275 lines
7.4 KiB
C
275 lines
7.4 KiB
C
![]() |
/* arch/arm/mach-msm/generic_gpio.c
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*
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* Copyright (C) 2007 Google, Inc.
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*
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* This software is licensed under the terms of the GNU General Public
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* License version 2, as published by the Free Software Foundation, and
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* may be copied, distributed, and modified under those terms.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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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/errno.h>
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#include <linux/slab.h>
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#include <linux/spinlock.h>
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#include <asm/gpio.h>
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#include "gpio_chip.h"
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#define GPIO_NUM_TO_CHIP_INDEX(gpio) ((gpio)>>5)
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struct gpio_state {
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unsigned long flags;
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int refcount;
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};
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static DEFINE_SPINLOCK(gpio_chips_lock);
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static LIST_HEAD(gpio_chip_list);
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static struct gpio_chip **gpio_chip_array;
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static unsigned long gpio_chip_array_size;
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int register_gpio_chip(struct gpio_chip *new_gpio_chip)
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{
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int err = 0;
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struct gpio_chip *gpio_chip;
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int i;
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unsigned long irq_flags;
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unsigned int chip_array_start_index, chip_array_end_index;
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new_gpio_chip->state = kzalloc((new_gpio_chip->end + 1 - new_gpio_chip->start) * sizeof(new_gpio_chip->state[0]), GFP_KERNEL);
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if (new_gpio_chip->state == NULL) {
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printk(KERN_ERR "register_gpio_chip: failed to allocate state\n");
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return -ENOMEM;
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}
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spin_lock_irqsave(&gpio_chips_lock, irq_flags);
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chip_array_start_index = GPIO_NUM_TO_CHIP_INDEX(new_gpio_chip->start);
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chip_array_end_index = GPIO_NUM_TO_CHIP_INDEX(new_gpio_chip->end);
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if (chip_array_end_index >= gpio_chip_array_size) {
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struct gpio_chip **new_gpio_chip_array;
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unsigned long new_gpio_chip_array_size = chip_array_end_index + 1;
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new_gpio_chip_array = kmalloc(new_gpio_chip_array_size * sizeof(new_gpio_chip_array[0]), GFP_ATOMIC);
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if (new_gpio_chip_array == NULL) {
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printk(KERN_ERR "register_gpio_chip: failed to allocate array\n");
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err = -ENOMEM;
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goto failed;
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}
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for (i = 0; i < gpio_chip_array_size; i++)
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new_gpio_chip_array[i] = gpio_chip_array[i];
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for (i = gpio_chip_array_size; i < new_gpio_chip_array_size; i++)
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new_gpio_chip_array[i] = NULL;
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gpio_chip_array = new_gpio_chip_array;
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gpio_chip_array_size = new_gpio_chip_array_size;
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}
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list_for_each_entry(gpio_chip, &gpio_chip_list, list) {
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if (gpio_chip->start > new_gpio_chip->end) {
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list_add_tail(&new_gpio_chip->list, &gpio_chip->list);
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goto added;
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}
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if (gpio_chip->end >= new_gpio_chip->start) {
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printk(KERN_ERR "register_gpio_source %u-%u overlaps with %u-%u\n",
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new_gpio_chip->start, new_gpio_chip->end,
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gpio_chip->start, gpio_chip->end);
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err = -EBUSY;
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goto failed;
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}
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}
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list_add_tail(&new_gpio_chip->list, &gpio_chip_list);
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added:
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for (i = chip_array_start_index; i <= chip_array_end_index; i++) {
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if (gpio_chip_array[i] == NULL || gpio_chip_array[i]->start > new_gpio_chip->start)
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gpio_chip_array[i] = new_gpio_chip;
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}
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failed:
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spin_unlock_irqrestore(&gpio_chips_lock, irq_flags);
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if (err)
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kfree(new_gpio_chip->state);
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return err;
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}
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static struct gpio_chip *get_gpio_chip_locked(unsigned int gpio)
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{
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unsigned long i;
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struct gpio_chip *chip;
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i = GPIO_NUM_TO_CHIP_INDEX(gpio);
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if (i >= gpio_chip_array_size)
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return NULL;
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chip = gpio_chip_array[i];
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if (chip == NULL)
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return NULL;
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list_for_each_entry_from(chip, &gpio_chip_list, list) {
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if (gpio < chip->start)
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return NULL;
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if (gpio <= chip->end)
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return chip;
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}
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return NULL;
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}
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static int request_gpio(unsigned int gpio, unsigned long flags)
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{
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int err = 0;
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struct gpio_chip *chip;
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unsigned long irq_flags;
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unsigned long chip_index;
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spin_lock_irqsave(&gpio_chips_lock, irq_flags);
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chip = get_gpio_chip_locked(gpio);
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if (chip == NULL) {
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err = -EINVAL;
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goto err;
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}
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chip_index = gpio - chip->start;
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if (chip->state[chip_index].refcount == 0) {
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chip->configure(chip, gpio, flags);
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chip->state[chip_index].flags = flags;
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chip->state[chip_index].refcount++;
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} else if ((flags & IRQF_SHARED) && (chip->state[chip_index].flags & IRQF_SHARED))
