panel-mipi-dbi.c

  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#include <drm/drm_print.h>
 29
 30#include <video/mipi_display.h>
 31
 32struct panel_mipi_dbi_format {
 33	const char *name;
 34	u32 fourcc;
 35	unsigned int bpp;
 36};
 37
 38static const struct panel_mipi_dbi_format panel_mipi_dbi_formats[] = {
 39	{ "r5g6b5", DRM_FORMAT_RGB565, 16 },
 40	{ "b6x2g6x2r6x2", DRM_FORMAT_RGB888, 24 },
 41};
 42
 43static int panel_mipi_dbi_get_format(struct device *dev, u32 *formats, unsigned int *bpp)
 44{
 45	const char *format_name;
 46	unsigned int i;
 47	int ret;
 48
 49	formats[1] = DRM_FORMAT_XRGB8888;
 50
 51	ret = device_property_read_string(dev, "format", &format_name);
 52	if (ret) {
 53		/* Old Device Trees don't have this property */
 54		formats[0] = DRM_FORMAT_RGB565;
 55		*bpp = 16;
 56		return 0;
 57	}
 58
 59	for (i = 0; i < ARRAY_SIZE(panel_mipi_dbi_formats); i++) {
 60		const struct panel_mipi_dbi_format *format = &panel_mipi_dbi_formats[i];
 61
 62		if (strcmp(format_name, format->name))
 63			continue;
 64
 65		formats[0] = format->fourcc;
 66		*bpp = format->bpp;
 67		return 0;
 68	}
 69
 70	dev_err(dev, "Pixel format is not supported: '%s'\n", format_name);
 71
 72	return -EINVAL;
 73}
 74
 75static const u8 panel_mipi_dbi_magic[15] = { 'M', 'I', 'P', 'I', ' ', 'D', 'B', 'I',
 76					     0, 0, 0, 0, 0, 0, 0 };
 77
 78/*
 79 * The display controller configuration is stored in a firmware file.
 80 * The Device Tree 'compatible' property value with a '.bin' suffix is passed
 81 * to request_firmware() to fetch this file.
 82 */
 83struct panel_mipi_dbi_config {
 84	/* Magic string: panel_mipi_dbi_magic */
 85	u8 magic[15];
 86
 87	/* Config file format version */
 88	u8 file_format_version;
 89
 90	/*
 91	 * MIPI commands to execute when the display pipeline is enabled.
 92	 * This is used to configure the display controller.
 93	 *
 94	 * The commands are stored in a byte array with the format:
 95	 *     command, num_parameters, [ parameter, ...], command, ...
 96	 *
 97	 * Some commands require a pause before the next command can be received.
 98	 * Inserting a delay in the command sequence is done by using the NOP command with one
 99	 * parameter: delay in miliseconds (the No Operation command is part of the MIPI Display
100	 * Command Set where it has no parameters).
101	 *
102	 * Example:
103	 *     command 0x11
104	 *     sleep 120ms
105	 *     command 0xb1 parameters 0x01, 0x2c, 0x2d
106	 *     command 0x29
107	 *
108	 * Byte sequence:
109	 *     0x11 0x00
110	 *     0x00 0x01 0x78
111	 *     0xb1 0x03 0x01 0x2c 0x2d
112	 *     0x29 0x00
113	 */
114	u8 commands[];
115};
116
117struct panel_mipi_dbi_commands {
118	const u8 *buf;
119	size_t len;
120};
121
122static struct panel_mipi_dbi_commands *
123panel_mipi_dbi_check_commands(struct device *dev, const struct firmware *fw)
124{
125	const struct panel_mipi_dbi_config *config = (struct panel_mipi_dbi_config *)fw->data;
126	struct panel_mipi_dbi_commands *commands;
127	size_t size = fw->size, commands_len;
128	unsigned int i = 0;
129
130	if (size < sizeof(*config) + 2) { /* At least 1 command */
131		dev_err(dev, "config: file size=%zu is too small\n", size);
132		return ERR_PTR(-EINVAL);
133	}
134
135	if (memcmp(config->magic, panel_mipi_dbi_magic, sizeof(config->magic))) {
