linux/drivers/gpu/drm/tinydrm/st7586.c
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   1/*
   2 * DRM driver for Sitronix ST7586 panels
   3 *
   4 * Copyright 2017 David Lechner <david@lechnology.com>
   5 *
   6 * This program is free software; you can redistribute it and/or modify
   7 * it under the terms of the GNU General Public License as published by
   8 * the Free Software Foundation; either version 2 of the License, or
   9 * (at your option) any later version.
  10 */
  11
  12#include <linux/delay.h>
  13#include <linux/dma-buf.h>
  14#include <linux/gpio/consumer.h>
  15#include <linux/module.h>
  16#include <linux/property.h>
  17#include <linux/spi/spi.h>
  18#include <video/mipi_display.h>
  19
  20#include <drm/drm_fb_helper.h>
  21#include <drm/drm_gem_framebuffer_helper.h>
  22#include <drm/tinydrm/mipi-dbi.h>
  23#include <drm/tinydrm/tinydrm-helpers.h>
  24
  25/* controller-specific commands */
  26#define ST7586_DISP_MODE_GRAY   0x38
  27#define ST7586_DISP_MODE_MONO   0x39
  28#define ST7586_ENABLE_DDRAM     0x3a
  29#define ST7586_SET_DISP_DUTY    0xb0
  30#define ST7586_SET_PART_DISP    0xb4
  31#define ST7586_SET_NLINE_INV    0xb5
  32#define ST7586_SET_VOP          0xc0
  33#define ST7586_SET_BIAS_SYSTEM  0xc3
  34#define ST7586_SET_BOOST_LEVEL  0xc4
  35#define ST7586_SET_VOP_OFFSET   0xc7
  36#define ST7586_ENABLE_ANALOG    0xd0
  37#define ST7586_AUTO_READ_CTRL   0xd7
  38#define ST7586_OTP_RW_CTRL      0xe0
  39#define ST7586_OTP_CTRL_OUT     0xe1
  40#define ST7586_OTP_READ         0xe3
  41
  42#define ST7586_DISP_CTRL_MX     BIT(6)
  43#define ST7586_DISP_CTRL_MY     BIT(7)
  44
  45/*
  46 * The ST7586 controller has an unusual pixel format where 2bpp grayscale is
  47 * packed 3 pixels per byte with the first two pixels using 3 bits and the 3rd
  48 * pixel using only 2 bits.
  49 *
  50 * |  D7  |  D6  |  D5  ||      |      || 2bpp |
  51 * | (D4) | (D3) | (D2) ||  D1  |  D0  || GRAY |
  52 * +------+------+------++------+------++------+
  53 * |  1   |  1   |  1   ||  1   |  1   || 0  0 | black
  54 * |  1   |  0   |  0   ||  1   |  0   || 0  1 | dark gray
  55 * |  0   |  1   |  0   ||  0   |  1   || 1  0 | light gray
  56 * |  0   |  0   |  0   ||  0   |  0   || 1  1 | white
  57 */
  58
  59static const u8 st7586_lookup[] = { 0x7, 0x4, 0x2, 0x0 };
  60
  61static void st7586_xrgb8888_to_gray332(u8 *dst, void *vaddr,
  62                                       struct drm_framebuffer *fb,
  63                                       struct drm_clip_rect *clip)
  64{
  65        size_t len = (clip->x2 - clip->x1) * (clip->y2 - clip->y1);
  66        unsigned int x, y;
  67        u8 *src, *buf, val;
  68
  69        buf = kmalloc(len, GFP_KERNEL);
  70        if (!buf)
  71                return;
  72
  73        tinydrm_xrgb8888_to_gray8(buf, vaddr, fb, clip);
  74        src = buf;
  75
  76        for (y = clip->y1; y < clip->y2; y++) {
  77                for (x = clip->x1; x < clip->x2; x += 3) {
  78                        val = st7586_lookup[*src++ >> 6] << 5;
  79                        val |= st7586_lookup[*src++ >> 6] << 2;
  80                        val |= st7586_lookup[*src++ >> 6] >> 1;
  81                        *dst++ = val;
  82                }
  83        }
  84
  85        kfree(buf);
  86}
  87
  88static int st7586_buf_copy(void *dst, struct drm_framebuffer *fb,
  89                           struct drm_clip_rect *clip)
  90{
  91        struct drm_gem_cma_object *cma_obj = drm_fb_cma_get_gem_obj(fb, 0);
  92        struct dma_buf_attachment *import_attach = cma_obj->base.import_attach;
  93        void *src = cma_obj->vaddr;
  94        int ret = 0;
  95
  96        if (import_attach) {
  97                ret = dma_buf_begin_cpu_access(import_attach->dmabuf,
  98                                               DMA_FROM_DEVICE);
