 118 else 119 write_reg(par, VRHS, 0x0B); 120 121 /* VDV = 0V */ 122 write_reg(par, VDVS, 0x20); 123 124 /* VCOM = 0.9V */ 125 if (HSD20_IPS) 126 write_reg(par, VCOMS, 0x22); 127 else 128 write_reg(par, VCOMS, 0x20); 129 130 /* VCOM offset = 0V */ 131 write_reg(par, VCMOFSET, 0x20); 132 133 /* 134 * AVDD = 6.8V 135 * AVCL = -4.8V 136 * VDS = 2.3V 137 */ 138 write_reg(par, PWCTRL1, 0xA4, 0xA1); 139 140 write_reg(par, MIPI_DCS_SET_DISPLAY_ON); 141 142 if (HSD20_IPS) 143 write_reg(par, MIPI_DCS_ENTER_INVERT_MODE); 144 145 return 0; 146 } 147 148 /** 149 * set_var() - apply LCD properties like rotation and BGR mode 150 * 151 * @par: FBTFT parameter object 152 * 153 * Return: 0 on success, < 0 if error occurred. 154 */ 155 static int set_var(struct fbtft_par *par) 156 { 157 u8 madctl_par = 0; 158 159 if (par->bgr) 160 madctl_par |= MADCTL_BGR; 161 switch (par->info->var.rotate) { 162 case 0: 163 break; 164 case 90: 165 madctl_par |= (MADCTL_MV | MADCTL_MY); 166 break; 167 case 180: 168 madctl_par |= (MADCTL_MX | MADCTL_MY); 169 break; 170 case 270: 171 madctl_par |= (MADCTL_MV | MADCTL_MX); 172 break; 173 default: 174 return -EINVAL; 175 } 176 write_reg(par, MIPI_DCS_SET_ADDRESS_MODE, madctl_par); 177 return 0; 178 } 179 180 /** 181 * set_gamma() - set gamma curves 182 * 183 * @par: FBTFT parameter object 184 * @curves: gamma curves 185 * 186 * Before the gamma curves are applied, they are preprocessed with a bitmask 187 * to ensure syntactically correct input for the display controller. 188 * This implies that the curves input parameter might be changed by this 189 * function and that illegal gamma values are auto-corrected and not 190 * reported as errors. 191 * 192 * Return: 0 on success, < 0 if error occurred. 193 */ 194 static int set_gamma(struct fbtft_par *par, u32 *curves) 195 { 196 int i; 197 int j; 198 int c; /* curve index offset */ 199 200 /* 201 * Bitmasks for gamma curve command parameters. 202 * The masks are the same for both positive and negative voltage 203 * gamma curves. 204 */ 205 static const u8 gamma_par_mask[] = { 206 0xFF, /* V63[3:0], V0[3:0]*/ 207 0x3F, /* V1[5:0] */ 208 0x3F, /* V2[5:0] */ 209 0x1F, /* V4[4:0] */ 210 0x1F, /* V6[4:0] */ 211 0x3F, /* J0[1:0], V13[3:0] */ 212 0x7F, /* V20[6:0] */ 213 0x77, /* V36[2:0], V27[2:0] */ 214 0x7F, /* V43[6:0] */ 215 0x3F, /* J1[1:0], V50[3:0] */ 216 0x1F, /* V57[4:0] */ 217 0x1F, /* V59[4:0] */ 218 0x3F, /* V61[5:0] */ 219 0x3F, /* V62[5:0] */ 220 }; 221 222 for (i = 0; i < par->gamma.num_curves; i++) { 223 c = i * par->gamma.num_values; 224 for (j = 0; j < par->gamma.num_values; j++) 225 curves[c + j] &= gamma_par_mask[j]; 226 write_reg(par, PVGAMCTRL + i, 227 curves[c + 0], curves[c + 1], curves[c + 2], 228 curves[c + 3], curves[c + 4], curves[c + 5], 229 curves[c + 6], curves[c + 7], curves[c + 8], 230 curves[c + 9], curves[c + 10], curves[c + 11], 231 curves[c + 12], curves[c + 13]); 232 } 233 return 0; 234 } 235 236 /** 237 * blank() - blank the display 238 * 239 * @par: FBTFT parameter object 240 * @on: whether to enable or disable blanking the display 241 * 242 * Return: 0 on success, < 0 if error occurred. 243 */ 244 static int blank(struct fbtft_par *par, bool on) 245 { 246 if (on) 247 write_reg(par, MIPI_DCS_SET_DISPLAY_OFF); 248 else 249 write_reg(par, MIPI_DCS_SET_DISPLAY_ON); 250 return 0; 251 } 252 253 static struct fbtft_display display = { 254 .regwidth = 8, 255 .width = 240, 256 .height = 320, 257 .gamma_num = 2, 258 .gamma_len = 14, 259 .gamma = HSD20_IPS_GAMMA, 260 .fbtftops = { 261 .init_display = init_display, 262 .set_var = set_var, 263 .set_gamma = set_gamma, 264 .blank = blank, 265 }, 266 }; 267 268 FBTFT_REGISTER_DRIVER(DRVNAME, "sitronix,st7789v", &display); 269 270 MODULE_ALIAS("spi:" DRVNAME); 271 MODULE_ALIAS("platform:" DRVNAME); 272 MODULE_ALIAS("spi:st7789v"); 273 MODULE_ALIAS("platform:st7789v"); 274 275 MODULE_DESCRIPTION("FB driver for the ST7789V LCD Controller"); 276 MODULE_AUTHOR("Dennis Menschel"); 277 MODULE_LICENSE("GPL"); 278