linux/drivers/gpu/drm/vc4/vc4_dpi.c
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   1/*
   2 * Copyright (C) 2016 Broadcom Limited
   3 *
   4 * This program is free software; you can redistribute it and/or modify it
   5 * under the terms of the GNU General Public License version 2 as published by
   6 * the Free Software Foundation.
   7 *
   8 * This program is distributed in the hope that it will be useful, but WITHOUT
   9 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  10 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  11 * more details.
  12 *
  13 * You should have received a copy of the GNU General Public License along with
  14 * this program.  If not, see <http://www.gnu.org/licenses/>.
  15 */
  16
  17/**
  18 * DOC: VC4 DPI module
  19 *
  20 * The VC4 DPI hardware supports MIPI DPI type 4 and Nokia ViSSI
  21 * signals.  On BCM2835, these can be routed out to GPIO0-27 with the
  22 * ALT2 function.
  23 */
  24
  25#include <drm/drm_atomic_helper.h>
  26#include <drm/drm_bridge.h>
  27#include <drm/drm_edid.h>
  28#include <drm/drm_of.h>
  29#include <drm/drm_panel.h>
  30#include <drm/drm_probe_helper.h>
  31#include <linux/clk.h>
  32#include <linux/component.h>
  33#include <linux/of_graph.h>
  34#include <linux/of_platform.h>
  35#include "vc4_drv.h"
  36#include "vc4_regs.h"
  37
  38#define DPI_C                   0x00
  39# define DPI_OUTPUT_ENABLE_MODE         BIT(16)
  40
  41/* The order field takes the incoming 24 bit RGB from the pixel valve
  42 * and shuffles the 3 channels.
  43 */
  44# define DPI_ORDER_MASK                 VC4_MASK(15, 14)
  45# define DPI_ORDER_SHIFT                14
  46# define DPI_ORDER_RGB                  0
  47# define DPI_ORDER_BGR                  1
  48# define DPI_ORDER_GRB                  2
  49# define DPI_ORDER_BRG                  3
  50
  51/* The format field takes the ORDER-shuffled pixel valve data and
  52 * formats it onto the output lines.
  53 */
  54# define DPI_FORMAT_MASK                VC4_MASK(13, 11)
  55# define DPI_FORMAT_SHIFT               11
  56/* This define is named in the hardware, but actually just outputs 0. */
  57# define DPI_FORMAT_9BIT_666_RGB        0
  58/* Outputs 00000000rrrrrggggggbbbbb */
  59# define DPI_FORMAT_16BIT_565_RGB_1     1
  60/* Outputs 000rrrrr00gggggg000bbbbb */
  61# define DPI_FORMAT_16BIT_565_RGB_2     2
  62/* Outputs 00rrrrr000gggggg00bbbbb0 */
  63# define DPI_FORMAT_16BIT_565_RGB_3     3
  64/* Outputs 000000rrrrrrggggggbbbbbb */
  65# define DPI_FORMAT_18BIT_666_RGB_1     4
  66/* Outputs 00rrrrrr00gggggg00bbbbbb */
  67# define DPI_FORMAT_18BIT_666_RGB_2     5
  68/* Outputs rrrrrrrrggggggggbbbbbbbb */
  69# define DPI_FORMAT_24BIT_888_RGB       6
  70
  71/* Reverses the polarity of the corresponding signal */
  72# define DPI_PIXEL_CLK_INVERT           BIT(10)
  73# define DPI_HSYNC_INVERT               BIT(9)
  74# define DPI_VSYNC_INVERT               BIT(8)
  75# define DPI_OUTPUT_ENABLE_INVERT       BIT(7)
  76
  77/* Outputs the signal the falling clock edge instead of rising. */
  78# define DPI_HSYNC_NEGATE               BIT(6)
  79# define DPI_VSYNC_NEGATE               BIT(5)
  80# define DPI_OUTPUT_ENABLE_NEGATE       BIT(4)
  81
  82/* Disables the signal */
