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
  24 struct mtk_reset {
  25         struct regmap *regmap;
  26         int regofs;
  27         struct reset_controller_dev rcdev;
  28 };
  29
  30 static 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
  39 static 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
  48 static 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
  60 static const struct reset_control_ops mtk_reset_ops = {
  61         .assert = mtk_reset_assert,
  62         .deassert = mtk_reset_deassert,
  63         .reset = mtk_reset,
  64 };
  65
  66 void 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 }