drm/tiny/st7586.c

0001 // SPDX-License-Identifier: GPL-2.0-or-later
0002 /*
0003  * DRM driver for Sitronix ST7586 panels
0004  *
0005  * Copyright 2017 David Lechner <david@lechnology.com>
0006  */
0007
0008 #include <linux/delay.h>
0009 #include <linux/gpio/consumer.h>
0010 #include <linux/module.h>
0011 #include <linux/property.h>
0012 #include <linux/spi/spi.h>
0013 #include <video/mipi_display.h>
0014
0015 #include <drm/drm_atomic_helper.h>
0016 #include <drm/drm_damage_helper.h>
0017 #include <drm/drm_drv.h>
0018 #include <drm/drm_fb_cma_helper.h>
0019 #include <drm/drm_fb_helper.h>
0020 #include <drm/drm_format_helper.h>
0021 #include <drm/drm_framebuffer.h>
0022 #include <drm/drm_gem_atomic_helper.h>
0023 #include <drm/drm_gem_cma_helper.h>
0024 #include <drm/drm_gem_framebuffer_helper.h>
0025 #include <drm/drm_managed.h>
0026 #include <drm/drm_mipi_dbi.h>
0027 #include <drm/drm_rect.h>
0028
0029 /* controller-specific commands */
0030 #define ST7586_DISP_MODE_GRAY   0x38
0031 #define ST7586_DISP_MODE_MONO   0x39
0032 #define ST7586_ENABLE_DDRAM 0x3a
0033 #define ST7586_SET_DISP_DUTY    0xb0
0034 #define ST7586_SET_PART_DISP    0xb4
0035 #define ST7586_SET_NLINE_INV    0xb5
0036 #define ST7586_SET_VOP      0xc0
0037 #define ST7586_SET_BIAS_SYSTEM  0xc3
0038 #define ST7586_SET_BOOST_LEVEL  0xc4
0039 #define ST7586_SET_VOP_OFFSET   0xc7
0040 #define ST7586_ENABLE_ANALOG    0xd0
0041 #define ST7586_AUTO_READ_CTRL   0xd7
0042 #define ST7586_OTP_RW_CTRL  0xe0
0043 #define ST7586_OTP_CTRL_OUT 0xe1
0044 #define ST7586_OTP_READ     0xe3
0045
0046 #define ST7586_DISP_CTRL_MX BIT(6)
0047 #define ST7586_DISP_CTRL_MY BIT(7)
0048
0049 /*
0050  * The ST7586 controller has an unusual pixel format where 2bpp grayscale is
0051  * packed 3 pixels per byte with the first two pixels using 3 bits and the 3rd
0052  * pixel using only 2 bits.
0053  *
0054  * |  D7  |  D6  |  D5  ||      |      || 2bpp |
0055  * | (D4) | (D3) | (D2) ||  D1  |  D0  || GRAY |
0056  * +------+------+------++------+------++------+
0057  * |  1   |  1   |  1   ||  1   |  1   || 0  0 | black
0058  * |  1   |  0   |  0   ||  1   |  0   || 0  1 | dark gray
0059  * |  0   |  1   |  0   ||  0   |  1   || 1  0 | light gray
0060  * |  0   |  0   |  0   ||  0   |  0   || 1  1 | white
0061  */
0062
0063 static const u8 st7586_lookup[] = { 0x7, 0x4, 0x2, 0x0 };
0064
0065 static void st7586_xrgb8888_to_gray332(u8 *dst, void *vaddr,
0066                        struct drm_framebuffer *fb,
0067                        struct drm_rect *clip)
0068 {
0069     size_t len = (clip->x2 - clip->x1) * (clip->y2 - clip->y1);
0070     unsigned int x, y;
0071     u8 *src, *buf, val;
0072
0073     buf = kmalloc(len, GFP_KERNEL);
0074     if (!buf)
0075         return;
0076
0077     drm_fb_xrgb8888_to_gray8(buf, 0, vaddr, fb, clip);
0078     src = buf;
0079
0080     for (y = clip->y1; y < clip->y2; y++) {
