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_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 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 .mode_valid = mipi_dbi_pipe_mode_valid,
216 .enable = panel_mipi_dbi_enable,
217 .disable = mipi_dbi_pipe_disable,
218 .update = mipi_dbi_pipe_update,
219 };
220
221 DEFINE_DRM_GEM_DMA_FOPS(panel_mipi_dbi_fops);
222
223 static const struct drm_driver panel_mipi_dbi_driver = {
224 .driver_features = DRIVER_GEM | DRIVER_MODESET | DRIVER_ATOMIC,
225 .fops = &panel_mipi_dbi_fops,
226 DRM_GEM_DMA_DRIVER_OPS_VMAP,
227 .debugfs_init = mipi_dbi_debugfs_init,
228 .name = "panel-mipi-dbi",
229 .desc = "MIPI DBI compatible display panel",
230 .date = "20220103",
231 .major = 1,
232 .minor = 0,
233 };
234
panel_mipi_dbi_get_mode(struct mipi_dbi_dev * dbidev,struct drm_display_mode * mode)235 static int panel_mipi_dbi_get_mode(struct mipi_dbi_dev *dbidev, struct drm_display_mode *mode)
236 {
237 struct device *dev = dbidev->drm.dev;
238 u16 hback_porch, vback_porch;
239 int ret;
240
241 ret = of_get_drm_panel_display_mode(dev->of_node, mode, NULL);
242 if (ret) {
243 dev_err(dev, "%pOF: failed to get panel-timing (error=%d)\n", dev->of_node, ret);
244 return ret;
245 }
246
247 mode->type = DRM_MODE_TYPE_DRIVER | DRM_MODE_TYPE_PREFERRED;
248
249 hback_porch = mode->htotal - mode->hsync_end;
250 vback_porch = mode->vtotal - mode->vsync_end;
251
252 /*
253 * Make sure width and height are set and that only back porch and
254 * pixelclock are set in the other timing values. Also check that
255 * width and height don't exceed the 16-bit value specified by MIPI DCS.
256 */
257 if (!mode->hdisplay || !mode->vdisplay || mode->flags ||
258 mode->hsync_end > mode->hdisplay || (hback_porch + mode->hdisplay) > 0xffff ||
259 mode->vsync_end > mode->vdisplay || (vback_porch + mode->vdisplay) > 0xffff) {
260 dev_err(dev, "%pOF: panel-timing out of bounds\n", dev->of_node);
261 return -EINVAL;
262 }
263
264 /* The driver doesn't use the pixel clock but it is mandatory so fake one if not set */
265 if (!mode->clock)
266 mode->clock = mode->htotal * mode->vtotal * 60 / 1000;
267
268 dbidev->top_offset = vback_porch;
269 dbidev->left_offset = hback_porch;
270
271 return 0;
272 }
273
panel_mipi_dbi_spi_probe(struct spi_device * spi)274 static int panel_mipi_dbi_spi_probe(struct spi_device *spi)
275 {
276 struct device *dev = &spi->dev;
277 struct drm_display_mode mode;
278 struct mipi_dbi_dev *dbidev;
279 struct drm_device *drm;
280 struct mipi_dbi *dbi;
281 struct gpio_desc *dc;
282 int ret;
283
284 dbidev = devm_drm_dev_alloc(dev, &panel_mipi_dbi_driver, struct mipi_dbi_dev, drm);
285 if (IS_ERR(dbidev))
286 return PTR_ERR(dbidev);
287
288 dbi = &dbidev->dbi;
289 drm = &dbidev->drm;
290
291 ret = panel_mipi_dbi_get_mode(dbidev, &mode);
292 if (ret)
293 return ret;
294
295 dbidev->regulator = devm_regulator_get(dev, "power");
296 if (IS_ERR(dbidev->regulator))
297 return dev_err_probe(dev, PTR_ERR(dbidev->regulator),
298 "Failed to get regulator 'power'\n");
299
300 dbidev->backlight = devm_of_find_backlight(dev);
