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 <[email protected]>
   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_cma_helper.h>
  23 #include <drm/drm_gem_framebuffer_helper.h>
  24 #include <drm/drm_mipi_dbi.h>
  25 #include <drm/drm_rect.h>
  26
  27 /* controller-specific commands */
  28 #define ST7586_DISP_MODE_GRAY   0x38
  29 #define ST7586_DISP_MODE_MONO   0x39
  30 #define ST7586_ENABLE_DDRAM     0x3a
  31 #define ST7586_SET_DISP_DUTY    0xb0
  32 #define ST7586_SET_PART_DISP    0xb4
  33 #define ST7586_SET_NLINE_INV    0xb5
  34 #define ST7586_SET_VOP          0xc0
  35 #define ST7586_SET_BIAS_SYSTEM  0xc3
  36 #define ST7586_SET_BOOST_LEVEL  0xc4
  37 #define ST7586_SET_VOP_OFFSET   0xc7
  38 #define ST7586_ENABLE_ANALOG    0xd0
  39 #define ST7586_AUTO_READ_CTRL   0xd7
  40 #define ST7586_OTP_RW_CTRL      0xe0
  41 #define ST7586_OTP_CTRL_OUT     0xe1
  42 #define ST7586_OTP_READ         0xe3
  43
  44 #define ST7586_DISP_CTRL_MX     BIT(6)
  45 #define ST7586_DISP_CTRL_MY     BIT(7)
  46
  47 /*
  48  * The ST7586 controller has an unusual pixel format where 2bpp grayscale is
  49  * packed 3 pixels per byte with the first two pixels using 3 bits and the 3rd
  50  * pixel using only 2 bits.
  51  *
  52  * |  D7  |  D6  |  D5  ||      |      || 2bpp |
  53  * | (D4) | (D3) | (D2) ||  D1  |  D0  || GRAY |
  54  * +------+------+------++------+------++------+
  55  * |  1   |  1   |  1   ||  1   |  1   || 0  0 | black
  56  * |  1   |  0   |  0   ||  1   |  0   || 0  1 | dark gray
  57  * |  0   |  1   |  0   ||  0   |  1   || 1  0 | light gray
  58  * |  0   |  0   |  0   ||  0   |  0   || 1  1 | white
  59  */
  60
  61 static const u8 st7586_lookup[] = { 0x7, 0x4, 0x2, 0x0 };
  62
  63 static void st7586_xrgb8888_to_gray332(u8 *dst, void *vaddr,
  64                                        struct drm_framebuffer *fb,
  65                                        struct drm_rect *clip)
  66 {
  67         size_t len = (clip->x2 - clip->x1) * (clip->y2 - clip->y1);
  68         unsigned int x, y;
  69         u8 *src, *buf, val;
  70
  71         buf = kmalloc(len, GFP_KERNEL);
  72         if (!buf)
  73                 return;
  74
  75         drm_fb_xrgb8888_to_gray8(buf, vaddr, fb, clip);
  76         src = buf;
  77
  78         for (y = clip->y1; y < clip->y2; y++) {
  79                 for (x = clip->x1; x < clip->x2; x += 3) {
  80                         val = st7586_lookup[*src++ >> 6] << 5;
  81                         val |= st7586_lookup[*src++ >> 6] << 2;
  82                         val |= st7586_lookup[*src++ >> 6] >> 1;
  83                         *dst++ = val;
  84                 }
  85         }
  86
  87         kfree(buf);
  88 }
  89
  90 static int st7586_buf_copy(void *dst, struct drm_framebuffer *fb,
  91                            struct drm_rect *clip)
  92 {
  93         struct drm_gem_cma_object *cma_obj = drm_fb_cma_get_gem_obj(fb, 0);
  94         struct dma_buf_attachment *import_attach = cma_obj->base.import_attach;
  95         void *src = cma_obj->vaddr;
  96         int ret = 0;
  97
  98         if (import_attach) {
  99                 ret = dma_buf_begin_cpu_access(import_attach->dmabuf,
 100                                                DMA_FROM_DEVICE);
 101                 if (ret)
 102                         return ret;
 103         }
 104
 105         st7586_xrgb8888_to_gray332(dst, src, fb, clip);
 106
 107         if (import_attach)
