1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * DRM driver for MIPI DBI compatible display panels
4 *
5 * Copyright 2022 Noralf Trønnes
6 */
7
8 #include <linux/backlight.h>
9 #include <linux/delay.h>
10 #include <linux/firmware.h>
11 #include <linux/gpio/consumer.h>
12 #include <linux/module.h>
13 #include <linux/of.h>
14 #include <linux/property.h>
15 #include <linux/regulator/consumer.h>
16 #include <linux/spi/spi.h>
17
18 #include <drm/clients/drm_client_setup.h>
19 #include <drm/drm_atomic_helper.h>
20 #include <drm/drm_drv.h>
21 #include <drm/drm_fbdev_dma.h>
22 #include <drm/drm_gem_atomic_helper.h>
23 #include <drm/drm_gem_dma_helper.h>
24 #include <drm/drm_managed.h>
25 #include <drm/drm_mipi_dbi.h>
26 #include <drm/drm_modes.h>
27 #include <drm/drm_modeset_helper.h>
28
29 #include <video/mipi_display.h>
30
31 struct panel_mipi_dbi_format {
32 const char *name;
33 u32 fourcc;
34 unsigned int bpp;
35 };
36
37 static const struct panel_mipi_dbi_format panel_mipi_dbi_formats[] = {
38 { "r5g6b5", DRM_FORMAT_RGB565, 16 },
39 { "b6x2g6x2r6x2", DRM_FORMAT_RGB888, 24 },
40 };
41
panel_mipi_dbi_get_format(struct device * dev,u32 * formats,unsigned int * bpp)42 static int panel_mipi_dbi_get_format(struct device *dev, u32 *formats, unsigned int *bpp)
43 {
44 const char *format_name;
45 unsigned int i;
46 int ret;
47
48 formats[1] = DRM_FORMAT_XRGB8888;
49
50 ret = device_property_read_string(dev, "format", &format_name);
51 if (ret) {
52 /* Old Device Trees don't have this property */
53 formats[0] = DRM_FORMAT_RGB565;
54 *bpp = 16;
55 return 0;
56 }
57
58 for (i = 0; i < ARRAY_SIZE(panel_mipi_dbi_formats); i++) {
59 const struct panel_mipi_dbi_format *format = &panel_mipi_dbi_formats[i];
60
61 if (strcmp(format_name, format->name))
62 continue;
63
64 formats[0] = format->fourcc;
65 *bpp = format->bpp;
66 return 0;
67 }
68
69 dev_err(dev, "Pixel format is not supported: '%s'\n", format_name);
70
71 return -EINVAL;
72 }
73
74 static const u8 panel_mipi_dbi_magic[15] = { 'M', 'I', 'P', 'I', ' ', 'D', 'B', 'I',
75 0, 0, 0, 0, 0, 0, 0 };
76
77 /*
78 * The display controller configuration is stored in a firmware file.
79 * The Device Tree 'compatible' property value with a '.bin' suffix is passed
80 * to request_firmware() to fetch this file.
81 */
82 struct panel_mipi_dbi_config {
83 /* Magic string: panel_mipi_dbi_magic */
84 u8 magic[15];
85
86 /* Config file format version */
87 u8 file_format_version;
88
89 /*
90 * MIPI commands to execute when the display pipeline is enabled.
91 * This is used to configure the display controller.
92 *
93 * The commands are stored in a byte array with the format:
94 * command, num_parameters, [ parameter, ...], command, ...
95 *
96 * Some commands require a pause before the next command can be received.
97 * Inserting a delay in the command sequence is done by using the NOP command with one
98 * parameter: delay in miliseconds (the No Operation command is part of the MIPI Display
99 * Command Set where it has no parameters).
