1 /* 2 * FB driver for the UltraChip UC1611 LCD controller 3 * 4 * The display is 4-bit grayscale (16 shades) 240x160. 5 * 6 * Copyright (C) 2015 Henri Chain 7 * 8 * This program is free software; you can redistribute it and/or modify 9 * it under the terms of the GNU General Public License as published by 10 * the Free Software Foundation; either version 2 of the License, or 11 * (at your option) any later version. 12 * 13 * This program is distributed in the hope that it will be useful, 14 * but WITHOUT ANY WARRANTY; without even the implied warranty of 15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 16 * GNU General Public License for more details. 17 */ 18 19 #include <linux/module.h> 20 #include <linux/kernel.h> 21 #include <linux/init.h> 22 #include <linux/gpio.h> 23 #include <linux/spi/spi.h> 24 #include <linux/delay.h> 25 26 #include "fbtft.h" 27 28 #define DRVNAME "fb_uc1611" 29 #define WIDTH 240 30 #define HEIGHT 160 31 #define BPP 8 32 #define FPS 40 33 34 /* 35 * LCD voltage is a combination of ratio, gain, pot and temp 36 * 37 * V_LCD = V_BIAS * ratio 38 * V_LCD = (C_V0 + C_PM × pot) * (1 + (T - 25) * temp) 39 * C_V0 and C_PM depend on ratio and gain 40 * T is ambient temperature 41 */ 42 43 /* BR -> actual ratio: 0-3 -> 5, 10, 11, 13 */ 44 static unsigned ratio = 2; 45 module_param(ratio, uint, 0); 46 MODULE_PARM_DESC(ratio, "BR[1:0] Bias voltage ratio: 0-3 (default: 2)"); 47 48 static unsigned gain = 3; 49 module_param(gain, uint, 0); 50 MODULE_PARM_DESC(gain, "GN[1:0] Bias voltage gain: 0-3 (default: 3)"); 51 52 static unsigned pot = 16; 53 module_param(pot, uint, 0); 54 MODULE_PARM_DESC(pot, "PM[6:0] Bias voltage pot.: 0-63 (default: 16)"); 55 56 /* TC -> % compensation per deg C: 0-3 -> -.05, -.10, -.015, -.20 */ 57 static unsigned temp; 58 module_param(temp, uint, 0); 59 MODULE_PARM_DESC(temp, "TC[1:0] Temperature compensation: 0-3 (default: 0)"); 60 61 /* PC[1:0] -> LCD capacitance: 0-3 -> <20nF, 20-28 nF, 29-40 nF, 40-56 nF */ 62 static unsigned load = 1; 63 module_param(load, uint, 0); 64 MODULE_PARM_DESC(load, "PC[1:0] Panel Loading: 0-3 (default: 1)"); 65 66 /* PC[3:2] -> V_LCD: 0, 1, 3 -> ext., int. with ratio = 5, int. standard */ 67 static unsigned pump = 3; 68 module_param(pump, uint, 0); 69 MODULE_PARM_DESC(pump, "PC[3:2] Pump control: 0,1,3 (default: 3)"); 70 71 static int init_display(struct fbtft_par *par) 72 { 73 int ret; 74 75 /* Set CS active high */ 76 par->spi->mode |= SPI_CS_HIGH; 77 ret = spi_setup(par->spi); 78 if (ret) { 79 dev_err(par->info->device, "Could not set SPI_CS_HIGH\n"); 80 return ret; 81 } 82 83 /* Reset controller */ 84 write_reg(par, 0xE2); 85 86 /* Set bias ratio */ 87 write_reg(par, 0xE8 | (ratio & 0x03)); 88 89 /* Set bias gain and potentiometer */ 90 write_reg(par, 0x81); 91 write_reg(par, (gain & 0x03) << 6 | (pot & 0x3F)); 92 93 /* Set temperature compensation */ 94 write_reg(par, 0x24 | (temp & 0x03)); 95 96 /* Set panel loading */ 97 write_reg(par, 0x28 | (load & 0x03)); 98 99 /* Set pump control */ 100 write_reg(par, 0x2C | (pump & 0x03)); 101 102 /* Set inverse display */ 103 write_reg(par, 0xA6 | (0x01 & 0x01)); 104 105 /* Set 4-bit grayscale mode */ 106 write_reg(par, 0xD0 | (0x02 & 0x03)); 107 108 /* Set Display enable */ 109 write_reg(par, 0xA8 | 0x07); 110 111 return 0; 112 } 113 114 static void set_addr_win(struct fbtft_par *par, int xs, int ys, int xe, int ye) 115 { 116 switch (par->info->var.rotate) { 117 case 90: 118 case 270: 119 /* Set column address */ 120 write_reg(par, ys & 0x0F); 121 write_reg(par, 0x10 | (ys >> 4)); 122 123 /* Set page address (divide xs by 2) (not used by driver) */ 124 write_reg(par, 0x60 | ((xs >> 1) & 0x0F)); 125 write_reg(par, 0x70 | (xs >> 5)); 126 break; 127 default: 128 /* Set column address (not used by driver) */ 129 write_reg(par, xs & 0x0F); 130 write_reg(par, 0x10 | (xs >> 4)); 131 132 /* Set page address (divide ys by 2) */ 133 write_reg(par, 0x60 | ((ys >> 1) & 0x0F)); 134 write_reg(par, 0x70 | (ys >> 5)); 135 break; 136 } 137 } 138 139 static int blank(struct fbtft_par *par, bool on) 140 { 141 fbtft_par_dbg(DEBUG_BLANK, par, "%s(blank=%s)\n", 142 __func__, on ? "true" : "false"); 143 144 if (on) 145 write_reg(par, 0xA8 | 0x00); 146 else 147 write_reg(par, 0xA8 | 0x07); 148 return 0; 149 } 150 151 static int set_var(struct fbtft_par *par) 152 { 153 /* par->info->fix.visual = FB_VISUAL_PSEUDOCOLOR; */ 154 par->info->var.grayscale = 1; 155 par->info->var.red.offset = 0; 156 par->info->var.red.length = 8; 157 par->info->var.green.offset = 0; 158 par->info->var.green.length = 8; 159 par->info->var.blue.offset = 0; 160 par->info->var.blue.length = 8; 161 par->info->var.transp.offset = 0; 162 par->info->var.transp.length = 0; 163 164 switch (par->info->var.rotate) { 165 case 90: 166 /* Set RAM address control */ 167 write_reg(par, 0x88 168 | (0x0 & 0x1) << 2 /* Increment positively */ 169 | (0x1 & 0x1) << 1 /* Increment page first */ 170 | (0x1 & 0x1)); /* Wrap around (default) */ 171 172 /* Set LCD mapping */ 173 write_reg(par, 0xC0 174 | (0x0 & 0x1) << 2 /* Mirror Y OFF */ 175 | (0x0 & 0x1) << 1 /* Mirror X OFF */ 176 | (0x0 & 0x1)); /* MS nibble last (default) */ 177 break; 178 case 180: 179 /* Set RAM address control */ 180 write_reg(par, 0x88 181 | (0x0 & 0x1) << 2 /* Increment positively */ 182 | (0x0 & 0x1) << 1 /* Increment column first */ 183 | (0x1 & 0x1)); /* Wrap around (default) */ 184 185 /* Set LCD mapping */ 186 write_reg(par, 0xC0 187 | (0x1 & 0x1) << 2 /* Mirror Y ON */ 188 | (0x0 & 0x1) << 1 /* Mirror X OFF */ 189 | (0x0 & 0x1)); /* MS nibble last (default) */ 190 break; 191 case 270: 192 /* Set RAM address control */ 193 write_reg(par, 0x88 194 | (0x0 & 0x1) << 2 /* Increment positively */ 195 | (0x1 & 0x1) << 1 /* Increment page first */ 196 | (0x1 & 0x1)); /* Wrap around (default) */ 197 198 /* Set LCD mapping */ 199 write_reg(par, 0xC0 200 | (0x1 & 0x1) << 2 /* Mirror Y ON */ 201 | (0x1 & 0x1) << 1 /* Mirror X ON */ 202 | (0x0 & 0x1)); /* MS nibble last (default) */ 203 break; 204 default: 205 /* Set RAM address control */ 206 write_reg(par, 0x88 207 | (0x0 & 0x1) << 2 /* Increment positively */ 208 | (0x0 & 0x1) << 1 /* Increment column first */ 209 | (0x1 & 0x1)); /* Wrap around (default) */ 210 211 /* Set LCD