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