drivers/gpu/drm/tiny/st7586.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * DRM driver for Sitronix ST7586 panels
   4  *
   5  * Copyright 2017 David Lechner <david@lechnology.com>
   6  */
   7
   8 #include <linux/delay.h>
   9 #include <linux/gpio/consumer.h>
  10 #include <linux/module.h>
  11 #include <linux/property.h>
  12 #include <linux/spi/spi.h>
  13 #include <video/mipi_display.h>
  14
  15 #include <drm/drm_atomic_helper.h>
  16 #include <drm/drm_damage_helper.h>
  17 #include <drm/drm_drv.h>
  18 #include <drm/drm_fb_cma_helper.h>
  19 #include <drm/drm_fb_helper.h>
  20 #include <drm/drm_format_helper.h>
  21 #include <drm/drm_gem_atomic_helper.h>
  22 #include <drm/drm_gem_cma_helper.h>
  23 #include <drm/drm_gem_framebuffer_helper.h>
  24 #include <drm/drm_managed.h>
  25 #include <drm/drm_mipi_dbi.h>
  26 #include <drm/drm_rect.h>
  27
  28 /* controller-specific commands */
  29 #define ST7586_DISP_MODE_GRAY   0x38
  30 #define ST7586_DISP_MODE_MONO   0x39
  31 #define ST7586_ENABLE_DDRAM     0x3a
  32 #define ST7586_SET_DISP_DUTY    0xb0
  33 #define ST7586_SET_PART_DISP    0xb4
  34 #define ST7586_SET_NLINE_INV    0xb5
  35 #define ST7586_SET_VOP          0xc0
  36 #define ST7586_SET_BIAS_SYSTEM  0xc3
  37 #define ST7586_SET_BOOST_LEVEL  0xc4
  38 #define ST7586_SET_VOP_OFFSET   0xc7
  39 #define ST7586_ENABLE_ANALOG    0xd0
  40 #define ST7586_AUTO_READ_CTRL   0xd7
  41 #define ST7586_OTP_RW_CTRL      0xe0
  42 #define ST7586_OTP_CTRL_OUT     0xe1
  43 #define ST7586_OTP_READ         0xe3
  44
  45 #define ST7586_DISP_CTRL_MX     BIT(6)
  46 #define ST7586_DISP_CTRL_MY     BIT(7)
  47
  48 /*
  49  * The ST7586 controller has an unusual pixel format where 2bpp grayscale is
  50  * packed 3 pixels per byte with the first two pixels using 3 bits and the 3rd
  51  * pixel using only 2 bits.
  52  *
  53  * |  D7  |  D6  |  D5  ||      |      || 2bpp |
  54  * | (D4) | (D3) | (D2) ||  D1  |  D0  || GRAY |
  55  * +------+------+------++------+------++------+
  56  * |  1   |  1   |  1   ||  1   |  1   || 0  0 | black
  57  * |  1   |  0   |  0   ||  1   |  0   || 0  1 | dark gray
  58  * |  0   |  1   |  0   ||  0   |  1   || 1  0 | light gray
  59  * |  0   |  0   |  0   ||  0   |  0   || 1  1 | white
  60  */
  61
  62 static const u8 st7586_lookup[] = { 0x7, 0x4, 0x2, 0x0 };
  63
  64 static void st7586_xrgb8888_to_gray332(u8 *dst, void *vaddr,
  65                                        struct drm_framebuffer *fb,
  66                                        struct drm_rect *clip)
  67 {
  68         size_t len = (clip->x2 - clip->x1) * (clip->y2 - clip->y1);
  69         unsigned int x, y;
  70         u8 *src, *buf, val;
  71
  72         buf = kmalloc(len, GFP_KERNEL);
  73         if (!buf)
  74                 return;
  75
  76         drm_fb_xrgb8888_to_gray8(buf, 0, vaddr, fb, clip);
  77         src = buf;
  78
  79         for (y = clip->y1; y < clip->y2; y++) {
  80                 for (x = clip->x1; x < clip->x2; x += 3) {
  81                         val = st7586_lookup[*src++ >> 6] << 5;
  82                         val |= st7586_lookup[*src++ >> 6] << 2;