  83# define DPI_HSYNC_DISABLE              BIT(3)
  84# define DPI_VSYNC_DISABLE              BIT(2)
  85# define DPI_OUTPUT_ENABLE_DISABLE      BIT(1)
  86
  87/* Power gate to the device, full reset at 0 -> 1 transition */
  88# define DPI_ENABLE                     BIT(0)
  89
  90/* All other registers besides DPI_C return the ID */
  91#define DPI_ID                  0x04
  92# define DPI_ID_VALUE           0x00647069
  93
  94/* General DPI hardware state. */
  95struct vc4_dpi {
  96        struct platform_device *pdev;
  97
  98        struct drm_encoder *encoder;
  99
 100        void __iomem *regs;
 101
 102        struct clk *pixel_clock;
 103        struct clk *core_clock;
 104};
 105
 106#define DPI_READ(offset) readl(dpi->regs + (offset))
 107#define DPI_WRITE(offset, val) writel(val, dpi->regs + (offset))
 108
 109/* VC4 DPI encoder KMS struct */
 110struct vc4_dpi_encoder {
 111        struct vc4_encoder base;
 112        struct vc4_dpi *dpi;
 113};
 114
 115static inline struct vc4_dpi_encoder *
 116to_vc4_dpi_encoder(struct drm_encoder *encoder)
 117{
 118        return container_of(encoder, struct vc4_dpi_encoder, base.base);
 119}
 120
 121#define DPI_REG(reg) { reg, #reg }
 122static const struct {
 123        u32 reg;
 124        const char *name;
 125} dpi_regs[] = {
 126        DPI_REG(DPI_C),
 127        DPI_REG(DPI_ID),
 128};
 129
 130#ifdef CONFIG_DEBUG_FS
 131int vc4_dpi_debugfs_regs(struct seq_file *m, void *unused)
 132{
 133        struct drm_info_node *node = (struct drm_info_node *)m->private;
 134        struct drm_device *dev = node->minor->dev;
 135        struct vc4_dev *vc4 = to_vc4_dev(dev);
 136        struct vc4_dpi *dpi = vc4->dpi;
 137        int i;
 138
 139        if (!dpi)
 140                return 0;
 141
 142        for (i = 0; i < ARRAY_SIZE(dpi_regs); i++) {
 143                seq_printf(m, "%s (0x%04x): 0x%08x\n",
 144                           dpi_regs[i].name, dpi_regs[i].reg,
 145                           DPI_READ(dpi_regs[i].reg));
 146        }
 147
 148        return 0;
 149}
 150#endif
 151
 152static const struct drm_encoder_funcs vc4_dpi_encoder_funcs = {
 153        .destroy = drm_encoder_cleanup,
 154};
 155
 156static void vc4_dpi_encoder_disable(struct drm_encoder *encoder)
 157{
 158        struct vc4_dpi_encoder *vc4_encoder = to_vc4_dpi_encoder(encoder);
 159        struct vc4_dpi *dpi = vc4_encoder->dpi;
 160
 161        clk_disable_unprepare(dpi->pixel_clock);
 162}
 163
 164static void vc4_dpi_encoder_enable(struct drm_encoder *encoder)
 165{
 166        struct drm_device *dev = encoder->dev;
 167        struct drm_display_mode *mode = &encoder->crtc->mode;
 168        struct vc4_dpi_encoder *vc4_encoder = to_vc4_dpi_encoder(encoder);
 169        struct vc4_dpi *dpi = vc4_encoder->dpi;
 170        struct drm_connector_list_iter conn_iter;
 171        struct drm_connector *connector = NULL, *connector_scan;
 172        u32 dpi_c = DPI_ENABLE | DPI_OUTPUT_ENABLE_MODE;
 173        int ret;
 174
 175        /* Look up the connector attached to DPI so we can get the
 176         * bus_format.  Ideally the bridge would tell us the
 177         * bus_format we want, but it doesn't yet, so assume that it's
 178         * uniform throughout the bridge chain.