0081         for (x = clip->x1; x < clip->x2; x += 3) {
0082             val = st7586_lookup[*src++ >> 6] << 5;
0083             val |= st7586_lookup[*src++ >> 6] << 2;
0084             val |= st7586_lookup[*src++ >> 6] >> 1;
0085             *dst++ = val;
0086         }
0087     }
0088
0089     kfree(buf);
0090 }
0091
0092 static int st7586_buf_copy(void *dst, struct drm_framebuffer *fb,
0093                struct drm_rect *clip)
0094 {
0095     struct drm_gem_cma_object *cma_obj = drm_fb_cma_get_gem_obj(fb, 0);
0096     void *src = cma_obj->vaddr;
0097     int ret = 0;
0098
0099     ret = drm_gem_fb_begin_cpu_access(fb, DMA_FROM_DEVICE);
0100     if (ret)
0101         return ret;
0102
0103     st7586_xrgb8888_to_gray332(dst, src, fb, clip);
0104
0105     drm_gem_fb_end_cpu_access(fb, DMA_FROM_DEVICE);
0106
0107     return 0;
0108 }
0109
0110 static void st7586_fb_dirty(struct drm_framebuffer *fb, struct drm_rect *rect)
0111 {
0112     struct mipi_dbi_dev *dbidev = drm_to_mipi_dbi_dev(fb->dev);
0113     struct mipi_dbi *dbi = &dbidev->dbi;
0114     int start, end, idx, ret = 0;
0115
0116     if (!drm_dev_enter(fb->dev, &idx))
0117         return;
0118
0119     /* 3 pixels per byte, so grow clip to nearest multiple of 3 */
0120     rect->x1 = rounddown(rect->x1, 3);
0121     rect->x2 = roundup(rect->x2, 3);
0122
0123     DRM_DEBUG_KMS("Flushing [FB:%d] " DRM_RECT_FMT "\n", fb->base.id, DRM_RECT_ARG(rect));
0124
0125     ret = st7586_buf_copy(dbidev->tx_buf, fb, rect);
0126     if (ret)
0127         goto err_msg;
0128
0129     /* Pixels are packed 3 per byte */
0130     start = rect->x1 / 3;
0131     end = rect->x2 / 3;
0132
0133     mipi_dbi_command(dbi, MIPI_DCS_SET_COLUMN_ADDRESS,
0134              (start >> 8) & 0xFF, start & 0xFF,
0135              (end >> 8) & 0xFF, (end - 1) & 0xFF);
0136     mipi_dbi_command(dbi, MIPI_DCS_SET_PAGE_ADDRESS,
0137              (rect->y1 >> 8) & 0xFF, rect->y1 & 0xFF,
0138              (rect->y2 >> 8) & 0xFF, (rect->y2 - 1) & 0xFF);
0139
0140     ret = mipi_dbi_command_buf(dbi, MIPI_DCS_WRITE_MEMORY_START,
0141                    (u8 *)dbidev->tx_buf,
0142                    (end - start) * (rect->y2 - rect->y1));
0143 err_msg:
0144     if (ret)
0145         dev_err_once(fb->dev->dev, "Failed to update display %d\n", ret);
0146
0147     drm_dev_exit(idx);
0148 }
0149
0150 static void st7586_pipe_update(struct drm_simple_display_pipe *pipe,
0151                    struct drm_plane_state *old_state)
0152 {
0153     struct drm_plane_state *state = pipe->plane.state;
0154     struct drm_rect rect;
0155
0156     if (!pipe->crtc.state->active)
0157         return;
0158
0159     if (drm_atomic_helper_damage_merged(old_state, state, &rect))
0160         st7586_fb_dirty(state->fb, &rect);
0161 }
0162
0163 static void st7586_pipe_enable(struct drm_simple_display_pipe *pipe,
0164                    struct drm_crtc_state *crtc_state,
