drivers/reset/reset-oxnas.c

   1 /*
   2  * drivers/reset/reset-oxnas.c
   3  *
   4  * Copyright (C) 2016 Neil Armstrong <narmstrong@baylibre.com>
   5  * Copyright (C) 2014 Ma Haijun <mahaijuns@gmail.com>
   6  * Copyright (C) 2009 Oxford Semiconductor Ltd
   7  *
   8  * This program is free software; you can redistribute it and/or modify it
   9  * under the terms and conditions of the GNU General Public License,
  10  * version 2, as published by the Free Software Foundation.
  11  *
  12  * This program is distributed in the hope it will be useful, but WITHOUT
  13  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  14  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  15  * more details.
  16  *
  17  * You should have received a copy of the GNU General Public License
  18  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  19  */
  20 #include <linux/err.h>
  21 #include <linux/init.h>
  22 #include <linux/of.h>
  23 #include <linux/platform_device.h>
  24 #include <linux/reset-controller.h>
  25 #include <linux/slab.h>
  26 #include <linux/delay.h>
  27 #include <linux/types.h>
  28 #include <linux/regmap.h>
  29 #include <linux/mfd/syscon.h>
  30
  31 /* Regmap offsets */
  32 #define RST_SET_REGOFFSET       0x34
  33 #define RST_CLR_REGOFFSET       0x38
  34
  35 struct oxnas_reset {
  36         struct regmap *regmap;
  37         struct reset_controller_dev rcdev;
  38 };
  39
  40 static int oxnas_reset_reset(struct reset_controller_dev *rcdev,
  41                               unsigned long id)
  42 {
  43         struct oxnas_reset *data =
  44                 container_of(rcdev, struct oxnas_reset, rcdev);
  45
  46         regmap_write(data->regmap, RST_SET_REGOFFSET, BIT(id));
  47         msleep(50);
  48         regmap_write(data->regmap, RST_CLR_REGOFFSET, BIT(id));
  49
  50         return 0;
  51 }
  52
  53 static int oxnas_reset_assert(struct reset_controller_dev *rcdev,
  54                               unsigned long id)
  55 {
  56         struct oxnas_reset *data =
  57                 container_of(rcdev, struct oxnas_reset, rcdev);
  58
  59         regmap_write(data->regmap, RST_SET_REGOFFSET, BIT(id));
  60
  61         return 0;
  62 }
  63
  64 static int oxnas_reset_deassert(struct reset_controller_dev *rcdev,
  65                                 unsigned long id)
  66 {
  67         struct oxnas_reset *data =
  68                 container_of(rcdev, struct oxnas_reset, rcdev);
  69
  70         regmap_write(data->regmap, RST_CLR_REGOFFSET, BIT(id));
  71
  72         return 0;
  73 }
  74
  75 static const struct reset_control_ops oxnas_reset_ops = {
  76         .reset          = oxnas_reset_reset,
  77         .assert         = oxnas_reset_assert,
  78         .deassert       = oxnas_reset_deassert,
  79 };
  80
  81 static const struct of_device_id oxnas_reset_dt_ids[] = {
  82          { .compatible = "oxsemi,ox810se-reset", },
  83          { .compatible = "oxsemi,ox820-reset", },
  84          { /* sentinel */ },
  85 };
  86
  87 static int oxnas_reset_probe(struct platform_device *pdev)
  88 {
  89         struct oxnas_reset *data;
  90         struct device *parent;
  91
  92         parent = pdev->dev.parent;
  93         if (!parent) {
  94                 dev_err(&pdev->dev, "no parent\n");
  95                 return -ENODEV;
  96         }
  97
  98         data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
  99         if (!data)
 100                 return -ENOMEM;
 101
 102         data->regmap = syscon_node_to_regmap(parent->of_node);
 103         if (IS_ERR(data->regmap)) {
 104                 dev_err(&pdev->dev, "failed to get parent regmap\n");
 105                 return PTR_ERR(data->regmap);
 106         }
 107
 108         platform_set_drvdata(pdev, data);
 109
 110         data->rcdev.owner = THIS_MODULE;
 111         data->rcdev.nr_resets = 32;
 112         data->rcdev.ops = &oxnas_reset_ops;
 113         data->rcdev.of_node = pdev->dev.of_node;
 114
 115         return devm_reset_controller_register(&pdev->dev, &data->rcdev);
 116 }
 117
 118 static struct platform_driver oxnas_reset_driver = {
 119         .probe  = oxnas_reset_probe,
 120         .driver = {
 121                 .name           = "oxnas-reset",
 122                 .of_match_table = oxnas_reset_dt_ids,
 123         },
 124 };
 125 builtin_platform_driver(oxnas_reset_driver);