301 if (IS_ERR(dbidev->backlight))
302 return dev_err_probe(dev, PTR_ERR(dbidev->backlight), "Failed to get backlight\n");
303
304 dbi->reset = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_HIGH);
305 if (IS_ERR(dbi->reset))
306 return dev_err_probe(dev, PTR_ERR(dbi->reset), "Failed to get GPIO 'reset'\n");
307
308 dc = devm_gpiod_get_optional(dev, "dc", GPIOD_OUT_LOW);
309 if (IS_ERR(dc))
310 return dev_err_probe(dev, PTR_ERR(dc), "Failed to get GPIO 'dc'\n");
311
312 ret = mipi_dbi_spi_init(spi, dbi, dc);
313 if (ret)
314 return ret;
315
316 if (device_property_present(dev, "write-only"))
317 dbi->read_commands = NULL;
318
319 dbidev->driver_private = panel_mipi_dbi_commands_from_fw(dev);
320 if (IS_ERR(dbidev->driver_private))
321 return PTR_ERR(dbidev->driver_private);
322
323 ret = mipi_dbi_dev_init(dbidev, &panel_mipi_dbi_pipe_funcs, &mode, 0);
324 if (ret)
325 return ret;
326
327 drm_mode_config_reset(drm);
328
329 ret = drm_dev_register(drm, 0);
330 if (ret)
331 return ret;
332
333 spi_set_drvdata(spi, drm);
334
335 drm_fbdev_generic_setup(drm, 0);
336
337 return 0;
338 }
339
panel_mipi_dbi_spi_remove(struct spi_device * spi)340 static void panel_mipi_dbi_spi_remove(struct spi_device *spi)
341 {
342 struct drm_device *drm = spi_get_drvdata(spi);
343
344 drm_dev_unplug(drm);
345 drm_atomic_helper_shutdown(drm);
346 }
347
panel_mipi_dbi_spi_shutdown(struct spi_device * spi)348 static void panel_mipi_dbi_spi_shutdown(struct spi_device *spi)
349 {
350 drm_atomic_helper_shutdown(spi_get_drvdata(spi));
351 }
352
panel_mipi_dbi_pm_suspend(struct device * dev)353 static int __maybe_unused panel_mipi_dbi_pm_suspend(struct device *dev)
354 {
355 return drm_mode_config_helper_suspend(dev_get_drvdata(dev));
356 }
357
panel_mipi_dbi_pm_resume(struct device * dev)358 static int __maybe_unused panel_mipi_dbi_pm_resume(struct device *dev)
359 {
360 drm_mode_config_helper_resume(dev_get_drvdata(dev));
361
362 return 0;
363 }
364
365 static const struct dev_pm_ops panel_mipi_dbi_pm_ops = {
366 SET_SYSTEM_SLEEP_PM_OPS(panel_mipi_dbi_pm_suspend, panel_mipi_dbi_pm_resume)
367 };
368
369 static const struct of_device_id panel_mipi_dbi_spi_of_match[] = {
370 { .compatible = "panel-mipi-dbi-spi" },
371 {},
372 };
373 MODULE_DEVICE_TABLE(of, panel_mipi_dbi_spi_of_match);
374
375 static const struct spi_device_id panel_mipi_dbi_spi_id[] = {
376 { "panel-mipi-dbi-spi", 0 },
377 { },
378 };
379 MODULE_DEVICE_TABLE(spi, panel_mipi_dbi_spi_id);
380
381 static struct spi_driver panel_mipi_dbi_spi_driver = {
382 .driver = {
383 .name = "panel-mipi-dbi-spi",
384 .owner = THIS_MODULE,
385 .of_match_table = panel_mipi_dbi_spi_of_match,
386 .pm = &panel_mipi_dbi_pm_ops,
387 },
388 .id_table = panel_mipi_dbi_spi_id,
389 .probe = panel_mipi_dbi_spi_probe,
390 .remove = panel_mipi_dbi_spi_remove,
391 .shutdown = panel_mipi_dbi_spi_shutdown,
392 };
393 module_spi_driver(panel_mipi_dbi_spi_driver);
394
395 MODULE_DESCRIPTION("MIPI DBI compatible display panel driver");
396 MODULE_AUTHOR("Noralf Trønnes");
397 MODULE_LICENSE("GPL");
398