0165                    struct drm_plane_state *plane_state)
0166 {
0167     struct mipi_dbi_dev *dbidev = drm_to_mipi_dbi_dev(pipe->crtc.dev);
0168     struct drm_framebuffer *fb = plane_state->fb;
0169     struct mipi_dbi *dbi = &dbidev->dbi;
0170     struct drm_rect rect = {
0171         .x1 = 0,
0172         .x2 = fb->width,
0173         .y1 = 0,
0174         .y2 = fb->height,
0175     };
0176     int idx, ret;
0177     u8 addr_mode;
0178
0179     if (!drm_dev_enter(pipe->crtc.dev, &idx))
0180         return;
0181
0182     DRM_DEBUG_KMS("\n");
0183
0184     ret = mipi_dbi_poweron_reset(dbidev);
0185     if (ret)
0186         goto out_exit;
0187
0188     mipi_dbi_command(dbi, ST7586_AUTO_READ_CTRL, 0x9f);
0189     mipi_dbi_command(dbi, ST7586_OTP_RW_CTRL, 0x00);
0190
0191     msleep(10);
0192
0193     mipi_dbi_command(dbi, ST7586_OTP_READ);
0194
0195     msleep(20);
0196
0197     mipi_dbi_command(dbi, ST7586_OTP_CTRL_OUT);
0198     mipi_dbi_command(dbi, MIPI_DCS_EXIT_SLEEP_MODE);
0199     mipi_dbi_command(dbi, MIPI_DCS_SET_DISPLAY_OFF);
0200
0201     msleep(50);
0202
0203     mipi_dbi_command(dbi, ST7586_SET_VOP_OFFSET, 0x00);
0204     mipi_dbi_command(dbi, ST7586_SET_VOP, 0xe3, 0x00);
0205     mipi_dbi_command(dbi, ST7586_SET_BIAS_SYSTEM, 0x02);
0206     mipi_dbi_command(dbi, ST7586_SET_BOOST_LEVEL, 0x04);
0207     mipi_dbi_command(dbi, ST7586_ENABLE_ANALOG, 0x1d);
0208     mipi_dbi_command(dbi, ST7586_SET_NLINE_INV, 0x00);
0209     mipi_dbi_command(dbi, ST7586_DISP_MODE_GRAY);
0210     mipi_dbi_command(dbi, ST7586_ENABLE_DDRAM, 0x02);
0211
0212     switch (dbidev->rotation) {
0213     default:
0214         addr_mode = 0x00;
0215         break;
0216     case 90:
0217         addr_mode = ST7586_DISP_CTRL_MY;
0218         break;
0219     case 180:
0220         addr_mode = ST7586_DISP_CTRL_MX | ST7586_DISP_CTRL_MY;
0221         break;
0222     case 270:
0223         addr_mode = ST7586_DISP_CTRL_MX;
0224         break;
0225     }
0226     mipi_dbi_command(dbi, MIPI_DCS_SET_ADDRESS_MODE, addr_mode);
0227
0228     mipi_dbi_command(dbi, ST7586_SET_DISP_DUTY, 0x7f);
0229     mipi_dbi_command(dbi, ST7586_SET_PART_DISP, 0xa0);
0230     mipi_dbi_command(dbi, MIPI_DCS_SET_PARTIAL_ROWS, 0x00, 0x00, 0x00, 0x77);
0231     mipi_dbi_command(dbi, MIPI_DCS_EXIT_INVERT_MODE);
0232
0233     msleep(100);
0234
0235     st7586_fb_dirty(fb, &rect);
0236
0237     mipi_dbi_command(dbi, MIPI_DCS_SET_DISPLAY_ON);
0238 out_exit:
0239     drm_dev_exit(idx);
0240 }
0241
0242 static void st7586_pipe_disable(struct drm_simple_display_pipe *pipe)
0243 {
0244     struct mipi_dbi_dev *dbidev = drm_to_mipi_dbi_dev(pipe->crtc.dev);
0245
0246     /*
0247      * This callback is not protected by drm_dev_enter/exit since we want to
0248      * turn off the display on regular driver unload. It's highly unlikely
0249      * that the underlying SPI controller is gone should this be called after
0250      * unplug.
