1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * Cobalt/SEAD3 LCD frame buffer driver.
4 *
5 * Copyright (C) 2008 Yoichi Yuasa <yuasa@linux-mips.org>
6 * Copyright (C) 2012 MIPS Technologies, Inc.
7 */
8 #include <linux/delay.h>
9 #include <linux/fb.h>
10 #include <linux/init.h>
11 #include <linux/io.h>
12 #include <linux/ioport.h>
13 #include <linux/uaccess.h>
14 #include <linux/platform_device.h>
15 #include <linux/module.h>
16 #include <linux/sched/signal.h>
17
18 /*
19 * Cursor position address
20 * \X 0 1 2 ... 14 15
21 * Y+----+----+----+---+----+----+
22 * 0|0x00|0x01|0x02|...|0x0e|0x0f|
23 * +----+----+----+---+----+----+
24 * 1|0x40|0x41|0x42|...|0x4e|0x4f|
25 * +----+----+----+---+----+----+
26 */
27 #define LCD_DATA_REG_OFFSET 0x10
28 #define LCD_XRES_MAX 16
29 #define LCD_YRES_MAX 2
30 #define LCD_CHARS_MAX 32
31
32 #define LCD_CLEAR 0x01
33 #define LCD_CURSOR_MOVE_HOME 0x02
34 #define LCD_RESET 0x06
35 #define LCD_OFF 0x08
36 #define LCD_CURSOR_OFF 0x0c
37 #define LCD_CURSOR_BLINK_OFF 0x0e
38 #define LCD_CURSOR_ON 0x0f
39 #define LCD_ON LCD_CURSOR_ON
40 #define LCD_CURSOR_MOVE_LEFT 0x10
41 #define LCD_CURSOR_MOVE_RIGHT 0x14
42 #define LCD_DISPLAY_LEFT 0x18
43 #define LCD_DISPLAY_RIGHT 0x1c
44 #define LCD_PRERESET 0x3f /* execute 4 times continuously */
45 #define LCD_BUSY 0x80
46
47 #define LCD_GRAPHIC_MODE 0x40
48 #define LCD_TEXT_MODE 0x80
49 #define LCD_CUR_POS_MASK 0x7f
50
51 #define LCD_CUR_POS(x) ((x) & LCD_CUR_POS_MASK)
52 #define LCD_TEXT_POS(x) ((x) | LCD_TEXT_MODE)
53
lcd_write_control(struct fb_info * info,u8 control)54 static inline void lcd_write_control(struct fb_info *info, u8 control)
55 {
56 writel((u32)control << 24, info->screen_base);
57 }
58
lcd_read_control(struct fb_info * info)59 static inline u8 lcd_read_control(struct fb_info *info)
60 {
61 return readl(info->screen_base) >> 24;
62 }
63
lcd_write_data(struct fb_info * info,u8 data)64 static inline void lcd_write_data(struct fb_info *info, u8 data)
65 {
66 writel((u32)data << 24, info->screen_base + LCD_DATA_REG_OFFSET);
67 }
68
lcd_read_data(struct fb_info * info)69 static inline u8 lcd_read_data(struct fb_info *info)
70 {
71 return readl(info->screen_base + LCD_DATA_REG_OFFSET) >> 24;
72 }
73
lcd_busy_wait(struct fb_info * info)74 static int lcd_busy_wait(struct fb_info *info)
75 {
76 u8 val = 0;
77 int timeout = 10, retval = 0;
78
79 do {
80 val = lcd_read_control(info);
81 val &= LCD_BUSY;
82 if (val != LCD_BUSY)
83 break;
84
85 if (msleep_interruptible(1))
86 return -EINTR;
87
88 timeout--;
89 } while (timeout);
90
91 if (val == LCD_BUSY)
92 retval = -EBUSY;
93
94 return retval;
95 }
96
lcd_clear(struct fb_info * info)97 static void lcd_clear(struct fb_info *info)
98 {
99 int i;
100
101 for (i = 0; i < 4; i++) {
102 udelay(150);
103
104 lcd_write_control(info, LCD_PRERESET);
105 }
106
107 udelay(150);
108
