drivers/video/fbdev/cobalt_lcdfb.c

   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
  67 static inline void lcd_write_control(struct fb_info *info, u8 control)
  68 {
  69         writel((u32)control << 24, info->screen_base);
  70 }
  71
  72 static inline u8 lcd_read_control(struct fb_info *info)
  73 {
  74         return readl(info->screen_base) >> 24;
  75 }
  76
  77 static 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
  82 static inline u8 lcd_read_data(struct fb_info *info)
  83 {
  84         return readl(info->screen_base + LCD_DATA_REG_OFFSET) >> 24;
  85 }
  86
  87 static 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
 110 static 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
 129 static const 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
 138 static 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
 184 static 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
 230 static 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
 250 static 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
 285 static 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
 293 static 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
 340 static 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
 353 static struct platform_driver cobalt_lcdfb_driver = {
 354         .probe  = cobalt_lcdfb_probe,
 355         .remove = cobalt_lcdfb_remove,
 356         .driver = {
 357                 .name   = "cobalt-lcd",
 358         },
 359 };
 360 module_platform_driver(cobalt_lcdfb_driver);
 361
 362 MODULE_LICENSE("GPL v2");
 363 MODULE_AUTHOR("Yoichi Yuasa");
 364 MODULE_DESCRIPTION("Cobalt server LCD frame buffer driver");