tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1/*
2 * Cobalt/SEAD3 LCD frame buffer driver.
3 *
4 * Copyright (C) 2008 Yoichi Yuasa <yuasa@linux-mips.org>
5 * Copyright (C) 2012 MIPS Technologies, Inc.
6 *
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License as published by
9 * the Free Software Foundation; either version 2 of the License, or
10 * (at your option) any later version.
11 *
12 * This program is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 * GNU General Public License for more details.
16 *
17 * You should have received a copy of the GNU General Public License
18 * along with this program; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20 */
21#include <linux/delay.h>
22#include <linux/fb.h>
23#include <linux/init.h>
24#include <linux/io.h>
25#include <linux/ioport.h>
26#include <linux/uaccess.h>
27#include <linux/platform_device.h>
28#include <linux/module.h>
29#include <linux/sched/signal.h>
30
31/*
32 * Cursor position address
33 * \X 0 1 2 ... 14 15
34 * Y+----+----+----+---+----+----+
35 * 0|0x00|0x01|0x02|...|0x0e|0x0f|
36 * +----+----+----+---+----+----+
37 * 1|0x40|0x41|0x42|...|0x4e|0x4f|
38 * +----+----+----+---+----+----+
39 */
40#define LCD_DATA_REG_OFFSET 0x10
41#define LCD_XRES_MAX 16
42#define LCD_YRES_MAX 2
43#define LCD_CHARS_MAX 32
44
45#define LCD_CLEAR 0x01
46#define LCD_CURSOR_MOVE_HOME 0x02
47#define LCD_RESET 0x06
48#define LCD_OFF 0x08
49#define LCD_CURSOR_OFF 0x0c
50#define LCD_CURSOR_BLINK_OFF 0x0e
51#define LCD_CURSOR_ON 0x0f
52#define LCD_ON LCD_CURSOR_ON
53#define LCD_CURSOR_MOVE_LEFT 0x10
54#define LCD_CURSOR_MOVE_RIGHT 0x14
55#define LCD_DISPLAY_LEFT 0x18
56#define LCD_DISPLAY_RIGHT 0x1c
57#define LCD_PRERESET 0x3f /* execute 4 times continuously */
58#define LCD_BUSY 0x80
59
60#define LCD_GRAPHIC_MODE 0x40
61#define LCD_TEXT_MODE 0x80
62#define LCD_CUR_POS_MASK 0x7f
63
64#define LCD_CUR_POS(x) ((x) & LCD_CUR_POS_MASK)
65#define LCD_TEXT_POS(x) ((x) | LCD_TEXT_MODE)
66
67static inline void lcd_write_control(struct fb_info *info, u8 control)
68{
69 writel((u32)control << 24, info->screen_base);
70}
71
72static inline u8 lcd_read_control(struct fb_info *info)
73{
74 return readl(info->screen_base) >> 24;
75}
76
77static inline void lcd_write_data(struct fb_info *info, u8 data)
78{
79 writel((u32)data << 24, info->screen_base + LCD_DATA_REG_OFFSET);
80}
81
82static inline u8 lcd_read_data(struct fb_info *info)
83{
84 return readl(info->screen_base + LCD_DATA_REG_OFFSET) >> 24;
85}
86
87static int lcd_busy_wait(struct fb_info *info)
88{
89 u8 val = 0;
90 int timeout = 10, retval = 0;
91
92 do {
93 val = lcd_read_control(info);
94 val &= LCD_BUSY;
95 if (val != LCD_BUSY)
96 break;
97
98 if (msleep_interruptible(1))
99 return -EINTR;
100
101 timeout--;
102 } while (timeout);
103
104 if (val == LCD_BUSY)
105 retval = -EBUSY;
106
107 return retval;
108}
109
110static void lcd_clear(struct fb_info *info)
111{
112 int i;
113
114 for (i = 0; i < 4; i++) {
115 udelay(150);
116
117 lcd_write_control(info, LCD_PRERESET);
118 }
119
120 udelay(150);
121
122 lcd_write_control(info, LCD_CLEAR);
123
124 udelay(150);
125
126 lcd_write_control(info, LCD_RESET);
127}
128
129static struct fb_fix_screeninfo cobalt_lcdfb_fix = {
130 .id = "cobalt-lcd",
131 .type = FB_TYPE_TEXT,
132 .type_aux = FB_AUX_TEXT_MDA,
133 .visual = FB_VISUAL_MONO01,
134 .line_length = LCD_XRES_MAX,
135 .accel = FB_ACCEL_NONE,
136};
137
138static ssize_t cobalt_lcdfb_read(struct fb_info *info, char __user *buf,
139 size_t count, loff_t *ppos)
140{
141 char src[LCD_CHARS_MAX];
142 unsigned long pos;
143 int len, retval = 0;
144
145 pos = *ppos;
146 if (pos >= LCD_CHARS_MAX || count == 0)
147 return 0;
148
149 if (count > LCD_CHARS_MAX)
150 count = LCD_CHARS_MAX;
151
152 if (pos + count > LCD_CHARS_MAX)
153 count = LCD_CHARS_MAX - pos;
154
155 for (len = 0; len < count; len++) {
156 retval = lcd_busy_wait(info);
157 if (retval < 0)
158 break;
159
160 lcd_write_control(info, LCD_TEXT_POS(pos));
161
162 retval = lcd_busy_wait(info);
163 if (retval < 0)
164 break;
165
166 src[len] = lcd_read_data(info);
167 if (pos == 0x0f)
168 pos = 0x40;
169 else
170 pos++;
171 }