mapping */ 212 write_reg(par, 0xC0 213 | (0x0 & 0x1) << 2 /* Mirror Y OFF */ 214 | (0x1 & 0x1) << 1 /* Mirror X ON */ 215 | (0x0 & 0x1)); /* MS nibble last (default) */ 216 break; 217 } 218 219 return 0; 220 } 221 222 static int write_vmem(struct fbtft_par *par, size_t offset, size_t len) 223 { 224 u8 *vmem8 = (u8 *)(par->info->screen_buffer); 225 u8 *buf8 = (u8 *)(par->txbuf.buf); 226 u16 *buf16 = (u16 *)(par->txbuf.buf); 227 int line_length = par->info->fix.line_length; 228 int y_start = (offset / line_length); 229 int y_end = (offset + len - 1) / line_length; 230 int x, y, i; 231 int ret = 0; 232 233 switch (par->pdata->display.buswidth) { 234 case 8: 235 switch (par->info->var.rotate) { 236 case 90: 237 case 270: 238 i = y_start * line_length; 239 for (y = y_start; y <= y_end; y++) { 240 for (x = 0; x < line_length; x += 2) { 241 *buf8 = vmem8[i] >> 4; 242 *buf8 |= vmem8[i + 1] & 0xF0; 243 buf8++; 244 i += 2; 245 } 246 } 247 break; 248 default: 249 /* Must be even because pages are two lines */ 250 y_start &= 0xFE; 251 i = y_start * line_length; 252 for (y = y_start; y <= y_end; y += 2) { 253 for (x = 0; x < line_length; x++) { 254 *buf8 = vmem8[i] >> 4; 255 *buf8 |= vmem8[i + line_length] & 0xF0; 256 buf8++; 257 i++; 258 } 259 i += line_length; 260 } 261 break; 262 } 263 gpio_set_value(par->gpio.dc, 1); 264 265 /* Write data */ 266 ret = par->fbtftops.write(par, par->txbuf.buf, len / 2); 267 break; 268 case 9: 269 switch (par->info->var.rotate) { 270 case 90: 271 case 270: 272 i = y_start * line_length; 273 for (y = y_start; y <= y_end; y++) { 274 for (x = 0; x < line_length; x += 2) { 275 *buf16 = 0x100; 276 *buf16 |= vmem8[i] >> 4; 277 *buf16 |= vmem8[i + 1] & 0xF0; 278 buf16++; 279 i += 2; 280 } 281 } 282 break; 283 default: 284 /* Must be even because pages are two lines */ 285 y_start &= 0xFE; 286 i = y_start * line_length; 287 for (y = y_start; y <= y_end; y += 2) { 288 for (x = 0; x < line_length; x++) { 289 *buf16 = 0x100; 290 *buf16 |= vmem8[i] >> 4; 291 *buf16 |= vmem8[i + line_length] & 0xF0; 292 buf16++; 293 i++; 294 } 295 i += line_length; 296 } 297 break; 298 } 299 300 /* Write data */ 301 ret = par->fbtftops.write(par, par->txbuf.buf, len); 302 break; 303 default: 304 dev_err(par->info->device, "unsupported buswidth %d\n", 305 par->pdata->display.buswidth); 306 } 307 308 if (ret < 0) 309 dev_err(par->info->device, "write failed and returned: %d\n", 310 ret); 311 312 return ret; 313 } 314 315 static struct fbtft_display display = { 316 .txbuflen = -1, 317 .regwidth = 8, 318 .width = WIDTH, 319 .height = HEIGHT, 320 .bpp = BPP, 321 .fps = FPS, 322 .fbtftops = { 323 .write_vmem = write_vmem, 324 .init_display = init_display, 325 .set_addr_win = set_addr_win, 326 .set_var = set_var, 327 .blank = blank, 328 }, 329 }; 330 331 FBTFT_REGISTER_DRIVER(DRVNAME, "ultrachip,uc1611", &display); 332 333 MODULE_ALIAS("spi:" DRVNAME); 334 MODULE_ALIAS("platform:" DRVNAME); 335 MODULE_ALIAS("spi:uc1611"); 336 MODULE_ALIAS("platform:uc1611"); 337 338 MODULE_DESCRIPTION("FB driver for the UC1611 LCD controller"); 339 MODULE_AUTHOR("Henri Chain"); 340 MODULE_LICENSE("GPL"); 341