drivers/gpu/drm/sun4i/sun4i_tcon.c

   1 /*
   2  * Copyright (C) 2015 Free Electrons
   3  * Copyright (C) 2015 NextThing Co
   4  *
   5  * Maxime Ripard <[email protected]>
   6  *
   7  * This program is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU General Public License as
   9  * published by the Free Software Foundation; either version 2 of
  10  * the License, or (at your option) any later version.
  11  */
  12
  13 #include <drm/drmP.h>
  14 #include <drm/drm_atomic_helper.h>
  15 #include <drm/drm_crtc.h>
  16 #include <drm/drm_crtc_helper.h>
  17 #include <drm/drm_modes.h>
  18 #include <drm/drm_panel.h>
  19
  20 #include <linux/component.h>
  21 #include <linux/ioport.h>
  22 #include <linux/of_address.h>
  23 #include <linux/of_graph.h>
  24 #include <linux/of_irq.h>
  25 #include <linux/regmap.h>
  26 #include <linux/reset.h>
  27
  28 #include "sun4i_crtc.h"
  29 #include "sun4i_dotclock.h"
  30 #include "sun4i_drv.h"
  31 #include "sun4i_rgb.h"
  32 #include "sun4i_tcon.h"
  33
  34 void sun4i_tcon_disable(struct sun4i_tcon *tcon)
  35 {
  36         DRM_DEBUG_DRIVER("Disabling TCON\n");
  37
  38         /* Disable the TCON */
  39         regmap_update_bits(tcon->regs, SUN4I_TCON_GCTL_REG,
  40                            SUN4I_TCON_GCTL_TCON_ENABLE, 0);
  41 }
  42 EXPORT_SYMBOL(sun4i_tcon_disable);
  43
  44 void sun4i_tcon_enable(struct sun4i_tcon *tcon)
  45 {
  46         DRM_DEBUG_DRIVER("Enabling TCON\n");
  47
  48         /* Enable the TCON */
  49         regmap_update_bits(tcon->regs, SUN4I_TCON_GCTL_REG,
  50                            SUN4I_TCON_GCTL_TCON_ENABLE,
  51                            SUN4I_TCON_GCTL_TCON_ENABLE);
  52 }
  53 EXPORT_SYMBOL(sun4i_tcon_enable);
  54
  55 void sun4i_tcon_channel_disable(struct sun4i_tcon *tcon, int channel)
  56 {
  57         /* Disable the TCON's channel */
  58         if (channel == 0) {
  59                 regmap_update_bits(tcon->regs, SUN4I_TCON0_CTL_REG,
  60                                    SUN4I_TCON0_CTL_TCON_ENABLE, 0);
  61                 clk_disable_unprepare(tcon->dclk);
  62                 return;
  63         }
  64
  65         WARN_ON(!tcon->has_channel_1);
  66         regmap_update_bits(tcon->regs, SUN4I_TCON1_CTL_REG,
  67                            SUN4I_TCON1_CTL_TCON_ENABLE, 0);
  68         clk_disable_unprepare(tcon->sclk1);
  69 }
  70 EXPORT_SYMBOL(sun4i_tcon_channel_disable);
  71
  72 void sun4i_tcon_channel_enable(struct sun4i_tcon *tcon, int channel)
  73 {
  74         /* Enable the TCON's channel */
  75         if (channel == 0) {
  76                 regmap_update_bits(tcon->regs, SUN4I_TCON0_CTL_REG,
  77                                    SUN4I_TCON0_CTL_TCON_ENABLE,
  78                                    SUN4I_TCON0_CTL_TCON_ENABLE);
  79                 clk_prepare_enable(tcon->dclk);
  80                 return;
  81         }
  82
  83         WARN_ON(!tcon->has_channel_1);
  84         regmap_update_bits(tcon->regs, SUN4I_TCON1_CTL_REG,
  85                            SUN4I_TCON1_CTL_TCON_ENABLE,
  86                            SUN4I_TCON1_CTL_TCON_ENABLE);
  87         clk_prepare_enable(tcon->sclk1);
  88 }
  89 EXPORT_SYMBOL(sun4i_tcon_channel_enable);
  90
  91 void sun4i_tcon_enable_vblank(struct sun4i_tcon *tcon, bool enable)
