LXR linux/drivers/staging/fbtft/fb

   1// SPDX-License-Identifier: GPL-2.0+
   2/*
   3 * FB driver for the UltraChip UC1611 LCD controller
   4 *
   5 * The display is 4-bit grayscale (16 shades) 240x160.
   6 *
   7 * Copyright (C) 2015 Henri Chain
   8 */
   9
  10#include <linux/module.h>
  11#include <linux/kernel.h>
  12#include <linux/init.h>
  13#include <linux/gpio.h>
  14#include <linux/spi/spi.h>
  15#include <linux/delay.h>
  16
  17#include "fbtft.h"
  18
  19#define DRVNAME         "fb_uc1611"
  20#define WIDTH           240
  21#define HEIGHT          160
  22#define BPP             8
  23#define FPS             40
  24
  25/*
  26 * LCD voltage is a combination of ratio, gain, pot and temp
  27 *
  28 * V_LCD = V_BIAS * ratio
  29 * V_LCD = (C_V0 + C_PM × pot) * (1 + (T - 25) * temp)
  30 * C_V0 and C_PM depend on ratio and gain
  31 * T is ambient temperature
  32 */
  33
  34/* BR -> actual ratio: 0-3 -> 5, 10, 11, 13 */
  35static unsigned int ratio = 2;
  36module_param(ratio, uint, 0000);
  37MODULE_PARM_DESC(ratio, "BR[1:0] Bias voltage ratio: 0-3 (default: 2)");
  38
  39static unsigned int gain = 3;
  40module_param(gain, uint, 0000);
  41MODULE_PARM_DESC(gain, "GN[1:0] Bias voltage gain: 0-3 (default: 3)");
  42
  43static unsigned int pot = 16;
  44module_param(pot, uint, 0000);
  45MODULE_PARM_DESC(pot, "PM[6:0] Bias voltage pot.: 0-63 (default: 16)");
  46
  47/* TC -> % compensation per deg C: 0-3 -> -.05, -.10, -.015, -.20 */
  48static unsigned int temp;
  49module_param(temp, uint, 0000);
  50MODULE_PARM_DESC(temp, "TC[1:0] Temperature compensation: 0-3 (default: 0)");
  51
  52/* PC[1:0] -> LCD capacitance: 0-3 -> <20nF, 20-28 nF, 29-40 nF, 40-56 nF */
  53static unsigned int load = 1;
  54module_param(load, uint, 0000);
  55MODULE_PARM_DESC(load, "PC[1:0] Panel Loading: 0-3 (default: 1)");
  56
  57/* PC[3:2] -> V_LCD: 0, 1, 3 -> ext., int. with ratio = 5, int. standard */
  58static unsigned int pump = 3;
  59module_param(pump, uint, 0000);
  60MODULE_PARM_DESC(pump, "PC[3:2] Pump control: 0,1,3 (default: 3)");
  61
  62static int init_display(struct fbtft_par *par)
  63{
  64        int ret;
  65
  66        /* Set CS active high */
  67        par->spi->mode |= SPI_CS_HIGH;
  68        ret = spi_setup(par->spi);
  69        if (ret) {
  70                dev_err(par->info->device, "Could not set SPI_CS_HIGH\n");
  71                return ret;
  72        }
  73
  74        /* Reset controller */
  75        write_reg(par, 0xE2);
  76
  77        /* Set bias ratio */
  78        write_reg(par, 0xE8 | (ratio & 0x03));
  79
  80        /* Set bias gain and potentiometer */
  81        write_reg(par, 0x81);
  82        write_reg(par, (gain & 0x03) << 6 | (pot & 0x3F));
  83
  84        /* Set temperature compensation */
  85        write_reg(par, 0x24 | (temp & 0x03));
  86
  87        /* Set panel loading */
  88        write_reg(par, 0x28 | (load & 0x03));
  89
  90        /* Set pump control */
  91        write_reg(par, 0x2C | (pump & 0x03));
  92
  93        /* Set inverse display */
  94        write_reg(par, 0xA6 | (0x01 & 0x01));
  95
  96        /* Set 4-bit grayscale mode */
  97        write_reg(par, 0xD0 | (0x02 & 0x03));
  98
  99        /* Set Display enable */
 100        write_reg(par, 0xA8 | 0x07);
 101
 102        return 0;
 103}
 104
 105static void set_addr_win(struct fbtft_par *par, int xs, int ys, int xe, int ye)
 106{
 107        switch (par->info->var.rotate) {
 108        case 90:
 109        case 270:
 110                /* Set column address */
 111                write_reg(par, ys & 0x0F);
 112                write_reg(par, 0x10 | (ys >> 4));
 113
 114                /* Set page address (divide xs by 2) (not used by driver) */
 115                write_reg(par, 0x60 | ((xs >> 1) & 0x0F));
 116                write_reg(par, 0x70 | (xs >> 5));
 117                break;
 118        default:
 119                /* Set column address (not used by driver) */
 120                write_reg(par, xs & 0x0F);
 121                write_reg(par, 0x10 | (xs >> 4));
 122
 123                /* Set page address (divide ys by 2) */
 124                write_reg(par, 0x60 | ((ys >> 1) & 0x0F));
 125                write_reg(par, 0x70 | (ys >> 5));
 126                break;
 127        }
 128}
 129
