1// SPDX-License-Identifier: GPL-2.0-or-later
  2/*
  3 * Copyright (c) 2020 Western Digital Corporation or its affiliates.
  4 */
  5#include <linux/of.h>
  6#include <linux/platform_device.h>
  7#include <linux/reset-controller.h>
  8#include <linux/delay.h>
  9#include <linux/mfd/syscon.h>
 10#include <linux/regmap.h>
 11#include <soc/canaan/k210-sysctl.h>
 12
 13#include <dt-bindings/reset/k210-rst.h>
 14
 15#define K210_RST_MASK	0x27FFFFFF
 16
 17struct k210_rst {
 18	struct regmap *map;
 19	struct reset_controller_dev rcdev;
 20};
 21
 22static inline struct k210_rst *
 23to_k210_rst(struct reset_controller_dev *rcdev)
 24{
 25	return container_of(rcdev, struct k210_rst, rcdev);
 26}
 27
 28static inline int k210_rst_assert(struct reset_controller_dev *rcdev,
 29				  unsigned long id)
 30{
 31	struct k210_rst *ksr = to_k210_rst(rcdev);
 32
 33	return regmap_update_bits(ksr->map, K210_SYSCTL_PERI_RESET, BIT(id), 1);
 34}
 35
 36static inline int k210_rst_deassert(struct reset_controller_dev *rcdev,
 37				    unsigned long id)
 38{
 39	struct k210_rst *ksr = to_k210_rst(rcdev);
 40
 41	return regmap_update_bits(ksr->map, K210_SYSCTL_PERI_RESET, BIT(id), 0);
 42}
 43
 44static int k210_rst_reset(struct reset_controller_dev *rcdev,
 45			  unsigned long id)
 46{
 47	int ret;
 48
 49	ret = k210_rst_assert(rcdev, id);
 50	if (ret == 0) {
 51		udelay(10);
 52		ret = k210_rst_deassert(rcdev, id);
 53	}
 54
 55	return ret;
 56}
 57
 58static int k210_rst_status(struct reset_controller_dev *rcdev,
 59			   unsigned long id)
 60{
 61	struct k210_rst *ksr = to_k210_rst(rcdev);
 62	u32 reg, bit = BIT(id);
 63	int ret;
 64
 65	ret = regmap_read(ksr->map, K210_SYSCTL_PERI_RESET, &reg);
 66	if (ret)
 67		return ret;
 68
 69	return reg & bit;
 70}
 71
 72static int k210_rst_xlate(struct reset_controller_dev *rcdev,
 73			  const struct of_phandle_args *reset_spec)
 74{
 75	unsigned long id = reset_spec->args[0];
 76
 77	if (!(BIT(id) & K210_RST_MASK))
 78		return -EINVAL;
 79
 80	return id;
 81}
 82
 83static const struct reset_control_ops k210_rst_ops = {
 84	.assert		= k210_rst_assert,
 85	.deassert	= k210_rst_deassert,
 86	.reset		= k210_rst_reset,
 87	.status		= k210_rst_status,
 88};
 89
 90static int k210_rst_probe(struct platform_device *pdev)
 91{
 92	struct device *dev = &pdev->dev;
 93	struct device_node *parent_np;
 94	struct k210_rst *ksr;
 95
 96	dev_info(dev, "K210 reset controller\n");
 97
 98	ksr = devm_kzalloc(dev, sizeof(*ksr), GFP_KERNEL);
 99	if (!ksr)
100		return -ENOMEM;
101
102	parent_np = of_get_parent(dev->of_node);
103	ksr->map = syscon_node_to_regmap(parent_np);
104	of_node_put(parent_np);
105	if (IS_ERR(ksr->map))
106		return PTR_ERR(ksr->map);
107
108	ksr->rcdev.owner = THIS_MODULE;
109	ksr->rcdev.dev = dev;
110	ksr->rcdev.of_node = dev->of_node;
111	ksr->rcdev.ops = &k210_rst_ops;
112	ksr->rcdev.nr_resets = fls(K210_RST_MASK);
113	ksr->rcdev.of_reset_n_cells = 1;
114	ksr->rcdev.of_xlate = k210_rst_xlate;
115
116	return devm_reset_controller_register(dev, &ksr->rcdev);
117}
118
119static const struct of_device_id k210_rst_dt_ids[] = {
120	{ .compatible = "canaan,k210-rst" },
121	{ /* sentinel */ },
122};
123
124static struct platform_driver k210_rst_driver = {
125	.probe	= k210_rst_probe,
126	.driver = {
127		.name		= "k210-rst",
128		.of_match_table	= k210_rst_dt_ids,
129	},
130};
131builtin_platform_driver(k210_rst_driver);