include/linux/mc6821.h

   1 #ifndef _MC6821_H_
   2 #define _MC6821_H_
   3
   4 /*
   5  * This file describes the memery mapping of the MC6821 PIA.
   6  * The unions describe overlayed registers. Which of them is used is
   7  * determined by bit 2 of the corresponding control register.
   8  * this files expects the PIA_REG_PADWIDTH to be defined the numeric
   9  * value of the register spacing.
  10  *
  11  * Data came from MFC-31-Developer Kit (from Ralph Seidel,
  12  * zodiac@darkness.gun.de) and Motorola Data Sheet (from
  13  * Richard Hirst, srh@gpt.co.uk)
  14  *
  15  * 6.11.95 copyright Joerg Dorchain (dorchain@mpi-sb.mpg.de)
  16  *
  17  */
  18
  19 #ifndef PIA_REG_PADWIDTH
  20 #define PIA_REG_PADWIDTH 255
  21 #endif
  22
  23 struct pia {
  24         union {
  25                 volatile u_char pra;
  26                 volatile u_char ddra;
  27         } ua;
  28         u_char pad1[PIA_REG_PADWIDTH];
  29         volatile u_char cra;
  30         u_char pad2[PIA_REG_PADWIDTH];
  31         union {
  32                 volatile u_char prb;
  33                 volatile u_char ddrb;
  34         } ub;
  35         u_char pad3[PIA_REG_PADWIDTH];
  36         volatile u_char crb;
  37         u_char pad4[PIA_REG_PADWIDTH];
  38 };
  39
  40 #define ppra ua.pra
  41 #define pddra ua.ddra
  42 #define pprb ub.prb
  43 #define pddrb ub.ddrb
  44
  45 #define PIA_C1_ENABLE_IRQ (1<<0)
  46 #define PIA_C1_LOW_TO_HIGH (1<<1)
  47 #define PIA_DDR (1<<2)
  48 #define PIA_IRQ2 (1<<6)
  49 #define PIA_IRQ1 (1<<7)
  50
  51 #endif