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1/*
2 * DRM driver for Sitronix ST7586 panels
3 *
4 * Copyright 2017 David Lechner <david@lechnology.com>
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; either version 2 of the License, or
9 * (at your option) any later version.
10 */
11
12#include <linux/delay.h>
13#include <linux/dma-buf.h>
14#include <linux/gpio/consumer.h>
15#include <linux/module.h>
16#include <linux/property.h>
17#include <linux/spi/spi.h>
18#include <video/mipi_display.h>
19
20#include <drm/drm_fb_helper.h>
21#include <drm/drm_gem_framebuffer_helper.h>
22#include <drm/tinydrm/mipi-dbi.h>
23#include <drm/tinydrm/tinydrm-helpers.h>
24
25/* controller-specific commands */
26#define ST7586_DISP_MODE_GRAY 0x38
27#define ST7586_DISP_MODE_MONO 0x39
28#define ST7586_ENABLE_DDRAM 0x3a
29#define ST7586_SET_DISP_DUTY 0xb0
30#define ST7586_SET_PART_DISP 0xb4
31#define ST7586_SET_NLINE_INV 0xb5
32#define ST7586_SET_VOP 0xc0
33#define ST7586_SET_BIAS_SYSTEM 0xc3
34#define ST7586_SET_BOOST_LEVEL 0xc4
35#define ST7586_SET_VOP_OFFSET 0xc7
36#define ST7586_ENABLE_ANALOG 0xd0
37#define ST7586_AUTO_READ_CTRL 0xd7
38#define ST7586_OTP_RW_CTRL 0xe0
39#define ST7586_OTP_CTRL_OUT 0xe1
40#define ST7586_OTP_READ 0xe3
41
42#define ST7586_DISP_CTRL_MX BIT(6)
43#define ST7586_DISP_CTRL_MY BIT(7)
44
45/*
46 * The ST7586 controller has an unusual pixel format where 2bpp grayscale is
47 * packed 3 pixels per byte with the first two pixels using 3 bits and the 3rd
48 * pixel using only 2 bits.
49 *
50 * | D7 | D6 | D5 || | || 2bpp |
51 * | (D4) | (D3) | (D2) || D1 | D0 || GRAY |
52 * +------+------+------++------+------++------+
53 * | 1 | 1 | 1 || 1 | 1 || 0 0 | black
54 * | 1 | 0 | 0 || 1 | 0 || 0 1 | dark gray
55 * | 0 | 1 | 0 || 0 | 1 || 1 0 | light gray
56 * | 0 | 0 | 0 || 0 | 0 || 1 1 | white
57 */
58
59static const u8 st7586_lookup[] = { 0x7, 0x4, 0x2, 0x0 };
60
61static void st7586_xrgb8888_to_gray332(u8 *dst, void *vaddr,
62 struct drm_framebuffer *fb,
63 struct drm_clip_rect *clip)
64{
65 size_t len = (clip->x2 - clip->x1) * (clip->y2 - clip->y1);
66 unsigned int x, y;
67 u8 *src, *buf, val;
68
69 buf = kmalloc(len, GFP_KERNEL);
70 if (!buf)
71 return;
72
73 tinydrm_xrgb8888_to_gray8(buf, vaddr, fb, clip);
74 src = buf;
75
76 for (y = clip->y1; y < clip->y2; y++) {
77 for (x = clip->x1; x < clip->x2; x += 3) {
78 val = st7586_lookup[*src++ >> 6] << 5;
79 val |= st7586_lookup[*src++ >> 6] << 2;
80 val |= st7586_lookup[*src++ >> 6] >> 1;
81 *dst++ = val;
82 }
83 }
84
85 kfree(buf);
86}
87
88static int st7586_buf_copy(void *dst, struct drm_framebuffer *fb,
89 struct drm_clip_rect *clip)
90{
91 struct drm_gem_cma_object *cma_obj = drm_fb_cma_get_gem_obj(fb, 0);
92 struct dma_buf_attachment *import_attach = cma_obj->base.import_attach;
93 void *src = cma_obj->vaddr;
94 int ret = 0;
95
96 if (import_attach) {
97 ret = dma_buf_begin_cpu_access(import_attach->dmabuf,