109 lcd_write_control(info, LCD_CLEAR);
110
111 udelay(150);
112
113 lcd_write_control(info, LCD_RESET);
114 }
115
116 static const struct fb_fix_screeninfo cobalt_lcdfb_fix = {
117 .id = "cobalt-lcd",
118 .type = FB_TYPE_TEXT,
119 .type_aux = FB_AUX_TEXT_MDA,
120 .visual = FB_VISUAL_MONO01,
121 .line_length = LCD_XRES_MAX,
122 .accel = FB_ACCEL_NONE,
123 };
124
cobalt_lcdfb_read(struct fb_info * info,char __user * buf,size_t count,loff_t * ppos)125 static ssize_t cobalt_lcdfb_read(struct fb_info *info, char __user *buf,
126 size_t count, loff_t *ppos)
127 {
128 char src[LCD_CHARS_MAX];
129 unsigned long pos;
130 int len, retval = 0;
131
132 if (!info->screen_base)
133 return -ENODEV;
134
135 pos = *ppos;
136 if (pos >= LCD_CHARS_MAX || count == 0)
137 return 0;
138
139 if (count > LCD_CHARS_MAX)
140 count = LCD_CHARS_MAX;
141
142 if (pos + count > LCD_CHARS_MAX)
143 count = LCD_CHARS_MAX - pos;
144
145 for (len = 0; len < count; len++) {
146 retval = lcd_busy_wait(info);
147 if (retval < 0)
148 break;
149
150 lcd_write_control(info, LCD_TEXT_POS(pos));
151
152 retval = lcd_busy_wait(info);
153 if (retval < 0)
154 break;
155
156 src[len] = lcd_read_data(info);
157 if (pos == 0x0f)
158 pos = 0x40;
159 else
160 pos++;
161 }
162
163 if (retval < 0 && signal_pending(current))
164 return -ERESTARTSYS;
165
166 if (copy_to_user(buf, src, len))
167 return -EFAULT;
168
169 *ppos += len;
170
171 return len;
172 }
173
cobalt_lcdfb_write(struct fb_info * info,const char __user * buf,size_t count,loff_t * ppos)174 static ssize_t cobalt_lcdfb_write(struct fb_info *info, const char __user *buf,
175 size_t count, loff_t *ppos)
176 {
177 char dst[LCD_CHARS_MAX];
178 unsigned long pos;
179 int len, retval = 0;
180
181 if (!info->screen_base)
182 return -ENODEV;
183
184 pos = *ppos;
185 if (pos >= LCD_CHARS_MAX || count == 0)
186 return 0;
187
188 if (count > LCD_CHARS_MAX)
189 count = LCD_CHARS_MAX;
190
191 if (pos + count > LCD_CHARS_MAX)
192 count = LCD_CHARS_MAX - pos;
193
194 if (copy_from_user(dst, buf, count))
195 return -EFAULT;
196
197 for (len = 0; len < count; len++) {
198 retval = lcd_busy_wait(info);
199 if (retval < 0)
200 break;
201
202 lcd_write_control(info, LCD_TEXT_POS(pos));
203
204 retval = lcd_busy_wait(info);
205 if (retval < 0)
206 break;
207
208 lcd_write_data(info, dst[len]);
209 if (pos == 0x0f)
210 pos = 0x40;
211 else
212 pos++;
213 }
214
215 if (retval < 0 && signal_pending(current))
216 return -ERESTARTSYS;
217
218 *ppos += len;
219
220 return len;
221 }
222
cobalt_lcdfb_blank(int blank_mode,struct fb_info * info)223 static int cobalt_lcdfb_blank(int blank_mode, struct fb_info *info)
224 {
225 int retval;
226
227 retval = lcd_busy_wait(info);
228 if (retval < 0)
229 return retval;
230
231 switch (blank_mode) {
232 case FB_BLANK_UNBLANK:
233 lcd_write_control(info, LCD_ON);
234 break;
235 default:
236 lcd_write_control(info, LCD_OFF);