136		dev_err(dev, "config: Bad magic: %15ph\n", config->magic);
137		return ERR_PTR(-EINVAL);
138	}
139
140	if (config->file_format_version != 1) {
141		dev_err(dev, "config: version=%u is not supported\n", config->file_format_version);
142		return ERR_PTR(-EINVAL);
143	}
144
145	drm_dev_dbg(dev, DRM_UT_DRIVER, "size=%zu version=%u\n", size, config->file_format_version);
146
147	commands_len = size - sizeof(*config);
148
149	while ((i + 1) < commands_len) {
150		u8 command = config->commands[i++];
151		u8 num_parameters = config->commands[i++];
152		const u8 *parameters = &config->commands[i];
153
154		i += num_parameters;
155		if (i > commands_len) {
156			dev_err(dev, "config: command=0x%02x num_parameters=%u overflows\n",
157				command, num_parameters);
158			return ERR_PTR(-EINVAL);
159		}
160
161		if (command == 0x00 && num_parameters == 1)
162			drm_dev_dbg(dev, DRM_UT_DRIVER, "sleep %ums\n", parameters[0]);
163		else
164			drm_dev_dbg(dev, DRM_UT_DRIVER, "command %02x %*ph\n",
165				    command, num_parameters, parameters);
166	}
167
168	if (i != commands_len) {
169		dev_err(dev, "config: malformed command array\n");
170		return ERR_PTR(-EINVAL);
171	}
172
173	commands = devm_kzalloc(dev, sizeof(*commands), GFP_KERNEL);
174	if (!commands)
175		return ERR_PTR(-ENOMEM);
176
177	commands->len = commands_len;
178	commands->buf = devm_kmemdup(dev, config->commands, commands->len, GFP_KERNEL);
179	if (!commands->buf)
180		return ERR_PTR(-ENOMEM);
181
182	return commands;
183}
184
185static struct panel_mipi_dbi_commands *panel_mipi_dbi_commands_from_fw(struct device *dev)
186{
187	struct panel_mipi_dbi_commands *commands;
188	const struct firmware *fw;
189	const char *compatible;
190	char fw_name[40];
191	int ret;
192
193	ret = of_property_read_string_index(dev->of_node, "compatible", 0, &compatible);
194	if (ret)
195		return ERR_PTR(ret);
196
197	snprintf(fw_name, sizeof(fw_name), "%s.bin", compatible);
198	ret = request_firmware(&fw, fw_name, dev);
199	if (ret) {
200		dev_err(dev, "No config file found for compatible '%s' (error=%d)\n",
201			compatible, ret);
202
203		return ERR_PTR(ret);
204	}
205
206	commands = panel_mipi_dbi_check_commands(dev, fw);
207	release_firmware(fw);
208
209	return commands;
210}
211
212static void panel_mipi_dbi_commands_execute(struct mipi_dbi *dbi,
213					    struct panel_mipi_dbi_commands *commands)
214{
215	unsigned int i = 0;
216
217	if (!commands)
218		return;
219
220	while (i < commands->len) {
221		u8 command = commands->buf[i++];
222		u8 num_parameters = commands->buf[i++];
223		const u8 *parameters = &commands->buf[i];
224
225		if (command == 0x00 && num_parameters == 1)
226			msleep(parameters[0]);
227		else if (num_parameters)
228			mipi_dbi_command_stackbuf(dbi, command, parameters, num_parameters);
229		else
230			mipi_dbi_command(dbi, command);
231
232		i += num_parameters;
233	}
234}
235
236static void panel_mipi_dbi_enable(struct drm_simple_display_pipe *pipe,
237				  struct drm_crtc_state *crtc_state,
238				  struct drm_plane_state *plane_state)
239{
240	struct mipi_dbi_dev *dbidev = drm_to_mipi_dbi_dev(pipe->crtc.dev);
241	struct mipi_dbi *dbi = &dbidev->dbi;
242	int ret, idx;
243
244	if (!drm_dev_enter(pipe->crtc.dev, &idx))
245		return;
246
247	drm_dbg(pipe->crtc.dev, "\n");
248
249	ret = mipi_dbi_poweron_conditional_reset(dbidev);