100 *
101 * Example:
102 * command 0x11
103 * sleep 120ms
104 * command 0xb1 parameters 0x01, 0x2c, 0x2d
105 * command 0x29
106 *
107 * Byte sequence:
108 * 0x11 0x00
109 * 0x00 0x01 0x78
110 * 0xb1 0x03 0x01 0x2c 0x2d
111 * 0x29 0x00
112 */
113 u8 commands[];
114 };
115
116 struct panel_mipi_dbi_commands {
117 const u8 *buf;
118 size_t len;
119 };
120
121 static struct panel_mipi_dbi_commands *
panel_mipi_dbi_check_commands(struct device * dev,const struct firmware * fw)122 panel_mipi_dbi_check_commands(struct device *dev, const struct firmware *fw)
123 {
124 const struct panel_mipi_dbi_config *config = (struct panel_mipi_dbi_config *)fw->data;
125 struct panel_mipi_dbi_commands *commands;
126 size_t size = fw->size, commands_len;
127 unsigned int i = 0;
128
129 if (size < sizeof(*config) + 2) { /* At least 1 command */
130 dev_err(dev, "config: file size=%zu is too small\n", size);
131 return ERR_PTR(-EINVAL);
132 }
133
134 if (memcmp(config->magic, panel_mipi_dbi_magic, sizeof(config->magic))) {
135 dev_err(dev, "config: Bad magic: %15ph\n", config->magic);
136 return ERR_PTR(-EINVAL);
137 }
138
139 if (config->file_format_version != 1) {
140 dev_err(dev, "config: version=%u is not supported\n", config->file_format_version);
141 return ERR_PTR(-EINVAL);
142 }
143
144 drm_dev_dbg(dev, DRM_UT_DRIVER, "size=%zu version=%u\n", size, config->file_format_version);
145
146 commands_len = size - sizeof(*config);
147
148 while ((i + 1) < commands_len) {
149 u8 command = config->commands[i++];
150 u8 num_parameters = config->commands[i++];
151 const u8 *parameters = &config->commands[i];
152
153 i += num_parameters;
154 if (i > commands_len) {
155 dev_err(dev, "config: command=0x%02x num_parameters=%u overflows\n",
156 command, num_parameters);
157 return ERR_PTR(-EINVAL);
158 }
159
160 if (command == 0x00 && num_parameters == 1)
161 drm_dev_dbg(dev, DRM_UT_DRIVER, "sleep %ums\n", parameters[0]);
162 else
163 drm_dev_dbg(dev, DRM_UT_DRIVER, "command %02x %*ph\n",
164 command, num_parameters, parameters);
165 }
166
167 if (i != commands_len) {
168 dev_err(dev, "config: malformed command array\n");
169 return ERR_PTR(-EINVAL);
170 }
171
172 commands = devm_kzalloc(dev, sizeof(*commands), GFP_KERNEL);
173 if (!commands)
174 return ERR_PTR(-ENOMEM);
175
176 commands->len = commands_len;
177 commands->buf = devm_kmemdup(dev, config->commands, commands->len, GFP_KERNEL);
178 if (!commands->buf)
179 return ERR_PTR(-ENOMEM);
180
181 return commands;
182 }
183
panel_mipi_dbi_commands_from_fw(struct device * dev)184 static struct panel_mipi_dbi_commands *panel_mipi_dbi_commands_from_fw(struct device *dev)
185 {
186 struct panel_mipi_dbi_commands *commands;
187 const struct firmware *fw;
188 const char *compatible;
189 char fw_name[40];
190 int ret;
191
192 ret = of_property_read_string_index(dev->of_node, "compatible", 0, &compatible);
193 if (ret)
194 return ERR_PTR(ret);
195
196 snprintf(fw_name, sizeof(fw_name), "%s.bin", compatible);
197 ret = request_firmware(&fw, fw_name, dev);
198 if (ret) {
199 dev_err(dev, "No config file found for compatible '%s' (error=%d)\n",
200 compatible, ret);
201
202 return ERR_PTR(ret);
203 }
204
205 commands = panel_mipi_dbi_check_commands(dev, fw);
206 release_firmware(fw);
207
208 return commands;
209 }
210
panel_mipi_dbi_commands_execute(struct mipi_dbi * dbi,struct panel_mipi_dbi_commands * commands)211 static void panel_mipi_dbi_commands_execute(struct mipi_dbi *dbi,
212 struct panel_mipi_dbi_commands *commands)
213 {
214 unsigned int i = 0;
215
216 if (!commands)
217 return;
218
219 while (i < commands->len) {
220 u8 command = commands->buf[i++];
221 u8 num_parameters = commands->buf[i++];
222 const u8 *parameters = &commands->buf[i];
223
224 if (command == 0x00 && num_parameters == 1)
225 msleep(parameters[0]);
