include/linux/mc6821.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 #ifndef _MC6821_H_
   3 #define _MC6821_H_
   4
   5 /*
   6  * This file describes the memery mapping of the MC6821 PIA.
   7  * The unions describe overlayed registers. Which of them is used is
   8  * determined by bit 2 of the corresponding control register.
   9  * this files expects the PIA_REG_PADWIDTH to be defined the numeric
  10  * value of the register spacing.
  11  *
  12  * Data came from MFC-31-Developer Kit (from Ralph Seidel,
  13  * zodiac@darkness.gun.de) and Motorola Data Sheet (from
  14  * Richard Hirst, srh@gpt.co.uk)
  15  *
  16  * 6.11.95 copyright Joerg Dorchain (dorchain@mpi-sb.mpg.de)
  17  *
  18  */
  19
  20 #ifndef PIA_REG_PADWIDTH
  21 #define PIA_REG_PADWIDTH 255
  22 #endif
  23
  24 struct pia {
  25         union {
  26                 volatile u_char pra;
  27                 volatile u_char ddra;
  28         } ua;
  29         u_char pad1[PIA_REG_PADWIDTH];
  30         volatile u_char cra;
  31         u_char pad2[PIA_REG_PADWIDTH];
  32         union {
  33                 volatile u_char prb;
  34                 volatile u_char ddrb;
  35         } ub;
  36         u_char pad3[PIA_REG_PADWIDTH];
  37         volatile u_char crb;
  38         u_char pad4[PIA_REG_PADWIDTH];
  39 };
  40
  41 #define ppra ua.pra
  42 #define pddra ua.ddra
  43 #define pprb ub.prb
  44 #define pddrb ub.ddrb
  45
  46 #define PIA_C1_ENABLE_IRQ (1<<0)
  47 #define PIA_C1_LOW_TO_HIGH (1<<1)
  48 #define PIA_DDR (1<<2)
  49 #define PIA_IRQ2 (1<<6)
  50 #define PIA_IRQ1 (1<<7)
  51
  52 #endif