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/property.h>
14 #include <linux/regulator/consumer.h>
15 #include <linux/spi/spi.h>
16
17 #include <drm/drm_atomic_helper.h>
18 #include <drm/drm_drv.h>
19 #include <drm/drm_fbdev_dma.h>
20 #include <drm/drm_gem_atomic_helper.h>
21 #include <drm/drm_gem_dma_helper.h>
22 #include <drm/drm_managed.h>
23 #include <drm/drm_mipi_dbi.h>
24 #include <drm/drm_modes.h>
25 #include <drm/drm_modeset_helper.h>
26
27 #include <video/mipi_display.h>
28
29 struct panel_mipi_dbi_format {
30 const char *name;
31 u32 fourcc;
32 unsigned int bpp;
33 };
34
35 static const struct panel_mipi_dbi_format panel_mipi_dbi_formats[] = {
36 { "r5g6b5", DRM_FORMAT_RGB565, 16 },
37 { "b6x2g6x2r6x2", DRM_FORMAT_RGB888, 24 },
38 };
39
panel_mipi_dbi_get_format(struct device * dev,u32 * formats,unsigned int * bpp)40 static int panel_mipi_dbi_get_format(struct device *dev, u32 *formats, unsigned int *bpp)
41 {
42 const char *format_name;
43 unsigned int i;
44 int ret;
45
46 formats[1] = DRM_FORMAT_XRGB8888;
47
48 ret = device_property_read_string(dev, "format", &format_name);
49 if (ret) {
50 /* Old Device Trees don't have this property */
51 formats[0] = DRM_FORMAT_RGB565;
52 *bpp = 16;
53 return 0;
54 }
55
56 for (i = 0; i < ARRAY_SIZE(panel_mipi_dbi_formats); i++) {
57 const struct panel_mipi_dbi_format *format = &panel_mipi_dbi_formats[i];
58
59 if (strcmp(format_name, format->name))
60 continue;
61
62 formats[0] = format->fourcc;
63 *bpp = format->bpp;
64 return 0;
65 }
66
67 dev_err(dev, "Pixel format is not supported: '%s'\n", format_name);
68
69 return -EINVAL;
70 }
71
72 static const u8 panel_mipi_dbi_magic[15] = { 'M', 'I', 'P', 'I', ' ', 'D', 'B', 'I',
73 0, 0, 0, 0, 0, 0, 0 };
74
75 /*
76 * The display controller configuration is stored in a firmware file.
77 * The Device Tree 'compatible' property value with a '.bin' suffix is passed
78 * to request_firmware() to fetch this file.
79 */
80 struct panel_mipi_dbi_config {
81 /* Magic string: panel_mipi_dbi_magic */
82 u8 magic[15];
83
84 /* Config file format version */
85 u8 file_format_version;
86
87 /*
88 * MIPI commands to execute when the display pipeline is enabled.
89 * This is used to configure the display controller.
90 *
91 * The commands are stored in a byte array with the format:
92 * command, num_parameters, [ parameter, ...], command, ...
93 *
94 * Some commands require a pause before the next command can be received.
95 * Inserting a delay in the command sequence is done by using the NOP command with one
96 * parameter: delay in miliseconds (the No Operation command is part of the MIPI Display
97 * Command Set where it has no parameters).
