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/*
* 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) 2010 John Crispin <blogic@openwrt.org>
*/
#include <linux/init.h>
#include <linux/export.h>
#include <linux/types.h>
#include <linux/platform_device.h>
#include <linux/mutex.h>
#include <linux/gpio.h>
#include <linux/io.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 */
/* we keep a shadow value of the last value written to the ebu */
static int ltq_ebu_gpio_shadow = 0x0;
static void __iomem *ltq_ebu_gpio_membase;
static void ltq_ebu_apply(void)
{
unsigned long flags;
spin_lock_irqsave(&ebu_lock, flags);
ltq_ebu_w32(LTQ_EBU_BUSCON, LTQ_EBU_BUSCON1);
*((__u16 *)ltq_ebu_gpio_membase) = ltq_ebu_gpio_shadow;
ltq_ebu_w32(LTQ_EBU_BUSCON | LTQ_EBU_WP, LTQ_EBU_BUSCON1);
spin_unlock_irqrestore(&ebu_lock, flags);
}
static void ltq_ebu_set(struct gpio_chip *chip, unsigned offset, int value)
{
if (value)
ltq_ebu_gpio_shadow |= (1 << offset);
else
ltq_ebu_gpio_shadow &= ~(1 << offset);
ltq_ebu_apply();
}
static int ltq_ebu_direction_output(struct gpio_chip *chip, unsigned offset,
int value)
{
ltq_ebu_set(chip, offset, value);
return 0;
}
static struct gpio_chip ltq_ebu_chip = {
.label = "ltq_ebu",
.direction_output = ltq_ebu_direction_output,
.set = ltq_ebu_set,
.base = 72,
.ngpio = 16,
.can_sleep = 1,
.owner = THIS_MODULE,
};
static int ltq_ebu_probe(struct platform_device *pdev)
{
int ret = 0;
struct resource *res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
if (!res) {
dev_err(&pdev->dev, "failed to get memory resource\n");
return -ENOENT;
}
res = devm_request_mem_region(&pdev->dev, res->start,
resource_size(res), dev_name(&pdev->dev));
if (!res) {
dev_err(&pdev->dev, "failed to request memory resource\n");
return -EBUSY;
}
ltq_ebu_gpio_membase = devm_ioremap_nocache(&pdev->dev, res->start,
resource_size(res));
if (!ltq_ebu_gpio_membase) {
dev_err(&pdev->dev, "Failed to ioremap mem region\n");
return -ENOMEM;
}
/* grab the default shadow value passed form the platform code */
ltq_ebu_gpio_shadow = (unsigned int) pdev->dev.platform_data;
/* tell the ebu controller which memory address we will be using */
ltq_ebu_w32(pdev->resource->start | 0x1, LTQ_EBU_ADDRSEL1);
/* write protect the region */
ltq_ebu_w32(LTQ_EBU_BUSCON | LTQ_EBU_WP, LTQ_EBU_BUSCON1);
ret = gpiochip_add(<q_ebu_chip);
if (!ret)
ltq_ebu_apply();
return ret;
}
static struct platform_driver ltq_ebu_driver = {
.probe = ltq_ebu_probe,
.driver = {
.name = "ltq_ebu",
.owner = THIS_MODULE,
},
};
static int __init ltq_ebu_init(void)
{
int ret = platform_driver_register(<q_ebu_driver);
if (ret)
pr_info("ltq_ebu : Error registering platform driver!");
return ret;
}
postcore_initcall(ltq_ebu_init);
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