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