linux/drivers/reset/reset-berlin.c

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/*
* Copyright (C) 2014 Marvell Technology Group Ltd.
*
* Antoine Tenart <antoine.tenart@free-electrons.com>
* Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>
*
* This file is licensed under the terms of the GNU General Public
* License version 2. This program is licensed "as is" without any
* warranty of any kind, whether express or implied.
*/
#include <linux/delay.h>
#include <linux/io.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/platform_device.h>
#include <linux/reset-controller.h>
#include <linux/slab.h>
#include <linux/types.h>
#define BERLIN_MAX_RESETS 32
#define to_berlin_reset_priv(p) \
container_of((p), struct berlin_reset_priv, rcdev)
struct berlin_reset_priv {
void __iomem *base;
unsigned int size;
struct reset_controller_dev rcdev;
};
static int berlin_reset_reset(struct reset_controller_dev *rcdev,
unsigned long id)
{
struct berlin_reset_priv *priv = to_berlin_reset_priv(rcdev);
int offset = id >> 8;
int mask = BIT(id & 0x1f);
writel(mask, priv->base + offset);
/* let the reset be effective */
udelay(10);
return 0;
}
static struct reset_control_ops berlin_reset_ops = {
.reset = berlin_reset_reset,
};
static int berlin_reset_xlate(struct reset_controller_dev *rcdev,
const struct of_phandle_args *reset_spec)
{
struct berlin_reset_priv *priv = to_berlin_reset_priv(rcdev);
unsigned offset, bit;
if (WARN_ON(reset_spec->args_count != rcdev->of_reset_n_cells))
return -EINVAL;
offset = reset_spec->args[0];
bit = reset_spec->args[1];
if (offset >= priv->size)
return -EINVAL;
if (bit >= BERLIN_MAX_RESETS)
return -EINVAL;
return (offset << 8) | bit;
}
static int __berlin_reset_init(struct device_node *np)
{
struct berlin_reset_priv *priv;
struct resource res;
resource_size_t size;
int ret;
priv = kzalloc(sizeof(*priv), GFP_KERNEL);
if (!priv)
return -ENOMEM;
ret = of_address_to_resource(np, 0, &res);
if (ret)
goto err;
size = resource_size(&res);
priv->base = ioremap(res.start, size);
if (!priv->base) {
ret = -ENOMEM;
goto err;
}
priv->size = size;
priv->rcdev.owner = THIS_MODULE;
priv->rcdev.ops = &berlin_reset_ops;
priv->rcdev.of_node = np;
priv->rcdev.of_reset_n_cells = 2;
priv->rcdev.of_xlate = berlin_reset_xlate;
reset_controller_register(&priv->rcdev);
return 0;
err:
kfree(priv);
return ret;
}
static const struct of_device_id berlin_reset_of_match[] __initconst = {
{ .compatible = "marvell,berlin2-chip-ctrl" },
{ .compatible = "marvell,berlin2cd-chip-ctrl" },
{ .compatible = "marvell,berlin2q-chip-ctrl" },
{ },
};
static int __init berlin_reset_init(void)
{
struct device_node *np;
int ret;
for_each_matching_node(np, berlin_reset_of_match) {
ret = __berlin_reset_init(np);
if (ret)
return ret;
}
return 0;
}
arch_initcall(berlin_reset_init);