 179         */
 180        drm_connector_list_iter_begin(dev, &conn_iter);
 181        drm_for_each_connector_iter(connector_scan, &conn_iter) {
 182                if (connector_scan->encoder == encoder) {
 183                        connector = connector_scan;
 184                        break;
 185                }
 186        }
 187        drm_connector_list_iter_end(&conn_iter);
 188
 189        if (connector && connector->display_info.num_bus_formats) {
 190                u32 bus_format = connector->display_info.bus_formats[0];
 191
 192                switch (bus_format) {
 193                case MEDIA_BUS_FMT_RGB888_1X24:
 194                        dpi_c |= VC4_SET_FIELD(DPI_FORMAT_24BIT_888_RGB,
 195                                               DPI_FORMAT);
 196                        break;
 197                case MEDIA_BUS_FMT_BGR888_1X24:
 198                        dpi_c |= VC4_SET_FIELD(DPI_FORMAT_24BIT_888_RGB,
 199                                               DPI_FORMAT);
 200                        dpi_c |= VC4_SET_FIELD(DPI_ORDER_BGR, DPI_ORDER);
 201                        break;
 202                case MEDIA_BUS_FMT_RGB666_1X24_CPADHI:
 203                        dpi_c |= VC4_SET_FIELD(DPI_FORMAT_18BIT_666_RGB_2,
 204                                               DPI_FORMAT);
 205                        break;
 206                case MEDIA_BUS_FMT_RGB666_1X18:
 207                        dpi_c |= VC4_SET_FIELD(DPI_FORMAT_18BIT_666_RGB_1,
 208                                               DPI_FORMAT);
 209                        break;
 210                case MEDIA_BUS_FMT_RGB565_1X16:
 211                        dpi_c |= VC4_SET_FIELD(DPI_FORMAT_16BIT_565_RGB_3,
 212                                               DPI_FORMAT);
 213                        break;
 214                default:
 215                        DRM_ERROR("Unknown media bus format %d\n", bus_format);
 216                        break;
 217                }
 218        } else {
 219                /* Default to 24bit if no connector found. */
 220                dpi_c |= VC4_SET_FIELD(DPI_FORMAT_24BIT_888_RGB, DPI_FORMAT);
 221        }
 222
 223        if (mode->flags & DRM_MODE_FLAG_NHSYNC)
 224                dpi_c |= DPI_HSYNC_INVERT;
 225        else if (!(mode->flags & DRM_MODE_FLAG_PHSYNC))
 226                dpi_c |= DPI_HSYNC_DISABLE;
 227
 228        if (mode->flags & DRM_MODE_FLAG_NVSYNC)
 229                dpi_c |= DPI_VSYNC_INVERT;
 230        else if (!(mode->flags & DRM_MODE_FLAG_PVSYNC))
 231                dpi_c |= DPI_VSYNC_DISABLE;
 232
 233        DPI_WRITE(DPI_C, dpi_c);
 234
 235        ret = clk_set_rate(dpi->pixel_clock, mode->clock * 1000);
 236        if (ret)
 237                DRM_ERROR("Failed to set clock rate: %d\n", ret);
 238
 239        ret = clk_prepare_enable(dpi->pixel_clock);
 240        if (ret)
 241                DRM_ERROR("Failed to set clock rate: %d\n", ret);
 242}
 243
 244static enum drm_mode_status vc4_dpi_encoder_mode_valid(struct drm_encoder *encoder,
 245                                                       const struct drm_display_mode *mode)
 246{
 247        if (mode->flags & DRM_MODE_FLAG_INTERLACE)
 248                return MODE_NO_INTERLACE;
 249
 250        return MODE_OK;
 251}
 252
 253static const struct drm_encoder_helper_funcs vc4_dpi_encoder_helper_funcs = {
 254        .disable = vc4_dpi_encoder_disable,
 255        .enable = vc4_dpi_encoder_enable,
 256        .mode_valid = vc4_dpi_encoder_mode_valid,
 257};
 258
 259static const struct of_device_id vc4_dpi_dt_match[] = {
 260        { .compatible = "brcm,bcm2835-dpi", .data = NULL },
 261        {}
 262};
 263
 264/* Sets up the next link in the display chain, whether it's a panel or
 265 * a bridge.
 266 */
 267static int vc4_dpi_init_bridge(struct vc4_dpi *dpi)
 268{
 269        struct device *dev = &dpi->pdev->dev;
 270        struct drm_panel *panel;
 271        struct drm_bridge *bridge;
 272        int ret;
 273
 274        ret = drm_of_find_panel_or_bridge(dev->of_node, 0, 0,
 275                                          &panel, &bridge);
 276        if (ret) {
 277                /* If nothing was connected in the DT, that's not an
 278                 * error.
