1/*
  2 * Copyright (C) 2014 Marvell Technology Group Ltd.
  3 *
  4 * Antoine Tenart <antoine.tenart@free-electrons.com>
  5 * Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>
  6 *
  7 * This file is licensed under the terms of the GNU General Public
  8 * License version 2. This program is licensed "as is" without any
  9 * warranty of any kind, whether express or implied.
 10 */
 11
 12#include <linux/delay.h>
 13#include <linux/io.h>
 14#include <linux/mfd/syscon.h>
 15#include <linux/module.h>
 16#include <linux/of.h>
 17#include <linux/of_address.h>
 18#include <linux/platform_device.h>
 19#include <linux/regmap.h>
 20#include <linux/reset-controller.h>
 21#include <linux/slab.h>
 22#include <linux/types.h>
 23
 24#define BERLIN_MAX_RESETS	32
 25
 26#define to_berlin_reset_priv(p)		\
 27	container_of((p), struct berlin_reset_priv, rcdev)
 28
 29struct berlin_reset_priv {
 30	struct regmap			*regmap;
 31	struct reset_controller_dev	rcdev;
 32};
 33
 34static int berlin_reset_reset(struct reset_controller_dev *rcdev,
 35			      unsigned long id)
 36{
 37	struct berlin_reset_priv *priv = to_berlin_reset_priv(rcdev);
 38	int offset = id >> 8;
 39	int mask = BIT(id & 0x1f);
 40
 41	regmap_write(priv->regmap, offset, mask);
 42
 43	/* let the reset be effective */
 44	udelay(10);
 45
 46	return 0;
 47}
 48
 49static const struct reset_control_ops berlin_reset_ops = {
 50	.reset	= berlin_reset_reset,
 51};
 52
 53static int berlin_reset_xlate(struct reset_controller_dev *rcdev,
 54			      const struct of_phandle_args *reset_spec)
 55{
 56	unsigned offset, bit;
 57
 58	offset = reset_spec->args[0];
 59	bit = reset_spec->args[1];
 60
 61	if (bit >= BERLIN_MAX_RESETS)
 62		return -EINVAL;
 63
 64	return (offset << 8) | bit;
 65}
 66
 67static int berlin2_reset_probe(struct platform_device *pdev)
 68{
 69	struct device_node *parent_np = of_get_parent(pdev->dev.of_node);
 70	struct berlin_reset_priv *priv;
 71
 72	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
 73	if (!priv)
 74		return -ENOMEM;
 75
 76	priv->regmap = syscon_node_to_regmap(parent_np);
 77	of_node_put(parent_np);
 78	if (IS_ERR(priv->regmap))
 79		return PTR_ERR(priv->regmap);
 80
 81	priv->rcdev.owner = THIS_MODULE;
 82	priv->rcdev.ops = &berlin_reset_ops;
 83	priv->rcdev.of_node = pdev->dev.of_node;
 84	priv->rcdev.of_reset_n_cells = 2;
 85	priv->rcdev.of_xlate = berlin_reset_xlate;
 86
 87	return reset_controller_register(&priv->rcdev);
 88}
 89
 90static const struct of_device_id berlin_reset_dt_match[] = {
 91	{ .compatible = "marvell,berlin2-reset" },
 92	{ },
 93};
 94MODULE_DEVICE_TABLE(of, berlin_reset_dt_match);
 95
 96static struct platform_driver berlin_reset_driver = {
 97	.probe	= berlin2_reset_probe,
 98	.driver	= {
 99		.name = "berlin2-reset",
100		.of_match_table = berlin_reset_dt_match,
101	},
102};
103module_platform_driver(berlin_reset_driver);
104
105MODULE_AUTHOR("Antoine Tenart <antoine.tenart@free-electrons.com>");
106MODULE_AUTHOR("Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>");
107MODULE_DESCRIPTION("Marvell Berlin reset driver");
108MODULE_LICENSE("GPL");