98 DMA_FROM_DEVICE);
99 if (ret)
100 return ret;
101 }
102
103 st7586_xrgb8888_to_gray332(dst, src, fb, clip);
104
105 if (import_attach)
106 ret = dma_buf_end_cpu_access(import_attach->dmabuf,
107 DMA_FROM_DEVICE);
108
109 return ret;
110}
111
112static int st7586_fb_dirty(struct drm_framebuffer *fb,
113 struct drm_file *file_priv, unsigned int flags,
114 unsigned int color, struct drm_clip_rect *clips,
115 unsigned int num_clips)
116{
117 struct tinydrm_device *tdev = fb->dev->dev_private;
118 struct mipi_dbi *mipi = mipi_dbi_from_tinydrm(tdev);
119 struct drm_clip_rect clip;
120 int start, end;
121 int ret = 0;
122
123 mutex_lock(&tdev->dirty_lock);
124
125 if (!mipi->enabled)
126 goto out_unlock;
127
128 /* fbdev can flush even when we're not interested */
129 if (tdev->pipe.plane.fb != fb)
130 goto out_unlock;
131
132 tinydrm_merge_clips(&clip, clips, num_clips, flags, fb->width,
133 fb->height);
134
135 /* 3 pixels per byte, so grow clip to nearest multiple of 3 */
136 clip.x1 = rounddown(clip.x1, 3);
137 clip.x2 = roundup(clip.x2, 3);
138
139 DRM_DEBUG("Flushing [FB:%d] x1=%u, x2=%u, y1=%u, y2=%u\n", fb->base.id,
140 clip.x1, clip.x2, clip.y1, clip.y2);
141
142 ret = st7586_buf_copy(mipi->tx_buf, fb, &clip);
143 if (ret)
144 goto out_unlock;
145
146 /* Pixels are packed 3 per byte */
147 start = clip.x1 / 3;
148 end = clip.x2 / 3;
149
150 mipi_dbi_command(mipi, MIPI_DCS_SET_COLUMN_ADDRESS,
151 (start >> 8) & 0xFF, start & 0xFF,
152 (end >> 8) & 0xFF, (end - 1) & 0xFF);
153 mipi_dbi_command(mipi, MIPI_DCS_SET_PAGE_ADDRESS,
154 (clip.y1 >> 8) & 0xFF, clip.y1 & 0xFF,
155 (clip.y2 >> 8) & 0xFF, (clip.y2 - 1) & 0xFF);
156
157 ret = mipi_dbi_command_buf(mipi, MIPI_DCS_WRITE_MEMORY_START,
158 (u8 *)mipi->tx_buf,
159 (end - start) * (clip.y2 - clip.y1));
160
161out_unlock:
162 mutex_unlock(&tdev->dirty_lock);
163
164 if (ret)
165 dev_err_once(fb->dev->dev, "Failed to update display %d\n",
166 ret);
167
168 return ret;
169}
170
171static const struct drm_framebuffer_funcs st7586_fb_funcs = {
172 .destroy = drm_gem_fb_destroy,
173 .create_handle = drm_gem_fb_create_handle,
174 .dirty = st7586_fb_dirty,
175};
176
177static void st7586_pipe_enable(struct drm_simple_display_pipe *pipe,
178 struct drm_crtc_state *crtc_state)
179{
180 struct tinydrm_device *tdev = pipe_to_tinydrm(pipe);
181 struct mipi_dbi *mipi = mipi_dbi_from_tinydrm(tdev);
182 int ret;
183 u8 addr_mode;
184
185 DRM_DEBUG_KMS("\n");
186
187 ret = mipi_dbi_poweron_reset(mipi);
188 if (ret)
189 return;
190
191 mipi_dbi_command(mipi, ST7586_AUTO_READ_CTRL, 0x9f);
192 mipi_dbi_command(mipi, ST7586_OTP_RW_CTRL, 0x00);
193
194 msleep(10);
195
196 mipi_dbi_command(mipi, ST7586_OTP_READ);
197
198 msleep(20);
199
200 mipi_dbi_command(mipi, ST7586_OTP_CTRL_OUT);
201 mipi_dbi_command(mipi, MIPI_DCS_EXIT_SLEEP_MODE);
202 mipi_dbi_command(mipi, MIPI_DCS_SET_DISPLAY_OFF);
203
204 msleep(50);
