linux_module_learn/examples/shortprint/shortprint.h

47 lines
1.1 KiB
C

/*
* Useful info describing the parallel port device.
*
* Copyright (C) 2001 Alessandro Rubini and Jonathan Corbet
* Copyright (C) 2001 O'Reilly & Associates
*
* The source code in this file can be freely used, adapted,
* and redistributed in source or binary form, so long as an
* acknowledgment appears in derived source files. The citation
* should list that the code comes from the book "Linux Device
* Drivers" by Alessandro Rubini and Jonathan Corbet, published
* by O'Reilly & Associates. No warranty is attached;
* we cannot take responsibility for errors or fitness for use.
*
*/
/*
* Register offsets
*/
#define SP_DATA 0x00
#define SP_STATUS 0x01
#define SP_CONTROL 0x02
#define SP_NPORTS 3
/*
* Status register bits.
*/
#define SP_SR_BUSY 0x80
#define SP_SR_ACK 0x40
#define SP_SR_PAPER 0x20
#define SP_SR_ONLINE 0x10
#define SP_SR_ERR 0x08
/*
* Control register.
*/
#define SP_CR_IRQ 0x10
#define SP_CR_SELECT 0x08
#define SP_CR_INIT 0x04
#define SP_CR_AUTOLF 0x02
#define SP_CR_STROBE 0x01
/*
* Minimum space before waking up a writer.
*/
#define SP_MIN_SPACE PAGE_SIZE/2