1 // SPDX-License-Identifier: GPL-2.0-or-later
3 * DRM driver for Sitronix ST7586 panels
5 * Copyright 2017 David Lechner <david@lechnology.com>
8 #include <linux/delay.h>
9 #include <linux/dma-buf.h>
10 #include <linux/gpio/consumer.h>
11 #include <linux/module.h>
12 #include <linux/property.h>
13 #include <linux/spi/spi.h>
14 #include <video/mipi_display.h>
16 #include <drm/drm_atomic_helper.h>
17 #include <drm/drm_damage_helper.h>
18 #include <drm/drm_drv.h>
19 #include <drm/drm_fb_cma_helper.h>
20 #include <drm/drm_fb_helper.h>
21 #include <drm/drm_format_helper.h>
22 #include <drm/drm_gem_cma_helper.h>
23 #include <drm/drm_gem_framebuffer_helper.h>
24 #include <drm/drm_rect.h>
25 #include <drm/drm_vblank.h>
26 #include <drm/tinydrm/mipi-dbi.h>
27 #include <drm/tinydrm/tinydrm-helpers.h>
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
46 #define ST7586_DISP_CTRL_MX BIT(6)
47 #define ST7586_DISP_CTRL_MY BIT(7)
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.
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
63 static const u8 st7586_lookup[] = { 0x7, 0x4, 0x2, 0x0 };
65 static void st7586_xrgb8888_to_gray332(u8 *dst, void *vaddr,
66 struct drm_framebuffer *fb,
67 struct drm_rect *clip)
69 size_t len = (clip->x2 - clip->x1) * (clip->y2 - clip->y1);
73 buf = kmalloc(len, GFP_KERNEL);
77 drm_fb_xrgb8888_to_gray8(buf, vaddr, fb, clip);
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;
92 static int st7586_buf_copy(void *dst, struct drm_framebuffer *fb,
93 struct drm_rect *clip)
95 struct drm_gem_cma_object *cma_obj = drm_fb_cma_get_gem_obj(fb, 0);
96 struct dma_buf_attachment *import_attach = cma_obj->base.import_attach;
97 void *src = cma_obj->vaddr;
101 ret = dma_buf_begin_cpu_access(import_attach->dmabuf,
107 st7586_xrgb8888_to_gray332(dst, src, fb, clip);
110 ret = dma_buf_end_cpu_access(import_attach->dmabuf,
116 static void st7586_fb_dirty(struct drm_framebuffer *fb, struct drm_rect *rect)
118 struct mipi_dbi *mipi = drm_to_mipi_dbi(fb->dev);
119 int start, end, idx, ret = 0;
124 if (!drm_dev_enter(fb->dev, &idx))
127 /* 3 pixels per byte, so grow clip to nearest multiple of 3 */
128 rect->x1 = rounddown(rect->x1, 3);
129 rect->x2 = roundup(rect->x2, 3);
131 DRM_DEBUG_KMS("Flushing [FB:%d] " DRM_RECT_FMT "\n", fb->base.id, DRM_RECT_ARG(rect));
133 ret = st7586_buf_copy(mipi->tx_buf, fb, rect);
137 /* Pixels are packed 3 per byte */
138 start = rect->x1 / 3;
141 mipi_dbi_command(mipi, MIPI_DCS_SET_COLUMN_ADDRESS,
142 (start >> 8) & 0xFF, start & 0xFF,
143 (end >> 8) & 0xFF, (end - 1) & 0xFF);
144 mipi_dbi_command(mipi, MIPI_DCS_SET_PAGE_ADDRESS,
145 (rect->y1 >> 8) & 0xFF, rect->y1 & 0xFF,
146 (rect->y2 >> 8) & 0xFF, (rect->y2 - 1) & 0xFF);
148 ret = mipi_dbi_command_buf(mipi, MIPI_DCS_WRITE_MEMORY_START,
150 (end - start) * (rect->y2 - rect->y1));
153 dev_err_once(fb->dev->dev, "Failed to update display %d\n", ret);
158 static void st7586_pipe_update(struct drm_simple_display_pipe *pipe,
159 struct drm_plane_state *old_state)
