1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * DRM driver for Sitronix ST7586 panels
4 *
5 * Copyright 2017 David Lechner <david@lechnology.com>
6 */
7
8#include <linux/delay.h>
9#include <linux/gpio/consumer.h>
10#include <linux/module.h>
11#include <linux/property.h>
12#include <linux/spi/spi.h>
13#include <video/mipi_display.h>
14
15#include <drm/drm_atomic_helper.h>
16#include <drm/drm_damage_helper.h>
17#include <drm/drm_drv.h>
18#include <drm/drm_fb_dma_helper.h>
19#include <drm/drm_fbdev_generic.h>
20#include <drm/drm_format_helper.h>
21#include <drm/drm_framebuffer.h>
22#include <drm/drm_gem_atomic_helper.h>
23#include <drm/drm_gem_dma_helper.h>
24#include <drm/drm_gem_framebuffer_helper.h>
25#include <drm/drm_managed.h>
26#include <drm/drm_mipi_dbi.h>
27#include <drm/drm_rect.h>
28
29/* controller-specific commands */
30#define ST7586_DISP_MODE_GRAY	0x38
31#define ST7586_DISP_MODE_MONO	0x39
32#define ST7586_ENABLE_DDRAM	0x3a
33#define ST7586_SET_DISP_DUTY	0xb0
34#define ST7586_SET_PART_DISP	0xb4
35#define ST7586_SET_NLINE_INV	0xb5
36#define ST7586_SET_VOP		0xc0
37#define ST7586_SET_BIAS_SYSTEM	0xc3
38#define ST7586_SET_BOOST_LEVEL	0xc4
39#define ST7586_SET_VOP_OFFSET	0xc7
40#define ST7586_ENABLE_ANALOG	0xd0
41#define ST7586_AUTO_READ_CTRL	0xd7
42#define ST7586_OTP_RW_CTRL	0xe0
43#define ST7586_OTP_CTRL_OUT	0xe1
44#define ST7586_OTP_READ		0xe3
45
46#define ST7586_DISP_CTRL_MX	BIT(6)
47#define ST7586_DISP_CTRL_MY	BIT(7)
48
49/*
50 * The ST7586 controller has an unusual pixel format where 2bpp grayscale is
51 * packed 3 pixels per byte with the first two pixels using 3 bits and the 3rd
52 * pixel using only 2 bits.
53 *
54 * |  D7  |  D6  |  D5  ||      |      || 2bpp |
55 * | (D4) | (D3) | (D2) ||  D1  |  D0  || GRAY |
56 * +------+------+------++------+------++------+
57 * |  1   |  1   |  1   ||  1   |  1   || 0  0 | black
58 * |  1   |  0   |  0   ||  1   |  0   || 0  1 | dark gray
59 * |  0   |  1   |  0   ||  0   |  1   || 1  0 | light gray
60 * |  0   |  0   |  0   ||  0   |  0   || 1  1 | white
61 */
62
63static const u8 st7586_lookup[] = { 0x7, 0x4, 0x2, 0x0 };
64
65static void st7586_xrgb8888_to_gray332(u8 *dst, void *vaddr,
66				       struct drm_framebuffer *fb,
67				       struct drm_rect *clip,
68				       struct drm_format_conv_state *fmtcnv_state)
69{
70	size_t len = (clip->x2 - clip->x1) * (clip->y2 - clip->y1);
71	unsigned int x, y;
72	u8 *src, *buf, val;
73	struct iosys_map dst_map, vmap;
74
75	buf = kmalloc(len, GFP_KERNEL);
76	if (!buf)
77		return;
78
79	iosys_map_set_vaddr(&dst_map, buf);
80	iosys_map_set_vaddr(&vmap, vaddr);
81	drm_fb_xrgb8888_to_gray8(&dst_map, NULL, &vmap, fb, clip, fmtcnv_state);
82	src = buf;
83
84	for (y = clip->y1; y < clip->y2; y++) {
