75f10b465a
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>
95 lines
1.7 KiB
C
95 lines
1.7 KiB
C
/*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/delay.h>
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#include <linux/gpio.h>
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#include <asm/io.h>
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#include <asm/proc-fns.h>
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#include <asm/arch/pxa-regs.h>
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static void do_hw_reset(void);
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static int reset_gpio = -1;
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int init_gpio_reset(int gpio)
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{
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int rc;
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rc = gpio_request(gpio, "reset generator");
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if (rc) {
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printk(KERN_ERR "Can't request reset_gpio\n");
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goto out;
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}
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rc = gpio_direction_input(gpio);
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if (rc) {
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printk(KERN_ERR "Can't configure reset_gpio for input\n");
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gpio_free(gpio);
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goto out;
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}
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out:
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if (!rc)
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reset_gpio = gpio;
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return rc;
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}
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/*
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* Trigger GPIO reset.
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* This covers various types of logic connecting gpio pin
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* to RESET pins (nRESET or GPIO_RESET):
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*/
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static void do_gpio_reset(void)
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{
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BUG_ON(reset_gpio == -1);
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/* drive it low */
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gpio_direction_output(reset_gpio, 0);
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mdelay(2);
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/* rising edge or drive high */
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gpio_set_value(reset_gpio, 1);
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mdelay(2);
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/* falling edge */
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gpio_set_value(reset_gpio, 0);
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/* give it some time */
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mdelay(10);
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WARN_ON(1);
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/* fallback */
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do_hw_reset();
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}
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static void do_hw_reset(void)
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{
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/* Initialize the watchdog and let it fire */
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OWER = OWER_WME;
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OSSR = OSSR_M3;
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OSMR3 = OSCR + 368640; /* ... in 100 ms */
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}
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void arch_reset(char mode)
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{
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if (cpu_is_pxa2xx())
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RCSR = RCSR_HWR | RCSR_WDR | RCSR_SMR | RCSR_GPR;
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switch (mode) {
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case 's':
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/* Jump into ROM at address 0 */
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cpu_reset(0);
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break;
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case 'h':
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do_hw_reset();
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break;
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case 'g':
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do_gpio_reset();
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break;
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}
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}
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