LXR linux/drivers/staging/fbtft/fb

   1// SPDX-License-Identifier: GPL-2.0
   2#include <linux/module.h>
   3#include <linux/kernel.h>
   4#include <linux/init.h>
   5#include <linux/spi/spi.h>
   6#include <linux/delay.h>
   7
   8#include "fbtft.h"
   9
  10#define DRVNAME         "fb_ssd1351"
  11#define WIDTH           128
  12#define HEIGHT          128
  13#define GAMMA_NUM       1
  14#define GAMMA_LEN       63
  15#define DEFAULT_GAMMA   "0 2 2 2 2 2 2 2 " \
  16                        "2 2 2 2 2 2 2 2 " \
  17                        "2 2 2 2 2 2 2 2 " \
  18                        "2 2 2 2 2 2 2 2 " \
  19                        "2 2 2 2 2 2 2 2 " \
  20                        "2 2 2 2 2 2 2 2 " \
  21                        "2 2 2 2 2 2 2 2 " \
  22                        "2 2 2 2 2 2 2" \
  23
  24static void register_onboard_backlight(struct fbtft_par *par);
  25
  26static int init_display(struct fbtft_par *par)
  27{
  28        if (par->pdata &&
  29            par->pdata->display.backlight == FBTFT_ONBOARD_BACKLIGHT) {
  30                /* module uses onboard GPIO for panel power */
  31                par->fbtftops.register_backlight = register_onboard_backlight;
  32        }
  33
  34        par->fbtftops.reset(par);
  35
  36        write_reg(par, 0xfd, 0x12); /* Command Lock */
  37        write_reg(par, 0xfd, 0xb1); /* Command Lock */
  38        write_reg(par, 0xae); /* Display Off */
  39        write_reg(par, 0xb3, 0xf1); /* Front Clock Div */
  40        write_reg(par, 0xca, 0x7f); /* Set Mux Ratio */
  41        write_reg(par, 0x15, 0x00, 0x7f); /* Set Column Address */
  42        write_reg(par, 0x75, 0x00, 0x7f); /* Set Row Address */
  43        write_reg(par, 0xa1, 0x00); /* Set Display Start Line */
  44        write_reg(par, 0xa2, 0x00); /* Set Display Offset */
  45        write_reg(par, 0xb5, 0x00); /* Set GPIO */
  46        write_reg(par, 0xab, 0x01); /* Set Function Selection */
  47        write_reg(par, 0xb1, 0x32); /* Set Phase Length */
  48        write_reg(par, 0xb4, 0xa0, 0xb5, 0x55); /* Set Segment Low Voltage */
  49        write_reg(par, 0xbb, 0x17); /* Set Precharge Voltage */
  50        write_reg(par, 0xbe, 0x05); /* Set VComH Voltage */
  51        write_reg(par, 0xc1, 0xc8, 0x80, 0xc8); /* Set Contrast */
  52        write_reg(par, 0xc7, 0x0f); /* Set Master Contrast */
  53        write_reg(par, 0xb6, 0x01); /* Set Second Precharge Period */
  54        write_reg(par, 0xa6); /* Set Display Mode Reset */
  55        write_reg(par, 0xaf); /* Set Sleep Mode Display On */
  56
  57        return 0;
  58}
  59
  60static void set_addr_win(struct fbtft_par *par, int xs, int ys, int xe, int ye)
  61{
  62        write_reg(par, 0x15, xs, xe);
  63        write_reg(par, 0x75, ys, ye);
  64        write_reg(par, 0x5c);
  65}
  66
  67static int set_var(struct fbtft_par *par)
  68{
  69        unsigned int remap;
  70
  71        if (par->fbtftops.init_display != init_display) {
  72                /* don't risk messing up register A0h */
  73                fbtft_par_dbg(DEBUG_INIT_DISPLAY, par,
  74                              "%s: skipping since custom init_display() is used\n",
  75                               __func__);
  76                return 0;
  77        }
  78
  79        remap = 0x60 | (par->bgr << 2); /* Set Colour Depth */
  80
  81        switch (par->info->var.rotate) {
  82        case 0:
  83                write_reg(par, 0xA0, remap | 0x00 | BIT(4));
  84                break;
  85        case 270:
  86                write_reg(par, 0xA0, remap | 0x03 | BIT(4));
  87                break;
  88        case 180:
  89                write_reg(par, 0xA0, remap | 0x02);
  90                break;
  91        case 90:
  92                write_reg(par, 0xA0, remap | 0x01);
  93                break;
  94        }
  95
  96        return 0;
  97}
  98
  99/*
 100 * Grayscale Lookup Table
 101 * GS1 - GS63
 102 * The driver Gamma curve contains the relative values between the entries
 103 * in the Lookup table.
 104 *
 105 * From datasheet:
 106 * 8.8 Gray Scale Decoder
 107 *
 108 *      there are total 180 Gamma Settings (Setting 0 to Setting 180)
 109 *      available for the Gray Scale table.
