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awilliam
GitHub Repository: awilliam/linux-vfio
 Path: blob/master/arch/mips/kernel/gpio_txx9.c
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/*

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 * A gpio chip driver for TXx9 SoCs

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 *

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 * Copyright (C) 2008 Atsushi Nemoto <[email protected]>

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 *

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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/init.h>

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#include <linux/spinlock.h>

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#include <linux/gpio.h>

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#include <linux/errno.h>

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#include <linux/io.h>

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#include <asm/txx9pio.h>

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static DEFINE_SPINLOCK(txx9_gpio_lock);

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static struct txx9_pio_reg __iomem *txx9_pioptr;

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static int txx9_gpio_get(struct gpio_chip *chip, unsigned int offset)

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{

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	return __raw_readl(&txx9_pioptr->din) & (1 << offset);

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}

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static void txx9_gpio_set_raw(unsigned int offset, int value)

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{

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	u32 val;

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	val = __raw_readl(&txx9_pioptr->dout);

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	if (value)

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		val |= 1 << offset;

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	else

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		val &= ~(1 << offset);

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	__raw_writel(val, &txx9_pioptr->dout);

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}

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static void txx9_gpio_set(struct gpio_chip *chip, unsigned int offset,

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			  int value)

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{

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	unsigned long flags;

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	spin_lock_irqsave(&txx9_gpio_lock, flags);

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	txx9_gpio_set_raw(offset, value);

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	mmiowb();

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	spin_unlock_irqrestore(&txx9_gpio_lock, flags);

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}

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static int txx9_gpio_dir_in(struct gpio_chip *chip, unsigned int offset)

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{

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	unsigned long flags;

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	spin_lock_irqsave(&txx9_gpio_lock, flags);

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	__raw_writel(__raw_readl(&txx9_pioptr->dir) & ~(1 << offset),

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		     &txx9_pioptr->dir);

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	mmiowb();

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	spin_unlock_irqrestore(&txx9_gpio_lock, flags);

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	return 0;

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}

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static int txx9_gpio_dir_out(struct gpio_chip *chip, unsigned int offset,

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			     int value)

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{

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	unsigned long flags;

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	spin_lock_irqsave(&txx9_gpio_lock, flags);

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	txx9_gpio_set_raw(offset, value);

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	__raw_writel(__raw_readl(&txx9_pioptr->dir) | (1 << offset),

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		     &txx9_pioptr->dir);

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	mmiowb();

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	spin_unlock_irqrestore(&txx9_gpio_lock, flags);

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	return 0;

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}

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static struct gpio_chip txx9_gpio_chip = {

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	.get = txx9_gpio_get,

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	.set = txx9_gpio_set,

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	.direction_input = txx9_gpio_dir_in,

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	.direction_output = txx9_gpio_dir_out,

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	.label = "TXx9",

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};

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int __init txx9_gpio_init(unsigned long baseaddr,

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			  unsigned int base, unsigned int num)

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{

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	txx9_pioptr = ioremap(baseaddr, sizeof(struct txx9_pio_reg));

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	if (!txx9_pioptr)

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		return -ENODEV;

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	txx9_gpio_chip.base = base;

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	txx9_gpio_chip.ngpio = num;

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	return gpiochip_add(&txx9_gpio_chip);

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}

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