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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_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{
69 size_t len = (clip->x2 - clip->x1) * (clip->y2 - clip->y1);
70 unsigned int x, y;
71 u8 *src, *buf, val;
72 struct iosys_map dst_map, vmap;
73
74 buf = kmalloc(len, GFP_KERNEL);
75 if (!buf)
76 return;
77
78 iosys_map_set_vaddr(&dst_map, buf);
79 iosys_map_set_vaddr(&vmap, vaddr);
80 drm_fb_xrgb8888_to_gray8(&dst_map, NULL, &vmap, fb, clip);
81 src = buf;
82
83 for (y = clip->y1; y < clip->y2; y++) {
84 for (x = clip->x1; x < clip->x2; x += 3) {
85 val = st7586_lookup[*src++ >> 6] << 5;
86 val |= st7586_lookup[*src++ >> 6] << 2;
87 val |= st7586_lookup[*src++ >> 6] >> 1;
88 *dst++ = val;
89 }
90 }
91
92 kfree(buf);
93}
94
95static int st7586_buf_copy(void *dst, struct drm_framebuffer *fb,
96 struct drm_rect *clip)
97{
98 struct drm_gem_dma_object *dma_obj = drm_fb_dma_get_gem_obj(fb, 0);
99 void *src = dma_obj->vaddr;
100 int ret = 0;
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, fb, clip);
107
108 drm_gem_fb_end_cpu_access(fb, DMA_FROM_DEVICE);
109
110 return 0;
111}
112
113static void st7586_fb_dirty(struct drm_framebuffer *fb, struct drm_rect *rect)
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, idx, ret = 0;
118
119 if (!drm_dev_enter(fb->dev, &idx))
120 return;
121
122 /* 3 pixels per byte, so grow clip to nearest multiple of 3 */
123 rect->x1 = rounddown(rect->x1, 3);
124 rect->x2 = roundup(rect->x2, 3);
125
126 DRM_DEBUG_KMS("Flushing [FB:%d] " DRM_RECT_FMT "\n", fb->base.id, DRM_RECT_ARG(rect));
127
128 ret = st7586_buf_copy(dbidev->tx_buf, fb, rect);
129 if (ret)
130 goto err_msg;
131
132 /* Pixels are packed 3 per byte */
133 start = rect->x1 / 3;
134 end = rect->x2 / 3;
135
136 mipi_dbi_command(dbi, MIPI_DCS_SET_COLUMN_ADDRESS,
137 (start >> 8) & 0xFF, start & 0xFF,
138 (end >> 8) & 0xFF, (end - 1) & 0xFF);
139 mipi_dbi_command(dbi, MIPI_DCS_SET_PAGE_ADDRESS,
140 (rect->y1 >> 8) & 0xFF, rect->y1 & 0xFF,
141 (rect->y2 >> 8) & 0xFF, (rect->y2 - 1) & 0xFF);
142
143 ret = mipi_dbi_command_buf(dbi, MIPI_DCS_WRITE_MEMORY_START,
144 (u8 *)dbidev->tx_buf,
145 (end - start) * (rect->y2 - rect->y1));
146err_msg:
147 if (ret)
148 dev_err_once(fb->dev->dev, "Failed to update display %d\n", ret);
149
150 drm_dev_exit(idx);
151}
152
153static void st7586_pipe_update(struct drm_simple_display_pipe *pipe,
154 struct drm_plane_state *old_state)
155{
156 struct drm_plane_state *state = pipe->plane.state;
157 struct drm_rect rect;
