1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * DRM driver for Sitronix ST7586 panels
4 *
5 * Copyright 2017 David Lechner <david@lechnology.com>
6 */
7
8 #include <linux/delay.h>
9 #include <linux/gpio/consumer.h>
10 #include <linux/module.h>
11 #include <linux/property.h>
12 #include <linux/spi/spi.h>
13 #include <video/mipi_display.h>
14
15 #include <drm/drm_atomic_helper.h>
16 #include <drm/drm_damage_helper.h>
17 #include <drm/drm_drv.h>
18 #include <drm/drm_fb_dma_helper.h>
19 #include <drm/drm_fbdev_generic.h>
20 #include <drm/drm_format_helper.h>
21 #include <drm/drm_framebuffer.h>
22 #include <drm/drm_gem_atomic_helper.h>
23 #include <drm/drm_gem_dma_helper.h>
24 #include <drm/drm_gem_framebuffer_helper.h>
25 #include <drm/drm_managed.h>
26 #include <drm/drm_mipi_dbi.h>
27 #include <drm/drm_rect.h>
28
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
45
46 #define ST7586_DISP_CTRL_MX BIT(6)
47 #define ST7586_DISP_CTRL_MY BIT(7)
48
49 /*
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.
53 *
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
61 */
62
63 static const u8 st7586_lookup[] = { 0x7, 0x4, 0x2, 0x0 };
64
st7586_xrgb8888_to_gray332(u8 * dst,void * vaddr,struct drm_framebuffer * fb,struct drm_rect * clip)65 static void st7586_xrgb8888_to_gray332(u8 *dst, void *vaddr,
66 struct drm_framebuffer *fb,
67 struct drm_rect *clip)
68 {
69 size_t len = (clip->x2 - clip->x1) * (clip->y2 - clip->y1);
70 unsigned int x, y;
71 u8 *src, *buf, val;
72 struct iosys_map dst_map, vmap;
73
74 buf = kmalloc(len, GFP_KERNEL);
75 if (!buf)
76 return;
77
78 iosys_map_set_vaddr(&dst_map, buf);
79 iosys_map_set_vaddr(&vmap, vaddr);
80 drm_fb_xrgb8888_to_gray8(&dst_map, NULL, &vmap, fb, clip);
81 src = buf;
82
83 for (y = clip->y1; y < clip->y2; y++) {
84 for (x = clip->x1; x < clip->x2; x += 3) {
85 val = st7586_lookup[*src++ >> 6] << 5;
86 val |= st7586_lookup[*src++ >> 6] << 2;
87 val |= st7586_lookup[*src++ >> 6] >> 1;
88 *dst++ = val;
89 }
90 }
91
92 kfree(buf);
93 }
94
st7586_buf_copy(void * dst,struct iosys_map * src,struct drm_framebuffer * fb,struct drm_rect * clip)95 static int st7586_buf_copy(void *dst, struct iosys_map *src, struct drm_framebuffer *fb,
96 struct drm_rect *clip)
97 {
98 int ret;
99
100 ret = drm_gem_fb_begin_cpu_access(fb, DMA_FROM_DEVICE);
101 if (ret)
102 return ret;
103
104 st7586_xrgb8888_to_gray332(dst, src->vaddr, fb, clip);
105
106 drm_gem_fb_end_cpu_access(fb, DMA_FROM_DEVICE);
107
108 return 0;
109 }
110
st7586_fb_dirty(struct iosys_map * src,struct drm_framebuffer * fb,struct drm_rect * rect)111 static void st7586_fb_dirty(struct iosys_map *src, struct drm_framebuffer *fb,
112 struct drm_rect *rect)
113 {
114 struct mipi_dbi_dev *dbidev = drm_to_mipi_dbi_dev(fb->dev);
115 struct mipi_dbi *dbi = &dbidev->dbi;
116 int start, end, ret = 0;
117
118 /* 3 pixels per byte, so grow clip to nearest multiple of 3 */