226 else if (num_parameters)
227 mipi_dbi_command_stackbuf(dbi, command, parameters, num_parameters);
228 else
229 mipi_dbi_command(dbi, command);
230
231 i += num_parameters;
232 }
233 }
234
panel_mipi_dbi_enable(struct drm_simple_display_pipe * pipe,struct drm_crtc_state * crtc_state,struct drm_plane_state * plane_state)235 static void panel_mipi_dbi_enable(struct drm_simple_display_pipe *pipe,
236 struct drm_crtc_state *crtc_state,
237 struct drm_plane_state *plane_state)
238 {
239 struct mipi_dbi_dev *dbidev = drm_to_mipi_dbi_dev(pipe->crtc.dev);
240 struct mipi_dbi *dbi = &dbidev->dbi;
241 int ret, idx;
242
243 if (!drm_dev_enter(pipe->crtc.dev, &idx))
244 return;
245
246 drm_dbg(pipe->crtc.dev, "\n");
247
248 ret = mipi_dbi_poweron_conditional_reset(dbidev);
249 if (ret < 0)
250 goto out_exit;
251 if (!ret)
252 panel_mipi_dbi_commands_execute(dbi, dbidev->driver_private);
253
254 mipi_dbi_enable_flush(dbidev, crtc_state, plane_state);
255 out_exit:
256 drm_dev_exit(idx);
257 }
258
259 static const struct drm_simple_display_pipe_funcs panel_mipi_dbi_pipe_funcs = {
260 DRM_MIPI_DBI_SIMPLE_DISPLAY_PIPE_FUNCS(panel_mipi_dbi_enable),
261 };
262
263 DEFINE_DRM_GEM_DMA_FOPS(panel_mipi_dbi_fops);
264
265 static const struct drm_driver panel_mipi_dbi_driver = {
266 .driver_features = DRIVER_GEM | DRIVER_MODESET | DRIVER_ATOMIC,
267 .fops = &panel_mipi_dbi_fops,
268 DRM_GEM_DMA_DRIVER_OPS_VMAP,
269 DRM_FBDEV_DMA_DRIVER_OPS,
270 .debugfs_init = mipi_dbi_debugfs_init,
271 .name = "panel-mipi-dbi",
272 .desc = "MIPI DBI compatible display panel",
273 .major = 1,
274 .minor = 0,
275 };
276
panel_mipi_dbi_get_mode(struct mipi_dbi_dev * dbidev,struct drm_display_mode * mode)277 static int panel_mipi_dbi_get_mode(struct mipi_dbi_dev *dbidev, struct drm_display_mode *mode)
278 {
279 struct device *dev = dbidev->drm.dev;
280 u16 hback_porch, vback_porch;
281 int ret;
282
283 ret = of_get_drm_panel_display_mode(dev->of_node, mode, NULL);
284 if (ret) {
285 dev_err(dev, "%pOF: failed to get panel-timing (error=%d)\n", dev->of_node, ret);
286 return ret;
287 }
288
289 mode->type = DRM_MODE_TYPE_DRIVER | DRM_MODE_TYPE_PREFERRED;
290
291 hback_porch = mode->htotal - mode->hsync_end;
292 vback_porch = mode->vtotal - mode->vsync_end;
293
294 /*
295 * Make sure width and height are set and that only back porch and
296 * pixelclock are set in the other timing values. Also check that
297 * width and height don't exceed the 16-bit value specified by MIPI DCS.
298 */
299 if (!mode->hdisplay || !mode->vdisplay || mode->flags ||
300 mode->hsync_end > mode->hdisplay || (hback_porch + mode->hdisplay) > 0xffff ||
301 mode->vsync_end > mode->vdisplay || (vback_porch + mode->vdisplay) > 0xffff) {
302 dev_err(dev, "%pOF: panel-timing out of bounds\n", dev->of_node);
303 return -EINVAL;
304 }
305
306 /* The driver doesn't use the pixel clock but it is mandatory so fake one if not set */
307 if (!mode->clock)
308 mode->clock = mode->htotal * mode->vtotal * 60 / 1000;
309
310 dbidev->top_offset = vback_porch;
311 dbidev->left_offset = hback_porch;
312
313 return 0;
314 }
315
panel_mipi_dbi_spi_probe(struct spi_device * spi)316 static int panel_mipi_dbi_spi_probe(struct spi_device *spi)
317 {
318 struct device *dev = &spi->dev;
319 struct drm_display_mode mode;
320 struct mipi_dbi_dev *dbidev;
321 struct drm_device *drm;
322 struct mipi_dbi *dbi;
323 struct gpio_desc *dc;
324 unsigned int bpp;
325 size_t buf_size;
326 u32 formats[2];
327 int ret;
328
329 dbidev = devm_drm_dev_alloc(dev, &panel_mipi_dbi_driver, struct mipi_dbi_dev, drm);
330 if (IS_ERR(dbidev))
331 return PTR_ERR(dbidev);
332
333 dbi = &dbidev->dbi;
334 drm = &dbidev->drm;
335
336 ret = panel_mipi_dbi_get_mode(dbidev, &mode);
337 if (ret)
338 return ret;
339
340 dbidev->regulator = devm_regulator_get(dev, "power");