 108                 ret = dma_buf_end_cpu_access(import_attach->dmabuf,
 109                                              DMA_FROM_DEVICE);
 110
 111         return ret;
 112 }
 113
 114 static void st7586_fb_dirty(struct drm_framebuffer *fb, struct drm_rect *rect)
 115 {
 116         struct mipi_dbi_dev *dbidev = drm_to_mipi_dbi_dev(fb->dev);
 117         struct mipi_dbi *dbi = &dbidev->dbi;
 118         int start, end, idx, ret = 0;
 119
 120         if (!dbidev->enabled)
 121                 return;
 122
 123         if (!drm_dev_enter(fb->dev, &idx))
 124                 return;
 125
 126         /* 3 pixels per byte, so grow clip to nearest multiple of 3 */
 127         rect->x1 = rounddown(rect->x1, 3);
 128         rect->x2 = roundup(rect->x2, 3);
 129
 130         DRM_DEBUG_KMS("Flushing [FB:%d] " DRM_RECT_FMT "\n", fb->base.id, DRM_RECT_ARG(rect));
 131
 132         ret = st7586_buf_copy(dbidev->tx_buf, fb, rect);
 133         if (ret)
 134                 goto err_msg;
 135
 136         /* Pixels are packed 3 per byte */
 137         start = rect->x1 / 3;
 138         end = rect->x2 / 3;
 139
 140         mipi_dbi_command(dbi, MIPI_DCS_SET_COLUMN_ADDRESS,
 141                          (start >> 8) & 0xFF, start & 0xFF,
 142                          (end >> 8) & 0xFF, (end - 1) & 0xFF);
 143         mipi_dbi_command(dbi, MIPI_DCS_SET_PAGE_ADDRESS,
 144                          (rect->y1 >> 8) & 0xFF, rect->y1 & 0xFF,
 145                          (rect->y2 >> 8) & 0xFF, (rect->y2 - 1) & 0xFF);
 146
 147         ret = mipi_dbi_command_buf(dbi, MIPI_DCS_WRITE_MEMORY_START,
 148                                    (u8 *)dbidev->tx_buf,
 149                                    (end - start) * (rect->y2 - rect->y1));
 150 err_msg:
 151         if (ret)
 152                 dev_err_once(fb->dev->dev, "Failed to update display %d\n", ret);
 153
 154         drm_dev_exit(idx);
 155 }
 156
 157 static void st7586_pipe_update(struct drm_simple_display_pipe *pipe,
 158                                struct drm_plane_state *old_state)
 159 {
 160         struct drm_plane_state *state = pipe->plane.state;
 161         struct drm_rect rect;
 162
 163         if (drm_atomic_helper_damage_merged(old_state, state, &rect))
 164                 st7586_fb_dirty(state->fb, &rect);
 165 }
 166
 167 static void st7586_pipe_enable(struct drm_simple_display_pipe *pipe,
 168                                struct drm_crtc_state *crtc_state,
 169                                struct drm_plane_state *plane_state)
 170 {
 171         struct mipi_dbi_dev *dbidev = drm_to_mipi_dbi_dev(pipe->crtc.dev);
 172         struct drm_framebuffer *fb = plane_state->fb;
 173         struct mipi_dbi *dbi = &dbidev->dbi;
 174         struct drm_rect rect = {
 175                 .x1 = 0,
 176                 .x2 = fb->width,
 177                 .y1 = 0,
 178                 .y2 = fb->height,
 179         };
 180         int idx, ret;
 181         u8 addr_mode;
 182
 183         if (!drm_dev_enter(pipe->crtc.dev, &idx))
 184                 return;
 185
 186         DRM_DEBUG_KMS("\n");
 187
 188         ret = mipi_dbi_poweron_reset(dbidev);
 189         if (ret)
 190                 goto out_exit;
 191
 192         mipi_dbi_command(dbi, ST7586_AUTO_READ_CTRL, 0x9f);
 193         mipi_dbi_command(dbi, ST7586_OTP_RW_CTRL, 0x00);
 194
 195         msleep(10);
 196
 197         mipi_dbi_command(dbi, ST7586_OTP_READ);
 198
 199         msleep(20);
 200
 201         mipi_dbi_command(dbi, ST7586_OTP_CTRL_OUT);