119 rect->x1 = rounddown(rect->x1, 3);
120 rect->x2 = roundup(rect->x2, 3);
121
122 DRM_DEBUG_KMS("Flushing [FB:%d] " DRM_RECT_FMT "\n", fb->base.id, DRM_RECT_ARG(rect));
123
124 ret = st7586_buf_copy(dbidev->tx_buf, src, fb, rect);
125 if (ret)
126 goto err_msg;
127
128 /* Pixels are packed 3 per byte */
129 start = rect->x1 / 3;
130 end = rect->x2 / 3;
131
132 mipi_dbi_command(dbi, MIPI_DCS_SET_COLUMN_ADDRESS,
133 (start >> 8) & 0xFF, start & 0xFF,
134 (end >> 8) & 0xFF, (end - 1) & 0xFF);
135 mipi_dbi_command(dbi, MIPI_DCS_SET_PAGE_ADDRESS,
136 (rect->y1 >> 8) & 0xFF, rect->y1 & 0xFF,
137 (rect->y2 >> 8) & 0xFF, (rect->y2 - 1) & 0xFF);
138
139 ret = mipi_dbi_command_buf(dbi, MIPI_DCS_WRITE_MEMORY_START,
140 (u8 *)dbidev->tx_buf,
141 (end - start) * (rect->y2 - rect->y1));
142 err_msg:
143 if (ret)
144 dev_err_once(fb->dev->dev, "Failed to update display %d\n", ret);
145 }
146
st7586_pipe_update(struct drm_simple_display_pipe * pipe,struct drm_plane_state * old_state)147 static void st7586_pipe_update(struct drm_simple_display_pipe *pipe,
148 struct drm_plane_state *old_state)
149 {
150 struct drm_plane_state *state = pipe->plane.state;
151 struct drm_shadow_plane_state *shadow_plane_state = to_drm_shadow_plane_state(state);
152 struct drm_framebuffer *fb = state->fb;
153 struct drm_rect rect;
154 int idx;
155
156 if (!pipe->crtc.state->active)
157 return;
158
159 if (!drm_dev_enter(fb->dev, &idx))
160 return;
161
162 if (drm_atomic_helper_damage_merged(old_state, state, &rect))
163 st7586_fb_dirty(&shadow_plane_state->data[0], fb, &rect);
164
165 drm_dev_exit(idx);
166 }
167
st7586_pipe_enable(struct drm_simple_display_pipe * pipe,struct drm_crtc_state * crtc_state,struct drm_plane_state * plane_state)168 static void st7586_pipe_enable(struct drm_simple_display_pipe *pipe,
169 struct drm_crtc_state *crtc_state,
170 struct drm_plane_state *plane_state)
171 {
172 struct mipi_dbi_dev *dbidev = drm_to_mipi_dbi_dev(pipe->crtc.dev);
173 struct drm_shadow_plane_state *shadow_plane_state = to_drm_shadow_plane_state(plane_state);
174 struct drm_framebuffer *fb = plane_state->fb;
175 struct mipi_dbi *dbi = &dbidev->dbi;
176 struct drm_rect rect = {
177 .x1 = 0,
178 .x2 = fb->width,
179 .y1 = 0,
180 .y2 = fb->height,
181 };
182 int idx, ret;
183 u8 addr_mode;
184
185 if (!drm_dev_enter(pipe->crtc.dev, &idx))
186 return;
187
188 DRM_DEBUG_KMS("\n");
189
190 ret = mipi_dbi_poweron_reset(dbidev);
191 if (ret)
192 goto out_exit;
193
194 mipi_dbi_command(dbi, ST7586_AUTO_READ_CTRL, 0x9f);
195 mipi_dbi_command(dbi, ST7586_OTP_RW_CTRL, 0x00);
196
197 msleep(10);
198
199 mipi_dbi_command(dbi, ST7586_OTP_READ);
200
201 msleep(20);
202
203 mipi_dbi_command(dbi, ST7586_OTP_CTRL_OUT);
204 mipi_dbi_command(dbi, MIPI_DCS_EXIT_SLEEP_MODE);
205 mipi_dbi_command(dbi, MIPI_DCS_SET_DISPLAY_OFF);
206
207 msleep(50);
208
209 mipi_dbi_command(dbi, ST7586_SET_VOP_OFFSET, 0x00);
210 mipi_dbi_command(dbi, ST7586_SET_VOP, 0xe3, 0x00);
