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[ARM] 5047/2: Support resetting by asserting GPIO pin

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This adds support for resetting via assertion of GPIO pin.
This e.g. is used on Sharp Zaurus SL-6000.

Signed-off-by: Dmitry Baryshkov <dbaryshkov@gmail.com>
Acked-by: Eric Miao <eric.miao@marvell.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
This commit is contained in:
Dmitry Baryshkov 2008-05-22 16:20:18 +01:00 committed by Russell King
parent b8291ad07a
commit 75f10b465a
4 changed files with 102 additions and 17 deletions
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2
arch/arm/mach-pxa/Makefile
View file

@ -4,7 +4,7 @@
# Common support (must be linked before board specific support)
obj-y += clock.o devices.o generic.o irq.o dma.o \
time.o gpio.o
time.o gpio.o reset.o
obj-$(CONFIG_PM) += pm.o sleep.o standby.o
obj-$(CONFIG_CPU_FREQ) += cpu-pxa.o

95
arch/arm/mach-pxa/reset.c Normal file
View file

@ -0,0 +1,95 @@
/*
* 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.
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/delay.h>
#include <linux/gpio.h>
#include <asm/io.h>
#include <asm/proc-fns.h>
#include <asm/arch/pxa-regs.h>
static void do_hw_reset(void);
static int reset_gpio = -1;
int init_gpio_reset(int gpio)
{
int rc;
rc = gpio_request(gpio, "reset generator");
if (rc) {
printk(KERN_ERR "Can't request reset_gpio\n");
goto out;
}
rc = gpio_direction_input(gpio);
if (rc) {
printk(KERN_ERR "Can't configure reset_gpio for input\n");
gpio_free(gpio);
goto out;
}
out:
if (!rc)
reset_gpio = gpio;
return rc;
}
/*
* Trigger GPIO reset.
* This covers various types of logic connecting gpio pin
* to RESET pins (nRESET or GPIO_RESET):
*/
static void do_gpio_reset(void)
{
BUG_ON(reset_gpio == -1);
/* drive it low */
gpio_direction_output(reset_gpio, 0);
mdelay(2);
/* rising edge or drive high */
gpio_set_value(reset_gpio, 1);
mdelay(2);
/* falling edge */
gpio_set_value(reset_gpio, 0);
/* give it some time */
mdelay(10);
WARN_ON(1);
/* fallback */
do_hw_reset();
}
static void do_hw_reset(void)
{
/* Initialize the watchdog and let it fire */
OWER = OWER_WME;
OSSR = OSSR_M3;
OSMR3 = OSCR + 368640; /* ... in 100 ms */
}
void arch_reset(char mode)
{
if (cpu_is_pxa2xx())
RCSR = RCSR_HWR | RCSR_WDR | RCSR_SMR | RCSR_GPR;
switch (mode) {
case 's':
/* Jump into ROM at address 0 */
cpu_reset(0);
break;
case 'h':
do_hw_reset();
break;
case 'g':
do_gpio_reset();
break;
}
}

5
include/asm-arm/arch-pxa/hardware.h
View file

@ -205,6 +205,11 @@ static inline void __deprecated pxa_set_cken(int clock, int enable)
*/
extern unsigned int get_memclk_frequency_10khz(void);
/*
* register GPIO as reset generator
*/
extern int init_gpio_reset(int gpio);
#endif
#if defined(CONFIG_MACH_ARMCORE) && defined(CONFIG_PCI)

17
include/asm-arm/arch-pxa/system.h
View file

@ -20,19 +20,4 @@ static inline void arch_idle(void)
}
static inline void arch_reset(char mode)
{
if (cpu_is_pxa2xx())
RCSR = RCSR_HWR | RCSR_WDR | RCSR_SMR | RCSR_GPR;
if (mode == 's') {
/* Jump into ROM at address 0 */
cpu_reset(0);
} else {
/* Initialize the watchdog and let it fire */
OWER = OWER_WME;
OSSR = OSSR_M3;
OSMR3 = OSCR + 368640; /* ... in 100 ms */
}
}
void arch_reset(char mode);