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