 130static int blank(struct fbtft_par *par, bool on)
 131{
 132        fbtft_par_dbg(DEBUG_BLANK, par, "%s(blank=%s)\n",
 133                      __func__, on ? "true" : "false");
 134
 135        if (on)
 136                write_reg(par, 0xA8 | 0x00);
 137        else
 138                write_reg(par, 0xA8 | 0x07);
 139        return 0;
 140}
 141
 142static int set_var(struct fbtft_par *par)
 143{
 144        /* par->info->fix.visual = FB_VISUAL_PSEUDOCOLOR; */
 145        par->info->var.grayscale = 1;
 146        par->info->var.red.offset    = 0;
 147        par->info->var.red.length    = 8;
 148        par->info->var.green.offset  = 0;
 149        par->info->var.green.length  = 8;
 150        par->info->var.blue.offset   = 0;
 151        par->info->var.blue.length   = 8;
 152        par->info->var.transp.offset = 0;
 153        par->info->var.transp.length = 0;
 154
 155        switch (par->info->var.rotate) {
 156        case 90:
 157                /* Set RAM address control */
 158                write_reg(par, 0x88
 159                        | (0x0 & 0x1) << 2 /* Increment positively */
 160                        | (0x1 & 0x1) << 1 /* Increment page first */
 161                        | (0x1 & 0x1));    /* Wrap around (default) */
 162
 163                /* Set LCD mapping */
 164                write_reg(par, 0xC0
 165                        | (0x0 & 0x1) << 2 /* Mirror Y OFF */
 166                        | (0x0 & 0x1) << 1 /* Mirror X OFF */
 167                        | (0x0 & 0x1));    /* MS nibble last (default) */
 168                break;
 169        case 180:
 170                /* Set RAM address control */
 171                write_reg(par, 0x88
 172                        | (0x0 & 0x1) << 2 /* Increment positively */
 173                        | (0x0 & 0x1) << 1 /* Increment column first */
 174                        | (0x1 & 0x1));    /* Wrap around (default) */
 175
 176                /* Set LCD mapping */
 177                write_reg(par, 0xC0
 178                        | (0x1 & 0x1) << 2 /* Mirror Y ON */
 179                        | (0x0 & 0x1) << 1 /* Mirror X OFF */
 180                        | (0x0 & 0x1));    /* MS nibble last (default) */
 181                break;
 182        case 270:
 183                /* Set RAM address control */
 184                write_reg(par, 0x88
 185                        | (0x0 & 0x1) << 2 /* Increment positively */
 186                        | (0x1 & 0x1) << 1 /* Increment page first */
 187                        | (0x1 & 0x1));    /* Wrap around (default) */
 188
 189                /* Set LCD mapping */
 190                write_reg(par, 0xC0
 191                        | (0x1 & 0x1) << 2 /* Mirror Y ON */
 192                        | (0x1 & 0x1) << 1 /* Mirror X ON */
 193                        | (0x0 & 0x1));    /* MS nibble last (default) */
 194                break;
 195        default:
 196                /* Set RAM address control */
 197                write_reg(par, 0x88
 198                        | (0x0 & 0x1) << 2 /* Increment positively */
 199                        | (0x0 & 0x1) << 1 /* Increment column first */
 200                        | (0x1 & 0x1));    /* Wrap around (default) */
 201
 202                /* Set LCD mapping */
 203                write_reg(par, 0xC0
 204                        | (0x0 & 0x1) << 2 /* Mirror Y OFF */
 205                        | (0x1 & 0x1) << 1 /* Mirror X ON */
 206                        | (0x0 & 0x1));    /* MS nibble last (default) */
 207                break;
 208        }
 209
 210        return 0;
 211}
 212
 213static int write_vmem(struct fbtft_par *par, size_t offset, size_t len)
 214{
 215        u8 *vmem8 = (u8 *)(par->info->screen_buffer);
 216        u8 *buf8 = par->txbuf.buf;
 217        u16 *buf16 = par->txbuf.buf;
 218        int line_length = par->info->fix.line_length;
 219        int y_start = offset / line_length;
 220        int y_end = (offset + len - 1) / line_length;
 221        int x, y, i;
 222        int ret = 0;
 223
 224        switch (par->pdata->display.buswidth) {
 225        case 8:
 226                switch (par->info->var.rotate) {
 227                case 90:
 228                case 270:
 229                        i = y_start * line_length;
 230                        for (y = y_start; y <= y_end; y++) {
