linux/arch/arm/mach-sa1100/ssp.c
Linus Torvalds 0cd61b68c3 Initial blind fixup for arm for irq changes
Untested, but this should fix up the bulk of the totally mechanical
issues, and should make the actual detail fixing easier.

Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-10-06 10:59:54 -07:00

245 lines
4.8 KiB
C

/*
* linux/arch/arm/mach-sa1100/ssp.c
*
* Copyright (C) 2003 Russell King.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* Generic SSP driver. This provides the generic core for simple
* IO-based SSP applications.
*/
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/errno.h>
#include <linux/interrupt.h>
#include <linux/ioport.h>
#include <linux/init.h>
#include <asm/io.h>
#include <asm/irq.h>
#include <asm/hardware.h>
#include <asm/hardware/ssp.h>
#define TIMEOUT 100000
static irqreturn_t ssp_interrupt(int irq, void *dev_id)
{
unsigned int status = Ser4SSSR;
if (status & SSSR_ROR) {
printk(KERN_WARNING "SSP: receiver overrun\n");
}
Ser4SSSR = SSSR_ROR;
return status ? IRQ_HANDLED : IRQ_NONE;
}
/**
* ssp_write_word - write a word to the SSP port
* @data: 16-bit, MSB justified data to write.
*
* Wait for a free entry in the SSP transmit FIFO, and write a data
* word to the SSP port. Wait for the SSP port to start sending
* the data.
*
* The caller is expected to perform the necessary locking.
*
* Returns:
* %-ETIMEDOUT timeout occurred
* 0 success
*/
int ssp_write_word(u16 data)
{
int timeout = TIMEOUT;
while (!(Ser4SSSR & SSSR_TNF)) {
if (!--timeout)
return -ETIMEDOUT;
cpu_relax();
}
Ser4SSDR = data;
timeout = TIMEOUT;
while (!(Ser4SSSR & SSSR_BSY)) {
if (!--timeout)
return -ETIMEDOUT;
cpu_relax();
}
return 0;
}
/**
* ssp_read_word - read a word from the SSP port
*
* Wait for a data word in the SSP receive FIFO, and return the
* received data. Data is LSB justified.
*
* Note: Currently, if data is not expected to be received, this
* function will wait for ever.
*
* The caller is expected to perform the necessary locking.
*
* Returns:
* %-ETIMEDOUT timeout occurred
* 16-bit data success
*/
int ssp_read_word(u16 *data)
{
int timeout = TIMEOUT;
while (!(Ser4SSSR & SSSR_RNE)) {
if (!--timeout)
return -ETIMEDOUT;
cpu_relax();
}
*data = (u16)Ser4SSDR;
return 0;
}
/**
* ssp_flush - flush the transmit and receive FIFOs
*
* Wait for the SSP to idle, and ensure that the receive FIFO
* is empty.
*
* The caller is expected to perform the necessary locking.
*
* Returns:
* %-ETIMEDOUT timeout occurred
* 0 success
*/
int ssp_flush(void)
{
int timeout = TIMEOUT * 2;
do {
while (Ser4SSSR & SSSR_RNE) {
if (!--timeout)
return -ETIMEDOUT;
(void) Ser4SSDR;
}
if (!--timeout)
return -ETIMEDOUT;
} while (Ser4SSSR & SSSR_BSY);
return 0;
}
/**
* ssp_enable - enable the SSP port
*
* Turn on the SSP port.
*/
void ssp_enable(void)
{
Ser4SSCR0 |= SSCR0_SSE;
}
/**
* ssp_disable - shut down the SSP port
*
* Turn off the SSP port, optionally powering it down.
*/
void ssp_disable(void)
{
Ser4SSCR0 &= ~SSCR0_SSE;
}
/**
* ssp_save_state - save the SSP configuration
* @ssp: pointer to structure to save SSP configuration
*
* Save the configured SSP state for suspend.
*/
void ssp_save_state(struct ssp_state *ssp)
{
ssp->cr0 = Ser4SSCR0;
ssp->cr1 = Ser4SSCR1;
Ser4SSCR0 &= ~SSCR0_SSE;
}
/**
* ssp_restore_state - restore a previously saved SSP configuration
* @ssp: pointer to configuration saved by ssp_save_state
*
* Restore the SSP configuration saved previously by ssp_save_state.
*/
void ssp_restore_state(struct ssp_state *ssp)
{
Ser4SSSR = SSSR_ROR;
Ser4SSCR0 = ssp->cr0 & ~SSCR0_SSE;
Ser4SSCR1 = ssp->cr1;
Ser4SSCR0 = ssp->cr0;
}
/**
* ssp_init - setup the SSP port
*
* initialise and claim resources for the SSP port.
*
* Returns:
* %-ENODEV if the SSP port is unavailable
* %-EBUSY if the resources are already in use
* %0 on success
*/
int ssp_init(void)
{
int ret;
if (!(PPAR & PPAR_SPR) && (Ser4MCCR0 & MCCR0_MCE))
return -ENODEV;
if (!request_mem_region(__PREG(Ser4SSCR0), 0x18, "SSP")) {
return -EBUSY;
}
Ser4SSSR = SSSR_ROR;
ret = request_irq(IRQ_Ser4SSP, ssp_interrupt, 0, "SSP", NULL);
if (ret)
goto out_region;
return 0;
out_region:
release_mem_region(__PREG(Ser4SSCR0), 0x18);
return ret;
}
/**
* ssp_exit - undo the effects of ssp_init
*
* release and free resources for the SSP port.
*/
void ssp_exit(void)
{
Ser4SSCR0 &= ~SSCR0_SSE;
free_irq(IRQ_Ser4SSP, NULL);
release_mem_region(__PREG(Ser4SSCR0), 0x18);
}
MODULE_AUTHOR("Russell King");
MODULE_DESCRIPTION("SA11x0 SSP PIO driver");
MODULE_LICENSE("GPL");
EXPORT_SYMBOL(ssp_write_word);
EXPORT_SYMBOL(ssp_read_word);
EXPORT_SYMBOL(ssp_flush);
EXPORT_SYMBOL(ssp_enable);
EXPORT_SYMBOL(ssp_disable);
EXPORT_SYMBOL(ssp_save_state);
EXPORT_SYMBOL(ssp_restore_state);
EXPORT_SYMBOL(ssp_init);
EXPORT_SYMBOL(ssp_exit);