205
206 mipi_dbi_command(mipi, ST7586_SET_VOP_OFFSET, 0x00);
207 mipi_dbi_command(mipi, ST7586_SET_VOP, 0xe3, 0x00);
208 mipi_dbi_command(mipi, ST7586_SET_BIAS_SYSTEM, 0x02);
209 mipi_dbi_command(mipi, ST7586_SET_BOOST_LEVEL, 0x04);
210 mipi_dbi_command(mipi, ST7586_ENABLE_ANALOG, 0x1d);
211 mipi_dbi_command(mipi, ST7586_SET_NLINE_INV, 0x00);
212 mipi_dbi_command(mipi, ST7586_DISP_MODE_GRAY);
213 mipi_dbi_command(mipi, ST7586_ENABLE_DDRAM, 0x02);
214
215 switch (mipi->rotation) {
216 default:
217 addr_mode = 0x00;
218 break;
219 case 90:
220 addr_mode = ST7586_DISP_CTRL_MY;
221 break;
222 case 180:
223 addr_mode = ST7586_DISP_CTRL_MX | ST7586_DISP_CTRL_MY;
224 break;
225 case 270:
226 addr_mode = ST7586_DISP_CTRL_MX;
227 break;
228 }
229 mipi_dbi_command(mipi, MIPI_DCS_SET_ADDRESS_MODE, addr_mode);
230
231 mipi_dbi_command(mipi, ST7586_SET_DISP_DUTY, 0x7f);
232 mipi_dbi_command(mipi, ST7586_SET_PART_DISP, 0xa0);
233 mipi_dbi_command(mipi, MIPI_DCS_SET_PARTIAL_AREA, 0x00, 0x00, 0x00, 0x77);
234 mipi_dbi_command(mipi, MIPI_DCS_EXIT_INVERT_MODE);
235
236 msleep(100);
237
238 mipi_dbi_command(mipi, MIPI_DCS_SET_DISPLAY_ON);
239
240 mipi_dbi_enable_flush(mipi);
241}
242
243static void st7586_pipe_disable(struct drm_simple_display_pipe *pipe)
244{
245 struct tinydrm_device *tdev = pipe_to_tinydrm(pipe);
246 struct mipi_dbi *mipi = mipi_dbi_from_tinydrm(tdev);
247
248 DRM_DEBUG_KMS("\n");
249
250 if (!mipi->enabled)
251 return;
252
253 mipi_dbi_command(mipi, MIPI_DCS_SET_DISPLAY_OFF);
254 mipi->enabled = false;
255}
256
257static const u32 st7586_formats[] = {
258 DRM_FORMAT_XRGB8888,
259};
260
261static int st7586_init(struct device *dev, struct mipi_dbi *mipi,
262 const struct drm_simple_display_pipe_funcs *pipe_funcs,
263 struct drm_driver *driver, const struct drm_display_mode *mode,
264 unsigned int rotation)
265{
266 size_t bufsize = (mode->vdisplay + 2) / 3 * mode->hdisplay;
267 struct tinydrm_device *tdev = &mipi->tinydrm;
268 int ret;
269
270 mutex_init(&mipi->cmdlock);
271
272 mipi->tx_buf = devm_kmalloc(dev, bufsize, GFP_KERNEL);
273 if (!mipi->tx_buf)
274 return -ENOMEM;
275
276 ret = devm_tinydrm_init(dev, tdev, &st7586_fb_funcs, driver);
277 if (ret)
278 return ret;
279
280 ret = tinydrm_display_pipe_init(tdev, pipe_funcs,
281 DRM_MODE_CONNECTOR_VIRTUAL,
282 st7586_formats,
283 ARRAY_SIZE(st7586_formats),
284 mode, rotation);
285 if (ret)
286 return ret;
287
288 tdev->drm->mode_config.preferred_depth = 32;
289 mipi->rotation = rotation;
290
291 drm_mode_config_reset(tdev->drm);
292
293 DRM_DEBUG_KMS("preferred_depth=%u, rotation = %u\n",
294 tdev->drm->mode_config.preferred_depth, rotation);
295
296 return 0;
297}
298
299static const struct drm_simple_display_pipe_funcs st7586_pipe_funcs = {
300 .enable = st7586_pipe_enable,
301 .disable = st7586_pipe_disable,
302 .update = tinydrm_display_pipe_update,
303 .prepare_fb = tinydrm_display_pipe_prepare_fb,