  92 {
  93         u32 mask, val = 0;
  94
  95         DRM_DEBUG_DRIVER("%sabling VBLANK interrupt\n", enable ? "En" : "Dis");
  96
  97         mask = SUN4I_TCON_GINT0_VBLANK_ENABLE(0) |
  98                SUN4I_TCON_GINT0_VBLANK_ENABLE(1);
  99
 100         if (enable)
 101                 val = mask;
 102
 103         regmap_update_bits(tcon->regs, SUN4I_TCON_GINT0_REG, mask, val);
 104 }
 105 EXPORT_SYMBOL(sun4i_tcon_enable_vblank);
 106
 107 static int sun4i_tcon_get_clk_delay(struct drm_display_mode *mode,
 108                                     int channel)
 109 {
 110         int delay = mode->vtotal - mode->vdisplay;
 111
 112         if (mode->flags & DRM_MODE_FLAG_INTERLACE)
 113                 delay /= 2;
 114
 115         if (channel == 1)
 116                 delay -= 2;
 117
 118         delay = min(delay, 30);
 119
 120         DRM_DEBUG_DRIVER("TCON %d clock delay %u\n", channel, delay);
 121
 122         return delay;
 123 }
 124
 125 void sun4i_tcon0_mode_set(struct sun4i_tcon *tcon,
 126                           struct drm_display_mode *mode)
 127 {
 128         unsigned int bp, hsync, vsync;
 129         u8 clk_delay;
 130         u32 val = 0;
 131
 132         /* Adjust clock delay */
 133         clk_delay = sun4i_tcon_get_clk_delay(mode, 0);
 134         regmap_update_bits(tcon->regs, SUN4I_TCON0_CTL_REG,
 135                            SUN4I_TCON0_CTL_CLK_DELAY_MASK,
 136                            SUN4I_TCON0_CTL_CLK_DELAY(clk_delay));
 137
 138         /* Set the resolution */
 139         regmap_write(tcon->regs, SUN4I_TCON0_BASIC0_REG,
 140                      SUN4I_TCON0_BASIC0_X(mode->crtc_hdisplay) |
 141                      SUN4I_TCON0_BASIC0_Y(mode->crtc_vdisplay));
 142
 143         /*
 144          * This is called a backporch in the register documentation,
 145          * but it really is the front porch + hsync
 146          */
 147         bp = mode->crtc_htotal - mode->crtc_hsync_start;
 148         DRM_DEBUG_DRIVER("Setting horizontal total %d, backporch %d\n",
 149                          mode->crtc_htotal, bp);
 150
 151         /* Set horizontal display timings */
 152         regmap_write(tcon->regs, SUN4I_TCON0_BASIC1_REG,
 153                      SUN4I_TCON0_BASIC1_H_TOTAL(mode->crtc_htotal) |
 154                      SUN4I_TCON0_BASIC1_H_BACKPORCH(bp));
 155
 156         /*
 157          * This is called a backporch in the register documentation,
 158          * but it really is the front porch + hsync
 159          */
 160         bp = mode->crtc_vtotal - mode->crtc_vsync_start;
 161         DRM_DEBUG_DRIVER("Setting vertical total %d, backporch %d\n",
 162                          mode->crtc_vtotal, bp);
 163
 164         /* Set vertical display timings */
 165         regmap_write(tcon->regs, SUN4I_TCON0_BASIC2_REG,
 166                      SUN4I_TCON0_BASIC2_V_TOTAL(mode->crtc_vtotal) |
 167                      SUN4I_TCON0_BASIC2_V_BACKPORCH(bp));
 168
 169         /* Set Hsync and Vsync length */
 170         hsync = mode->crtc_hsync_end - mode->crtc_hsync_start;
 171         vsync = mode->crtc_vsync_end - mode->crtc_vsync_start;
 172         DRM_DEBUG_DRIVER("Setting HSYNC %d, VSYNC %d\n", hsync, vsync);
 173         regmap_write(tcon->regs, SUN4I_TCON0_BASIC3_REG,