  99                if (ret)
 100                        return ret;
 101        }
 102
 103        st7586_xrgb8888_to_gray332(dst, src, fb, clip);
 104
 105        if (import_attach)
 106                ret = dma_buf_end_cpu_access(import_attach->dmabuf,
 107                                             DMA_FROM_DEVICE);
 108
 109        return ret;
 110}
 111
 112static int st7586_fb_dirty(struct drm_framebuffer *fb,
 113                           struct drm_file *file_priv, unsigned int flags,
 114                           unsigned int color, struct drm_clip_rect *clips,
 115                           unsigned int num_clips)
 116{
 117        struct tinydrm_device *tdev = fb->dev->dev_private;
 118        struct mipi_dbi *mipi = mipi_dbi_from_tinydrm(tdev);
 119        struct drm_clip_rect clip;
 120        int start, end;
 121        int ret = 0;
 122
 123        mutex_lock(&tdev->dirty_lock);
 124
 125        if (!mipi->enabled)
 126                goto out_unlock;
 127
 128        /* fbdev can flush even when we're not interested */
 129        if (tdev->pipe.plane.fb != fb)
 130                goto out_unlock;
 131
 132        tinydrm_merge_clips(&clip, clips, num_clips, flags, fb->width,
 133                            fb->height);
 134
 135        /* 3 pixels per byte, so grow clip to nearest multiple of 3 */
 136        clip.x1 = rounddown(clip.x1, 3);
 137        clip.x2 = roundup(clip.x2, 3);
 138
 139        DRM_DEBUG("Flushing [FB:%d] x1=%u, x2=%u, y1=%u, y2=%u\n", fb->base.id,
 140                  clip.x1, clip.x2, clip.y1, clip.y2);
 141
 142        ret = st7586_buf_copy(mipi->tx_buf, fb, &clip);
 143        if (ret)
 144                goto out_unlock;
 145
 146        /* Pixels are packed 3 per byte */
 147        start = clip.x1 / 3;
 148        end = clip.x2 / 3;
 149
 150        mipi_dbi_command(mipi, MIPI_DCS_SET_COLUMN_ADDRESS,
 151                         (start >> 8) & 0xFF, start & 0xFF,
 152                         (end >> 8) & 0xFF, (end - 1) & 0xFF);
 153        mipi_dbi_command(mipi, MIPI_DCS_SET_PAGE_ADDRESS,
 154                         (clip.y1 >> 8) & 0xFF, clip.y1 & 0xFF,
 155                         (clip.y2 >> 8) & 0xFF, (clip.y2 - 1) & 0xFF);
 156
 157        ret = mipi_dbi_command_buf(mipi, MIPI_DCS_WRITE_MEMORY_START,
 158                                   (u8 *)mipi->tx_buf,
 159                                   (end - start) * (clip.y2 - clip.y1));
 160
 161out_unlock:
 162        mutex_unlock(&tdev->dirty_lock);
 163
 164        if (ret)
 165                dev_err_once(fb->dev->dev, "Failed to update display %d\n",
 166                             ret);
 167
 168        return ret;
 169}
 170
 171static const struct drm_framebuffer_funcs st7586_fb_funcs = {
 172        .destroy        = drm_gem_fb_destroy,
 173        .create_handle  = drm_gem_fb_create_handle,
 174        .dirty          = st7586_fb_dirty,
 175};
 176
 177static void st7586_pipe_enable(struct drm_simple_display_pipe *pipe,
 178                               struct drm_crtc_state *crtc_state)
 179{
 180        struct tinydrm_device *tdev = pipe_to_tinydrm(pipe);
 181        struct mipi_dbi *mipi = mipi_dbi_from_tinydrm(tdev);
 182        struct drm_framebuffer *fb = pipe->plane.fb;
 183        struct device *dev = tdev->drm->dev;
 184        int ret;
 185        u8 addr_mode;
 186
 187        DRM_DEBUG_KMS("\n");
 188
 189        mipi_dbi_hw_reset(mipi);
 190        ret = mipi_dbi_command(mipi, ST7586_AUTO_READ_CTRL, 0x9f);
 191        if (ret) {
 192                DRM_DEV_ERROR(dev, "Error sending command %d\n", ret);
 193                return;
 194        }
 195
 196        mipi_dbi_command(mipi, ST7586_OTP_RW_CTRL, 0x00);
 197
 198        msleep(10);
 199
 200        mipi_dbi_command(mipi, ST7586_OTP_READ);
 201
 202        msleep(20);
 203
 204        mipi_dbi_command(mipi, ST7586_OTP_CTRL_OUT);
