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