 174                      SUN4I_TCON0_BASIC3_V_SYNC(vsync) |
 175                      SUN4I_TCON0_BASIC3_H_SYNC(hsync));
 176
 177         /* Setup the polarity of the various signals */
 178         if (!(mode->flags & DRM_MODE_FLAG_PHSYNC))
 179                 val |= SUN4I_TCON0_IO_POL_HSYNC_POSITIVE;
 180
 181         if (!(mode->flags & DRM_MODE_FLAG_PVSYNC))
 182                 val |= SUN4I_TCON0_IO_POL_VSYNC_POSITIVE;
 183
 184         regmap_update_bits(tcon->regs, SUN4I_TCON0_IO_POL_REG,
 185                            SUN4I_TCON0_IO_POL_HSYNC_POSITIVE | SUN4I_TCON0_IO_POL_VSYNC_POSITIVE,
 186                            val);
 187
 188         /* Map output pins to channel 0 */
 189         regmap_update_bits(tcon->regs, SUN4I_TCON_GCTL_REG,
 190                            SUN4I_TCON_GCTL_IOMAP_MASK,
 191                            SUN4I_TCON_GCTL_IOMAP_TCON0);
 192
 193         /* Enable the output on the pins */
 194         regmap_write(tcon->regs, SUN4I_TCON0_IO_TRI_REG, 0);
 195 }
 196 EXPORT_SYMBOL(sun4i_tcon0_mode_set);
 197
 198 void sun4i_tcon1_mode_set(struct sun4i_tcon *tcon,
 199                           struct drm_display_mode *mode)
 200 {
 201         unsigned int bp, hsync, vsync;
 202         u8 clk_delay;
 203         u32 val;
 204
 205         WARN_ON(!tcon->has_channel_1);
 206
 207         /* Adjust clock delay */
 208         clk_delay = sun4i_tcon_get_clk_delay(mode, 1);
 209         regmap_update_bits(tcon->regs, SUN4I_TCON1_CTL_REG,
 210                            SUN4I_TCON1_CTL_CLK_DELAY_MASK,
 211                            SUN4I_TCON1_CTL_CLK_DELAY(clk_delay));
 212
 213         /* Set interlaced mode */
 214         if (mode->flags & DRM_MODE_FLAG_INTERLACE)
 215                 val = SUN4I_TCON1_CTL_INTERLACE_ENABLE;
 216         else
 217                 val = 0;
 218         regmap_update_bits(tcon->regs, SUN4I_TCON1_CTL_REG,
 219                            SUN4I_TCON1_CTL_INTERLACE_ENABLE,
 220                            val);
 221
 222         /* Set the input resolution */
 223         regmap_write(tcon->regs, SUN4I_TCON1_BASIC0_REG,
 224                      SUN4I_TCON1_BASIC0_X(mode->crtc_hdisplay) |
 225                      SUN4I_TCON1_BASIC0_Y(mode->crtc_vdisplay));
 226
 227         /* Set the upscaling resolution */
 228         regmap_write(tcon->regs, SUN4I_TCON1_BASIC1_REG,
 229                      SUN4I_TCON1_BASIC1_X(mode->crtc_hdisplay) |
 230                      SUN4I_TCON1_BASIC1_Y(mode->crtc_vdisplay));
 231
 232         /* Set the output resolution */
 233         regmap_write(tcon->regs, SUN4I_TCON1_BASIC2_REG,
 234                      SUN4I_TCON1_BASIC2_X(mode->crtc_hdisplay) |
 235                      SUN4I_TCON1_BASIC2_Y(mode->crtc_vdisplay));
 236
 237         /* Set horizontal display timings */
 238         bp = mode->crtc_htotal - mode->crtc_hsync_end;
 239         DRM_DEBUG_DRIVER("Setting horizontal total %d, backporch %d\n",
 240                          mode->htotal, bp);
 241         regmap_write(tcon->regs, SUN4I_TCON1_BASIC3_REG,
 242                      SUN4I_TCON1_BASIC3_H_TOTAL(mode->crtc_htotal) |
 243                      SUN4I_TCON1_BASIC3_H_BACKPORCH(bp));
 244
 245         /* Set vertical display timings */
 246         bp = mode->crtc_vtotal - mode->crtc_vsync_end;