 205        mipi_dbi_command(mipi, MIPI_DCS_EXIT_SLEEP_MODE);
 206        mipi_dbi_command(mipi, MIPI_DCS_SET_DISPLAY_OFF);
 207
 208        msleep(50);
 209
 210        mipi_dbi_command(mipi, ST7586_SET_VOP_OFFSET, 0x00);
 211        mipi_dbi_command(mipi, ST7586_SET_VOP, 0xe3, 0x00);
 212        mipi_dbi_command(mipi, ST7586_SET_BIAS_SYSTEM, 0x02);
 213        mipi_dbi_command(mipi, ST7586_SET_BOOST_LEVEL, 0x04);
 214        mipi_dbi_command(mipi, ST7586_ENABLE_ANALOG, 0x1d);
 215        mipi_dbi_command(mipi, ST7586_SET_NLINE_INV, 0x00);
 216        mipi_dbi_command(mipi, ST7586_DISP_MODE_GRAY);
 217        mipi_dbi_command(mipi, ST7586_ENABLE_DDRAM, 0x02);
 218
 219        switch (mipi->rotation) {
 220        default:
 221                addr_mode = 0x00;
 222                break;
 223        case 90:
 224                addr_mode = ST7586_DISP_CTRL_MY;
 225                break;
 226        case 180:
 227                addr_mode = ST7586_DISP_CTRL_MX | ST7586_DISP_CTRL_MY;
 228                break;
 229        case 270:
 230                addr_mode = ST7586_DISP_CTRL_MX;
 231                break;
 232        }
 233        mipi_dbi_command(mipi, MIPI_DCS_SET_ADDRESS_MODE, addr_mode);
 234
 235        mipi_dbi_command(mipi, ST7586_SET_DISP_DUTY, 0x7f);
 236        mipi_dbi_command(mipi, ST7586_SET_PART_DISP, 0xa0);
 237        mipi_dbi_command(mipi, MIPI_DCS_SET_PARTIAL_AREA, 0x00, 0x00, 0x00, 0x77);
 238        mipi_dbi_command(mipi, MIPI_DCS_EXIT_INVERT_MODE);
 239
 240        msleep(100);
 241
 242        mipi_dbi_command(mipi, MIPI_DCS_SET_DISPLAY_ON);
 243
 244        mipi->enabled = true;
 245
 246        if (fb)
 247                fb->funcs->dirty(fb, NULL, 0, 0, NULL, 0);
 248}
 249
 250static void st7586_pipe_disable(struct drm_simple_display_pipe *pipe)
 251{
 252        struct tinydrm_device *tdev = pipe_to_tinydrm(pipe);
 253        struct mipi_dbi *mipi = mipi_dbi_from_tinydrm(tdev);
 254
 255        DRM_DEBUG_KMS("\n");
 256
 257        if (!mipi->enabled)
 258                return;
 259
 260        mipi_dbi_command(mipi, MIPI_DCS_SET_DISPLAY_OFF);
 261        mipi->enabled = false;
 262}
 263
 264static const u32 st7586_formats[] = {
 265        DRM_FORMAT_XRGB8888,
 266};
 267
 268static int st7586_init(struct device *dev, struct mipi_dbi *mipi,
 269                const struct drm_simple_display_pipe_funcs *pipe_funcs,
 270                struct drm_driver *driver, const struct drm_display_mode *mode,
 271                unsigned int rotation)
 272{
 273        size_t bufsize = (mode->vdisplay + 2) / 3 * mode->hdisplay;
 274        struct tinydrm_device *tdev = &mipi->tinydrm;
 275        int ret;
 276
 277        mutex_init(&mipi->cmdlock);
 278
 279        mipi->tx_buf = devm_kmalloc(dev, bufsize, GFP_KERNEL);
 280        if (!mipi->tx_buf)
 281                return -ENOMEM;
 282
 283        ret = devm_tinydrm_init(dev, tdev, &st7586_fb_funcs, driver);
 284        if (ret)
 285                return ret;
 286
 287        ret = tinydrm_display_pipe_init(tdev, pipe_funcs,
 288                                        DRM_MODE_CONNECTOR_VIRTUAL,
 289                                        st7586_formats,
 290                                        ARRAY_SIZE(st7586_formats),
 291                                        mode, rotation);
 292        if (ret)
 293                return ret;
 294
 295        tdev->drm->mode_config.preferred_depth = 32;
 296        mipi->rotation = rotation;
 297
 298        drm_mode_config_reset(tdev->drm);
 299
 300        DRM_DEBUG_KMS("preferred_depth=%u, rotation = %u\n",
 301                      tdev->drm->mode_config.preferred_depth, rotation);
 302
 303        return 0;
 304}
 305
 306static const struct drm_simple_display_pipe_funcs st7586_pipe_funcs = {
 307        .enable         = st7586_pipe_enable,