85		for (x = clip->x1; x < clip->x2; x += 3) {
86			val = st7586_lookup[*src++ >> 6] << 5;
87			val |= st7586_lookup[*src++ >> 6] << 2;
88			val |= st7586_lookup[*src++ >> 6] >> 1;
89			*dst++ = val;
90		}
91	}
92
93	kfree(buf);
94}
95
96static int st7586_buf_copy(void *dst, struct iosys_map *src, struct drm_framebuffer *fb,
97			   struct drm_rect *clip, struct drm_format_conv_state *fmtcnv_state)
98{
99	int ret;
100
101	ret = drm_gem_fb_begin_cpu_access(fb, DMA_FROM_DEVICE);
102	if (ret)
103		return ret;
104
105	st7586_xrgb8888_to_gray332(dst, src->vaddr, fb, clip, fmtcnv_state);
106
107	drm_gem_fb_end_cpu_access(fb, DMA_FROM_DEVICE);
108
109	return 0;
110}
111
112static void st7586_fb_dirty(struct iosys_map *src, struct drm_framebuffer *fb,
113			    struct drm_rect *rect, struct drm_format_conv_state *fmtcnv_state)
114{
115	struct mipi_dbi_dev *dbidev = drm_to_mipi_dbi_dev(fb->dev);
116	struct mipi_dbi *dbi = &dbidev->dbi;
117	int start, end, ret = 0;
118
119	/* 3 pixels per byte, so grow clip to nearest multiple of 3 */
120	rect->x1 = rounddown(rect->x1, 3);
121	rect->x2 = roundup(rect->x2, 3);
122
123	DRM_DEBUG_KMS("Flushing [FB:%d] " DRM_RECT_FMT "\n", fb->base.id, DRM_RECT_ARG(rect));
124
125	ret = st7586_buf_copy(dbidev->tx_buf, src, fb, rect, fmtcnv_state);
126	if (ret)
127		goto err_msg;
128
129	/* Pixels are packed 3 per byte */
130	start = rect->x1 / 3;
131	end = rect->x2 / 3;
132
133	mipi_dbi_command(dbi, MIPI_DCS_SET_COLUMN_ADDRESS,
134			 (start >> 8) & 0xFF, start & 0xFF,
135			 (end >> 8) & 0xFF, (end - 1) & 0xFF);
136	mipi_dbi_command(dbi, MIPI_DCS_SET_PAGE_ADDRESS,
137			 (rect->y1 >> 8) & 0xFF, rect->y1 & 0xFF,
138			 (rect->y2 >> 8) & 0xFF, (rect->y2 - 1) & 0xFF);
139
140	ret = mipi_dbi_command_buf(dbi, MIPI_DCS_WRITE_MEMORY_START,
141				   (u8 *)dbidev->tx_buf,
142				   (end - start) * (rect->y2 - rect->y1));
143err_msg:
144	if (ret)
145		dev_err_once(fb->dev->dev, "Failed to update display %d\n", ret);
146}
147
148static void st7586_pipe_update(struct drm_simple_display_pipe *pipe,
149			       struct drm_plane_state *old_state)
150{
151	struct drm_plane_state *state = pipe->plane.state;
152	struct drm_shadow_plane_state *shadow_plane_state = to_drm_shadow_plane_state(state);
153	struct drm_framebuffer *fb = state->fb;
154	struct drm_rect rect;
155	int idx;
156
157	if (!pipe->crtc.state->active)
158		return;
159
160	if (!drm_dev_enter(fb->dev, &idx))
161		return;
162
163	if (drm_atomic_helper_damage_merged(old_state, state, &rect))
164		st7586_fb_dirty(&shadow_plane_state->data[0], fb, &rect,
165				&shadow_plane_state->fmtcnv_state);
166
167	drm_dev_exit(idx);
168}
169
170static void st7586_pipe_enable(struct drm_simple_display_pipe *pipe,