 279                 */
 280                if (ret == -ENODEV)
 281                        return 0;
 282                else
 283                        return ret;
 284        }
 285
 286        if (panel)
 287                bridge = drm_panel_bridge_add(panel, DRM_MODE_CONNECTOR_DPI);
 288
 289        return drm_bridge_attach(dpi->encoder, bridge, NULL);
 290}
 291
 292static int vc4_dpi_bind(struct device *dev, struct device *master, void *data)
 293{
 294        struct platform_device *pdev = to_platform_device(dev);
 295        struct drm_device *drm = dev_get_drvdata(master);
 296        struct vc4_dev *vc4 = to_vc4_dev(drm);
 297        struct vc4_dpi *dpi;
 298        struct vc4_dpi_encoder *vc4_dpi_encoder;
 299        int ret;
 300
 301        dpi = devm_kzalloc(dev, sizeof(*dpi), GFP_KERNEL);
 302        if (!dpi)
 303                return -ENOMEM;
 304
 305        vc4_dpi_encoder = devm_kzalloc(dev, sizeof(*vc4_dpi_encoder),
 306                                       GFP_KERNEL);
 307        if (!vc4_dpi_encoder)
 308                return -ENOMEM;
 309        vc4_dpi_encoder->base.type = VC4_ENCODER_TYPE_DPI;
 310        vc4_dpi_encoder->dpi = dpi;
 311        dpi->encoder = &vc4_dpi_encoder->base.base;
 312
 313        dpi->pdev = pdev;
 314        dpi->regs = vc4_ioremap_regs(pdev, 0);
 315        if (IS_ERR(dpi->regs))
 316                return PTR_ERR(dpi->regs);
 317
 318        if (DPI_READ(DPI_ID) != DPI_ID_VALUE) {
 319                dev_err(dev, "Port returned 0x%08x for ID instead of 0x%08x\n",
 320                        DPI_READ(DPI_ID), DPI_ID_VALUE);
 321                return -ENODEV;
 322        }
 323
 324        dpi->core_clock = devm_clk_get(dev, "core");
 325        if (IS_ERR(dpi->core_clock)) {
 326                ret = PTR_ERR(dpi->core_clock);
 327                if (ret != -EPROBE_DEFER)
 328                        DRM_ERROR("Failed to get core clock: %d\n", ret);
 329                return ret;
 330        }
 331        dpi->pixel_clock = devm_clk_get(dev, "pixel");
 332        if (IS_ERR(dpi->pixel_clock)) {
 333                ret = PTR_ERR(dpi->pixel_clock);
 334                if (ret != -EPROBE_DEFER)
 335                        DRM_ERROR("Failed to get pixel clock: %d\n", ret);
 336                return ret;
 337        }
 338
 339        ret = clk_prepare_enable(dpi->core_clock);
 340        if (ret)
 341                DRM_ERROR("Failed to turn on core clock: %d\n", ret);
 342
 343        drm_encoder_init(drm, dpi->encoder, &vc4_dpi_encoder_funcs,
 344                         DRM_MODE_ENCODER_DPI, NULL);
 345        drm_encoder_helper_add(dpi->encoder, &vc4_dpi_encoder_helper_funcs);
 346
 347        ret = vc4_dpi_init_bridge(dpi);
 348        if (ret)
 349                goto err_destroy_encoder;
 350
 351        dev_set_drvdata(dev, dpi);
 352
 353        vc4->dpi = dpi;
 354
 355        return 0;
 356
 357err_destroy_encoder:
 358        drm_encoder_cleanup(dpi->encoder);
 359        clk_disable_unprepare(dpi->core_clock);
 360        return ret;
 361}
 362
 363static void vc4_dpi_unbind(struct device *dev, struct device *master,
 364                           void *data)
 365{
 366        struct drm_device *drm = dev_get_drvdata(master);
 367        struct vc4_dev *vc4 = to_vc4_dev(drm);
 368        struct vc4_dpi *dpi = dev_get_drvdata(dev);
 369
 370        drm_of_panel_bridge_remove(dev->of_node, 0, 0);
 371
 372        drm_encoder_cleanup(dpi->encoder);
 373
 374        clk_disable_unprepare(dpi->core_clock);
 375
 376        vc4->dpi = NULL;
 377}
 378
 379static const struct component_ops vc4_dpi_ops = {
 380        .bind   = vc4_dpi_bind,
 381        .unbind = vc4_dpi_unbind,
 382};
 383
 384static int vc4_dpi_dev_probe(struct platform_device *pdev)
 385{
 386        return component_add(&pdev->dev, &vc4_dpi_ops);
 387}
 388
 389static int vc4_dpi_dev_remove(struct platform_device *pdev)
 390{
 391        component_del(&pdev->dev, &vc4_dpi_ops);
 392        return 0;
 393}
 394
 395struct platform_driver vc4_dpi_driver = {
 396        .probe = vc4_dpi_dev_probe,
 397        .remove = vc4_dpi_dev_remove,
 398        .driver = {
 399                .name = "vc4_dpi",
 400                .of_match_table = vc4_dpi_dt_match,
 401        },
 402};
 403