161 struct drm_plane_state *state = pipe->plane.state;
162 struct drm_crtc *crtc = &pipe->crtc;
163 struct drm_rect rect;
165 if (drm_atomic_helper_damage_merged(old_state, state, &rect))
166 st7586_fb_dirty(state->fb, &rect);
168 if (crtc->state->event) {
169 spin_lock_irq(&crtc->dev->event_lock);
170 drm_crtc_send_vblank_event(crtc, crtc->state->event);
171 spin_unlock_irq(&crtc->dev->event_lock);
172 crtc->state->event = NULL;
176 static void st7586_pipe_enable(struct drm_simple_display_pipe *pipe,
177 struct drm_crtc_state *crtc_state,
178 struct drm_plane_state *plane_state)
180 struct mipi_dbi *mipi = drm_to_mipi_dbi(pipe->crtc.dev);
181 struct drm_framebuffer *fb = plane_state->fb;
182 struct drm_rect rect = {
191 if (!drm_dev_enter(pipe->crtc.dev, &idx))
196 ret = mipi_dbi_poweron_reset(mipi);
200 mipi_dbi_command(mipi, ST7586_AUTO_READ_CTRL, 0x9f);
201 mipi_dbi_command(mipi, ST7586_OTP_RW_CTRL, 0x00);
205 mipi_dbi_command(mipi, ST7586_OTP_READ);
209 mipi_dbi_command(mipi, ST7586_OTP_CTRL_OUT);
210 mipi_dbi_command(mipi, MIPI_DCS_EXIT_SLEEP_MODE);
211 mipi_dbi_command(mipi, MIPI_DCS_SET_DISPLAY_OFF);
215 mipi_dbi_command(mipi, ST7586_SET_VOP_OFFSET, 0x00);
216 mipi_dbi_command(mipi, ST7586_SET_VOP, 0xe3, 0x00);
217 mipi_dbi_command(mipi, ST7586_SET_BIAS_SYSTEM, 0x02);
218 mipi_dbi_command(mipi, ST7586_SET_BOOST_LEVEL, 0x04);
219 mipi_dbi_command(mipi, ST7586_ENABLE_ANALOG, 0x1d);
220 mipi_dbi_command(mipi, ST7586_SET_NLINE_INV, 0x00);
221 mipi_dbi_command(mipi, ST7586_DISP_MODE_GRAY);
222 mipi_dbi_command(mipi, ST7586_ENABLE_DDRAM, 0x02);
224 switch (mipi->rotation) {
229 addr_mode = ST7586_DISP_CTRL_MY;
232 addr_mode = ST7586_DISP_CTRL_MX | ST7586_DISP_CTRL_MY;
235 addr_mode = ST7586_DISP_CTRL_MX;
238 mipi_dbi_command(mipi, MIPI_DCS_SET_ADDRESS_MODE, addr_mode);
240 mipi_dbi_command(mipi, ST7586_SET_DISP_DUTY, 0x7f);
241 mipi_dbi_command(mipi, ST7586_SET_PART_DISP, 0xa0);
242 mipi_dbi_command(mipi, MIPI_DCS_SET_PARTIAL_AREA, 0x00, 0x00, 0x00, 0x77);
243 mipi_dbi_command(mipi, MIPI_DCS_EXIT_INVERT_MODE);
247 mipi->enabled = true;
248 st7586_fb_dirty(fb, &rect);
250 mipi_dbi_command(mipi, MIPI_DCS_SET_DISPLAY_ON);
255 static void st7586_pipe_disable(struct drm_simple_display_pipe *pipe)
257 struct mipi_dbi *mipi = drm_to_mipi_dbi(pipe->crtc.dev);
260 * This callback is not protected by drm_dev_enter/exit since we want to
261 * turn off the display on regular driver unload. It's highly unlikely
262 * that the underlying SPI controller is gone should this be called after
271 mipi_dbi_command(mipi, MIPI_DCS_SET_DISPLAY_OFF);
272 mipi->enabled = false;
275 static const u32 st7586_formats[] = {
279 static const struct drm_simple_display_pipe_funcs st7586_pipe_funcs = {
280 .enable = st7586_pipe_enable,
281 .disable = st7586_pipe_disable,
282 .update = st7586_pipe_update,
283 .prepare_fb = drm_gem_fb_simple_display_pipe_prepare_fb,
286 static const struct drm_mode_config_funcs st7586_mode_config_funcs = {
287 .fb_create = drm_gem_fb_create_with_dirty,
288 .atomic_check = drm_atomic_helper_check,
