tjh.dev
Linux kernel mirror (for testing)
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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_damage_helper.h>
17#include <drm/drm_drv.h>
18#include <drm/drm_fb_cma_helper.h>
19#include <drm/drm_fb_helper.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_cma_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{
69 size_t len = (clip->x2 - clip->x1) * (clip->y2 - clip->y1);
70 unsigned int x, y;
71 u8 *src, *buf, val;
72
73 buf = kmalloc(len, GFP_KERNEL);
74 if (!buf)
75 return;
76
77 drm_fb_xrgb8888_to_gray8(buf, 0, vaddr, fb, clip);
78 src = buf;
79
80 for (y = clip->y1; y < clip->y2; y++) {
81 for (x = clip->x1; x < clip->x2; x += 3) {
82 val = st7586_lookup[*src++ >> 6] << 5;
83 val |= st7586_lookup[*src++ >> 6] << 2;
84 val |= st7586_lookup[*src++ >> 6] >> 1;
85 *dst++ = val;
86 }
87 }
88
89 kfree(buf);
90}
91
92static int st7586_buf_copy(void *dst, struct drm_framebuffer *fb,
93 struct drm_rect *clip)
94{
95 struct drm_gem_cma_object *cma_obj = drm_fb_cma_get_gem_obj(fb, 0);
96 void *src = cma_obj->vaddr;
97 int ret = 0;
98
99 ret = drm_gem_fb_begin_cpu_access(fb, DMA_FROM_DEVICE);
100 if (ret)
101 return ret;
102
103 st7586_xrgb8888_to_gray332(dst, src, fb, clip);
104
105 drm_gem_fb_end_cpu_access(fb, DMA_FROM_DEVICE);
106
107 return 0;
108}
109
110static void st7586_fb_dirty(struct drm_framebuffer *fb, struct drm_rect *rect)
111{
112 struct mipi_dbi_dev *dbidev = drm_to_mipi_dbi_dev(fb->dev);
113 struct mipi_dbi *dbi = &dbidev->dbi;
114 int start, end, idx, ret = 0;
115
116 if (!drm_dev_enter(fb->dev, &idx))
117 return;
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, fb, rect);
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 drm_dev_exit(idx);
148}
149
150static void st7586_pipe_update(struct drm_simple_display_pipe *pipe,
151 struct drm_plane_state *old_state)
152{
153 struct drm_plane_state *state = pipe->plane.state;
154 struct drm_rect rect;
155
156 if (!pipe->crtc.state->active)
157 return;
158
159 if (drm_atomic_helper_damage_merged(old_state, state, &rect))
160 st7586_fb_dirty(state->fb, &rect);
161}
162
163static void st7586_pipe_enable(struct drm_simple_display_pipe *pipe,
164 struct drm_crtc_state *crtc_state,
165 struct drm_plane_state *plane_state)
166{
167 struct mipi_dbi_dev *dbidev = drm_to_mipi_dbi_dev(pipe->crtc.dev);
