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/dma-buf.h>
  10 #include <linux/gpio/consumer.h>
  11 #include <linux/module.h>
  12 #include <linux/property.h>
  13 #include <linux/spi/spi.h>
  14 #include <video/mipi_display.h>
  15
  16 #include <drm/drm_atomic_helper.h>
  17 #include <drm/drm_damage_helper.h>
  18 #include <drm/drm_drv.h>
  19 #include <drm/drm_fb_cma_helper.h>
  20 #include <drm/drm_fb_helper.h>
  21 #include <drm/drm_format_helper.h>
  22 #include <drm/drm_gem_atomic_helper.h>
  23 #include <drm/drm_gem_cma_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, 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         struct dma_buf_attachment *import_attach = cma_obj->base.import_attach;
  96         void *src = cma_obj->vaddr;
  97         int ret = 0;
  98
  99         if (import_attach) {
 100                 ret = dma_buf_begin_cpu_access(import_attach->dmabuf,
 101                                                DMA_FROM_DEVICE);
 102                 if (ret)
 103                         return ret;
 104         }
 105
 106         st7586_xrgb8888_to_gray332(dst, src, fb, clip);
 107
 108         if (import_attach)
 109                 ret = dma_buf_end_cpu_access(import_attach->dmabuf,
 110                                              DMA_FROM_DEVICE);
 111
 112         return ret;
 113 }
 114
 115 static void st7586_fb_dirty(struct drm_framebuffer *fb, struct drm_rect *rect)
 116 {
 117         struct mipi_dbi_dev *dbidev = drm_to_mipi_dbi_dev(fb->dev);
 118         struct mipi_dbi *dbi = &dbidev->dbi;
 119         int start, end, idx, ret = 0;
 120
 121         if (!drm_dev_enter(fb->dev, &idx))
 122                 return;
 123
 124         /* 3 pixels per byte, so grow clip to nearest multiple of 3 */
 125         rect->x1 = rounddown(rect->x1, 3);
 126         rect->x2 = roundup(rect->x2, 3);
 127
 128         DRM_DEBUG_KMS("Flushing [FB:%d] " DRM_RECT_FMT "\n", fb->base.id, DRM_RECT_ARG(rect));
 129
 130         ret = st7586_buf_copy(dbidev->tx_buf, fb, rect);
 131         if (ret)
 132                 goto err_msg;
 133
 134         /* Pixels are packed 3 per byte */
 135         start = rect->x1 / 3;
 136         end = rect->x2 / 3;
 137
 138         mipi_dbi_command(dbi, MIPI_DCS_SET_COLUMN_ADDRESS,
 139                          (start >> 8) & 0xFF, start & 0xFF,
 140                          (end >> 8) & 0xFF, (end - 1) & 0xFF);
 141         mipi_dbi_command(dbi, MIPI_DCS_SET_PAGE_ADDRESS,
 142                          (rect->y1 >> 8) & 0xFF, rect->y1 & 0xFF,
 143                          (rect->y2 >> 8) & 0xFF, (rect->y2 - 1) & 0xFF);
 144
 145         ret = mipi_dbi_command_buf(dbi, MIPI_DCS_WRITE_MEMORY_START,
 146                                    (u8 *)dbidev->tx_buf,
 147                                    (end - start) * (rect->y2 - rect->y1));
 148 err_msg:
 149         if (ret)
 150                 dev_err_once(fb->dev->dev, "Failed to update display %d\n", ret);
 151
 152         drm_dev_exit(idx);
 153 }
 154
 155 static void st7586_pipe_update(struct drm_simple_display_pipe *pipe,
 156                                struct drm_plane_state *old_state)
 157 {
 158         struct drm_plane_state *state = pipe->plane.state;
 159         struct drm_rect rect;
 160
 161         if (!pipe->crtc.state->active)
 162                 return;
 163
 164         if (drm_atomic_helper_damage_merged(old_state, state, &rect))