289 .atomic_commit = drm_atomic_helper_commit,
292 static const struct drm_display_mode st7586_mode = {
293 DRM_SIMPLE_MODE(178, 128, 37, 27),
296 DEFINE_DRM_GEM_CMA_FOPS(st7586_fops);
298 static struct drm_driver st7586_driver = {
299 .driver_features = DRIVER_GEM | DRIVER_MODESET | DRIVER_PRIME |
301 .fops = &st7586_fops,
302 .release = mipi_dbi_release,
303 DRM_GEM_CMA_VMAP_DRIVER_OPS,
304 .debugfs_init = mipi_dbi_debugfs_init,
306 .desc = "Sitronix ST7586",
312 static const struct of_device_id st7586_of_match[] = {
313 { .compatible = "lego,ev3-lcd" },
316 MODULE_DEVICE_TABLE(of, st7586_of_match);
318 static const struct spi_device_id st7586_id[] = {
322 MODULE_DEVICE_TABLE(spi, st7586_id);
324 static int st7586_probe(struct spi_device *spi)
326 struct device *dev = &spi->dev;
327 struct drm_device *drm;
328 struct mipi_dbi *mipi;
329 struct gpio_desc *a0;
334 mipi = kzalloc(sizeof(*mipi), GFP_KERNEL);
339 ret = devm_drm_dev_init(dev, drm, &st7586_driver);
345 drm_mode_config_init(drm);
346 drm->mode_config.preferred_depth = 32;
347 drm->mode_config.funcs = &st7586_mode_config_funcs;
349 mutex_init(&mipi->cmdlock);
351 bufsize = (st7586_mode.vdisplay + 2) / 3 * st7586_mode.hdisplay;
352 mipi->tx_buf = devm_kmalloc(dev, bufsize, GFP_KERNEL);
356 mipi->reset = devm_gpiod_get(dev, "reset", GPIOD_OUT_HIGH);
357 if (IS_ERR(mipi->reset)) {
358 DRM_DEV_ERROR(dev, "Failed to get gpio 'reset'\n");
359 return PTR_ERR(mipi->reset);
362 a0 = devm_gpiod_get(dev, "a0", GPIOD_OUT_LOW);
364 DRM_DEV_ERROR(dev, "Failed to get gpio 'a0'\n");
368 device_property_read_u32(dev, "rotation", &rotation);
369 mipi->rotation = rotation;
371 ret = mipi_dbi_spi_init(spi, mipi, a0);
375 /* Cannot read from this controller via SPI */
376 mipi->read_commands = NULL;
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).
385 mipi->swap_bytes = true;
387 ret = tinydrm_display_pipe_init(drm, &mipi->pipe, &st7586_pipe_funcs,
388 DRM_MODE_CONNECTOR_VIRTUAL,
389 st7586_formats, ARRAY_SIZE(st7586_formats),
390 &st7586_mode, rotation);
394 drm_plane_enable_fb_damage_clips(&mipi->pipe.plane);
396 drm_mode_config_reset(drm);
398 ret = drm_dev_register(drm, 0);
402 spi_set_drvdata(spi, drm);
404 DRM_DEBUG_KMS("preferred_depth=%u, rotation = %u\n",
405 drm->mode_config.preferred_depth, rotation);
407 drm_fbdev_generic_setup(drm, 0);
412 static int st7586_remove(struct spi_device *spi)
414 struct drm_device *drm = spi_get_drvdata(spi);
417 drm_atomic_helper_shutdown(drm);
422 static void st7586_shutdown(struct spi_device *spi)
424 drm_atomic_helper_shutdown(spi_get_drvdata(spi));
427 static struct spi_driver st7586_spi_driver = {
430 .owner = THIS_MODULE,
431 .of_match_table = st7586_of_match,
433 .id_table = st7586_id,
434 .probe = st7586_probe,
435 .remove = st7586_remove,
436 .shutdown = st7586_shutdown,
438 module_spi_driver(st7586_spi_driver);
440 MODULE_DESCRIPTION("Sitronix ST7586 DRM driver");
441 MODULE_AUTHOR("David Lechner <david@lechnology.com>");
442 MODULE_LICENSE("GPL");