158
159 if (!pipe->crtc.state->active)
160 return;
161
162 if (drm_atomic_helper_damage_merged(old_state, state, &rect))
163 st7586_fb_dirty(state->fb, &rect);
164}
165
166static void st7586_pipe_enable(struct drm_simple_display_pipe *pipe,
167 struct drm_crtc_state *crtc_state,
168 struct drm_plane_state *plane_state)
169{
170 struct mipi_dbi_dev *dbidev = drm_to_mipi_dbi_dev(pipe->crtc.dev);
171 struct drm_framebuffer *fb = plane_state->fb;
172 struct mipi_dbi *dbi = &dbidev->dbi;
173 struct drm_rect rect = {
174 .x1 = 0,
175 .x2 = fb->width,
176 .y1 = 0,
177 .y2 = fb->height,
178 };
179 int idx, ret;
180 u8 addr_mode;
181
182 if (!drm_dev_enter(pipe->crtc.dev, &idx))
183 return;
184
185 DRM_DEBUG_KMS("\n");
186
187 ret = mipi_dbi_poweron_reset(dbidev);
188 if (ret)
189 goto out_exit;
190
191 mipi_dbi_command(dbi, ST7586_AUTO_READ_CTRL, 0x9f);
192 mipi_dbi_command(dbi, ST7586_OTP_RW_CTRL, 0x00);
193
194 msleep(10);
195
196 mipi_dbi_command(dbi, ST7586_OTP_READ);
197
198 msleep(20);
199
200 mipi_dbi_command(dbi, ST7586_OTP_CTRL_OUT);
201 mipi_dbi_command(dbi, MIPI_DCS_EXIT_SLEEP_MODE);
202 mipi_dbi_command(dbi, MIPI_DCS_SET_DISPLAY_OFF);
203
204 msleep(50);
205
206 mipi_dbi_command(dbi, ST7586_SET_VOP_OFFSET, 0x00);
207 mipi_dbi_command(dbi, ST7586_SET_VOP, 0xe3, 0x00);
208 mipi_dbi_command(dbi, ST7586_SET_BIAS_SYSTEM, 0x02);
209 mipi_dbi_command(dbi, ST7586_SET_BOOST_LEVEL, 0x04);
210 mipi_dbi_command(dbi, ST7586_ENABLE_ANALOG, 0x1d);
211 mipi_dbi_command(dbi, ST7586_SET_NLINE_INV, 0x00);
212 mipi_dbi_command(dbi, ST7586_DISP_MODE_GRAY);
213 mipi_dbi_command(dbi, ST7586_ENABLE_DDRAM, 0x02);
214
215 switch (dbidev->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(dbi, MIPI_DCS_SET_ADDRESS_MODE, addr_mode);
230
231 mipi_dbi_command(dbi, ST7586_SET_DISP_DUTY, 0x7f);
232 mipi_dbi_command(dbi, ST7586_SET_PART_DISP, 0xa0);
233 mipi_dbi_command(dbi, MIPI_DCS_SET_PARTIAL_ROWS, 0x00, 0x00, 0x00, 0x77);
234 mipi_dbi_command(dbi, MIPI_DCS_EXIT_INVERT_MODE);
235
236 msleep(100);
237
238 st7586_fb_dirty(fb, &rect);
239
240 mipi_dbi_command(dbi, MIPI_DCS_SET_DISPLAY_ON);
241out_exit:
242 drm_dev_exit(idx);
243}
244
245static void st7586_pipe_disable(struct drm_simple_display_pipe *pipe)
246{
247 struct mipi_dbi_dev *dbidev = drm_to_mipi_dbi_dev(pipe->crtc.dev);
248
249 /*
250 * This callback is not protected by drm_dev_enter/exit since we want to
251 * turn off the display on regular driver unload. It's highly unlikely
252 * that the underlying SPI controller is gone should this be called after
253 * unplug.
