LXR linux/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
  24struct 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
  53