211 mipi_dbi_command(dbi, ST7586_SET_BIAS_SYSTEM, 0x02);
212 mipi_dbi_command(dbi, ST7586_SET_BOOST_LEVEL, 0x04);
213 mipi_dbi_command(dbi, ST7586_ENABLE_ANALOG, 0x1d);
214 mipi_dbi_command(dbi, ST7586_SET_NLINE_INV, 0x00);
215 mipi_dbi_command(dbi, ST7586_DISP_MODE_GRAY);
216 mipi_dbi_command(dbi, ST7586_ENABLE_DDRAM, 0x02);
217
218 switch (dbidev->rotation) {
219 default:
220 addr_mode = 0x00;
221 break;
222 case 90:
223 addr_mode = ST7586_DISP_CTRL_MY;
224 break;
225 case 180:
226 addr_mode = ST7586_DISP_CTRL_MX | ST7586_DISP_CTRL_MY;
227 break;
228 case 270:
229 addr_mode = ST7586_DISP_CTRL_MX;
230 break;
231 }
232 mipi_dbi_command(dbi, MIPI_DCS_SET_ADDRESS_MODE, addr_mode);
233
234 mipi_dbi_command(dbi, ST7586_SET_DISP_DUTY, 0x7f);
235 mipi_dbi_command(dbi, ST7586_SET_PART_DISP, 0xa0);
236 mipi_dbi_command(dbi, MIPI_DCS_SET_PARTIAL_ROWS, 0x00, 0x00, 0x00, 0x77);
237 mipi_dbi_command(dbi, MIPI_DCS_EXIT_INVERT_MODE);
238
239 msleep(100);
240
241 st7586_fb_dirty(&shadow_plane_state->data[0], fb, &rect);
242
243 mipi_dbi_command(dbi, MIPI_DCS_SET_DISPLAY_ON);
244 out_exit:
245 drm_dev_exit(idx);
246 }
247
st7586_pipe_disable(struct drm_simple_display_pipe * pipe)248 static void st7586_pipe_disable(struct drm_simple_display_pipe *pipe)
249 {
250 struct mipi_dbi_dev *dbidev = drm_to_mipi_dbi_dev(pipe->crtc.dev);
251
252 /*
253 * This callback is not protected by drm_dev_enter/exit since we want to
254 * turn off the display on regular driver unload. It's highly unlikely
255 * that the underlying SPI controller is gone should this be called after
256 * unplug.
257 */
258
259 DRM_DEBUG_KMS("\n");
260
261 mipi_dbi_command(&dbidev->dbi, MIPI_DCS_SET_DISPLAY_OFF);
262 }
263
264 static const u32 st7586_formats[] = {
265 DRM_FORMAT_XRGB8888,
266 };
267
268 static const struct drm_simple_display_pipe_funcs st7586_pipe_funcs = {
269 .mode_valid = mipi_dbi_pipe_mode_valid,
270 .enable = st7586_pipe_enable,
271 .disable = st7586_pipe_disable,
272 .update = st7586_pipe_update,
273 .begin_fb_access = mipi_dbi_pipe_begin_fb_access,
274 .end_fb_access = mipi_dbi_pipe_end_fb_access,
275 .reset_plane = mipi_dbi_pipe_reset_plane,
276 .duplicate_plane_state = mipi_dbi_pipe_duplicate_plane_state,
277 .destroy_plane_state = mipi_dbi_pipe_destroy_plane_state,
278 };
279
280 static const struct drm_display_mode st7586_mode = {
281 DRM_SIMPLE_MODE(178, 128, 37, 27),
282 };
283
284 DEFINE_DRM_GEM_DMA_FOPS(st7586_fops);
285
286 static const struct drm_driver st7586_driver = {
287 .driver_features = DRIVER_GEM | DRIVER_MODESET | DRIVER_ATOMIC,
288 .fops = &st7586_fops,
289 DRM_GEM_DMA_DRIVER_OPS_VMAP,
290 .debugfs_init = mipi_dbi_debugfs_init,
291 .name = "st7586",
292 .desc = "Sitronix ST7586",
293 .date = "20170801",
294 .major = 1,
295 .minor = 0,
296 };
297
298 static const struct of_device_id st7586_of_match[] = {
299 { .compatible = "lego,ev3-lcd" },
300 {},
301 };