237 break;
238 }
239
240 return 0;
241 }
242
cobalt_lcdfb_cursor(struct fb_info * info,struct fb_cursor * cursor)243 static int cobalt_lcdfb_cursor(struct fb_info *info, struct fb_cursor *cursor)
244 {
245 u32 x, y;
246 int retval;
247
248 switch (cursor->set) {
249 case FB_CUR_SETPOS:
250 x = cursor->image.dx;
251 y = cursor->image.dy;
252 if (x >= LCD_XRES_MAX || y >= LCD_YRES_MAX)
253 return -EINVAL;
254
255 retval = lcd_busy_wait(info);
256 if (retval < 0)
257 return retval;
258
259 lcd_write_control(info,
260 LCD_TEXT_POS(info->fix.line_length * y + x));
261 break;
262 default:
263 return -EINVAL;
264 }
265
266 retval = lcd_busy_wait(info);
267 if (retval < 0)
268 return retval;
269
270 if (cursor->enable)
271 lcd_write_control(info, LCD_CURSOR_ON);
272 else
273 lcd_write_control(info, LCD_CURSOR_OFF);
274
275 return 0;
276 }
277
278 static const struct fb_ops cobalt_lcd_fbops = {
279 .owner = THIS_MODULE,
280 .fb_read = cobalt_lcdfb_read,
281 .fb_write = cobalt_lcdfb_write,
282 .fb_blank = cobalt_lcdfb_blank,
283 .fb_cursor = cobalt_lcdfb_cursor,
284 };
285
cobalt_lcdfb_probe(struct platform_device * dev)286 static int cobalt_lcdfb_probe(struct platform_device *dev)
287 {
288 struct fb_info *info;
289 struct resource *res;
290 int retval;
291
292 info = framebuffer_alloc(0, &dev->dev);
293 if (!info)
294 return -ENOMEM;
295
296 res = platform_get_resource(dev, IORESOURCE_MEM, 0);
297 if (!res) {
298 framebuffer_release(info);
299 return -EBUSY;
300 }
301
302 info->screen_size = resource_size(res);
303 info->screen_base = devm_ioremap(&dev->dev, res->start,
304 info->screen_size);
305 if (!info->screen_base) {
306 framebuffer_release(info);
307 return -ENOMEM;
308 }
309
310 info->fbops = &cobalt_lcd_fbops;
311 info->fix = cobalt_lcdfb_fix;
312 info->fix.smem_start = res->start;
313 info->fix.smem_len = info->screen_size;
314 info->pseudo_palette = NULL;
315 info->par = NULL;
316
317 retval = register_framebuffer(info);
318 if (retval < 0) {
319 framebuffer_release(info);
320 return retval;
321 }
322
323 platform_set_drvdata(dev, info);
324
325 lcd_clear(info);
326
327 fb_info(info, "Cobalt server LCD frame buffer device\n");
328
329 return 0;
330 }
331
cobalt_lcdfb_remove(struct platform_device * dev)332 static void cobalt_lcdfb_remove(struct platform_device *dev)
333 {
334 struct fb_info *info;
335
336 info = platform_get_drvdata(dev);
337 if (info) {
338 unregister_framebuffer(info);
339 framebuffer_release(info);
340 }
341 }
342
343 static struct platform_driver cobalt_lcdfb_driver = {
344 .probe = cobalt_lcdfb_probe,
345 .remove_new = cobalt_lcdfb_remove,
346 .driver = {
347 .name = "cobalt-lcd",
348 },
349 };
350 module_platform_driver(cobalt_lcdfb_driver);
351
352 MODULE_LICENSE("GPL v2");
353 MODULE_AUTHOR("Yoichi Yuasa");
354 MODULE_DESCRIPTION("Cobalt server LCD frame buffer driver");
355