 247         DRM_DEBUG_DRIVER("Setting vertical total %d, backporch %d\n",
 248                          mode->vtotal, bp);
 249         regmap_write(tcon->regs, SUN4I_TCON1_BASIC4_REG,
 250                      SUN4I_TCON1_BASIC4_V_TOTAL(mode->vtotal) |
 251                      SUN4I_TCON1_BASIC4_V_BACKPORCH(bp));
 252
 253         /* Set Hsync and Vsync length */
 254         hsync = mode->crtc_hsync_end - mode->crtc_hsync_start;
 255         vsync = mode->crtc_vsync_end - mode->crtc_vsync_start;
 256         DRM_DEBUG_DRIVER("Setting HSYNC %d, VSYNC %d\n", hsync, vsync);
 257         regmap_write(tcon->regs, SUN4I_TCON1_BASIC5_REG,
 258                      SUN4I_TCON1_BASIC5_V_SYNC(vsync) |
 259                      SUN4I_TCON1_BASIC5_H_SYNC(hsync));
 260
 261         /* Map output pins to channel 1 */
 262         regmap_update_bits(tcon->regs, SUN4I_TCON_GCTL_REG,
 263                            SUN4I_TCON_GCTL_IOMAP_MASK,
 264                            SUN4I_TCON_GCTL_IOMAP_TCON1);
 265
 266         /*
 267          * FIXME: Undocumented bits
 268          */
 269         if (tcon->has_mux)
 270                 regmap_write(tcon->regs, SUN4I_TCON_MUX_CTRL_REG, 1);
 271 }
 272 EXPORT_SYMBOL(sun4i_tcon1_mode_set);
 273
 274 static void sun4i_tcon_finish_page_flip(struct drm_device *dev,
 275                                         struct sun4i_crtc *scrtc)
 276 {
 277         unsigned long flags;
 278
 279         spin_lock_irqsave(&dev->event_lock, flags);
 280         if (scrtc->event) {
 281                 drm_crtc_send_vblank_event(&scrtc->crtc, scrtc->event);
 282                 drm_crtc_vblank_put(&scrtc->crtc);
 283                 scrtc->event = NULL;
 284         }
 285         spin_unlock_irqrestore(&dev->event_lock, flags);
 286 }
 287
 288 static irqreturn_t sun4i_tcon_handler(int irq, void *private)
 289 {
 290         struct sun4i_tcon *tcon = private;
 291         struct drm_device *drm = tcon->drm;
 292         struct sun4i_drv *drv = drm->dev_private;
 293         struct sun4i_crtc *scrtc = drv->crtc;
 294         unsigned int status;
 295
 296         regmap_read(tcon->regs, SUN4I_TCON_GINT0_REG, &status);
 297
 298         if (!(status & (SUN4I_TCON_GINT0_VBLANK_INT(0) |
 299                         SUN4I_TCON_GINT0_VBLANK_INT(1))))
 300                 return IRQ_NONE;
 301
 302         drm_crtc_handle_vblank(&scrtc->crtc);
 303         sun4i_tcon_finish_page_flip(drm, scrtc);
 304
 305         /* Acknowledge the interrupt */
 306         regmap_update_bits(tcon->regs, SUN4I_TCON_GINT0_REG,
 307                            SUN4I_TCON_GINT0_VBLANK_INT(0) |
 308                            SUN4I_TCON_GINT0_VBLANK_INT(1),
 309                            0);
 310
 311         return IRQ_HANDLED;
 312 }
 313
 314 static int sun4i_tcon_init_clocks(struct device *dev,
 315                                   struct sun4i_tcon *tcon)
 316 {
 317         tcon->clk = devm_clk_get(dev, "ahb");
 318         if (IS_ERR(tcon->clk)) {
 319                 dev_err(dev, "Couldn't get the TCON bus clock\n");
 320                 return PTR_ERR(tcon->clk);
 321         }
 322         clk_prepare_enable(tcon->clk);
 323
 324         tcon->sclk0 = devm_clk_get(dev, "tcon-ch0");
 325         if (IS_ERR(tcon->sclk0)) {
 326                 dev_err(dev, "Couldn't get the TCON channel 0 clock\n");