 231                                for (x = 0; x < line_length; x += 2) {
 232                                        *buf8 = vmem8[i] >> 4;
 233                                        *buf8 |= vmem8[i + 1] & 0xF0;
 234                                        buf8++;
 235                                        i += 2;
 236                                }
 237                        }
 238                        break;
 239                default:
 240                        /* Must be even because pages are two lines */
 241                        y_start &= 0xFE;
 242                        i = y_start * line_length;
 243                        for (y = y_start; y <= y_end; y += 2) {
 244                                for (x = 0; x < line_length; x++) {
 245                                        *buf8 = vmem8[i] >> 4;
 246                                        *buf8 |= vmem8[i + line_length] & 0xF0;
 247                                        buf8++;
 248                                        i++;
 249                                }
 250                                i += line_length;
 251                        }
 252                        break;
 253                }
 254                gpio_set_value(par->gpio.dc, 1);
 255
 256                /* Write data */
 257                ret = par->fbtftops.write(par, par->txbuf.buf, len / 2);
 258                break;
 259        case 9:
 260                switch (par->info->var.rotate) {
 261                case 90:
 262                case 270:
 263                        i = y_start * line_length;
 264                        for (y = y_start; y <= y_end; y++) {
 265                                for (x = 0; x < line_length; x += 2) {
 266                                        *buf16 = 0x100;
 267                                        *buf16 |= vmem8[i] >> 4;
 268                                        *buf16 |= vmem8[i + 1] & 0xF0;
 269                                        buf16++;
 270                                        i += 2;
 271                                }
 272                        }
 273                        break;
 274                default:
 275                        /* Must be even because pages are two lines */
 276                        y_start &= 0xFE;
 277                        i = y_start * line_length;
 278                        for (y = y_start; y <= y_end; y += 2) {
 279                                for (x = 0; x < line_length; x++) {
 280                                        *buf16 = 0x100;
 281                                        *buf16 |= vmem8[i] >> 4;
 282                                        *buf16 |= vmem8[i + line_length] & 0xF0;
 283                                        buf16++;
 284                                        i++;
 285                                }
 286                                i += line_length;
 287                        }
 288                        break;
 289                }
 290
 291                /* Write data */
 292                ret = par->fbtftops.write(par, par->txbuf.buf, len);
 293                break;
 294        default:
 295                dev_err(par->info->device, "unsupported buswidth %d\n",
 296                        par->pdata->display.buswidth);
 297        }
 298
 299        if (ret < 0)
 300                dev_err(par->info->device, "write failed and returned: %d\n",
 301                        ret);
 302
 303        return ret;
 304}
 305
 306static struct fbtft_display display = {
 307        .txbuflen = -1,
 308        .regwidth = 8,
 309        .width = WIDTH,
 310        .height = HEIGHT,
 311        .bpp = BPP,
 312        .fps = FPS,
 313        .fbtftops = {
 314                .write_vmem = write_vmem,
 315                .init_display = init_display,
 316                .set_addr_win = set_addr_win,
 317                .set_var = set_var,
 318                .blank = blank,
 319        },
 320};
 321
 322FBTFT_REGISTER_DRIVER(DRVNAME, "ultrachip,uc1611", &display);
 323
 324MODULE_ALIAS("spi:" DRVNAME);
 325MODULE_ALIAS("platform:" DRVNAME);
 326MODULE_ALIAS("spi:uc1611");
 327MODULE_ALIAS("platform:uc1611");
 328
 329MODULE_DESCRIPTION("FB driver for the UC1611 LCD controller");
 330MODULE_AUTHOR("Henri Chain");
 331MODULE_LICENSE("GPL");
 332