168 struct drm_framebuffer *fb = plane_state->fb;
169 struct mipi_dbi *dbi = &dbidev->dbi;
170 struct drm_rect rect = {
171 .x1 = 0,
172 .x2 = fb->width,
173 .y1 = 0,
174 .y2 = fb->height,
175 };
176 int idx, ret;
177 u8 addr_mode;
178
179 if (!drm_dev_enter(pipe->crtc.dev, &idx))
180 return;
181
182 DRM_DEBUG_KMS("\n");
183
184 ret = mipi_dbi_poweron_reset(dbidev);
185 if (ret)
186 goto out_exit;
187
188 mipi_dbi_command(dbi, ST7586_AUTO_READ_CTRL, 0x9f);
189 mipi_dbi_command(dbi, ST7586_OTP_RW_CTRL, 0x00);
190
191 msleep(10);
192
193 mipi_dbi_command(dbi, ST7586_OTP_READ);
194
195 msleep(20);
196
197 mipi_dbi_command(dbi, ST7586_OTP_CTRL_OUT);
198 mipi_dbi_command(dbi, MIPI_DCS_EXIT_SLEEP_MODE);
199 mipi_dbi_command(dbi, MIPI_DCS_SET_DISPLAY_OFF);
200
201 msleep(50);
202
203 mipi_dbi_command(dbi, ST7586_SET_VOP_OFFSET, 0x00);
204 mipi_dbi_command(dbi, ST7586_SET_VOP, 0xe3, 0x00);
205 mipi_dbi_command(dbi, ST7586_SET_BIAS_SYSTEM, 0x02);
206 mipi_dbi_command(dbi, ST7586_SET_BOOST_LEVEL, 0x04);
207 mipi_dbi_command(dbi, ST7586_ENABLE_ANALOG, 0x1d);
208 mipi_dbi_command(dbi, ST7586_SET_NLINE_INV, 0x00);
209 mipi_dbi_command(dbi, ST7586_DISP_MODE_GRAY);
210 mipi_dbi_command(dbi, ST7586_ENABLE_DDRAM, 0x02);
211
212 switch (dbidev->rotation) {
213 default:
214 addr_mode = 0x00;
215 break;
216 case 90:
217 addr_mode = ST7586_DISP_CTRL_MY;
218 break;
219 case 180:
220 addr_mode = ST7586_DISP_CTRL_MX | ST7586_DISP_CTRL_MY;
221 break;
222 case 270:
223 addr_mode = ST7586_DISP_CTRL_MX;
224 break;
225 }
226 mipi_dbi_command(dbi, MIPI_DCS_SET_ADDRESS_MODE, addr_mode);
227
228 mipi_dbi_command(dbi, ST7586_SET_DISP_DUTY, 0x7f);
229 mipi_dbi_command(dbi, ST7586_SET_PART_DISP, 0xa0);
230 mipi_dbi_command(dbi, MIPI_DCS_SET_PARTIAL_ROWS, 0x00, 0x00, 0x00, 0x77);
231 mipi_dbi_command(dbi, MIPI_DCS_EXIT_INVERT_MODE);
232
233 msleep(100);
234
235 st7586_fb_dirty(fb, &rect);
236
237 mipi_dbi_command(dbi, MIPI_DCS_SET_DISPLAY_ON);
238out_exit:
239 drm_dev_exit(idx);
240}
241
242static void st7586_pipe_disable(struct drm_simple_display_pipe *pipe)
243{
244 struct mipi_dbi_dev *dbidev = drm_to_mipi_dbi_dev(pipe->crtc.dev);
245
246 /*
247 * This callback is not protected by drm_dev_enter/exit since we want to
248 * turn off the display on regular driver unload. It's highly unlikely
249 * that the underlying SPI controller is gone should this be called after
250 * unplug.