 327                 return PTR_ERR(tcon->sclk0);
 328         }
 329
 330         if (tcon->has_channel_1) {
 331                 tcon->sclk1 = devm_clk_get(dev, "tcon-ch1");
 332                 if (IS_ERR(tcon->sclk1)) {
 333                         dev_err(dev, "Couldn't get the TCON channel 1 clock\n");
 334                         return PTR_ERR(tcon->sclk1);
 335                 }
 336         }
 337
 338         return sun4i_dclk_create(dev, tcon);
 339 }
 340
 341 static void sun4i_tcon_free_clocks(struct sun4i_tcon *tcon)
 342 {
 343         sun4i_dclk_free(tcon);
 344         clk_disable_unprepare(tcon->clk);
 345 }
 346
 347 static int sun4i_tcon_init_irq(struct device *dev,
 348                                struct sun4i_tcon *tcon)
 349 {
 350         struct platform_device *pdev = to_platform_device(dev);
 351         int irq, ret;
 352
 353         irq = platform_get_irq(pdev, 0);
 354         if (irq < 0) {
 355                 dev_err(dev, "Couldn't retrieve the TCON interrupt\n");
 356                 return irq;
 357         }
 358
 359         ret = devm_request_irq(dev, irq, sun4i_tcon_handler, 0,
 360                                dev_name(dev), tcon);
 361         if (ret) {
 362                 dev_err(dev, "Couldn't request the IRQ\n");
 363                 return ret;
 364         }
 365
 366         return 0;
 367 }
 368
 369 static struct regmap_config sun4i_tcon_regmap_config = {
 370         .reg_bits       = 32,
 371         .val_bits       = 32,
 372         .reg_stride     = 4,
 373         .max_register   = 0x800,
 374 };
 375
 376 static int sun4i_tcon_init_regmap(struct device *dev,
 377                                   struct sun4i_tcon *tcon)
 378 {
 379         struct platform_device *pdev = to_platform_device(dev);
 380         struct resource *res;
 381         void __iomem *regs;
 382
 383         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 384         regs = devm_ioremap_resource(dev, res);
 385         if (IS_ERR(regs))
 386                 return PTR_ERR(regs);
 387
 388         tcon->regs = devm_regmap_init_mmio(dev, regs,
 389                                            &sun4i_tcon_regmap_config);
 390         if (IS_ERR(tcon->regs)) {
 391                 dev_err(dev, "Couldn't create the TCON regmap\n");
 392                 return PTR_ERR(tcon->regs);
 393         }
 394
 395         /* Make sure the TCON is disabled and all IRQs are off */
 396         regmap_write(tcon->regs, SUN4I_TCON_GCTL_REG, 0);
 397         regmap_write(tcon->regs, SUN4I_TCON_GINT0_REG, 0);
 398         regmap_write(tcon->regs, SUN4I_TCON_GINT1_REG, 0);
 399
 400         /* Disable IO lines and set them to tristate */
 401         regmap_write(tcon->regs, SUN4I_TCON0_IO_TRI_REG, ~0);
 402         regmap_write(tcon->regs, SUN4I_TCON1_IO_TRI_REG, ~0);
 403
 404         return 0;
 405 }
 406
 407 struct drm_panel *sun4i_tcon_find_panel(struct device_node *node)
 408 {
 409         struct device_node *port, *remote, *child;
 410         struct device_node *end_node = NULL;
 411
 412         /* Inputs are listed first, then outputs */
 413         port = of_graph_get_port_by_id(node, 1);
 414
 415         /*
 416          * Our first output is the RGB interface where the panel will
 417          * be connected.