302 MODULE_DEVICE_TABLE(of, st7586_of_match);
303
304 static const struct spi_device_id st7586_id[] = {
305 { "ev3-lcd", 0 },
306 { },
307 };
308 MODULE_DEVICE_TABLE(spi, st7586_id);
309
st7586_probe(struct spi_device * spi)310 static int st7586_probe(struct spi_device *spi)
311 {
312 struct device *dev = &spi->dev;
313 struct mipi_dbi_dev *dbidev;
314 struct drm_device *drm;
315 struct mipi_dbi *dbi;
316 struct gpio_desc *a0;
317 u32 rotation = 0;
318 size_t bufsize;
319 int ret;
320
321 dbidev = devm_drm_dev_alloc(dev, &st7586_driver,
322 struct mipi_dbi_dev, drm);
323 if (IS_ERR(dbidev))
324 return PTR_ERR(dbidev);
325
326 dbi = &dbidev->dbi;
327 drm = &dbidev->drm;
328
329 bufsize = (st7586_mode.vdisplay + 2) / 3 * st7586_mode.hdisplay;
330
331 dbi->reset = devm_gpiod_get(dev, "reset", GPIOD_OUT_HIGH);
332 if (IS_ERR(dbi->reset))
333 return dev_err_probe(dev, PTR_ERR(dbi->reset), "Failed to get GPIO 'reset'\n");
334
335 a0 = devm_gpiod_get(dev, "a0", GPIOD_OUT_LOW);
336 if (IS_ERR(a0))
337 return dev_err_probe(dev, PTR_ERR(a0), "Failed to get GPIO 'a0'\n");
338
339 device_property_read_u32(dev, "rotation", &rotation);
340
341 ret = mipi_dbi_spi_init(spi, dbi, a0);
342 if (ret)
343 return ret;
344
345 /* Cannot read from this controller via SPI */
346 dbi->read_commands = NULL;
347
348 ret = mipi_dbi_dev_init_with_formats(dbidev, &st7586_pipe_funcs,
349 st7586_formats, ARRAY_SIZE(st7586_formats),
350 &st7586_mode, rotation, bufsize);
351 if (ret)
352 return ret;
353
354 /*
355 * we are using 8-bit data, so we are not actually swapping anything,
356 * but setting mipi->swap_bytes makes mipi_dbi_typec3_command() do the
357 * right thing and not use 16-bit transfers (which results in swapped
358 * bytes on little-endian systems and causes out of order data to be
359 * sent to the display).
360 */
361 dbi->swap_bytes = true;
362
363 drm_mode_config_reset(drm);
364
365 ret = drm_dev_register(drm, 0);
366 if (ret)
367 return ret;
368
369 spi_set_drvdata(spi, drm);
370
371 drm_fbdev_generic_setup(drm, 0);
372
373 return 0;
374 }
375
st7586_remove(struct spi_device * spi)376 static void st7586_remove(struct spi_device *spi)
377 {
378 struct drm_device *drm = spi_get_drvdata(spi);
379
380 drm_dev_unplug(drm);
381 drm_atomic_helper_shutdown(drm);
382 }
383
st7586_shutdown(struct spi_device * spi)384 static void st7586_shutdown(struct spi_device *spi)
385 {
386 drm_atomic_helper_shutdown(spi_get_drvdata(spi));
387 }
388
389 static struct spi_driver st7586_spi_driver = {
390 .driver = {
391 .name = "st7586",
392 .owner = THIS_MODULE,
393 .of_match_table = st7586_of_match,
394 },
395 .id_table = st7586_id,
396 .probe = st7586_probe,
397 .remove = st7586_remove,
398 .shutdown = st7586_shutdown,
399 };
400 module_spi_driver(st7586_spi_driver);
401
402 MODULE_DESCRIPTION("Sitronix ST7586 DRM driver");
403 MODULE_AUTHOR("David Lechner <david@lechnology.com>");
404 MODULE_LICENSE("GPL");
405