 165                 st7586_fb_dirty(state->fb, &rect);
 166 }
 167
 168 static void st7586_pipe_enable(struct drm_simple_display_pipe *pipe,
 169                                struct drm_crtc_state *crtc_state,
 170                                struct drm_plane_state *plane_state)
 171 {
 172         struct mipi_dbi_dev *dbidev = drm_to_mipi_dbi_dev(pipe->crtc.dev);
 173         struct drm_framebuffer *fb = plane_state->fb;
 174         struct mipi_dbi *dbi = &dbidev->dbi;
 175         struct drm_rect rect = {
 176                 .x1 = 0,
 177                 .x2 = fb->width,
 178                 .y1 = 0,
 179                 .y2 = fb->height,
 180         };
 181         int idx, ret;
 182         u8 addr_mode;
 183
 184         if (!drm_dev_enter(pipe->crtc.dev, &idx))
 185                 return;
 186
 187         DRM_DEBUG_KMS("\n");
 188
 189         ret = mipi_dbi_poweron_reset(dbidev);
 190         if (ret)
 191                 goto out_exit;
 192
 193         mipi_dbi_command(dbi, ST7586_AUTO_READ_CTRL, 0x9f);
 194         mipi_dbi_command(dbi, ST7586_OTP_RW_CTRL, 0x00);
 195
 196         msleep(10);
 197
 198         mipi_dbi_command(dbi, ST7586_OTP_READ);
 199
 200         msleep(20);
 201
 202         mipi_dbi_command(dbi, ST7586_OTP_CTRL_OUT);
 203         mipi_dbi_command(dbi, MIPI_DCS_EXIT_SLEEP_MODE);
 204         mipi_dbi_command(dbi, MIPI_DCS_SET_DISPLAY_OFF);
 205
 206         msleep(50);
 207
 208         mipi_dbi_command(dbi, ST7586_SET_VOP_OFFSET, 0x00);
 209         mipi_dbi_command(dbi, ST7586_SET_VOP, 0xe3, 0x00);
 210         mipi_dbi_command(dbi, ST7586_SET_BIAS_SYSTEM, 0x02);
 211         mipi_dbi_command(dbi, ST7586_SET_BOOST_LEVEL, 0x04);
 212         mipi_dbi_command(dbi, ST7586_ENABLE_ANALOG, 0x1d);
 213         mipi_dbi_command(dbi, ST7586_SET_NLINE_INV, 0x00);
 214         mipi_dbi_command(dbi, ST7586_DISP_MODE_GRAY);
 215         mipi_dbi_command(dbi, ST7586_ENABLE_DDRAM, 0x02);
 216
 217         switch (dbidev->rotation) {
 218         default:
 219                 addr_mode = 0x00;
 220                 break;
 221         case 90:
 222                 addr_mode = ST7586_DISP_CTRL_MY;
 223                 break;
 224         case 180:
 225                 addr_mode = ST7586_DISP_CTRL_MX | ST7586_DISP_CTRL_MY;
 226                 break;
 227         case 270:
 228                 addr_mode = ST7586_DISP_CTRL_MX;
 229                 break;
 230         }
 231         mipi_dbi_command(dbi, MIPI_DCS_SET_ADDRESS_MODE, addr_mode);
 232
 233         mipi_dbi_command(dbi, ST7586_SET_DISP_DUTY, 0x7f);
 234         mipi_dbi_command(dbi, ST7586_SET_PART_DISP, 0xa0);
 235         mipi_dbi_command(dbi, MIPI_DCS_SET_PARTIAL_ROWS, 0x00, 0x00, 0x00, 0x77);
 236         mipi_dbi_command(dbi, MIPI_DCS_EXIT_INVERT_MODE);
 237
 238         msleep(100);
 239
 240         st7586_fb_dirty(fb, &rect);
 241
 242         mipi_dbi_command(dbi, MIPI_DCS_SET_DISPLAY_ON);
 243 out_exit:
 244         drm_dev_exit(idx);
 245 }
 246
 247 static void st7586_pipe_disable(struct drm_simple_display_pipe *pipe)
 248 {
 249         struct mipi_dbi_dev *dbidev = drm_to_mipi_dbi_dev(pipe->crtc.dev);
 250
 251         /*
 252          * This callback is not protected by drm_dev_enter/exit since we want to
 253          * turn off the display on regular driver unload. It's highly unlikely
 254          * that the underlying SPI controller is gone should this be called after
 255          * unplug.