250	if (ret < 0)
251		goto out_exit;
252	if (!ret)
253		panel_mipi_dbi_commands_execute(dbi, dbidev->driver_private);
254
255	mipi_dbi_enable_flush(dbidev, crtc_state, plane_state);
256out_exit:
257	drm_dev_exit(idx);
258}
259
260static const struct drm_simple_display_pipe_funcs panel_mipi_dbi_pipe_funcs = {
261	DRM_MIPI_DBI_SIMPLE_DISPLAY_PIPE_FUNCS(panel_mipi_dbi_enable),
262};
263
264DEFINE_DRM_GEM_DMA_FOPS(panel_mipi_dbi_fops);
265
266static const struct drm_driver panel_mipi_dbi_driver = {
267	.driver_features	= DRIVER_GEM | DRIVER_MODESET | DRIVER_ATOMIC,
268	.fops			= &panel_mipi_dbi_fops,
269	DRM_GEM_DMA_DRIVER_OPS_VMAP,
270	DRM_FBDEV_DMA_DRIVER_OPS,
271	.debugfs_init		= mipi_dbi_debugfs_init,
272	.name			= "panel-mipi-dbi",
273	.desc			= "MIPI DBI compatible display panel",
274	.major			= 1,
275	.minor			= 0,
276};
277
278static int panel_mipi_dbi_get_mode(struct mipi_dbi_dev *dbidev, struct drm_display_mode *mode)
279{
280	struct device *dev = dbidev->drm.dev;
281	u16 hback_porch, vback_porch;
282	int ret;
283
284	ret = of_get_drm_panel_display_mode(dev->of_node, mode, NULL);
285	if (ret) {
286		dev_err(dev, "%pOF: failed to get panel-timing (error=%d)\n", dev->of_node, ret);
287		return ret;
288	}
289
290	mode->type = DRM_MODE_TYPE_DRIVER | DRM_MODE_TYPE_PREFERRED;
291
292	hback_porch = mode->htotal - mode->hsync_end;
293	vback_porch = mode->vtotal - mode->vsync_end;
294
295	/*
296	 * Make sure width and height are set and that only back porch and
297	 * pixelclock are set in the other timing values. Also check that
298	 * width and height don't exceed the 16-bit value specified by MIPI DCS.
299	 */
300	if (!mode->hdisplay || !mode->vdisplay || mode->flags ||
301	    mode->hsync_end > mode->hdisplay || (hback_porch + mode->hdisplay) > 0xffff ||
302	    mode->vsync_end > mode->vdisplay || (vback_porch + mode->vdisplay) > 0xffff) {
303		dev_err(dev, "%pOF: panel-timing out of bounds\n", dev->of_node);
304		return -EINVAL;
305	}
306
307	/* The driver doesn't use the pixel clock but it is mandatory so fake one if not set */
308	if (!mode->clock)
309		mode->clock = mode->htotal * mode->vtotal * 60 / 1000;
310
311	dbidev->top_offset = vback_porch;
312	dbidev->left_offset = hback_porch;
313
314	return 0;
315}
316
317static int panel_mipi_dbi_spi_probe(struct spi_device *spi)
318{
319	struct device *dev = &spi->dev;
320	struct drm_display_mode mode;
321	struct mipi_dbi_dev *dbidev;
322	struct drm_device *drm;
323	struct mipi_dbi *dbi;
324	struct gpio_desc *dc;
325	unsigned int bpp;
326	size_t buf_size;
327	u32 formats[2];
328	int ret;
329
330	dbidev = devm_drm_dev_alloc(dev, &panel_mipi_dbi_driver, struct mipi_dbi_dev, drm);
331	if (IS_ERR(dbidev))
332		return PTR_ERR(dbidev);
333
334	dbi = &dbidev->dbi;
335	drm = &dbidev->drm;
336
337	ret = panel_mipi_dbi_get_mode(dbidev, &mode);
338	if (ret)
339		return ret;
340
341	dbidev->regulator = devm_regulator_get(dev, "power");
342	if (IS_ERR(dbidev->regulator))
343		return dev_err_probe(dev, PTR_ERR(dbidev->regulator),
344				     "Failed to get regulator 'power'\n");
345
346	dbidev->io_regulator = devm_regulator_get(dev, "io");
347	if (IS_ERR(dbidev->io_regulator))
348		return dev_err_probe(dev, PTR_ERR(dbidev->io_regulator),
349				     "Failed to get regulator 'io'\n");
350
