LXR linux/drivers/reset/reset-berlin.c

   1/*
   2 * Copyright (C) 2014 Marvell Technology Group Ltd.
   3 *
   4 * Marvell Berlin reset driver
   5 *
   6 * Antoine Tenart <antoine.tenart@free-electrons.com>
   7 * Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>
   8 *
   9 * This file is licensed under the terms of the GNU General Public
  10 * License version 2. This program is licensed "as is" without any
  11 * warranty of any kind, whether express or implied.
  12 */
  13
  14#include <linux/delay.h>
  15#include <linux/io.h>
  16#include <linux/mfd/syscon.h>
  17#include <linux/module.h>
  18#include <linux/of.h>
  19#include <linux/of_address.h>
  20#include <linux/platform_device.h>
  21#include <linux/regmap.h>
  22#include <linux/reset-controller.h>
  23#include <linux/slab.h>
  24#include <linux/types.h>
  25
  26#define BERLIN_MAX_RESETS       32
  27
  28#define to_berlin_reset_priv(p)         \
  29        container_of((p), struct berlin_reset_priv, rcdev)
  30
  31struct berlin_reset_priv {
  32        struct regmap                   *regmap;
  33        struct reset_controller_dev     rcdev;
  34};
  35
  36static int berlin_reset_reset(struct reset_controller_dev *rcdev,
  37                              unsigned long id)
  38{
  39        struct berlin_reset_priv *priv = to_berlin_reset_priv(rcdev);
  40        int offset = id >> 8;
  41        int mask = BIT(id & 0x1f);
  42
  43        regmap_write(priv->regmap, offset, mask);
  44
  45        /* let the reset be effective */
  46        udelay(10);
  47
  48        return 0;
  49}
  50
  51static const struct reset_control_ops berlin_reset_ops = {
  52        .reset  = berlin_reset_reset,
  53};
  54
  55static int berlin_reset_xlate(struct reset_controller_dev *rcdev,
  56                              const struct of_phandle_args *reset_spec)
  57{
  58        unsigned int offset, bit;
  59
  60        offset = reset_spec->args[0];
  61        bit = reset_spec->args[1];
  62
  63        if (bit >= BERLIN_MAX_RESETS)
  64                return -EINVAL;
  65
  66        return (offset << 8) | bit;
  67}
  68
  69static int berlin2_reset_probe(struct platform_device *pdev)
  70{
  71        struct device_node *parent_np = of_get_parent(pdev->dev.of_node);
  72        struct berlin_reset_priv *priv;
  73
  74        priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
  75        if (!priv)
  76                return -ENOMEM;
  77
  78        priv->regmap = syscon_node_to_regmap(parent_np);
  79        of_node_put(parent_np);
  80        if (IS_ERR(priv->regmap))
  81                return PTR_ERR(priv->regmap);
  82
  83        priv->rcdev.owner = THIS_MODULE;
  84        priv->rcdev.ops = &berlin_reset_ops;
  85        priv->rcdev.of_node = pdev->dev.of_node;
  86        priv->rcdev.of_reset_n_cells = 2;
  87        priv->rcdev.of_xlate = berlin_reset_xlate;
  88
  89        return reset_controller_register(&priv->rcdev);
  90}
  91
  92static const struct of_device_id berlin_reset_dt_match[] = {
  93        { .compatible = "marvell,berlin2-reset" },
  94        { },
  95};
  96MODULE_DEVICE_TABLE(of, berlin_reset_dt_match);
  97
  98static struct platform_driver berlin_reset_driver = {
  99        .probe  = berlin2_reset_probe,
 100        .driver = {
 101                .name = "berlin2-reset",
 102                .of_match_table = berlin_reset_dt_match,
 103        },
 104};
 105module_platform_driver(berlin_reset_driver);
 106
 107MODULE_AUTHOR("Antoine Tenart <antoine.tenart@free-electrons.com>");
 108MODULE_AUTHOR("Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>");
 109MODULE_DESCRIPTION("Synaptics Berlin reset controller");
 110MODULE_LICENSE("GPL");
 111