  83                         val |= st7586_lookup[*src++ >> 6] >> 1;
  84                         *dst++ = val;
  85                 }
  86         }
  87
  88         kfree(buf);
  89 }
  90
  91 static int st7586_buf_copy(void *dst, struct drm_framebuffer *fb,
  92                            struct drm_rect *clip)
  93 {
  94         struct drm_gem_cma_object *cma_obj = drm_fb_cma_get_gem_obj(fb, 0);
  95         void *src = cma_obj->vaddr;
  96         int ret = 0;
  97
  98         ret = drm_gem_fb_begin_cpu_access(fb, DMA_FROM_DEVICE);
  99         if (ret)
 100                 return ret;
 101
 102         st7586_xrgb8888_to_gray332(dst, src, fb, clip);
 103
 104         drm_gem_fb_end_cpu_access(fb, DMA_FROM_DEVICE);
 105
 106         return 0;
 107 }
 108
 109 static void st7586_fb_dirty(struct drm_framebuffer *fb, struct drm_rect *rect)
 110 {
 111         struct mipi_dbi_dev *dbidev = drm_to_mipi_dbi_dev(fb->dev);
 112         struct mipi_dbi *dbi = &dbidev->dbi;
 113         int start, end, idx, ret = 0;
 114
 115         if (!drm_dev_enter(fb->dev, &idx))
 116                 return;
 117
 118         /* 3 pixels per byte, so grow clip to nearest multiple of 3 */
 119         rect->x1 = rounddown(rect->x1, 3);
 120         rect->x2 = roundup(rect->x2, 3);
 121
 122         DRM_DEBUG_KMS("Flushing [FB:%d] " DRM_RECT_FMT "\n", fb->base.id, DRM_RECT_ARG(rect));
 123
 124         ret = st7586_buf_copy(dbidev->tx_buf, fb, rect);
 125         if (ret)
 126                 goto err_msg;
 127
 128         /* Pixels are packed 3 per byte */
 129         start = rect->x1 / 3;
 130         end = rect->x2 / 3;
 131
 132         mipi_dbi_command(dbi, MIPI_DCS_SET_COLUMN_ADDRESS,
 133                          (start >> 8) & 0xFF, start & 0xFF,
 134                          (end >> 8) & 0xFF, (end - 1) & 0xFF);
 135         mipi_dbi_command(dbi, MIPI_DCS_SET_PAGE_ADDRESS,
 136                          (rect->y1 >> 8) & 0xFF, rect->y1 & 0xFF,
 137                          (rect->y2 >> 8) & 0xFF, (rect->y2 - 1) & 0xFF);
 138
 139         ret = mipi_dbi_command_buf(dbi, MIPI_DCS_WRITE_MEMORY_START,
 140                                    (u8 *)dbidev->tx_buf,
 141                                    (end - start) * (rect->y2 - rect->y1));
 142 err_msg:
 143         if (ret)
 144                 dev_err_once(fb->dev->dev, "Failed to update display %d\n", ret);
 145
 146         drm_dev_exit(idx);
 147 }
 148
 149 static void st7586_pipe_update(struct drm_simple_display_pipe *pipe,
 150                                struct drm_plane_state *old_state)
 151 {
 152         struct drm_plane_state *state = pipe->plane.state;
 153         struct drm_rect rect;
 154
 155         if (!pipe->crtc.state->active)
 156                 return;
 157
 158         if (drm_atomic_helper_damage_merged(old_state, state, &rect))
 159                 st7586_fb_dirty(state->fb, &rect);
 160 }
 161
 162 static void st7586_pipe_enable(struct drm_simple_display_pipe *pipe,
 163                                struct drm_crtc_state *crtc_state,
 164                                struct drm_plane_state *plane_state)
 165 {