171			       struct drm_crtc_state *crtc_state,
172			       struct drm_plane_state *plane_state)
173{
174	struct mipi_dbi_dev *dbidev = drm_to_mipi_dbi_dev(pipe->crtc.dev);
175	struct drm_shadow_plane_state *shadow_plane_state = to_drm_shadow_plane_state(plane_state);
176	struct drm_framebuffer *fb = plane_state->fb;
177	struct mipi_dbi *dbi = &dbidev->dbi;
178	struct drm_rect rect = {
179		.x1 = 0,
180		.x2 = fb->width,
181		.y1 = 0,
182		.y2 = fb->height,
183	};
184	int idx, ret;
185	u8 addr_mode;
186
187	if (!drm_dev_enter(pipe->crtc.dev, &idx))
188		return;
189
190	DRM_DEBUG_KMS("\n");
191
192	ret = mipi_dbi_poweron_reset(dbidev);
193	if (ret)
194		goto out_exit;
195
196	mipi_dbi_command(dbi, ST7586_AUTO_READ_CTRL, 0x9f);
197	mipi_dbi_command(dbi, ST7586_OTP_RW_CTRL, 0x00);
198
199	msleep(10);
200
201	mipi_dbi_command(dbi, ST7586_OTP_READ);
202
203	msleep(20);
204
205	mipi_dbi_command(dbi, ST7586_OTP_CTRL_OUT);
206	mipi_dbi_command(dbi, MIPI_DCS_EXIT_SLEEP_MODE);
207	mipi_dbi_command(dbi, MIPI_DCS_SET_DISPLAY_OFF);
208
209	msleep(50);
210
211	mipi_dbi_command(dbi, ST7586_SET_VOP_OFFSET, 0x00);
212	mipi_dbi_command(dbi, ST7586_SET_VOP, 0xe3, 0x00);
213	mipi_dbi_command(dbi, ST7586_SET_BIAS_SYSTEM, 0x02);
214	mipi_dbi_command(dbi, ST7586_SET_BOOST_LEVEL, 0x04);
215	mipi_dbi_command(dbi, ST7586_ENABLE_ANALOG, 0x1d);
216	mipi_dbi_command(dbi, ST7586_SET_NLINE_INV, 0x00);
217	mipi_dbi_command(dbi, ST7586_DISP_MODE_GRAY);
218	mipi_dbi_command(dbi, ST7586_ENABLE_DDRAM, 0x02);
219
220	switch (dbidev->rotation) {
221	default:
222		addr_mode = 0x00;
223		break;
224	case 90:
225		addr_mode = ST7586_DISP_CTRL_MY;
226		break;
227	case 180:
228		addr_mode = ST7586_DISP_CTRL_MX | ST7586_DISP_CTRL_MY;
229		break;
230	case 270:
231		addr_mode = ST7586_DISP_CTRL_MX;
232		break;
233	}
234	mipi_dbi_command(dbi, MIPI_DCS_SET_ADDRESS_MODE, addr_mode);
235
236	mipi_dbi_command(dbi, ST7586_SET_DISP_DUTY, 0x7f);
237	mipi_dbi_command(dbi, ST7586_SET_PART_DISP, 0xa0);
238	mipi_dbi_command(dbi, MIPI_DCS_SET_PARTIAL_ROWS, 0x00, 0x00, 0x00, 0x77);
239	mipi_dbi_command(dbi, MIPI_DCS_EXIT_INVERT_MODE);
240
241	msleep(100);
242
243	st7586_fb_dirty(&shadow_plane_state->data[0], fb, &rect,
244			&shadow_plane_state->fmtcnv_state);
245
246	mipi_dbi_command(dbi, MIPI_DCS_SET_DISPLAY_ON);
247out_exit:
248	drm_dev_exit(idx);
249}
250
251static void st7586_pipe_disable(struct drm_simple_display_pipe *pipe)
252{
253	struct mipi_dbi_dev *dbidev = drm_to_mipi_dbi_dev(pipe->crtc.dev);
254
255	/*
256	 * This callback is not protected by drm_dev_enter/exit since we want to
257	 * turn off the display on regular driver unload. It's highly unlikely
258	 * that the underlying SPI controller is gone should this be called after
259	 * unplug.