304};
305
306static const struct drm_display_mode st7586_mode = {
307 TINYDRM_MODE(178, 128, 37, 27),
308};
309
310DEFINE_DRM_GEM_CMA_FOPS(st7586_fops);
311
312static struct drm_driver st7586_driver = {
313 .driver_features = DRIVER_GEM | DRIVER_MODESET | DRIVER_PRIME |
314 DRIVER_ATOMIC,
315 .fops = &st7586_fops,
316 TINYDRM_GEM_DRIVER_OPS,
317 .lastclose = drm_fb_helper_lastclose,
318 .debugfs_init = mipi_dbi_debugfs_init,
319 .name = "st7586",
320 .desc = "Sitronix ST7586",
321 .date = "20170801",
322 .major = 1,
323 .minor = 0,
324};
325
326static const struct of_device_id st7586_of_match[] = {
327 { .compatible = "lego,ev3-lcd" },
328 {},
329};
330MODULE_DEVICE_TABLE(of, st7586_of_match);
331
332static const struct spi_device_id st7586_id[] = {
333 { "ev3-lcd", 0 },
334 { },
335};
336MODULE_DEVICE_TABLE(spi, st7586_id);
337
338static int st7586_probe(struct spi_device *spi)
339{
340 struct device *dev = &spi->dev;
341 struct mipi_dbi *mipi;
342 struct gpio_desc *a0;
343 u32 rotation = 0;
344 int ret;
345
346 mipi = devm_kzalloc(dev, sizeof(*mipi), GFP_KERNEL);
347 if (!mipi)
348 return -ENOMEM;
349
350 mipi->reset = devm_gpiod_get(dev, "reset", GPIOD_OUT_HIGH);
351 if (IS_ERR(mipi->reset)) {
352 DRM_DEV_ERROR(dev, "Failed to get gpio 'reset'\n");
353 return PTR_ERR(mipi->reset);
354 }
355
356 a0 = devm_gpiod_get(dev, "a0", GPIOD_OUT_LOW);
357 if (IS_ERR(a0)) {
358 DRM_DEV_ERROR(dev, "Failed to get gpio 'a0'\n");
359 return PTR_ERR(a0);
360 }
361
362 device_property_read_u32(dev, "rotation", &rotation);
363
364 ret = mipi_dbi_spi_init(spi, mipi, a0);
365 if (ret)
366 return ret;
367
368 /* Cannot read from this controller via SPI */
369 mipi->read_commands = NULL;
370
371 /*
372 * we are using 8-bit data, so we are not actually swapping anything,
373 * but setting mipi->swap_bytes makes mipi_dbi_typec3_command() do the
374 * right thing and not use 16-bit transfers (which results in swapped
375 * bytes on little-endian systems and causes out of order data to be
376 * sent to the display).
377 */
378 mipi->swap_bytes = true;
379
380 ret = st7586_init(&spi->dev, mipi, &st7586_pipe_funcs, &st7586_driver,
381 &st7586_mode, rotation);
382 if (ret)
383 return ret;
384
385 spi_set_drvdata(spi, mipi);
386
387 return devm_tinydrm_register(&mipi->tinydrm);
388}
389
390static void st7586_shutdown(struct spi_device *spi)
391{
392 struct mipi_dbi *mipi = spi_get_drvdata(spi);
393
394 tinydrm_shutdown(&mipi->tinydrm);
395}
396
397static struct spi_driver st7586_spi_driver = {
398 .driver = {
399 .name = "st7586",
400 .owner = THIS_MODULE,
401 .of_match_table = st7586_of_match,
402 },
403 .id_table = st7586_id,
404 .probe = st7586_probe,
405 .shutdown = st7586_shutdown,
406};
407module_spi_driver(st7586_spi_driver);
408
409MODULE_DESCRIPTION("Sitronix ST7586 DRM driver");
410MODULE_AUTHOR("David Lechner <david@lechnology.com>");
411MODULE_LICENSE("GPL");