 166         struct mipi_dbi_dev *dbidev = drm_to_mipi_dbi_dev(pipe->crtc.dev);
 167         struct drm_framebuffer *fb = plane_state->fb;
 168         struct mipi_dbi *dbi = &dbidev->dbi;
 169         struct drm_rect rect = {
 170                 .x1 = 0,
 171                 .x2 = fb->width,
 172                 .y1 = 0,
 173                 .y2 = fb->height,
 174         };
 175         int idx, ret;
 176         u8 addr_mode;
 177
 178         if (!drm_dev_enter(pipe->crtc.dev, &idx))
 179                 return;
 180
 181         DRM_DEBUG_KMS("\n");
 182
 183         ret = mipi_dbi_poweron_reset(dbidev);
 184         if (ret)
 185                 goto out_exit;
 186
 187         mipi_dbi_command(dbi, ST7586_AUTO_READ_CTRL, 0x9f);
 188         mipi_dbi_command(dbi, ST7586_OTP_RW_CTRL, 0x00);
 189
 190         msleep(10);
 191
 192         mipi_dbi_command(dbi, ST7586_OTP_READ);
 193
 194         msleep(20);
 195
 196         mipi_dbi_command(dbi, ST7586_OTP_CTRL_OUT);
 197         mipi_dbi_command(dbi, MIPI_DCS_EXIT_SLEEP_MODE);
 198         mipi_dbi_command(dbi, MIPI_DCS_SET_DISPLAY_OFF);
 199
 200         msleep(50);
 201
 202         mipi_dbi_command(dbi, ST7586_SET_VOP_OFFSET, 0x00);
 203         mipi_dbi_command(dbi, ST7586_SET_VOP, 0xe3, 0x00);
 204         mipi_dbi_command(dbi, ST7586_SET_BIAS_SYSTEM, 0x02);
 205         mipi_dbi_command(dbi, ST7586_SET_BOOST_LEVEL, 0x04);
 206         mipi_dbi_command(dbi, ST7586_ENABLE_ANALOG, 0x1d);
 207         mipi_dbi_command(dbi, ST7586_SET_NLINE_INV, 0x00);
 208         mipi_dbi_command(dbi, ST7586_DISP_MODE_GRAY);
 209         mipi_dbi_command(dbi, ST7586_ENABLE_DDRAM, 0x02);
 210
 211         switch (dbidev->rotation) {
 212         default:
 213                 addr_mode = 0x00;
 214                 break;
 215         case 90:
 216                 addr_mode = ST7586_DISP_CTRL_MY;
 217                 break;
 218         case 180:
 219                 addr_mode = ST7586_DISP_CTRL_MX | ST7586_DISP_CTRL_MY;
 220                 break;
 221         case 270:
 222                 addr_mode = ST7586_DISP_CTRL_MX;
 223                 break;
 224         }
 225         mipi_dbi_command(dbi, MIPI_DCS_SET_ADDRESS_MODE, addr_mode);
 226
 227         mipi_dbi_command(dbi, ST7586_SET_DISP_DUTY, 0x7f);
 228         mipi_dbi_command(dbi, ST7586_SET_PART_DISP, 0xa0);
 229         mipi_dbi_command(dbi, MIPI_DCS_SET_PARTIAL_ROWS, 0x00, 0x00, 0x00, 0x77);
 230         mipi_dbi_command(dbi, MIPI_DCS_EXIT_INVERT_MODE);
 231
 232         msleep(100);
 233
 234         st7586_fb_dirty(fb, &rect);
 235
 236         mipi_dbi_command(dbi, MIPI_DCS_SET_DISPLAY_ON);
 237 out_exit:
 238         drm_dev_exit(idx);
 239 }
 240
 241 static void st7586_pipe_disable(struct drm_simple_display_pipe *pipe)
 242 {
 243         struct mipi_dbi_dev *dbidev = drm_to_mipi_dbi_dev(pipe->crtc.dev);
 244
 245         /*
 246          * This callback is not protected by drm_dev_enter/exit since we want to
 247          * turn off the display on regular driver unload. It's highly unlikely
 248          * that the underlying SPI controller is gone should this be called after
 249          * unplug.
