reset-berlin.c
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/*
* Copyright (C) 2014 Marvell Technology Group Ltd.
*
* Marvell Berlin reset driver
*
* 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/mfd/syscon.h>
#include <linux/init.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/platform_device.h>
#include <linux/regmap.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 {
struct regmap *regmap;
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);
regmap_write(priv->regmap, offset, mask);
/* let the reset be effective */
udelay(10);
return 0;
}
static const 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)
{
unsigned offset, bit;
offset = reset_spec->args[0];
bit = reset_spec->args[1];
if (bit >= BERLIN_MAX_RESETS)
return -EINVAL;
return (offset << 8) | bit;
}
static int berlin2_reset_probe(struct platform_device *pdev)
{
struct device_node *parent_np = of_get_parent(pdev->dev.of_node);
struct berlin_reset_priv *priv;
priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
if (!priv)
return -ENOMEM;
priv->regmap = syscon_node_to_regmap(parent_np);
of_node_put(parent_np);
if (IS_ERR(priv->regmap))
return PTR_ERR(priv->regmap);
priv->rcdev.owner = THIS_MODULE;
priv->rcdev.ops = &berlin_reset_ops;
priv->rcdev.of_node = pdev->dev.of_node;
priv->rcdev.of_reset_n_cells = 2;
priv->rcdev.of_xlate = berlin_reset_xlate;
return reset_controller_register(&priv->rcdev);
}
static const struct of_device_id berlin_reset_dt_match[] = {
{ .compatible = "marvell,berlin2-reset" },
{ },
};
static struct platform_driver berlin_reset_driver = {
.probe = berlin2_reset_probe,
.driver = {
.name = "berlin2-reset",
.of_match_table = berlin_reset_dt_match,
},
};
builtin_platform_driver(berlin_reset_driver);