drivers/reset/reset-oxnas.c

0001 // SPDX-License-Identifier: GPL-2.0-only
0002 /*
0003  * Oxford Semiconductor Reset Controller driver
0004  *
0005  * Copyright (C) 2016 Neil Armstrong <narmstrong@baylibre.com>
0006  * Copyright (C) 2014 Ma Haijun <mahaijuns@gmail.com>
0007  * Copyright (C) 2009 Oxford Semiconductor Ltd
0008  */
0009 #include <linux/err.h>
0010 #include <linux/init.h>
0011 #include <linux/of.h>
0012 #include <linux/platform_device.h>
0013 #include <linux/reset-controller.h>
0014 #include <linux/slab.h>
0015 #include <linux/delay.h>
0016 #include <linux/types.h>
0017 #include <linux/regmap.h>
0018 #include <linux/mfd/syscon.h>
0019
0020 /* Regmap offsets */
0021 #define RST_SET_REGOFFSET   0x34
0022 #define RST_CLR_REGOFFSET   0x38
0023
0024 struct oxnas_reset {
0025     struct regmap *regmap;
0026     struct reset_controller_dev rcdev;
0027 };
0028
0029 static int oxnas_reset_reset(struct reset_controller_dev *rcdev,
0030                   unsigned long id)
0031 {
0032     struct oxnas_reset *data =
0033         container_of(rcdev, struct oxnas_reset, rcdev);
0034
0035     regmap_write(data->regmap, RST_SET_REGOFFSET, BIT(id));
0036     msleep(50);
0037     regmap_write(data->regmap, RST_CLR_REGOFFSET, BIT(id));
0038
0039     return 0;
0040 }
0041
0042 static int oxnas_reset_assert(struct reset_controller_dev *rcdev,
0043                   unsigned long id)
0044 {
0045     struct oxnas_reset *data =
0046         container_of(rcdev, struct oxnas_reset, rcdev);
0047
0048     regmap_write(data->regmap, RST_SET_REGOFFSET, BIT(id));
0049
0050     return 0;
0051 }
0052
0053 static int oxnas_reset_deassert(struct reset_controller_dev *rcdev,
0054                 unsigned long id)
0055 {
0056     struct oxnas_reset *data =
0057         container_of(rcdev, struct oxnas_reset, rcdev);
0058
0059     regmap_write(data->regmap, RST_CLR_REGOFFSET, BIT(id));
0060
0061     return 0;
0062 }
0063
0064 static const struct reset_control_ops oxnas_reset_ops = {
0065     .reset      = oxnas_reset_reset,
0066     .assert     = oxnas_reset_assert,
0067     .deassert   = oxnas_reset_deassert,
0068 };
0069
0070 static const struct of_device_id oxnas_reset_dt_ids[] = {
0071      { .compatible = "oxsemi,ox810se-reset", },
0072      { .compatible = "oxsemi,ox820-reset", },
0073      { /* sentinel */ },
0074 };
0075
0076 static int oxnas_reset_probe(struct platform_device *pdev)
0077 {
0078     struct oxnas_reset *data;
0079     struct device *parent;
0080
0081     parent = pdev->dev.parent;
0082     if (!parent) {
0083         dev_err(&pdev->dev, "no parent\n");
0084         return -ENODEV;
0085     }
0086
0087     data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
0088     if (!data)
0089         return -ENOMEM;
0090
0091     data->regmap = syscon_node_to_regmap(parent->of_node);
0092     if (IS_ERR(data->regmap)) {
0093         dev_err(&pdev->dev, "failed to get parent regmap\n");
0094         return PTR_ERR(data->regmap);
0095     }
0096
0097     platform_set_drvdata(pdev, data);
0098
0099     data->rcdev.owner = THIS_MODULE;
0100     data->rcdev.nr_resets = 32;
0101     data->rcdev.ops = &oxnas_reset_ops;
0102     data->rcdev.of_node = pdev->dev.of_node;
0103
0104     return devm_reset_controller_register(&pdev->dev, &data->rcdev);
0105 }
0106
0107 static struct platform_driver oxnas_reset_driver = {
0108     .probe  = oxnas_reset_probe,
0109     .driver = {
0110         .name       = "oxnas-reset",
0111         .of_match_table = oxnas_reset_dt_ids,
0112     },
0113 };
0114 builtin_platform_driver(oxnas_reset_driver);