 202         mipi_dbi_command(dbi, MIPI_DCS_EXIT_SLEEP_MODE);
 203         mipi_dbi_command(dbi, MIPI_DCS_SET_DISPLAY_OFF);
 204
 205         msleep(50);
 206
 207         mipi_dbi_command(dbi, ST7586_SET_VOP_OFFSET, 0x00);
 208         mipi_dbi_command(dbi, ST7586_SET_VOP, 0xe3, 0x00);
 209         mipi_dbi_command(dbi, ST7586_SET_BIAS_SYSTEM, 0x02);
 210         mipi_dbi_command(dbi, ST7586_SET_BOOST_LEVEL, 0x04);
 211         mipi_dbi_command(dbi, ST7586_ENABLE_ANALOG, 0x1d);
 212         mipi_dbi_command(dbi, ST7586_SET_NLINE_INV, 0x00);
 213         mipi_dbi_command(dbi, ST7586_DISP_MODE_GRAY);
 214         mipi_dbi_command(dbi, ST7586_ENABLE_DDRAM, 0x02);
 215
 216         switch (dbidev->rotation) {
 217         default:
 218                 addr_mode = 0x00;
 219                 break;
 220         case 90:
 221                 addr_mode = ST7586_DISP_CTRL_MY;
 222                 break;
 223         case 180:
 224                 addr_mode = ST7586_DISP_CTRL_MX | ST7586_DISP_CTRL_MY;
 225                 break;
 226         case 270:
 227                 addr_mode = ST7586_DISP_CTRL_MX;
 228                 break;
 229         }
 230         mipi_dbi_command(dbi, MIPI_DCS_SET_ADDRESS_MODE, addr_mode);
 231
 232         mipi_dbi_command(dbi, ST7586_SET_DISP_DUTY, 0x7f);
 233         mipi_dbi_command(dbi, ST7586_SET_PART_DISP, 0xa0);
 234         mipi_dbi_command(dbi, MIPI_DCS_SET_PARTIAL_ROWS, 0x00, 0x00, 0x00, 0x77);
 235         mipi_dbi_command(dbi, MIPI_DCS_EXIT_INVERT_MODE);
 236
 237         msleep(100);
 238
 239         dbidev->enabled = true;
 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         if (!dbidev->enabled)
 261                 return;
 262
 263         mipi_dbi_command(&dbidev->dbi, MIPI_DCS_SET_DISPLAY_OFF);
 264         dbidev->enabled = false;
 265 }
 266
 267 static const u32 st7586_formats[] = {
 268         DRM_FORMAT_XRGB8888,
 269 };
 270
 271 static const struct drm_simple_display_pipe_funcs st7586_pipe_funcs = {
 272         .enable         = st7586_pipe_enable,
 273         .disable        = st7586_pipe_disable,
 274         .update         = st7586_pipe_update,
 275         .prepare_fb     = drm_gem_fb_simple_display_pipe_prepare_fb,
 276 };
 277
 278 static const struct drm_display_mode st7586_mode = {
 279         DRM_SIMPLE_MODE(178, 128, 37, 27),
 280 };
 281
 282 DEFINE_DRM_GEM_CMA_FOPS(st7586_fops);
 283
 284 static struct drm_driver st7586_driver = {
 285         .driver_features        = DRIVER_GEM | DRIVER_MODESET | DRIVER_ATOMIC,
 286         .fops                   = &st7586_fops,
 287         .release                = mipi_dbi_release,
 288         DRM_GEM_CMA_VMAP_DRIVER_OPS,
 289         .debugfs_init           = mipi_dbi_debugfs_init,
 290         .name                   = "st7586",
 291         .desc                   = "Sitronix ST7586",
 292         .date                   = "20170801",
 293         .major                  = 1,
 294         .minor                  = 0,
 295 };
 296
 297 static const struct of_device_id st7586_of_match[] = {
 298         { .compatible = "lego,ev3-lcd" },
 299         {},
 300 };
 301 MODULE_DEVICE_TABLE(of, st7586_of_match);
 302
 303 static const struct spi_device_id st7586_id[] = {
 304         { "ev3-lcd", 0 },
 305         { },
 306 };
 307 MODULE_DEVICE_TABLE(spi, st7586_id);
 308
 309 static int st7586_probe(struct spi_device *spi)
 310 {
 311         struct device *dev = &spi->dev;