351	dbidev->backlight = devm_of_find_backlight(dev);
352	if (IS_ERR(dbidev->backlight))
353		return dev_err_probe(dev, PTR_ERR(dbidev->backlight), "Failed to get backlight\n");
354
355	dbi->reset = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_HIGH);
356	if (IS_ERR(dbi->reset))
357		return dev_err_probe(dev, PTR_ERR(dbi->reset), "Failed to get GPIO 'reset'\n");
358
359	/* Multiple panels can share the "dc" GPIO, but only if they are on the same SPI bus! */
360	dc = devm_gpiod_get_optional(dev, "dc", GPIOD_OUT_LOW | GPIOD_FLAGS_BIT_NONEXCLUSIVE);
361	if (IS_ERR(dc))
362		return dev_err_probe(dev, PTR_ERR(dc), "Failed to get GPIO 'dc'\n");
363
364	ret = mipi_dbi_spi_init(spi, dbi, dc);
365	if (ret)
366		return ret;
367
368	if (device_property_present(dev, "write-only"))
369		dbi->read_commands = NULL;
370
371	dbidev->driver_private = panel_mipi_dbi_commands_from_fw(dev);
372	if (IS_ERR(dbidev->driver_private))
373		return PTR_ERR(dbidev->driver_private);
374
375	ret = panel_mipi_dbi_get_format(dev, formats, &bpp);
376	if (ret)
377		return ret;
378
379	buf_size = DIV_ROUND_UP(mode.hdisplay * mode.vdisplay * bpp, 8);
380	ret = mipi_dbi_dev_init_with_formats(dbidev, &panel_mipi_dbi_pipe_funcs,
381					     formats, ARRAY_SIZE(formats),
382					     &mode, 0, buf_size);
383	if (ret)
384		return ret;
385
386	drm_mode_config_reset(drm);
387
388	ret = drm_dev_register(drm, 0);
389	if (ret)
390		return ret;
391
392	spi_set_drvdata(spi, drm);
393
394	if (bpp == 16)
395		drm_client_setup_with_fourcc(drm, DRM_FORMAT_RGB565);
396	else
397		drm_client_setup_with_fourcc(drm, DRM_FORMAT_RGB888);
398
399	return 0;
400}
401
402static void panel_mipi_dbi_spi_remove(struct spi_device *spi)
403{
404	struct drm_device *drm = spi_get_drvdata(spi);
405
406	drm_dev_unplug(drm);
407	drm_atomic_helper_shutdown(drm);
408}
409
410static void panel_mipi_dbi_spi_shutdown(struct spi_device *spi)
411{
412	drm_atomic_helper_shutdown(spi_get_drvdata(spi));
413}
414
415static int __maybe_unused panel_mipi_dbi_pm_suspend(struct device *dev)
416{
417	return drm_mode_config_helper_suspend(dev_get_drvdata(dev));
418}
419
420static int __maybe_unused panel_mipi_dbi_pm_resume(struct device *dev)
421{
422	drm_mode_config_helper_resume(dev_get_drvdata(dev));
423
424	return 0;
425}
426
427static const struct dev_pm_ops panel_mipi_dbi_pm_ops = {
428	SET_SYSTEM_SLEEP_PM_OPS(panel_mipi_dbi_pm_suspend, panel_mipi_dbi_pm_resume)
429};
430
431static const struct of_device_id panel_mipi_dbi_spi_of_match[] = {
432	{ .compatible = "panel-mipi-dbi-spi" },
433	{},
434};
435MODULE_DEVICE_TABLE(of, panel_mipi_dbi_spi_of_match);
436
437static const struct spi_device_id panel_mipi_dbi_spi_id[] = {
438	{ "panel-mipi-dbi-spi", 0 },
439	{ },
440};
441MODULE_DEVICE_TABLE(spi, panel_mipi_dbi_spi_id);
442
443static struct spi_driver panel_mipi_dbi_spi_driver = {
444	.driver = {
445		.name = "panel-mipi-dbi-spi",
446		.of_match_table = panel_mipi_dbi_spi_of_match,
447		.pm = &panel_mipi_dbi_pm_ops,
448	},
449	.id_table = panel_mipi_dbi_spi_id,
450	.probe = panel_mipi_dbi_spi_probe,
451	.remove = panel_mipi_dbi_spi_remove,
452	.shutdown = panel_mipi_dbi_spi_shutdown,
453};
454module_spi_driver(panel_mipi_dbi_spi_driver);
455
456MODULE_DESCRIPTION("MIPI DBI compatible display panel driver");
457MODULE_AUTHOR("Noralf Trønnes");
458MODULE_LICENSE("GPL");