260	 */
261
262	DRM_DEBUG_KMS("\n");
263
264	mipi_dbi_command(&dbidev->dbi, MIPI_DCS_SET_DISPLAY_OFF);
265}
266
267static const u32 st7586_formats[] = {
268	DRM_FORMAT_XRGB8888,
269};
270
271static const struct drm_simple_display_pipe_funcs st7586_pipe_funcs = {
272	.mode_valid	= mipi_dbi_pipe_mode_valid,
273	.enable		= st7586_pipe_enable,
274	.disable	= st7586_pipe_disable,
275	.update		= st7586_pipe_update,
276	.begin_fb_access = mipi_dbi_pipe_begin_fb_access,
277	.end_fb_access	= mipi_dbi_pipe_end_fb_access,
278	.reset_plane	= mipi_dbi_pipe_reset_plane,
279	.duplicate_plane_state = mipi_dbi_pipe_duplicate_plane_state,
280	.destroy_plane_state = mipi_dbi_pipe_destroy_plane_state,
281};
282
283static const struct drm_display_mode st7586_mode = {
284	DRM_SIMPLE_MODE(178, 128, 37, 27),
285};
286
287DEFINE_DRM_GEM_DMA_FOPS(st7586_fops);
288
289static const struct drm_driver st7586_driver = {
290	.driver_features	= DRIVER_GEM | DRIVER_MODESET | DRIVER_ATOMIC,
291	.fops			= &st7586_fops,
292	DRM_GEM_DMA_DRIVER_OPS_VMAP,
293	.debugfs_init		= mipi_dbi_debugfs_init,
294	.name			= "st7586",
295	.desc			= "Sitronix ST7586",
296	.date			= "20170801",
297	.major			= 1,
298	.minor			= 0,
299};
300
301static const struct of_device_id st7586_of_match[] = {
302	{ .compatible = "lego,ev3-lcd" },
303	{},
304};
305MODULE_DEVICE_TABLE(of, st7586_of_match);
306
307static const struct spi_device_id st7586_id[] = {
308	{ "ev3-lcd", 0 },
309	{ },
310};
311MODULE_DEVICE_TABLE(spi, st7586_id);
312
313static int st7586_probe(struct spi_device *spi)
314{
315	struct device *dev = &spi->dev;
316	struct mipi_dbi_dev *dbidev;
317	struct drm_device *drm;
318	struct mipi_dbi *dbi;
319	struct gpio_desc *a0;
320	u32 rotation = 0;
321	size_t bufsize;
322	int ret;
323
324	dbidev = devm_drm_dev_alloc(dev, &st7586_driver,
325				    struct mipi_dbi_dev, drm);
326	if (IS_ERR(dbidev))
327		return PTR_ERR(dbidev);
328
329	dbi = &dbidev->dbi;
330	drm = &dbidev->drm;
331
332	bufsize = (st7586_mode.vdisplay + 2) / 3 * st7586_mode.hdisplay;
333
334	dbi->reset = devm_gpiod_get(dev, "reset", GPIOD_OUT_HIGH);
335	if (IS_ERR(dbi->reset))
336		return dev_err_probe(dev, PTR_ERR(dbi->reset), "Failed to get GPIO 'reset'\n");
337
338	a0 = devm_gpiod_get(dev, "a0", GPIOD_OUT_LOW);
339	if (IS_ERR(a0))
340		return dev_err_probe(dev, PTR_ERR(a0), "Failed to get GPIO 'a0'\n");
341
342	device_property_read_u32(dev, "rotation", &rotation);
343
344	ret = mipi_dbi_spi_init(spi, dbi, a0);
345	if (ret)
346		return ret;
347
348	/* Cannot read from this controller via SPI */
349	dbi->read_commands = NULL;
350
351	ret = mipi_dbi_dev_init_with_formats(dbidev, &st7586_pipe_funcs,
352					     st7586_formats, ARRAY_SIZE(st7586_formats),
353					     &st7586_mode, rotation, bufsize);
354	if (ret)
355		return ret;
356
357	/*
358	 * we are using 8-bit data, so we are not actually swapping anything,
359	 * but setting mipi->swap_bytes makes mipi_dbi_typec3_command() do the
360	 * right thing and not use 16-bit transfers (which results in swapped
361	 * bytes on little-endian systems and causes out of order data to be
362	 * sent to the display).
363	 */
364	dbi->swap_bytes = true;
365
366	drm_mode_config_reset(drm);
367
368	ret = drm_dev_register(drm, 0);
369	if (ret)
370		return ret;
371
372	spi_set_drvdata(spi, drm);
373
374	drm_fbdev_generic_setup(drm, 0);
375
376	return 0;
377}
378
379static void st7586_remove(struct spi_device *spi)
380{
381	struct drm_device *drm = spi_get_drvdata(spi);
382
383	drm_dev_unplug(drm);
384	drm_atomic_helper_shutdown(drm);
385}
386
387static void st7586_shutdown(struct spi_device *spi)
388{
389	drm_atomic_helper_shutdown(spi_get_drvdata(spi));
390}
391
392static struct spi_driver st7586_spi_driver = {
393	.driver = {
394		.name = "st7586",
395		.owner = THIS_MODULE,
396		.of_match_table = st7586_of_match,
397	},
398	.id_table = st7586_id,
399	.probe = st7586_probe,
400	.remove = st7586_remove,
401	.shutdown = st7586_shutdown,
402};
403module_spi_driver(st7586_spi_driver);
404
405MODULE_DESCRIPTION("Sitronix ST7586 DRM driver");
406MODULE_AUTHOR("David Lechner <david@lechnology.com>");
407MODULE_LICENSE("GPL");
408