 418          */
 419         for_each_child_of_node(port, child) {
 420                 u32 reg;
 421
 422                 of_property_read_u32(child, "reg", &reg);
 423                 if (reg == 0)
 424                         end_node = child;
 425         }
 426
 427         if (!end_node) {
 428                 DRM_DEBUG_DRIVER("Missing panel endpoint\n");
 429                 return ERR_PTR(-ENODEV);
 430         }
 431
 432         remote = of_graph_get_remote_port_parent(end_node);
 433         if (!remote) {
 434                 DRM_DEBUG_DRIVER("Unable to parse remote node\n");
 435                 return ERR_PTR(-EINVAL);
 436         }
 437
 438         return of_drm_find_panel(remote) ?: ERR_PTR(-EPROBE_DEFER);
 439 }
 440
 441 struct drm_bridge *sun4i_tcon_find_bridge(struct device_node *node)
 442 {
 443         struct device_node *port, *remote, *child;
 444         struct device_node *end_node = NULL;
 445
 446         /* Inputs are listed first, then outputs */
 447         port = of_graph_get_port_by_id(node, 1);
 448
 449         /*
 450          * Our first output is the RGB interface where the panel will
 451          * be connected.
 452          */
 453         for_each_child_of_node(port, child) {
 454                 u32 reg;
 455
 456                 of_property_read_u32(child, "reg", &reg);
 457                 if (reg == 0)
 458                         end_node = child;
 459         }
 460
 461         if (!end_node) {
 462                 DRM_DEBUG_DRIVER("Missing bridge endpoint\n");
 463                 return ERR_PTR(-ENODEV);
 464         }
 465
 466         remote = of_graph_get_remote_port_parent(end_node);
 467         if (!remote) {
 468                 DRM_DEBUG_DRIVER("Enable to parse remote node\n");
 469                 return ERR_PTR(-EINVAL);
 470         }
 471
 472         return of_drm_find_bridge(remote) ?: ERR_PTR(-EPROBE_DEFER);
 473 }
 474
 475 static int sun4i_tcon_bind(struct device *dev, struct device *master,
 476                            void *data)
 477 {
 478         struct drm_device *drm = data;
 479         struct sun4i_drv *drv = drm->dev_private;
 480         struct sun4i_tcon *tcon;
 481         int ret;
 482
 483         tcon = devm_kzalloc(dev, sizeof(*tcon), GFP_KERNEL);
 484         if (!tcon)
 485                 return -ENOMEM;
 486         dev_set_drvdata(dev, tcon);
 487         drv->tcon = tcon;
 488         tcon->drm = drm;
 489         tcon->dev = dev;
 490
 491         if (of_device_is_compatible(dev->of_node, "allwinner,sun5i-a13-tcon")) {
 492                 tcon->has_mux = true;
 493                 tcon->has_channel_1 = true;
 494         } else {
 495                 tcon->has_mux = false;
 496                 tcon->has_channel_1 = false;
 497         }
 498
 499         tcon->lcd_rst = devm_reset_control_get(dev, "lcd");
 500         if (IS_ERR(tcon->lcd_rst)) {
 501                 dev_err(dev, "Couldn't get our reset line\n");
 502                 return PTR_ERR(tcon->lcd_rst);
 503         }
 504
 505         /* Make sure our TCON is reset */
 506         if (!reset_control_status(tcon->lcd_rst))
 507                 reset_control_assert(tcon->lcd_rst);
 508
 509         ret = reset_control_deassert(tcon->lcd_rst);
 510         if (ret) {
