linux-imx

/*

 *  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.

 *

 *  Copyright (C) 2012 John Crispin <john@phrozen.org>

 */

​

#include <linux/init.h>

#include <linux/module.h>

#include <linux/types.h>

#include <linux/platform_device.h>

#include <linux/mutex.h>

#include <linux/gpio/driver.h>

#include <linux/of.h>

#include <linux/of_gpio.h>

#include <linux/io.h>

#include <linux/slab.h>

​

#include <lantiq_soc.h>

​

/*

 * By attaching hardware latches to the EBU it is possible to create output

 * only gpios. This driver configures a special memory address, which when

 * written to outputs 16 bit to the latches.

 */

​

#define LTQ_EBU_BUSCON  0x1e7ff     /* 16 bit access, slowest timing */

#define LTQ_EBU_WP  0x80000000  /* write protect bit */

​

struct ltq_mm {

    struct of_mm_gpio_chip mmchip;

    u16 shadow; /* shadow the latches state */

};

​

/**

 * ltq_mm_apply() - write the shadow value to the ebu address.

 * @chip:     Pointer to our private data structure.

 *

 * Write the shadow value to the EBU to set the gpios. We need to set the

 * global EBU lock to make sure that PCI/MTD dont break.

 */

static void ltq_mm_apply(struct ltq_mm *chip)

{

    unsigned long flags;

​

    spin_lock_irqsave(&ebu_lock, flags);

    ltq_ebu_w32(LTQ_EBU_BUSCON, LTQ_EBU_BUSCON1);

    __raw_writew(chip->shadow, chip->mmchip.regs);

    ltq_ebu_w32(LTQ_EBU_BUSCON | LTQ_EBU_WP, LTQ_EBU_BUSCON1);

    spin_unlock_irqrestore(&ebu_lock, flags);

}

​

/**

 * ltq_mm_set() - gpio_chip->set - set gpios.

 * @gc:     Pointer to gpio_chip device structure.

 * @gpio:   GPIO signal number.

 * @val:    Value to be written to specified signal.

 *

 * Set the shadow value and call ltq_mm_apply.

 */

static void ltq_mm_set(struct gpio_chip *gc, unsigned offset, int value)

{