0251      */
0252
0253     DRM_DEBUG_KMS("\n");
0254
0255     mipi_dbi_command(&dbidev->dbi, MIPI_DCS_SET_DISPLAY_OFF);
0256 }
0257
0258 static const u32 st7586_formats[] = {
0259     DRM_FORMAT_XRGB8888,
0260 };
0261
0262 static const struct drm_simple_display_pipe_funcs st7586_pipe_funcs = {
0263     .enable     = st7586_pipe_enable,
0264     .disable    = st7586_pipe_disable,
0265     .update     = st7586_pipe_update,
0266 };
0267
0268 static const struct drm_display_mode st7586_mode = {
0269     DRM_SIMPLE_MODE(178, 128, 37, 27),
0270 };
0271
0272 DEFINE_DRM_GEM_CMA_FOPS(st7586_fops);
0273
0274 static const struct drm_driver st7586_driver = {
0275     .driver_features    = DRIVER_GEM | DRIVER_MODESET | DRIVER_ATOMIC,
0276     .fops           = &st7586_fops,
0277     DRM_GEM_CMA_DRIVER_OPS_VMAP,
0278     .debugfs_init       = mipi_dbi_debugfs_init,
0279     .name           = "st7586",
0280     .desc           = "Sitronix ST7586",
0281     .date           = "20170801",
0282     .major          = 1,
0283     .minor          = 0,
0284 };
0285
0286 static const struct of_device_id st7586_of_match[] = {
0287     { .compatible = "lego,ev3-lcd" },
0288     {},
0289 };
0290 MODULE_DEVICE_TABLE(of, st7586_of_match);
0291
0292 static const struct spi_device_id st7586_id[] = {
0293     { "ev3-lcd", 0 },
0294     { },
0295 };
0296 MODULE_DEVICE_TABLE(spi, st7586_id);
0297
0298 static int st7586_probe(struct spi_device *spi)
0299 {
0300     struct device *dev = &spi->dev;
0301     struct mipi_dbi_dev *dbidev;
0302     struct drm_device *drm;
0303     struct mipi_dbi *dbi;
0304     struct gpio_desc *a0;
0305     u32 rotation = 0;
0306     size_t bufsize;
0307     int ret;
0308
0309     dbidev = devm_drm_dev_alloc(dev, &st7586_driver,
0310                     struct mipi_dbi_dev, drm);
0311     if (IS_ERR(dbidev))
0312         return PTR_ERR(dbidev);
0313
0314     dbi = &dbidev->dbi;
0315     drm = &dbidev->drm;
0316
0317     bufsize = (st7586_mode.vdisplay + 2) / 3 * st7586_mode.hdisplay;
0318
0319     dbi->reset = devm_gpiod_get(dev, "reset", GPIOD_OUT_HIGH);
0320     if (IS_ERR(dbi->reset))
0321         return dev_err_probe(dev, PTR_ERR(dbi->reset), "Failed to get GPIO 'reset'\n");
0322
0323     a0 = devm_gpiod_get(dev, "a0", GPIOD_OUT_LOW);
0324     if (IS_ERR(a0))
0325         return dev_err_probe(dev, PTR_ERR(a0), "Failed to get GPIO 'a0'\n");
0326
0327     device_property_read_u32(dev, "rotation", &rotation);
0328
0329     ret = mipi_dbi_spi_init(spi, dbi, a0);
0330     if (ret)
0331         return ret;
0332
0333     /* Cannot read from this controller via SPI */
0334     dbi->read_commands = NULL;
0335
0336     ret = mipi_dbi_dev_init_with_formats(dbidev, &st7586_pipe_funcs,
0337                          st7586_formats, ARRAY_SIZE(st7586_formats),
0338                          &st7586_mode, rotation, bufsize);
0339     if (ret)
0340         return ret;
0341
0342     /*
0343      * we are using 8-bit data, so we are not actually swapping anything,
0344      * but setting mipi->swap_bytes makes mipi_dbi_typec3_command() do the
0345      * right thing and not use 16-bit transfers (which results in swapped
0346      * bytes on little-endian systems and causes out of order data to be
0347      * sent to the display).
0348      */
0349     dbi->swap_bytes = true;
0350
0351     drm_mode_config_reset(drm);
0352
0353     ret = drm_dev_register(drm, 0);
0354     if (ret)
0355         return ret;
0356
0357     spi_set_drvdata(spi, drm);
0358
0359     drm_fbdev_generic_setup(drm, 0);
0360
0361     return 0;
0362 }
0363
0364 static void st7586_remove(struct spi_device *spi)
0365 {
0366     struct drm_device *drm = spi_get_drvdata(spi);
0367
0368     drm_dev_unplug(drm);
0369     drm_atomic_helper_shutdown(drm);
0370 }
0371
0372 static void st7586_shutdown(struct spi_device *spi)
0373 {
0374     drm_atomic_helper_shutdown(spi_get_drvdata(spi));
0375 }
0376
0377 static struct spi_driver st7586_spi_driver = {
0378     .driver = {
0379         .name = "st7586",
0380         .owner = THIS_MODULE,
0381         .of_match_table = st7586_of_match,
0382     },
0383     .id_table = st7586_id,
0384     .probe = st7586_probe,
0385     .remove = st7586_remove,
0386     .shutdown = st7586_shutdown,
0387 };
0388 module_spi_driver(st7586_spi_driver);
0389
0390 MODULE_DESCRIPTION("Sitronix ST7586 DRM driver");
0391 MODULE_AUTHOR("David Lechner <david@lechnology.com>");
0392 MODULE_LICENSE("GPL");