251 */
252
253 DRM_DEBUG_KMS("\n");
254
255 mipi_dbi_command(&dbidev->dbi, MIPI_DCS_SET_DISPLAY_OFF);
256}
257
258static const u32 st7586_formats[] = {
259 DRM_FORMAT_XRGB8888,
260};
261
262static const struct drm_simple_display_pipe_funcs st7586_pipe_funcs = {
263 .enable = st7586_pipe_enable,
264 .disable = st7586_pipe_disable,
265 .update = st7586_pipe_update,
266};
267
268static const struct drm_display_mode st7586_mode = {
269 DRM_SIMPLE_MODE(178, 128, 37, 27),
270};
271
272DEFINE_DRM_GEM_CMA_FOPS(st7586_fops);
273
274static const struct drm_driver st7586_driver = {
275 .driver_features = DRIVER_GEM | DRIVER_MODESET | DRIVER_ATOMIC,
276 .fops = &st7586_fops,
277 DRM_GEM_CMA_DRIVER_OPS_VMAP,
278 .debugfs_init = mipi_dbi_debugfs_init,
279 .name = "st7586",
280 .desc = "Sitronix ST7586",
281 .date = "20170801",
282 .major = 1,
283 .minor = 0,
284};
285
286static const struct of_device_id st7586_of_match[] = {
287 { .compatible = "lego,ev3-lcd" },
288 {},
289};
290MODULE_DEVICE_TABLE(of, st7586_of_match);
291
292static const struct spi_device_id st7586_id[] = {
293 { "ev3-lcd", 0 },
294 { },
295};
296MODULE_DEVICE_TABLE(spi, st7586_id);
297
298static int st7586_probe(struct spi_device *spi)
299{
300 struct device *dev = &spi->dev;
301 struct mipi_dbi_dev *dbidev;
302 struct drm_device *drm;
303 struct mipi_dbi *dbi;
304 struct gpio_desc *a0;
305 u32 rotation = 0;
306 size_t bufsize;
307 int ret;
308
309 dbidev = devm_drm_dev_alloc(dev, &st7586_driver,
310 struct mipi_dbi_dev, drm);
311 if (IS_ERR(dbidev))
312 return PTR_ERR(dbidev);
313
314 dbi = &dbidev->dbi;
315 drm = &dbidev->drm;
316
317 bufsize = (st7586_mode.vdisplay + 2) / 3 * st7586_mode.hdisplay;
318
319 dbi->reset = devm_gpiod_get(dev, "reset", GPIOD_OUT_HIGH);
320 if (IS_ERR(dbi->reset))
321 return dev_err_probe(dev, PTR_ERR(dbi->reset), "Failed to get GPIO 'reset'\n");
322
323 a0 = devm_gpiod_get(dev, "a0", GPIOD_OUT_LOW);
324 if (IS_ERR(a0))
325 return dev_err_probe(dev, PTR_ERR(a0), "Failed to get GPIO 'a0'\n");
326
327 device_property_read_u32(dev, "rotation", &rotation);
328
329 ret = mipi_dbi_spi_init(spi, dbi, a0);
330 if (ret)
331 return ret;
332
333 /* Cannot read from this controller via SPI */
334 dbi->read_commands = NULL;
335
336 ret = mipi_dbi_dev_init_with_formats(dbidev, &st7586_pipe_funcs,
337 st7586_formats, ARRAY_SIZE(st7586_formats),
338 &st7586_mode, rotation, bufsize);
339 if (ret)
340 return ret;
341
342 /*
343 * we are using 8-bit data, so we are not actually swapping anything,
344 * but setting mipi->swap_bytes makes mipi_dbi_typec3_command() do the
345 * right thing and not use 16-bit transfers (which results in swapped
346 * bytes on little-endian systems and causes out of order data to be
347 * sent to the display).
348 */
349 dbi->swap_bytes = true;
350
351 drm_mode_config_reset(drm);
352
353 ret = drm_dev_register(drm, 0);
354 if (ret)
355 return ret;
356
357 spi_set_drvdata(spi, drm);
358
359 drm_fbdev_generic_setup(drm, 0);
360
361 return 0;
362}
363
364static void st7586_remove(struct spi_device *spi)
365{
366 struct drm_device *drm = spi_get_drvdata(spi);
367
368 drm_dev_unplug(drm);
369 drm_atomic_helper_shutdown(drm);
370}
371
372static void st7586_shutdown(struct spi_device *spi)
373{
374 drm_atomic_helper_shutdown(spi_get_drvdata(spi));
375}
376
377static struct spi_driver st7586_spi_driver = {
378 .driver = {
379 .name = "st7586",
380 .owner = THIS_MODULE,
381 .of_match_table = st7586_of_match,
382 },
383 .id_table = st7586_id,
384 .probe = st7586_probe,
385 .remove = st7586_remove,
386 .shutdown = st7586_shutdown,
387};
388module_spi_driver(st7586_spi_driver);
389
390MODULE_DESCRIPTION("Sitronix ST7586 DRM driver");
391MODULE_AUTHOR("David Lechner <david@lechnology.com>");
392MODULE_LICENSE("GPL");