 312         struct mipi_dbi_dev *dbidev;
 313         struct drm_device *drm;
 314         struct mipi_dbi *dbi;
 315         struct gpio_desc *a0;
 316         u32 rotation = 0;
 317         size_t bufsize;
 318         int ret;
 319
 320         dbidev = kzalloc(sizeof(*dbidev), GFP_KERNEL);
 321         if (!dbidev)
 322                 return -ENOMEM;
 323
 324         dbi = &dbidev->dbi;
 325         drm = &dbidev->drm;
 326         ret = devm_drm_dev_init(dev, drm, &st7586_driver);
 327         if (ret) {
 328                 kfree(dbidev);
 329                 return ret;
 330         }
 331
 332         drm_mode_config_init(drm);
 333
 334         bufsize = (st7586_mode.vdisplay + 2) / 3 * st7586_mode.hdisplay;
 335
 336         dbi->reset = devm_gpiod_get(dev, "reset", GPIOD_OUT_HIGH);
 337         if (IS_ERR(dbi->reset)) {
 338                 DRM_DEV_ERROR(dev, "Failed to get gpio 'reset'\n");
 339                 return PTR_ERR(dbi->reset);
 340         }
 341
 342         a0 = devm_gpiod_get(dev, "a0", GPIOD_OUT_LOW);
 343         if (IS_ERR(a0)) {
 344                 DRM_DEV_ERROR(dev, "Failed to get gpio 'a0'\n");
 345                 return PTR_ERR(a0);
 346         }
 347
 348         device_property_read_u32(dev, "rotation", &rotation);
 349
 350         ret = mipi_dbi_spi_init(spi, dbi, a0);
 351         if (ret)
 352                 return ret;
 353
 354         /* Cannot read from this controller via SPI */
 355         dbi->read_commands = NULL;
 356
 357         ret = mipi_dbi_dev_init_with_formats(dbidev, &st7586_pipe_funcs,
 358                                              st7586_formats, ARRAY_SIZE(st7586_formats),
 359                                              &st7586_mode, rotation, bufsize);
 360         if (ret)
 361                 return ret;
 362
 363         /*
 364          * we are using 8-bit data, so we are not actually swapping anything,
 365          * but setting mipi->swap_bytes makes mipi_dbi_typec3_command() do the
 366          * right thing and not use 16-bit transfers (which results in swapped
 367          * bytes on little-endian systems and causes out of order data to be
 368          * sent to the display).
 369          */
 370         dbi->swap_bytes = true;
 371
 372         drm_mode_config_reset(drm);
 373
 374         ret = drm_dev_register(drm, 0);
 375         if (ret)
 376                 return ret;
 377
 378         spi_set_drvdata(spi, drm);
 379
 380         drm_fbdev_generic_setup(drm, 0);
 381
 382         return 0;
 383 }
 384
 385 static int st7586_remove(struct spi_device *spi)
 386 {
 387         struct drm_device *drm = spi_get_drvdata(spi);
 388
 389         drm_dev_unplug(drm);
 390         drm_atomic_helper_shutdown(drm);
 391
 392         return 0;
 393 }
 394
 395 static void st7586_shutdown(struct spi_device *spi)
 396 {
 397         drm_atomic_helper_shutdown(spi_get_drvdata(spi));
 398 }
 399
 400 static struct spi_driver st7586_spi_driver = {
 401         .driver = {
 402                 .name = "st7586",
 403                 .owner = THIS_MODULE,
 404                 .of_match_table = st7586_of_match,
 405         },
 406         .id_table = st7586_id,
 407         .probe = st7586_probe,
 408         .remove = st7586_remove,
 409         .shutdown = st7586_shutdown,
 410 };
 411 module_spi_driver(st7586_spi_driver);
 412
 413 MODULE_DESCRIPTION("Sitronix ST7586 DRM driver");
 414 MODULE_AUTHOR("David Lechner <[email protected]>");
 415 MODULE_LICENSE("GPL");