android_kernel_motorola_sm6225/arch/arm/mach-at91/gpio.c
David Brownell 28735a7253 [PATCH] gpio_direction_output() needs an initial value
It's been pointed out that output GPIOs should have an initial value, to
avoid signal glitching ...  among other things, it can be some time before
a driver is ready.  This patch corrects that oversight, fixing

 - documentation
 - platforms supporting the GPIO interface
 - users of that call (just one for now, others are pending)

There's only one user of this call for now since most platforms are still
using non-generic GPIO setup code, which in most cases already couples the
initial value with its "set output mode" request.

Note that most platforms are clear about the hardware letting the output
value be set before the pin direction is changed, but the s3c241x docs are
vague on that topic ...  so those chips might not avoid the glitches.

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Acked-by: Andrew Victor <andrew@sanpeople.com>
Acked-by: Milan Svoboda <msvoboda@ra.rockwell.com>
Acked-by: Haavard Skinnemoen <hskinnemoen@atmel.com>
Cc: Russell King <rmk@arm.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-03-16 19:25:04 -07:00

463 lines
11 KiB
C

/*
* linux/arch/arm/mach-at91/gpio.c
*
* Copyright (C) 2005 HP Labs
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*/
#include <linux/clk.h>
#include <linux/errno.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/kernel.h>
#include <linux/list.h>
#include <linux/module.h>
#include <asm/io.h>
#include <asm/hardware.h>
#include <asm/arch/at91_pio.h>
#include <asm/arch/gpio.h>
#include "generic.h"
static struct at91_gpio_bank *gpio;
static int gpio_banks;
static inline void __iomem *pin_to_controller(unsigned pin)
{
void __iomem *sys_base = (void __iomem *) AT91_VA_BASE_SYS;
pin -= PIN_BASE;
pin /= 32;
if (likely(pin < gpio_banks))
return sys_base + gpio[pin].offset;
return NULL;
}
static inline unsigned pin_to_mask(unsigned pin)
{
pin -= PIN_BASE;
return 1 << (pin % 32);
}
/*--------------------------------------------------------------------------*/
/* Not all hardware capabilities are exposed through these calls; they
* only encapsulate the most common features and modes. (So if you
* want to change signals in groups, do it directly.)
*
* Bootloaders will usually handle some of the pin multiplexing setup.
* The intent is certainly that by the time Linux is fully booted, all
* pins should have been fully initialized. These setup calls should
* only be used by board setup routines, or possibly in driver probe().
*
* For bootloaders doing all that setup, these calls could be inlined
* as NOPs so Linux won't duplicate any setup code
*/
/*
* mux the pin to the "GPIO" peripheral role.
*/
int __init_or_module at91_set_GPIO_periph(unsigned pin, int use_pullup)
{
void __iomem *pio = pin_to_controller(pin);
unsigned mask = pin_to_mask(pin);
if (!pio)
return -EINVAL;
__raw_writel(mask, pio + PIO_IDR);
__raw_writel(mask, pio + (use_pullup ? PIO_PUER : PIO_PUDR));
__raw_writel(mask, pio + PIO_PER);
return 0;
}
EXPORT_SYMBOL(at91_set_GPIO_periph);
/*
* mux the pin to the "A" internal peripheral role.
*/
int __init_or_module at91_set_A_periph(unsigned pin, int use_pullup)
{
void __iomem *pio = pin_to_controller(pin);
unsigned mask = pin_to_mask(pin);
if (!pio)
return -EINVAL;
__raw_writel(mask, pio + PIO_IDR);
__raw_writel(mask, pio + (use_pullup ? PIO_PUER : PIO_PUDR));
__raw_writel(mask, pio + PIO_ASR);
__raw_writel(mask, pio + PIO_PDR);
return 0;
}
EXPORT_SYMBOL(at91_set_A_periph);
/*
* mux the pin to the "B" internal peripheral role.
*/
int __init_or_module at91_set_B_periph(unsigned pin, int use_pullup)
{
void __iomem *pio = pin_to_controller(pin);
unsigned mask = pin_to_mask(pin);
if (!pio)
return -EINVAL;
__raw_writel(mask, pio + PIO_IDR);
__raw_writel(mask, pio + (use_pullup ? PIO_PUER : PIO_PUDR));
__raw_writel(mask, pio + PIO_BSR);
__raw_writel(mask, pio + PIO_PDR);
return 0;