98 *
99 * Example:
100 * command 0x11
101 * sleep 120ms
102 * command 0xb1 parameters 0x01, 0x2c, 0x2d
103 * command 0x29
104 *
105 * Byte sequence:
106 * 0x11 0x00
107 * 0x00 0x01 0x78
108 * 0xb1 0x03 0x01 0x2c 0x2d
109 * 0x29 0x00
110 */
111 u8 commands[];
112 };
113
114 struct panel_mipi_dbi_commands {
115 const u8 *buf;
116 size_t len;
117 };
118
119 static struct panel_mipi_dbi_commands *
panel_mipi_dbi_check_commands(struct device * dev,const struct firmware * fw)120 panel_mipi_dbi_check_commands(struct device *dev, const struct firmware *fw)
121 {
122 const struct panel_mipi_dbi_config *config = (struct panel_mipi_dbi_config *)fw->data;
123 struct panel_mipi_dbi_commands *commands;
124 size_t size = fw->size, commands_len;
125 unsigned int i = 0;
126
127 if (size < sizeof(*config) + 2) { /* At least 1 command */
128 dev_err(dev, "config: file size=%zu is too small\n", size);
129 return ERR_PTR(-EINVAL);
130 }
131
132 if (memcmp(config->magic, panel_mipi_dbi_magic, sizeof(config->magic))) {
133 dev_err(dev, "config: Bad magic: %15ph\n", config->magic);
134 return ERR_PTR(-EINVAL);
135 }
136
137 if (config->file_format_version != 1) {
138 dev_err(dev, "config: version=%u is not supported\n", config->file_format_version);
139 return ERR_PTR(-EINVAL);
140 }
141
142 drm_dev_dbg(dev, DRM_UT_DRIVER, "size=%zu version=%u\n", size, config->file_format_version);
143
144 commands_len = size - sizeof(*config);
145
146 while ((i + 1) < commands_len) {
147 u8 command = config->commands[i++];
148 u8 num_parameters = config->commands[i++];
149 const u8 *parameters = &config->commands[i];
150
151 i += num_parameters;
152 if (i > commands_len) {
153 dev_err(dev, "config: command=0x%02x num_parameters=%u overflows\n",
154 command, num_parameters);
155 return ERR_PTR(-EINVAL);
156 }
157
158 if (command == 0x00 && num_parameters == 1)
159 drm_dev_dbg(dev, DRM_UT_DRIVER, "sleep %ums\n", parameters[0]);
160 else
161 drm_dev_dbg(dev, DRM_UT_DRIVER, "command %02x %*ph\n",
162 command, num_parameters, parameters);
163 }
164
165 if (i != commands_len) {
166 dev_err(dev, "config: malformed command array\n");
167 return ERR_PTR(-EINVAL);
168 }
169
170 commands = devm_kzalloc(dev, sizeof(*commands), GFP_KERNEL);
171 if (!commands)
172 return ERR_PTR(-ENOMEM);
173
174 commands->len = commands_len;
175 commands->buf = devm_kmemdup(dev, config->commands, commands->len, GFP_KERNEL);
176 if (!commands->buf)
177 return ERR_PTR(-ENOMEM);
178
179 return commands;
180 }
181
panel_mipi_dbi_commands_from_fw(struct device * dev)182 static struct panel_mipi_dbi_commands *panel_mipi_dbi_commands_from_fw(struct device *dev)
183 {
184 struct panel_mipi_dbi_commands *commands;
185 const struct firmware *fw;
186 const char *compatible;
187 char fw_name[40];
188 int ret;
189
190 ret = of_property_read_string_index(dev->of_node, "compatible", 0, &compatible);
191 if (ret)
192 return ERR_PTR(ret);
193
194 snprintf(fw_name, sizeof(fw_name), "%s.bin", compatible);
195 ret = request_firmware(&fw, fw_name, dev);
196 if (ret) {
197 dev_err(dev, "No config file found for compatible '%s' (error=%d)\n",
198 compatible, ret);
199
200 return ERR_PTR(ret);
201 }
202
203 commands = panel_mipi_dbi_check_commands(dev, fw);
204 release_firmware(fw);
205
206 return commands;
207 }
208
panel_mipi_dbi_commands_execute(struct mipi_dbi * dbi,struct panel_mipi_dbi_commands * commands)209 static void panel_mipi_dbi_commands_execute(struct mipi_dbi *dbi,
210 struct panel_mipi_dbi_commands *commands)
211 {
212 unsigned int i = 0;
213
214 if (!commands)
215 return;
216
217 while (i < commands->len) {
218 u8 command = commands->buf[i++];
219 u8 num_parameters = commands->buf[i++];
220 const u8 *parameters = &commands->buf[i];
221
222 if (command == 0x00 && num_parameters == 1)
223 msleep(parameters[0]);