172
173 if (retval < 0 && signal_pending(current))
174 return -ERESTARTSYS;
175
176 if (copy_to_user(buf, src, len))
177 return -EFAULT;
178
179 *ppos += len;
180
181 return len;
182}
183
184static ssize_t cobalt_lcdfb_write(struct fb_info *info, const char __user *buf,
185 size_t count, loff_t *ppos)
186{
187 char dst[LCD_CHARS_MAX];
188 unsigned long pos;
189 int len, retval = 0;
190
191 pos = *ppos;
192 if (pos >= LCD_CHARS_MAX || count == 0)
193 return 0;
194
195 if (count > LCD_CHARS_MAX)
196 count = LCD_CHARS_MAX;
197
198 if (pos + count > LCD_CHARS_MAX)
199 count = LCD_CHARS_MAX - pos;
200
201 if (copy_from_user(dst, buf, count))
202 return -EFAULT;
203
204 for (len = 0; len < count; len++) {
205 retval = lcd_busy_wait(info);
206 if (retval < 0)
207 break;
208
209 lcd_write_control(info, LCD_TEXT_POS(pos));
210
211 retval = lcd_busy_wait(info);
212 if (retval < 0)
213 break;
214
215 lcd_write_data(info, dst[len]);
216 if (pos == 0x0f)
217 pos = 0x40;
218 else
219 pos++;
220 }
221
222 if (retval < 0 && signal_pending(current))
223 return -ERESTARTSYS;
224
225 *ppos += len;
226
227 return len;
228}
229
230static int cobalt_lcdfb_blank(int blank_mode, struct fb_info *info)
231{
232 int retval;
233
234 retval = lcd_busy_wait(info);
235 if (retval < 0)
236 return retval;
237
238 switch (blank_mode) {
239 case FB_BLANK_UNBLANK:
240 lcd_write_control(info, LCD_ON);
241 break;
242 default:
243 lcd_write_control(info, LCD_OFF);
244 break;
245 }
246
247 return 0;
248}
249
250static int cobalt_lcdfb_cursor(struct fb_info *info, struct fb_cursor *cursor)
251{
252 u32 x, y;
253 int retval;
254
255 switch (cursor->set) {
256 case FB_CUR_SETPOS:
257 x = cursor->image.dx;
258 y = cursor->image.dy;
259 if (x >= LCD_XRES_MAX || y >= LCD_YRES_MAX)
260 return -EINVAL;
261
262 retval = lcd_busy_wait(info);
263 if (retval < 0)
264 return retval;
265
266 lcd_write_control(info,
267 LCD_TEXT_POS(info->fix.line_length * y + x));
268 break;
269 default:
270 return -EINVAL;
271 }
272
273 retval = lcd_busy_wait(info);
274 if (retval < 0)
275 return retval;
276
277 if (cursor->enable)
278 lcd_write_control(info, LCD_CURSOR_ON);
279 else
280 lcd_write_control(info, LCD_CURSOR_OFF);
281
282 return 0;
283}
284
285static struct fb_ops cobalt_lcd_fbops = {
286 .owner = THIS_MODULE,
287 .fb_read = cobalt_lcdfb_read,
288 .fb_write = cobalt_lcdfb_write,
289 .fb_blank = cobalt_lcdfb_blank,
290 .fb_cursor = cobalt_lcdfb_cursor,
291};
292
293static int cobalt_lcdfb_probe(struct platform_device *dev)
294{
295 struct fb_info *info;
296 struct resource *res;
297 int retval;
298
299 info = framebuffer_alloc(0, &dev->dev);
300 if (!info)
301 return -ENOMEM;
302
303 res = platform_get_resource(dev, IORESOURCE_MEM, 0);
304 if (!res) {
305 framebuffer_release(info);
306 return -EBUSY;
307 }
308
309 info->screen_size = resource_size(res);
310 info->screen_base = devm_ioremap(&dev->dev, res->start,
311 info->screen_size);
312 if (!info->screen_base) {
313 framebuffer_release(info);
314 return -ENOMEM;
315 }
316
317 info->fbops = &cobalt_lcd_fbops;
318 info->fix = cobalt_lcdfb_fix;
319 info->fix.smem_start = res->start;
320 info->fix.smem_len = info->screen_size;
321 info->pseudo_palette = NULL;
322 info->par = NULL;
323 info->flags = FBINFO_DEFAULT;
324
325 retval = register_framebuffer(info);
326 if (retval < 0) {
327 framebuffer_release(info);
328 return retval;
329 }
330
331 platform_set_drvdata(dev, info);
332
333 lcd_clear(info);
334
335 fb_info(info, "Cobalt server LCD frame buffer device\n");
336
337 return 0;
338}
339
340static int cobalt_lcdfb_remove(struct platform_device *dev)
341{
342 struct fb_info *info;
343
344 info = platform_get_drvdata(dev);
345 if (info) {
346 unregister_framebuffer(info);
347 framebuffer_release(info);
348 }
349
350 return 0;
351}
352
353static struct platform_driver cobalt_lcdfb_driver = {
354 .probe = cobalt_lcdfb_probe,
355 .remove = cobalt_lcdfb_remove,
356 .driver = {
357 .name = "cobalt-lcd",
358 },
359};
360module_platform_driver(cobalt_lcdfb_driver);
361
362MODULE_LICENSE("GPL v2");
363MODULE_AUTHOR("Yoichi Yuasa");
364MODULE_DESCRIPTION("Cobalt server LCD frame buffer driver");