341 if (IS_ERR(dbidev->regulator))
342 return dev_err_probe(dev, PTR_ERR(dbidev->regulator),
343 "Failed to get regulator 'power'\n");
344
345 dbidev->io_regulator = devm_regulator_get(dev, "io");
346 if (IS_ERR(dbidev->io_regulator))
347 return dev_err_probe(dev, PTR_ERR(dbidev->io_regulator),
348 "Failed to get regulator 'io'\n");
349
350 dbidev->backlight = devm_of_find_backlight(dev);
351 if (IS_ERR(dbidev->backlight))
352 return dev_err_probe(dev, PTR_ERR(dbidev->backlight), "Failed to get backlight\n");
353
354 dbi->reset = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_HIGH);
355 if (IS_ERR(dbi->reset))
356 return dev_err_probe(dev, PTR_ERR(dbi->reset), "Failed to get GPIO 'reset'\n");
357
358 /* Multiple panels can share the "dc" GPIO, but only if they are on the same SPI bus! */
359 dc = devm_gpiod_get_optional(dev, "dc", GPIOD_OUT_LOW | GPIOD_FLAGS_BIT_NONEXCLUSIVE);
360 if (IS_ERR(dc))
361 return dev_err_probe(dev, PTR_ERR(dc), "Failed to get GPIO 'dc'\n");
362
363 ret = mipi_dbi_spi_init(spi, dbi, dc);
364 if (ret)
365 return ret;
366
367 if (device_property_present(dev, "write-only"))
368 dbi->read_commands = NULL;
369
370 dbidev->driver_private = panel_mipi_dbi_commands_from_fw(dev);
371 if (IS_ERR(dbidev->driver_private))
372 return PTR_ERR(dbidev->driver_private);
373
374 ret = panel_mipi_dbi_get_format(dev, formats, &bpp);
375 if (ret)
376 return ret;
377
378 buf_size = DIV_ROUND_UP(mode.hdisplay * mode.vdisplay * bpp, 8);
379 ret = mipi_dbi_dev_init_with_formats(dbidev, &panel_mipi_dbi_pipe_funcs,
380 formats, ARRAY_SIZE(formats),
381 &mode, 0, buf_size);
382 if (ret)
383 return ret;
384
385 drm_mode_config_reset(drm);
386
387 ret = drm_dev_register(drm, 0);
388 if (ret)
389 return ret;
390
391 spi_set_drvdata(spi, drm);
392
393 drm_client_setup(drm, NULL);
394
395 return 0;
396 }
397
panel_mipi_dbi_spi_remove(struct spi_device * spi)398 static void panel_mipi_dbi_spi_remove(struct spi_device *spi)
399 {
400 struct drm_device *drm = spi_get_drvdata(spi);
401
402 drm_dev_unplug(drm);
403 drm_atomic_helper_shutdown(drm);
404 }
405
panel_mipi_dbi_spi_shutdown(struct spi_device * spi)406 static void panel_mipi_dbi_spi_shutdown(struct spi_device *spi)
407 {
408 drm_atomic_helper_shutdown(spi_get_drvdata(spi));
409 }
410
panel_mipi_dbi_pm_suspend(struct device * dev)411 static int __maybe_unused panel_mipi_dbi_pm_suspend(struct device *dev)
412 {
413 return drm_mode_config_helper_suspend(dev_get_drvdata(dev));
414 }
415
panel_mipi_dbi_pm_resume(struct device * dev)416 static int __maybe_unused panel_mipi_dbi_pm_resume(struct device *dev)
417 {
418 drm_mode_config_helper_resume(dev_get_drvdata(dev));
419
420 return 0;
421 }
422
423 static const struct dev_pm_ops panel_mipi_dbi_pm_ops = {
424 SET_SYSTEM_SLEEP_PM_OPS(panel_mipi_dbi_pm_suspend, panel_mipi_dbi_pm_resume)
425 };
426
427 static const struct of_device_id panel_mipi_dbi_spi_of_match[] = {
428 { .compatible = "panel-mipi-dbi-spi" },
429 {},
430 };
431 MODULE_DEVICE_TABLE(of, panel_mipi_dbi_spi_of_match);
432
433 static const struct spi_device_id panel_mipi_dbi_spi_id[] = {
434 { "panel-mipi-dbi-spi", 0 },
435 { },
436 };
437 MODULE_DEVICE_TABLE(spi, panel_mipi_dbi_spi_id);
438
439 static struct spi_driver panel_mipi_dbi_spi_driver = {
440 .driver = {
441 .name = "panel-mipi-dbi-spi",
442 .of_match_table = panel_mipi_dbi_spi_of_match,
443 .pm = &panel_mipi_dbi_pm_ops,
444 },
445 .id_table = panel_mipi_dbi_spi_id,
446 .probe = panel_mipi_dbi_spi_probe,
447 .remove = panel_mipi_dbi_spi_remove,
448 .shutdown = panel_mipi_dbi_spi_shutdown,
449 };
450 module_spi_driver(panel_mipi_dbi_spi_driver);
451
452 MODULE_DESCRIPTION("MIPI DBI compatible display panel driver");
453 MODULE_AUTHOR("Noralf Trønnes");
454 MODULE_LICENSE("GPL");
455