224 else if (num_parameters)
225 mipi_dbi_command_stackbuf(dbi, command, parameters, num_parameters);
226 else
227 mipi_dbi_command(dbi, command);
228
229 i += num_parameters;
230 }
231 }
232
panel_mipi_dbi_enable(struct drm_simple_display_pipe * pipe,struct drm_crtc_state * crtc_state,struct drm_plane_state * plane_state)233 static void panel_mipi_dbi_enable(struct drm_simple_display_pipe *pipe,
234 struct drm_crtc_state *crtc_state,
235 struct drm_plane_state *plane_state)
236 {
237 struct mipi_dbi_dev *dbidev = drm_to_mipi_dbi_dev(pipe->crtc.dev);
238 struct mipi_dbi *dbi = &dbidev->dbi;
239 int ret, idx;
240
241 if (!drm_dev_enter(pipe->crtc.dev, &idx))
242 return;
243
244 drm_dbg(pipe->crtc.dev, "\n");
245
246 ret = mipi_dbi_poweron_conditional_reset(dbidev);
247 if (ret < 0)
248 goto out_exit;
249 if (!ret)
250 panel_mipi_dbi_commands_execute(dbi, dbidev->driver_private);
251
252 mipi_dbi_enable_flush(dbidev, crtc_state, plane_state);
253 out_exit:
254 drm_dev_exit(idx);
255 }
256
257 static const struct drm_simple_display_pipe_funcs panel_mipi_dbi_pipe_funcs = {
258 DRM_MIPI_DBI_SIMPLE_DISPLAY_PIPE_FUNCS(panel_mipi_dbi_enable),
259 };
260
261 DEFINE_DRM_GEM_DMA_FOPS(panel_mipi_dbi_fops);
262
263 static const struct drm_driver panel_mipi_dbi_driver = {
264 .driver_features = DRIVER_GEM | DRIVER_MODESET | DRIVER_ATOMIC,
265 .fops = &panel_mipi_dbi_fops,
266 DRM_GEM_DMA_DRIVER_OPS_VMAP,
267 .debugfs_init = mipi_dbi_debugfs_init,
268 .name = "panel-mipi-dbi",
269 .desc = "MIPI DBI compatible display panel",
270 .date = "20220103",
271 .major = 1,
272 .minor = 0,
273 };
274
panel_mipi_dbi_get_mode(struct mipi_dbi_dev * dbidev,struct drm_display_mode * mode)275 static int panel_mipi_dbi_get_mode(struct mipi_dbi_dev *dbidev, struct drm_display_mode *mode)
276 {
277 struct device *dev = dbidev->drm.dev;
278 u16 hback_porch, vback_porch;
279 int ret;
280
281 ret = of_get_drm_panel_display_mode(dev->of_node, mode, NULL);
282 if (ret) {
283 dev_err(dev, "%pOF: failed to get panel-timing (error=%d)\n", dev->of_node, ret);
284 return ret;
285 }
286
287 mode->type = DRM_MODE_TYPE_DRIVER | DRM_MODE_TYPE_PREFERRED;
288
289 hback_porch = mode->htotal - mode->hsync_end;
290 vback_porch = mode->vtotal - mode->vsync_end;
291
292 /*
293 * Make sure width and height are set and that only back porch and
294 * pixelclock are set in the other timing values. Also check that
295 * width and height don't exceed the 16-bit value specified by MIPI DCS.
296 */
297 if (!mode->hdisplay || !mode->vdisplay || mode->flags ||
298 mode->hsync_end > mode->hdisplay || (hback_porch + mode->hdisplay) > 0xffff ||
299 mode->vsync_end > mode->vdisplay || (vback_porch + mode->vdisplay) > 0xffff) {
300 dev_err(dev, "%pOF: panel-timing out of bounds\n", dev->of_node);
301 return -EINVAL;
302 }
303
304 /* The driver doesn't use the pixel clock but it is mandatory so fake one if not set */
305 if (!mode->clock)
306 mode->clock = mode->htotal * mode->vtotal * 60 / 1000;
307
308 dbidev->top_offset = vback_porch;
309 dbidev->left_offset = hback_porch;
310
311 return 0;
312 }
313
panel_mipi_dbi_spi_probe(struct spi_device * spi)314 static int panel_mipi_dbi_spi_probe(struct spi_device *spi)
315 {
316 struct device *dev = &spi->dev;
317 struct drm_display_mode mode;
318 struct mipi_dbi_dev *dbidev;
319 struct drm_device *drm;
320 struct mipi_dbi *dbi;
321 struct gpio_desc *dc;
322 unsigned int bpp;
323 size_t buf_size;
324 u32 formats[2];
325 int ret;
326
327 dbidev = devm_drm_dev_alloc(dev, &panel_mipi_dbi_driver, struct mipi_dbi_dev, drm);
328 if (IS_ERR(dbidev))
329 return PTR_ERR(dbidev);
330
331 dbi = &dbidev->dbi;
332 drm = &dbidev->drm;
333
334 ret = panel_mipi_dbi_get_mode(dbidev, &mode);
335 if (ret)
336 return ret;
337
338 dbidev->regulator = devm_regulator_get(dev, "power");