 250          */
 251
 252         DRM_DEBUG_KMS("\n");
 253
 254         mipi_dbi_command(&dbidev->dbi, MIPI_DCS_SET_DISPLAY_OFF);
 255 }
 256
 257 static const u32 st7586_formats[] = {
 258         DRM_FORMAT_XRGB8888,
 259 };
 260
 261 static const struct drm_simple_display_pipe_funcs st7586_pipe_funcs = {
 262         .enable         = st7586_pipe_enable,
 263         .disable        = st7586_pipe_disable,
 264         .update         = st7586_pipe_update,
 265 };
 266
 267 static const struct drm_display_mode st7586_mode = {
 268         DRM_SIMPLE_MODE(178, 128, 37, 27),
 269 };
 270
 271 DEFINE_DRM_GEM_CMA_FOPS(st7586_fops);
 272
 273 static const struct drm_driver st7586_driver = {
 274         .driver_features        = DRIVER_GEM | DRIVER_MODESET | DRIVER_ATOMIC,
 275         .fops                   = &st7586_fops,
 276         DRM_GEM_CMA_DRIVER_OPS_VMAP,
 277         .debugfs_init           = mipi_dbi_debugfs_init,
 278         .name                   = "st7586",
 279         .desc                   = "Sitronix ST7586",
 280         .date                   = "20170801",
 281         .major                  = 1,
 282         .minor                  = 0,
 283 };
 284
 285 static const struct of_device_id st7586_of_match[] = {
 286         { .compatible = "lego,ev3-lcd" },
 287         {},
 288 };
 289 MODULE_DEVICE_TABLE(of, st7586_of_match);
 290
 291 static const struct spi_device_id st7586_id[] = {
 292         { "ev3-lcd", 0 },
 293         { },
 294 };
 295 MODULE_DEVICE_TABLE(spi, st7586_id);
 296
 297 static int st7586_probe(struct spi_device *spi)
 298 {
 299         struct device *dev = &spi->dev;
 300         struct mipi_dbi_dev *dbidev;
 301         struct drm_device *drm;
 302         struct mipi_dbi *dbi;
 303         struct gpio_desc *a0;
 304         u32 rotation = 0;
 305         size_t bufsize;
 306         int ret;
 307
 308         dbidev = devm_drm_dev_alloc(dev, &st7586_driver,
 309                                     struct mipi_dbi_dev, drm);
 310         if (IS_ERR(dbidev))
 311                 return PTR_ERR(dbidev);
 312
 313         dbi = &dbidev->dbi;
 314         drm = &dbidev->drm;
 315
 316         bufsize = (st7586_mode.vdisplay + 2) / 3 * st7586_mode.hdisplay;
 317
 318         dbi->reset = devm_gpiod_get(dev, "reset", GPIOD_OUT_HIGH);
 319         if (IS_ERR(dbi->reset))
 320                 return dev_err_probe(dev, PTR_ERR(dbi->reset), "Failed to get GPIO 'reset'\n");
 321
 322         a0 = devm_gpiod_get(dev, "a0", GPIOD_OUT_LOW);
 323         if (IS_ERR(a0))
 324                 return dev_err_probe(dev, PTR_ERR(a0), "Failed to get GPIO 'a0'\n");
 325
 326         device_property_read_u32(dev, "rotation", &rotation);
 327
 328         ret = mipi_dbi_spi_init(spi, dbi, a0);
 329         if (ret)
 330                 return ret;
 331
 332         /* Cannot read from this controller via SPI */
 333         dbi->read_commands = NULL;
 334
 335         ret = mipi_dbi_dev_init_with_formats(dbidev, &st7586_pipe_funcs,
 336                                              st7586_formats, ARRAY_SIZE(st7586_formats),
 337                                              &st7586_mode, rotation, bufsize);
 338         if (ret)
 339                 return ret;
 340
 341         /*
 342          * we are using 8-bit data, so we are not actually swapping anything,
 343          * but setting mipi->swap_bytes makes mipi_dbi_typec3_command() do the
 344          * right thing and not use 16-bit transfers (which results in swapped
 345          * bytes on little-endian systems and causes out of order data to be
 346          * sent to the display).
 347          */
 348         dbi->swap_bytes = true;
 349
 350         drm_mode_config_reset(drm);
 351
 352         ret = drm_dev_register(drm, 0);
 353         if (ret)
 354                 return ret;
 355
 356         spi_set_drvdata(spi, drm);
 357
 358         drm_fbdev_generic_setup(drm, 0);
 359
 360         return 0;
 361 }
 362
 363 static void st7586_remove(struct spi_device *spi)
 364 {
 365         struct drm_device *drm = spi_get_drvdata(spi);
 366
 367         drm_dev_unplug(drm);
 368         drm_atomic_helper_shutdown(drm);
 369 }
 370
 371 static void st7586_shutdown(struct spi_device *spi)
 372 {
 373         drm_atomic_helper_shutdown(spi_get_drvdata(spi));
 374 }
 375
 376 static struct spi_driver st7586_spi_driver = {
 377         .driver = {
 378                 .name = "st7586",
 379                 .owner = THIS_MODULE,
 380                 .of_match_table = st7586_of_match,
 381         },
 382         .id_table = st7586_id,
 383         .probe = st7586_probe,
 384         .remove = st7586_remove,
 385         .shutdown = st7586_shutdown,
 386 };
 387 module_spi_driver(st7586_spi_driver);
 388
 389 MODULE_DESCRIPTION("Sitronix ST7586 DRM driver");
 390 MODULE_AUTHOR("David Lechner <david@lechnology.com>");
 391 MODULE_LICENSE("GPL");