drivers/video/fbdev/cobalt_lcdfb.c

   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
  54 static inline void lcd_write_control(struct fb_info *info, u8 control)
  55 {
  56         writel((u32)control << 24, info->screen_base);
  57 }
  58
  59 static inline u8 lcd_read_control(struct fb_info *info)
  60 {
  61         return readl(info->screen_base) >> 24;
  62 }
  63
  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
  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
  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
  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
 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
 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
 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
 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
 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         info->flags = FBINFO_DEFAULT;
 317
 318         retval = register_framebuffer(info);
 319         if (retval < 0) {
 320                 framebuffer_release(info);
 321                 return retval;
 322         }
 323
 324         platform_set_drvdata(dev, info);
 325
 326         lcd_clear(info);
 327
 328         fb_info(info, "Cobalt server LCD frame buffer device\n");
 329
 330         return 0;
 331 }
 332
 333 static void cobalt_lcdfb_remove(struct platform_device *dev)
 334 {
 335         struct fb_info *info;
 336
 337         info = platform_get_drvdata(dev);
 338         if (info) {
 339                 unregister_framebuffer(info);
 340                 framebuffer_release(info);
 341         }
 342 }
 343
 344 static struct platform_driver cobalt_lcdfb_driver = {
 345         .probe  = cobalt_lcdfb_probe,
 346         .remove_new = cobalt_lcdfb_remove,
 347         .driver = {
 348                 .name   = "cobalt-lcd",
 349         },
 350 };
 351 module_platform_driver(cobalt_lcdfb_driver);
 352
 353 MODULE_LICENSE("GPL v2");
 354 MODULE_AUTHOR("Yoichi Yuasa");
 355 MODULE_DESCRIPTION("Cobalt server LCD frame buffer driver");