 256          */
 257
 258         DRM_DEBUG_KMS("\n");
 259
 260         mipi_dbi_command(&dbidev->dbi, MIPI_DCS_SET_DISPLAY_OFF);
 261 }
 262
 263 static const u32 st7586_formats[] = {
 264         DRM_FORMAT_XRGB8888,
 265 };
 266
 267 static const struct drm_simple_display_pipe_funcs st7586_pipe_funcs = {
 268         .enable         = st7586_pipe_enable,
 269         .disable        = st7586_pipe_disable,
 270         .update         = st7586_pipe_update,
 271         .prepare_fb     = drm_gem_simple_display_pipe_prepare_fb,
 272 };
 273
 274 static const struct drm_display_mode st7586_mode = {
 275         DRM_SIMPLE_MODE(178, 128, 37, 27),
 276 };
 277
 278 DEFINE_DRM_GEM_CMA_FOPS(st7586_fops);
 279
 280 static const struct drm_driver st7586_driver = {
 281         .driver_features        = DRIVER_GEM | DRIVER_MODESET | DRIVER_ATOMIC,
 282         .fops                   = &st7586_fops,
 283         DRM_GEM_CMA_DRIVER_OPS_VMAP,
 284         .debugfs_init           = mipi_dbi_debugfs_init,
 285         .name                   = "st7586",
 286         .desc                   = "Sitronix ST7586",
 287         .date                   = "20170801",
 288         .major                  = 1,
 289         .minor                  = 0,
 290 };
 291
 292 static const struct of_device_id st7586_of_match[] = {
 293         { .compatible = "lego,ev3-lcd" },
 294         {},
 295 };
 296 MODULE_DEVICE_TABLE(of, st7586_of_match);
 297
 298 static const struct spi_device_id st7586_id[] = {
 299         { "ev3-lcd", 0 },
 300         { },
 301 };
 302 MODULE_DEVICE_TABLE(spi, st7586_id);
 303
 304 static int st7586_probe(struct spi_device *spi)
 305 {
 306         struct device *dev = &spi->dev;
 307         struct mipi_dbi_dev *dbidev;
 308         struct drm_device *drm;
 309         struct mipi_dbi *dbi;
 310         struct gpio_desc *a0;
 311         u32 rotation = 0;
 312         size_t bufsize;
 313         int ret;
 314
 315         dbidev = devm_drm_dev_alloc(dev, &st7586_driver,
 316                                     struct mipi_dbi_dev, drm);
 317         if (IS_ERR(dbidev))
 318                 return PTR_ERR(dbidev);
 319
 320         dbi = &dbidev->dbi;
 321         drm = &dbidev->drm;
 322
 323         bufsize = (st7586_mode.vdisplay + 2) / 3 * st7586_mode.hdisplay;
 324
 325         dbi->reset = devm_gpiod_get(dev, "reset", GPIOD_OUT_HIGH);
 326         if (IS_ERR(dbi->reset))
 327                 return dev_err_probe(dev, PTR_ERR(dbi->reset), "Failed to get GPIO 'reset'\n");
 328
 329         a0 = devm_gpiod_get(dev, "a0", GPIOD_OUT_LOW);
 330         if (IS_ERR(a0))
 331                 return dev_err_probe(dev, PTR_ERR(a0), "Failed to get GPIO 'a0'\n");
 332
 333         device_property_read_u32(dev, "rotation", &rotation);
 334
 335         ret = mipi_dbi_spi_init(spi, dbi, a0);
 336         if (ret)
 337                 return ret;
 338
 339         /* Cannot read from this controller via SPI */
 340         dbi->read_commands = NULL;
 341
 342         ret = mipi_dbi_dev_init_with_formats(dbidev, &st7586_pipe_funcs,
 343                                              st7586_formats, ARRAY_SIZE(st7586_formats),
 344                                              &st7586_mode, rotation, bufsize);
 345         if (ret)
 346                 return ret;
 347
 348         /*
 349          * we are using 8-bit data, so we are not actually swapping anything,
 350          * but setting mipi->swap_bytes makes mipi_dbi_typec3_command() do the
 351          * right thing and not use 16-bit transfers (which results in swapped
 352          * bytes on little-endian systems and causes out of order data to be
 353          * sent to the display).
 354          */
 355         dbi->swap_bytes = true;
 356
 357         drm_mode_config_reset(drm);
 358
 359         ret = drm_dev_register(drm, 0);
 360         if (ret)
 361                 return ret;
 362
 363         spi_set_drvdata(spi, drm);
 364
 365         drm_fbdev_generic_setup(drm, 0);
 366
 367         return 0;
 368 }
 369
 370 static int st7586_remove(struct spi_device *spi)
 371 {
 372         struct drm_device *drm = spi_get_drvdata(spi);
 373
 374         drm_dev_unplug(drm);
 375         drm_atomic_helper_shutdown(drm);
 376
 377         return 0;
 378 }
 379
 380 static void st7586_shutdown(struct spi_device *spi)
 381 {
 382         drm_atomic_helper_shutdown(spi_get_drvdata(spi));
 383 }
 384
 385 static struct spi_driver st7586_spi_driver = {
 386         .driver = {
 387                 .name = "st7586",
 388                 .owner = THIS_MODULE,
 389                 .of_match_table = st7586_of_match,
 390         },
 391         .id_table = st7586_id,
 392         .probe = st7586_probe,
 393         .remove = st7586_remove,
 394         .shutdown = st7586_shutdown,
 395 };
 396 module_spi_driver(st7586_spi_driver);
 397
 398 MODULE_DESCRIPTION("Sitronix ST7586 DRM driver");
 399 MODULE_AUTHOR("David Lechner <david@lechnology.com>");
 400 MODULE_LICENSE("GPL");