}
EXPORT_SYMBOL(at91_set_B_periph);
/*
* mux the pin to the gpio controller (instead of "A" or "B" peripheral), and
* configure it for an input.
*/
int __init_or_module at91_set_gpio_input(unsigned pin, int use_pullup)
{
void __iomem *pio = pin_to_controller(pin);
unsigned mask = pin_to_mask(pin);
if (!pio)
return -EINVAL;
__raw_writel(mask, pio + PIO_IDR);
__raw_writel(mask, pio + (use_pullup ? PIO_PUER : PIO_PUDR));
__raw_writel(mask, pio + PIO_ODR);
__raw_writel(mask, pio + PIO_PER);
return 0;
}
EXPORT_SYMBOL(at91_set_gpio_input);
/*
* mux the pin to the gpio controller (instead of "A" or "B" peripheral),
* and configure it for an output.
*/
int __init_or_module at91_set_gpio_output(unsigned pin, int value)
{
void __iomem *pio = pin_to_controller(pin);
unsigned mask = pin_to_mask(pin);
if (!pio)
return -EINVAL;
__raw_writel(mask, pio + PIO_IDR);
__raw_writel(mask, pio + PIO_PUDR);
__raw_writel(mask, pio + (value ? PIO_SODR : PIO_CODR));
__raw_writel(mask, pio + PIO_OER);
__raw_writel(mask, pio + PIO_PER);
return 0;
}
EXPORT_SYMBOL(at91_set_gpio_output);
/*
* enable/disable the glitch filter; mostly used with IRQ handling.
*/
int __init_or_module at91_set_deglitch(unsigned pin, int is_on)
{
void __iomem *pio = pin_to_controller(pin);
unsigned mask = pin_to_mask(pin);
if (!pio)
return -EINVAL;
__raw_writel(mask, pio + (is_on ? PIO_IFER : PIO_IFDR));
return 0;
}
EXPORT_SYMBOL(at91_set_deglitch);
/*
* enable/disable the multi-driver; This is only valid for output and
* allows the output pin to run as an open collector output.
*/
int __init_or_module at91_set_multi_drive(unsigned pin, int is_on)
{
void __iomem *pio = pin_to_controller(pin);
unsigned mask = pin_to_mask(pin);
if (!pio)
return -EINVAL;
__raw_writel(mask, pio + (is_on ? PIO_MDER : PIO_MDDR));
return 0;
}
EXPORT_SYMBOL(at91_set_multi_drive);
/*--------------------------------------------------------------------------*/
/* new-style GPIO calls; these expect at91_set_GPIO_periph to have been
* called, and maybe at91_set_multi_drive() for putout pins.
*/
int gpio_direction_input(unsigned pin)
{
void __iomem *pio = pin_to_controller(pin);
unsigned mask = pin_to_mask(pin);
if (!pio || !(__raw_readl(pio + PIO_PSR) & mask))
return -EINVAL;
__raw_writel(mask, pio + PIO_ODR);
return 0;
}
EXPORT_SYMBOL(gpio_direction_input);
int gpio_direction_output(unsigned pin, int value)
{
void __iomem *pio = pin_to_controller(pin);
unsigned mask = pin_to_mask(pin);
if (!pio || !(__raw_readl(pio + PIO_PSR) & mask))
return -EINVAL;
__raw_writel(mask, pio + (value ? PIO_SODR : PIO_CODR));
__raw_writel(mask, pio + PIO_OER);
return 0;
}
EXPORT_SYMBOL(gpio_direction_output);
/*--------------------------------------------------------------------------*/
/*
* assuming the pin is muxed as a gpio output, set its value.
*/
int at91_set_gpio_value(unsigned pin, int value)
{
void __iomem *pio = pin_to_controller(pin);
unsigned mask = pin_to_mask(pin);
if (!pio)
return -EINVAL;
__raw_writel(mask, pio + (value ? PIO_SODR : PIO_CODR));
return 0;
}
EXPORT_SYMBOL(at91_set_gpio_value);
/*
* read the pin's value (works even if it's not muxed as a gpio).
*/
int at91_get_gpio_value(unsigned pin)
{
void __iomem *pio = pin_to_controller(pin);
unsigned mask = pin_to_mask(pin);
u32 pdsr;
if (!pio)
return -EINVAL;
pdsr = __raw_readl(pio + PIO_PDSR);
return (pdsr & mask) != 0;
}
EXPORT_SYMBOL(at91_get_gpio_value);
/*--------------------------------------------------------------------------*/
#ifdef CONFIG_PM
static u32 wakeups[MAX_GPIO_BANKS];
static u32 backups[MAX_GPIO_BANKS];
static int gpio_irq_set_wake(unsigned pin, unsigned state)
{
unsigned mask = pin_to_mask(pin);
unsigned bank = (pin - PIN_BASE) / 32;
if (unlikely(bank >= MAX_GPIO_BANKS))
return -EINVAL;
if (state)
wakeups[bank] |= mask;
else
wakeups[bank] &= ~mask;