339 if (IS_ERR(dbidev->regulator))
340 return dev_err_probe(dev, PTR_ERR(dbidev->regulator),
341 "Failed to get regulator 'power'\n");
342
343 dbidev->io_regulator = devm_regulator_get(dev, "io");
344 if (IS_ERR(dbidev->io_regulator))
345 return dev_err_probe(dev, PTR_ERR(dbidev->io_regulator),
346 "Failed to get regulator 'io'\n");
347
348 dbidev->backlight = devm_of_find_backlight(dev);
349 if (IS_ERR(dbidev->backlight))
350 return dev_err_probe(dev, PTR_ERR(dbidev->backlight), "Failed to get backlight\n");
351
352 dbi->reset = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_HIGH);
353 if (IS_ERR(dbi->reset))
354 return dev_err_probe(dev, PTR_ERR(dbi->reset), "Failed to get GPIO 'reset'\n");
355
356 /* Multiple panels can share the "dc" GPIO, but only if they are on the same SPI bus! */
357 dc = devm_gpiod_get_optional(dev, "dc", GPIOD_OUT_LOW | GPIOD_FLAGS_BIT_NONEXCLUSIVE);
358 if (IS_ERR(dc))
359 return dev_err_probe(dev, PTR_ERR(dc), "Failed to get GPIO 'dc'\n");
360
361 ret = mipi_dbi_spi_init(spi, dbi, dc);
362 if (ret)
363 return ret;
364
365 if (device_property_present(dev, "write-only"))
366 dbi->read_commands = NULL;
367
368 dbidev->driver_private = panel_mipi_dbi_commands_from_fw(dev);
369 if (IS_ERR(dbidev->driver_private))
370 return PTR_ERR(dbidev->driver_private);
371
372 ret = panel_mipi_dbi_get_format(dev, formats, &bpp);
373 if (ret)
374 return ret;
375
376 buf_size = DIV_ROUND_UP(mode.hdisplay * mode.vdisplay * bpp, 8);
377 ret = mipi_dbi_dev_init_with_formats(dbidev, &panel_mipi_dbi_pipe_funcs,
378 formats, ARRAY_SIZE(formats),
379 &mode, 0, buf_size);
380 if (ret)
381 return ret;
382
383 drm_mode_config_reset(drm);
384
385 ret = drm_dev_register(drm, 0);
386 if (ret)
387 return ret;
388
389 spi_set_drvdata(spi, drm);
390
391 drm_fbdev_dma_setup(drm, 0);
392
393 return 0;
394 }
395
panel_mipi_dbi_spi_remove(struct spi_device * spi)396 static void panel_mipi_dbi_spi_remove(struct spi_device *spi)
397 {
398 struct drm_device *drm = spi_get_drvdata(spi);
399
400 drm_dev_unplug(drm);
401 drm_atomic_helper_shutdown(drm);
402 }
403
panel_mipi_dbi_spi_shutdown(struct spi_device * spi)404 static void panel_mipi_dbi_spi_shutdown(struct spi_device *spi)
405 {
406 drm_atomic_helper_shutdown(spi_get_drvdata(spi));
407 }
408
panel_mipi_dbi_pm_suspend(struct device * dev)409 static int __maybe_unused panel_mipi_dbi_pm_suspend(struct device *dev)
410 {
411 return drm_mode_config_helper_suspend(dev_get_drvdata(dev));
412 }
413
panel_mipi_dbi_pm_resume(struct device * dev)414 static int __maybe_unused panel_mipi_dbi_pm_resume(struct device *dev)
415 {
416 drm_mode_config_helper_resume(dev_get_drvdata(dev));
417
418 return 0;
419 }
420
421 static const struct dev_pm_ops panel_mipi_dbi_pm_ops = {
422 SET_SYSTEM_SLEEP_PM_OPS(panel_mipi_dbi_pm_suspend, panel_mipi_dbi_pm_resume)
423 };
424
425 static const struct of_device_id panel_mipi_dbi_spi_of_match[] = {
426 { .compatible = "panel-mipi-dbi-spi" },
427 {},
428 };
429 MODULE_DEVICE_TABLE(of, panel_mipi_dbi_spi_of_match);
430
431 static const struct spi_device_id panel_mipi_dbi_spi_id[] = {
432 { "panel-mipi-dbi-spi", 0 },
433 { },
434 };
435 MODULE_DEVICE_TABLE(spi, panel_mipi_dbi_spi_id);
436
437 static struct spi_driver panel_mipi_dbi_spi_driver = {
438 .driver = {
439 .name = "panel-mipi-dbi-spi",
440 .of_match_table = panel_mipi_dbi_spi_of_match,
441 .pm = &panel_mipi_dbi_pm_ops,
442 },
443 .id_table = panel_mipi_dbi_spi_id,
444 .probe = panel_mipi_dbi_spi_probe,
445 .remove = panel_mipi_dbi_spi_remove,
446 .shutdown = panel_mipi_dbi_spi_shutdown,
447 };
448 module_spi_driver(panel_mipi_dbi_spi_driver);
449
450 MODULE_DESCRIPTION("MIPI DBI compatible display panel driver");
451 MODULE_AUTHOR("Noralf Trønnes");
452 MODULE_LICENSE("GPL");
453