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chip->state[chip_index].refcount++;
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else
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err = -EBUSY;
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err:
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spin_unlock_irqrestore(&gpio_chips_lock, irq_flags);
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return err;
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}
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int gpio_request(unsigned gpio, const char *label)
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{
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return request_gpio(gpio, 0);
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}
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EXPORT_SYMBOL(gpio_request);
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void gpio_free(unsigned gpio)
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{
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struct gpio_chip *chip;
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unsigned long irq_flags;
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unsigned long chip_index;
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spin_lock_irqsave(&gpio_chips_lock, irq_flags);
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chip = get_gpio_chip_locked(gpio);
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if (chip) {
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chip_index = gpio - chip->start;
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chip->state[chip_index].refcount--;
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}
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spin_unlock_irqrestore(&gpio_chips_lock, irq_flags);
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}
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EXPORT_SYMBOL(gpio_free);
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static int gpio_get_irq_num(unsigned int gpio, unsigned int *irqp, unsigned long *irqnumflagsp)
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{
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int ret = -ENOTSUPP;
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struct gpio_chip *chip;
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unsigned long irq_flags;
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spin_lock_irqsave(&gpio_chips_lock, irq_flags);
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chip = get_gpio_chip_locked(gpio);
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if (chip && chip->get_irq_num)
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ret = chip->get_irq_num(chip, gpio, irqp, irqnumflagsp);
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spin_unlock_irqrestore(&gpio_chips_lock, irq_flags);
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return ret;
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}
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int gpio_to_irq(unsigned gpio)
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{
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int ret, irq;
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ret = gpio_get_irq_num(gpio, &irq, NULL);
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if (ret)
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return ret;
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return irq;
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}
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EXPORT_SYMBOL(gpio_to_irq);
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int gpio_configure(unsigned int gpio, unsigned long flags)
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{
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int ret = -ENOTSUPP;
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struct gpio_chip *chip;
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unsigned long irq_flags;
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spin_lock_irqsave(&gpio_chips_lock, irq_flags);
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chip = get_gpio_chip_locked(gpio);
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if (chip)
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ret = chip->configure(chip, gpio, flags);
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spin_unlock_irqrestore(&gpio_chips_lock, irq_flags);
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return ret;
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}
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EXPORT_SYMBOL(gpio_configure);
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int gpio_direction_input(unsigned gpio)
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{
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return gpio_configure(gpio, GPIOF_INPUT);
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}
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EXPORT_SYMBOL(gpio_direction_input);
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int gpio_direction_output(unsigned gpio, int value)
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{
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gpio_set_value(gpio, value);
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return gpio_configure(gpio, GPIOF_DRIVE_OUTPUT);
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}
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EXPORT_SYMBOL(gpio_direction_output);
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int gpio_get_value(unsigned gpio)
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{
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int ret = -ENOTSUPP;
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struct gpio_chip *chip;
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unsigned long irq_flags;
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spin_lock_irqsave(&gpio_chips_lock, irq_flags);
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chip = get_gpio_chip_locked(gpio);
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if (chip && chip->read)
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ret = chip->read(chip, gpio);
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spin_unlock_irqrestore(&gpio_chips_lock, irq_flags);
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return ret;
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}
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EXPORT_SYMBOL(gpio_get_value);
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void gpio_set_value(unsigned gpio, int on)
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{
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int ret = -ENOTSUPP;
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struct gpio_chip *chip;
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unsigned long irq_flags;
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spin_lock_irqsave(&gpio_chips_lock, irq_flags);
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chip = get_gpio_chip_locked(gpio);
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if (chip && chip->write)
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ret = chip->write(chip, gpio, on);
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spin_unlock_irqrestore(&gpio_chips_lock, irq_flags);
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}
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EXPORT_SYMBOL(gpio_set_value);
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int gpio_read_detect_status(unsigned int gpio)
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{
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int ret = -ENOTSUPP;
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struct gpio_chip *chip;
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unsigned long irq_flags;
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spin_lock_irqsave(&gpio_chips_lock, irq_flags);
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chip = get_gpio_chip_locked(gpio);
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if (chip && chip->read_detect_status)
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ret = chip->read_detect_status(chip, gpio);
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spin_unlock_irqrestore(&gpio_chips_lock, irq_flags);
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return ret;
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}
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EXPORT_SYMBOL(gpio_read_detect_status);
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int gpio_clear_detect_status(unsigned int gpio)
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{
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int ret = -ENOTSUPP;
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struct gpio_chip *chip;
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unsigned long irq_flags;
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spin_lock_irqsave(&gpio_chips_lock, irq_flags);
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chip = get_gpio_chip_locked(gpio);
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if (chip && chip->clear_detect_status)
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ret = chip->clear_detect_status(chip, gpio);
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spin_unlock_irqrestore(&gpio_chips_lock, irq_flags);
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return ret;
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}
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EXPORT_SYMBOL(gpio_clear_detect_status);
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