 110 *
 111 *      The gray scale is defined in incremental way, with reference
 112 *      to the length of previous table entry:
 113 *              Setting of GS1 has to be >= 0
 114 *              Setting of GS2 has to be > Setting of GS1 +1
 115 *              Setting of GS3 has to be > Setting of GS2 +1
 116 *              :
 117 *              Setting of GS63 has to be > Setting of GS62 +1
 118 *
 119 */
 120static int set_gamma(struct fbtft_par *par, u32 *curves)
 121{
 122        unsigned long tmp[GAMMA_NUM * GAMMA_LEN];
 123        int i, acc = 0;
 124
 125        for (i = 0; i < 63; i++) {
 126                if (i > 0 && curves[i] < 2) {
 127                        dev_err(par->info->device,
 128                                "Illegal value in Grayscale Lookup Table at index %d : %d. Must be greater than 1\n",
 129                                i, curves[i]);
 130                        return -EINVAL;
 131                }
 132                acc += curves[i];
 133                tmp[i] = acc;
 134                if (acc > 180) {
 135                        dev_err(par->info->device,
 136                                "Illegal value(s) in Grayscale Lookup Table. At index=%d : %d, the accumulated value has exceeded 180\n",
 137                                i, acc);
 138                        return -EINVAL;
 139                }
 140        }
 141
 142        write_reg(par, 0xB8,
 143                  tmp[0],  tmp[1],  tmp[2],  tmp[3],
 144                  tmp[4],  tmp[5],  tmp[6],  tmp[7],
 145                  tmp[8],  tmp[9],  tmp[10], tmp[11],
 146                  tmp[12], tmp[13], tmp[14], tmp[15],
 147                  tmp[16], tmp[17], tmp[18], tmp[19],
 148                  tmp[20], tmp[21], tmp[22], tmp[23],
 149                  tmp[24], tmp[25], tmp[26], tmp[27],
 150                  tmp[28], tmp[29], tmp[30], tmp[31],
 151                  tmp[32], tmp[33], tmp[34], tmp[35],
 152                  tmp[36], tmp[37], tmp[38], tmp[39],
 153                  tmp[40], tmp[41], tmp[42], tmp[43],
 154                  tmp[44], tmp[45], tmp[46], tmp[47],
 155                  tmp[48], tmp[49], tmp[50], tmp[51],
 156                  tmp[52], tmp[53], tmp[54], tmp[55],
 157                  tmp[56], tmp[57], tmp[58], tmp[59],
 158                  tmp[60], tmp[61], tmp[62]);
 159
 160        return 0;
 161}
 162
 163static int blank(struct fbtft_par *par, bool on)
 164{
 165        fbtft_par_dbg(DEBUG_BLANK, par, "(%s=%s)\n",
 166                      __func__, on ? "true" : "false");
 167        if (on)
 168                write_reg(par, 0xAE);
 169        else
 170                write_reg(par, 0xAF);
 171        return 0;
 172}
 173
 174static struct fbtft_display display = {
 175        .regwidth = 8,
 176        .width = WIDTH,
 177        .height = HEIGHT,
 178        .gamma_num = GAMMA_NUM,
 179        .gamma_len = GAMMA_LEN,
 180        .gamma = DEFAULT_GAMMA,
 181        .fbtftops = {
 182                .init_display = init_display,
 183                .set_addr_win = set_addr_win,
 184                .set_var = set_var,
 185                .set_gamma = set_gamma,
 186                .blank = blank,
 187        },
 188};
 189
 190#ifdef CONFIG_FB_BACKLIGHT
 191static int update_onboard_backlight(struct backlight_device *bd)
 192{
 193        struct fbtft_par *par = bl_get_data(bd);
 194        bool on;
 195
 196        fbtft_par_dbg(DEBUG_BACKLIGHT, par,
 197                      "%s: power=%d, fb_blank=%d\n",
 198                      __func__, bd->props.power, bd->props.fb_blank);
 199
 200        on = (bd->props.power == FB_BLANK_UNBLANK) &&
 201             (bd->props.fb_blank == FB_BLANK_UNBLANK);
 202        /* Onboard backlight connected to GPIO0 on SSD1351, GPIO1 unused */
 203        write_reg(par, 0xB5, on ? 0x03 : 0x02);
 204
 205        return 0;
 206}
 207
 208static const struct backlight_ops bl_ops = {
 209        .update_status = update_onboard_backlight,
 210};
 211
 212static void register_onboard_backlight(struct fbtft_par *par)
 213{
 214        struct backlight_device *bd;
 215        struct backlight_properties bl_props = { 0, };
 216
 217        bl_props.type = BACKLIGHT_RAW;
 218        bl_props.power = FB_BLANK_POWERDOWN;
 219
 220        bd = backlight_device_register(dev_driver_string(par->info->device),
 221                                       par->info->device, par, &bl_ops,
 222                                       &bl_props);
 223        if (IS_ERR(bd)) {
 224                dev_err(par->info->device,
 225                        "cannot register backlight device (%ld)\n",
 226                        PTR_ERR(bd));
 227                return;
 228        }
 229        par->info->bl_dev = bd;
 230
 231        if (!par->fbtftops.unregister_backlight)
 232                par->fbtftops.unregister_backlight = fbtft_unregister_backlight;
 233}
 234#else
 235static void register_onboard_backlight(struct fbtft_par *par) { };
 236#endif
 237
 238FBTFT_REGISTER_DRIVER(DRVNAME, "solomon,ssd1351", &display);
 239
 240MODULE_ALIAS("spi:" DRVNAME);
 241MODULE_ALIAS("platform:" DRVNAME);
 242MODULE_ALIAS("spi:ssd1351");
 243MODULE_ALIAS("platform:ssd1351");
 244
 245MODULE_DESCRIPTION("SSD1351 OLED Driver");
 246MODULE_AUTHOR("James Davies");
 247MODULE_LICENSE("GPL");
 248