254 */
255
256 DRM_DEBUG_KMS("\n");
257
258 mipi_dbi_command(&dbidev->dbi, MIPI_DCS_SET_DISPLAY_OFF);
259}
260
261static const u32 st7586_formats[] = {
262 DRM_FORMAT_XRGB8888,
263};
264
265static const struct drm_simple_display_pipe_funcs st7586_pipe_funcs = {
266 .enable = st7586_pipe_enable,
267 .disable = st7586_pipe_disable,
268 .update = st7586_pipe_update,
269};
270
271static const struct drm_display_mode st7586_mode = {
272 DRM_SIMPLE_MODE(178, 128, 37, 27),
273};
274
275DEFINE_DRM_GEM_DMA_FOPS(st7586_fops);
276
277static const struct drm_driver st7586_driver = {
278 .driver_features = DRIVER_GEM | DRIVER_MODESET | DRIVER_ATOMIC,
279 .fops = &st7586_fops,
280 DRM_GEM_DMA_DRIVER_OPS_VMAP,
281 .debugfs_init = mipi_dbi_debugfs_init,
282 .name = "st7586",
283 .desc = "Sitronix ST7586",
284 .date = "20170801",
285 .major = 1,
286 .minor = 0,
287};
288
289static const struct of_device_id st7586_of_match[] = {
290 { .compatible = "lego,ev3-lcd" },
291 {},
292};
293MODULE_DEVICE_TABLE(of, st7586_of_match);
294
295static const struct spi_device_id st7586_id[] = {
296 { "ev3-lcd", 0 },
297 { },
298};
299MODULE_DEVICE_TABLE(spi, st7586_id);
300
301static int st7586_probe(struct spi_device *spi)
302{
303 struct device *dev = &spi->dev;
304 struct mipi_dbi_dev *dbidev;
305 struct drm_device *drm;
306 struct mipi_dbi *dbi;
307 struct gpio_desc *a0;
308 u32 rotation = 0;
309 size_t bufsize;
310 int ret;
311
312 dbidev = devm_drm_dev_alloc(dev, &st7586_driver,
313 struct mipi_dbi_dev, drm);
314 if (IS_ERR(dbidev))
315 return PTR_ERR(dbidev);
316
317 dbi = &dbidev->dbi;
318 drm = &dbidev->drm;
319
320 bufsize = (st7586_mode.vdisplay + 2) / 3 * st7586_mode.hdisplay;
321
322 dbi->reset = devm_gpiod_get(dev, "reset", GPIOD_OUT_HIGH);
323 if (IS_ERR(dbi->reset))
324 return dev_err_probe(dev, PTR_ERR(dbi->reset), "Failed to get GPIO 'reset'\n");
325
326 a0 = devm_gpiod_get(dev, "a0", GPIOD_OUT_LOW);
327 if (IS_ERR(a0))
328 return dev_err_probe(dev, PTR_ERR(a0), "Failed to get GPIO 'a0'\n");
329
330 device_property_read_u32(dev, "rotation", &rotation);
331
332 ret = mipi_dbi_spi_init(spi, dbi, a0);
333 if (ret)
334 return ret;
335
336 /* Cannot read from this controller via SPI */
337 dbi->read_commands = NULL;
338
339 ret = mipi_dbi_dev_init_with_formats(dbidev, &st7586_pipe_funcs,
340 st7586_formats, ARRAY_SIZE(st7586_formats),
341 &st7586_mode, rotation, bufsize);
342 if (ret)
343 return ret;
344
345 /*
346 * we are using 8-bit data, so we are not actually swapping anything,
347 * but setting mipi->swap_bytes makes mipi_dbi_typec3_command() do the
348 * right thing and not use 16-bit transfers (which results in swapped
349 * bytes on little-endian systems and causes out of order data to be
350 * sent to the display).
351 */
352 dbi->swap_bytes = true;
353
354 drm_mode_config_reset(drm);
355
356 ret = drm_dev_register(drm, 0);
357 if (ret)
358 return ret;
359
360 spi_set_drvdata(spi, drm);
361
362 drm_fbdev_generic_setup(drm, 0);
363
364 return 0;
365}
366
367static void st7586_remove(struct spi_device *spi)
368{
369 struct drm_device *drm = spi_get_drvdata(spi);
370
371 drm_dev_unplug(drm);
372 drm_atomic_helper_shutdown(drm);
373}
374
375static void st7586_shutdown(struct spi_device *spi)
376{
377 drm_atomic_helper_shutdown(spi_get_drvdata(spi));
378}
379
380static struct spi_driver st7586_spi_driver = {
381 .driver = {
382 .name = "st7586",
383 .owner = THIS_MODULE,
384 .of_match_table = st7586_of_match,
385 },
386 .id_table = st7586_id,
387 .probe = st7586_probe,
388 .remove = st7586_remove,
389 .shutdown = st7586_shutdown,
390};
391module_spi_driver(st7586_spi_driver);
392
393MODULE_DESCRIPTION("Sitronix ST7586 DRM driver");
394MODULE_AUTHOR("David Lechner <david@lechnology.com>");
395MODULE_LICENSE("GPL");