 308        .disable        = st7586_pipe_disable,
 309        .update         = tinydrm_display_pipe_update,
 310        .prepare_fb     = tinydrm_display_pipe_prepare_fb,
 311};
 312
 313static const struct drm_display_mode st7586_mode = {
 314        TINYDRM_MODE(178, 128, 37, 27),
 315};
 316
 317DEFINE_DRM_GEM_CMA_FOPS(st7586_fops);
 318
 319static struct drm_driver st7586_driver = {
 320        .driver_features        = DRIVER_GEM | DRIVER_MODESET | DRIVER_PRIME |
 321                                  DRIVER_ATOMIC,
 322        .fops                   = &st7586_fops,
 323        TINYDRM_GEM_DRIVER_OPS,
 324        .lastclose              = drm_fb_helper_lastclose,
 325        .debugfs_init           = mipi_dbi_debugfs_init,
 326        .name                   = "st7586",
 327        .desc                   = "Sitronix ST7586",
 328        .date                   = "20170801",
 329        .major                  = 1,
 330        .minor                  = 0,
 331};
 332
 333static const struct of_device_id st7586_of_match[] = {
 334        { .compatible = "lego,ev3-lcd" },
 335        {},
 336};
 337MODULE_DEVICE_TABLE(of, st7586_of_match);
 338
 339static const struct spi_device_id st7586_id[] = {
 340        { "ev3-lcd", 0 },
 341        { },
 342};
 343MODULE_DEVICE_TABLE(spi, st7586_id);
 344
 345static int st7586_probe(struct spi_device *spi)
 346{
 347        struct device *dev = &spi->dev;
 348        struct mipi_dbi *mipi;
 349        struct gpio_desc *a0;
 350        u32 rotation = 0;
 351        int ret;
 352
 353        mipi = devm_kzalloc(dev, sizeof(*mipi), GFP_KERNEL);
 354        if (!mipi)
 355                return -ENOMEM;
 356
 357        mipi->reset = devm_gpiod_get(dev, "reset", GPIOD_OUT_HIGH);
 358        if (IS_ERR(mipi->reset)) {
 359                DRM_DEV_ERROR(dev, "Failed to get gpio 'reset'\n");
 360                return PTR_ERR(mipi->reset);
 361        }
 362
 363        a0 = devm_gpiod_get(dev, "a0", GPIOD_OUT_LOW);
 364        if (IS_ERR(a0)) {
 365                DRM_DEV_ERROR(dev, "Failed to get gpio 'a0'\n");
 366                return PTR_ERR(a0);
 367        }
 368
 369        device_property_read_u32(dev, "rotation", &rotation);
 370
 371        ret = mipi_dbi_spi_init(spi, mipi, a0);
 372        if (ret)
 373                return ret;
 374
 375        /* Cannot read from this controller via SPI */
 376        mipi->read_commands = NULL;
 377
 378        /*
 379         * we are using 8-bit data, so we are not actually swapping anything,
 380         * but setting mipi->swap_bytes makes mipi_dbi_typec3_command() do the
 381         * right thing and not use 16-bit transfers (which results in swapped
 382         * bytes on little-endian systems and causes out of order data to be
 383         * sent to the display).
 384         */
 385        mipi->swap_bytes = true;
 386
 387        ret = st7586_init(&spi->dev, mipi, &st7586_pipe_funcs, &st7586_driver,
 388                          &st7586_mode, rotation);
 389        if (ret)
 390                return ret;
 391
 392        spi_set_drvdata(spi, mipi);
 393
 394        return devm_tinydrm_register(&mipi->tinydrm);
 395}
 396
 397static void st7586_shutdown(struct spi_device *spi)
 398{
 399        struct mipi_dbi *mipi = spi_get_drvdata(spi);
 400
 401        tinydrm_shutdown(&mipi->tinydrm);
 402}
 403
 404static struct spi_driver st7586_spi_driver = {
 405        .driver = {
 406                .name = "st7586",
 407                .owner = THIS_MODULE,
 408                .of_match_table = st7586_of_match,
 409        },
 410        .id_table = st7586_id,
 411        .probe = st7586_probe,
 412        .shutdown = st7586_shutdown,
 413};
 414module_spi_driver(st7586_spi_driver);
 415
 416MODULE_DESCRIPTION("Sitronix ST7586 DRM driver");
 417MODULE_AUTHOR("David Lechner <david@lechnology.com>");
 418MODULE_LICENSE("GPL");
 419