 511                 dev_err(dev, "Couldn't deassert our reset line\n");
 512                 return ret;
 513         }
 514
 515         ret = sun4i_tcon_init_regmap(dev, tcon);
 516         if (ret) {
 517                 dev_err(dev, "Couldn't init our TCON regmap\n");
 518                 goto err_assert_reset;
 519         }
 520
 521         ret = sun4i_tcon_init_clocks(dev, tcon);
 522         if (ret) {
 523                 dev_err(dev, "Couldn't init our TCON clocks\n");
 524                 goto err_assert_reset;
 525         }
 526
 527         ret = sun4i_tcon_init_irq(dev, tcon);
 528         if (ret) {
 529                 dev_err(dev, "Couldn't init our TCON interrupts\n");
 530                 goto err_free_clocks;
 531         }
 532
 533         ret = sun4i_rgb_init(drm);
 534         if (ret < 0)
 535                 goto err_free_clocks;
 536
 537         return 0;
 538
 539 err_free_clocks:
 540         sun4i_tcon_free_clocks(tcon);
 541 err_assert_reset:
 542         reset_control_assert(tcon->lcd_rst);
 543         return ret;
 544 }
 545
 546 static void sun4i_tcon_unbind(struct device *dev, struct device *master,
 547                               void *data)
 548 {
 549         struct sun4i_tcon *tcon = dev_get_drvdata(dev);
 550
 551         sun4i_tcon_free_clocks(tcon);
 552 }
 553
 554 static struct component_ops sun4i_tcon_ops = {
 555         .bind   = sun4i_tcon_bind,
 556         .unbind = sun4i_tcon_unbind,
 557 };
 558
 559 static int sun4i_tcon_probe(struct platform_device *pdev)
 560 {
 561         struct device_node *node = pdev->dev.of_node;
 562         struct drm_bridge *bridge;
 563         struct drm_panel *panel;
 564
 565         /*
 566          * Neither the bridge or the panel is ready.
 567          * Defer the probe.
 568          */
 569         panel = sun4i_tcon_find_panel(node);
 570         bridge = sun4i_tcon_find_bridge(node);
 571
 572         /*
 573          * If we don't have a panel endpoint, just go on
 574          */
 575         if ((PTR_ERR(panel) == -EPROBE_DEFER) &&
 576             (PTR_ERR(bridge) == -EPROBE_DEFER)) {
 577                 DRM_DEBUG_DRIVER("Still waiting for our panel/bridge. Deferring...\n");
 578                 return -EPROBE_DEFER;
 579         }
 580
 581         return component_add(&pdev->dev, &sun4i_tcon_ops);
 582 }
 583
 584 static int sun4i_tcon_remove(struct platform_device *pdev)
 585 {
 586         component_del(&pdev->dev, &sun4i_tcon_ops);
 587
 588         return 0;
 589 }
 590
 591 static const struct of_device_id sun4i_tcon_of_table[] = {
 592         { .compatible = "allwinner,sun5i-a13-tcon" },
 593         { .compatible = "allwinner,sun8i-a33-tcon" },
 594         { }
 595 };
 596 MODULE_DEVICE_TABLE(of, sun4i_tcon_of_table);
 597
 598 static struct platform_driver sun4i_tcon_platform_driver = {
 599         .probe          = sun4i_tcon_probe,
 600         .remove         = sun4i_tcon_remove,
 601         .driver         = {
 602                 .name           = "sun4i-tcon",
 603                 .of_match_table = sun4i_tcon_of_table,
 604         },
 605 };
 606 module_platform_driver(sun4i_tcon_platform_driver);
 607
 608 MODULE_AUTHOR("Maxime Ripard <[email protected]>");
 609 MODULE_DESCRIPTION("Allwinner A10 Timing Controller Driver");
 610 MODULE_LICENSE("GPL");