LXR linux/drivers/clk/mediatek/reset.c

   1/*
   2 * Copyright (c) 2014 MediaTek Inc.
   3 *
   4 * This program is free software; you can redistribute it and/or modify
   5 * it under the terms of the GNU General Public License version 2 as
   6 * published by the Free Software Foundation.
   7 *
   8 * This program is distributed in the hope that it will be useful,
   9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11 * GNU General Public License for more details.
  12 */
  13
  14#include <linux/mfd/syscon.h>
  15#include <linux/module.h>
  16#include <linux/of.h>
  17#include <linux/platform_device.h>
  18#include <linux/regmap.h>
  19#include <linux/reset-controller.h>
  20#include <linux/slab.h>
  21
  22#include "clk-mtk.h"
  23
  24struct mtk_reset {
  25        struct regmap *regmap;
  26        int regofs;
  27        struct reset_controller_dev rcdev;
  28};
  29
  30static int mtk_reset_assert(struct reset_controller_dev *rcdev,
  31                              unsigned long id)
  32{
  33        struct mtk_reset *data = container_of(rcdev, struct mtk_reset, rcdev);
  34
  35        return regmap_update_bits(data->regmap, data->regofs + ((id / 32) << 2),
  36                        BIT(id % 32), ~0);
  37}
  38
  39static int mtk_reset_deassert(struct reset_controller_dev *rcdev,
  40                                unsigned long id)
  41{
  42        struct mtk_reset *data = container_of(rcdev, struct mtk_reset, rcdev);
  43
  44        return regmap_update_bits(data->regmap, data->regofs + ((id / 32) << 2),
  45                        BIT(id % 32), 0);
  46}
  47
  48static int mtk_reset(struct reset_controller_dev *rcdev,
  49                              unsigned long id)
  50{
  51        int ret;
  52
  53        ret = mtk_reset_assert(rcdev, id);
  54        if (ret)
  55                return ret;
  56
  57        return mtk_reset_deassert(rcdev, id);
  58}
  59
  60static const struct reset_control_ops mtk_reset_ops = {
  61        .assert = mtk_reset_assert,
  62        .deassert = mtk_reset_deassert,
  63        .reset = mtk_reset,
  64};
  65
  66void mtk_register_reset_controller(struct device_node *np,
  67                        unsigned int num_regs, int regofs)
  68{
  69        struct mtk_reset *data;
  70        int ret;
  71        struct regmap *regmap;
  72
  73        regmap = syscon_node_to_regmap(np);
  74        if (IS_ERR(regmap)) {
  75                pr_err("Cannot find regmap for %pOF: %ld\n", np,
  76                                PTR_ERR(regmap));
  77                return;
  78        }
  79
  80        data = kzalloc(sizeof(*data), GFP_KERNEL);
  81        if (!data)
  82                return;
  83
  84        data->regmap = regmap;
  85        data->regofs = regofs;
  86        data->rcdev.owner = THIS_MODULE;
  87        data->rcdev.nr_resets = num_regs * 32;
  88        data->rcdev.ops = &mtk_reset_ops;
  89        data->rcdev.of_node = np;
  90
  91        ret = reset_controller_register(&data->rcdev);
  92        if (ret) {
  93                pr_err("could not register reset controller: %d\n", ret);
  94                kfree(data);
  95                return;
  96        }
  97}
  98