set_irq_wake(gpio[bank].id, state);
return 0;
}
void at91_gpio_suspend(void)
{
int i;
for (i = 0; i < gpio_banks; i++) {
u32 pio = gpio[i].offset;
backups[i] = at91_sys_read(pio + PIO_IMR);
at91_sys_write(pio + PIO_IDR, backups[i]);
at91_sys_write(pio + PIO_IER, wakeups[i]);
if (!wakeups[i])
clk_disable(gpio[i].clock);
else {
#ifdef CONFIG_PM_DEBUG
printk(KERN_DEBUG "GPIO-%c may wake for %08x\n", 'A'+i, wakeups[i]);
#endif
}
}
}
void at91_gpio_resume(void)
{
int i;
for (i = 0; i < gpio_banks; i++) {
u32 pio = gpio[i].offset;
if (!wakeups[i])
clk_enable(gpio[i].clock);
at91_sys_write(pio + PIO_IDR, wakeups[i]);
at91_sys_write(pio + PIO_IER, backups[i]);
}
}
#else
#define gpio_irq_set_wake NULL
#endif
/* Several AIC controller irqs are dispatched through this GPIO handler.
* To use any AT91_PIN_* as an externally triggered IRQ, first call
* at91_set_gpio_input() then maybe enable its glitch filter.
* Then just request_irq() with the pin ID; it works like any ARM IRQ
* handler, though it always triggers on rising and falling edges.
*
* Alternatively, certain pins may be used directly as IRQ0..IRQ6 after
* configuring them with at91_set_a_periph() or at91_set_b_periph().
* IRQ0..IRQ6 should be configurable, e.g. level vs edge triggering.
*/
static void gpio_irq_mask(unsigned pin)
{
void __iomem *pio = pin_to_controller(pin);
unsigned mask = pin_to_mask(pin);
if (pio)
__raw_writel(mask, pio + PIO_IDR);
}
static void gpio_irq_unmask(unsigned pin)
{
void __iomem *pio = pin_to_controller(pin);
unsigned mask = pin_to_mask(pin);
if (pio)
__raw_writel(mask, pio + PIO_IER);
}
static int gpio_irq_type(unsigned pin, unsigned type)
{
return (type == IRQT_BOTHEDGE) ? 0 : -EINVAL;
}
static struct irq_chip gpio_irqchip = {
.name = "GPIO",
.mask = gpio_irq_mask,
.unmask = gpio_irq_unmask,
.set_type = gpio_irq_type,
.set_wake = gpio_irq_set_wake,
};
static void gpio_irq_handler(unsigned irq, struct irq_desc *desc)
{
unsigned pin;
struct irq_desc *gpio;
void __iomem *pio;
u32 isr;
pio = get_irq_chip_data(irq);
/* temporarily mask (level sensitive) parent IRQ */
desc->chip->ack(irq);
for (;;) {
/* reading ISR acks the pending (edge triggered) GPIO interrupt */
isr = __raw_readl(pio + PIO_ISR) & __raw_readl(pio + PIO_IMR);
if (!isr)
break;
pin = (unsigned) get_irq_data(irq);
gpio = &irq_desc[pin];
while (isr) {
if (isr & 1) {
if (unlikely(gpio->depth)) {
/*
* The core ARM interrupt handler lazily disables IRQs so
* another IRQ must be generated before it actually gets
* here to be disabled on the GPIO controller.
*/
gpio_irq_mask(pin);
}
else
desc_handle_irq(pin, gpio);
}
pin++;
gpio++;
isr >>= 1;
}
}
desc->chip->unmask(irq);
/* now it may re-trigger */
}
/*--------------------------------------------------------------------------*/
/*
* Called from the processor-specific init to enable GPIO interrupt support.
*/
void __init at91_gpio_irq_setup(void)
{
unsigned pioc, pin;
for (pioc = 0, pin = PIN_BASE;
pioc < gpio_banks;
pioc++) {
void __iomem *controller;
unsigned id = gpio[pioc].id;
unsigned i;
clk_enable(gpio[pioc].clock); /* enable PIO controller's clock */
controller = (void __iomem *) AT91_VA_BASE_SYS + gpio[pioc].offset;
__raw_writel(~0, controller + PIO_IDR);
set_irq_data(id, (void *) pin);
set_irq_chip_data(id, controller);
for (i = 0; i < 32; i++, pin++) {
/*
* Can use the "simple" and not "edge" handler since it's
* shorter, and the AIC handles interupts sanely.
*/
set_irq_chip(pin, &gpio_irqchip);
set_irq_handler(pin, handle_simple_irq);
set_irq_flags(pin, IRQF_VALID);
}
set_irq_chained_handler(id, gpio_irq_handler);
}
pr_info("AT91: %d gpio irqs in %d banks\n", pin - PIN_BASE, gpio_banks);
}
/*
* Called from the processor-specific init to enable GPIO pin support.
*/
void __init at91_gpio_init(struct at91_gpio_bank *data, int nr_banks)
{
BUG_ON(nr_banks > MAX_GPIO_BANKS);
gpio = data;
gpio_banks = nr_banks;
}