reset-hi3660.c

  1// SPDX-License-Identifier: GPL-2.0-or-later
  2/*
  3 * Copyright (c) 2016-2017 Linaro Ltd.
  4 * Copyright (c) 2016-2017 HiSilicon Technologies Co., Ltd.
  5 */
  6#include <linux/kernel.h>
  7#include <linux/mfd/syscon.h>
  8#include <linux/module.h>
  9#include <linux/of.h>
 10#include <linux/platform_device.h>
 11#include <linux/regmap.h>
 12#include <linux/reset-controller.h>
 13
 14struct hi3660_reset_controller {
 15	struct reset_controller_dev rst;
 16	struct regmap *map;
 17};
 18
 19#define to_hi3660_reset_controller(_rst) \
 20	container_of(_rst, struct hi3660_reset_controller, rst)
 21
 22static int hi3660_reset_program_hw(struct reset_controller_dev *rcdev,
 23				   unsigned long idx, bool assert)
 24{
 25	struct hi3660_reset_controller *rc = to_hi3660_reset_controller(rcdev);
 26	unsigned int offset = idx >> 8;
 27	unsigned int mask = BIT(idx & 0x1f);
 28
 29	if (assert)
 30		return regmap_write(rc->map, offset, mask);
 31	else
 32		return regmap_write(rc->map, offset + 4, mask);
 33}
 34
 35static int hi3660_reset_assert(struct reset_controller_dev *rcdev,
 36			       unsigned long idx)
 37{
 38	return hi3660_reset_program_hw(rcdev, idx, true);
 39}
 40
 41static int hi3660_reset_deassert(struct reset_controller_dev *rcdev,
 42				 unsigned long idx)
 43{
 44	return hi3660_reset_program_hw(rcdev, idx, false);
 45}
 46
 47static int hi3660_reset_dev(struct reset_controller_dev *rcdev,
 48			    unsigned long idx)
 49{
 50	int err;
 51
 52	err = hi3660_reset_assert(rcdev, idx);
 53	if (err)
 54		return err;
 55
 56	return hi3660_reset_deassert(rcdev, idx);
 57}
 58
 59static const struct reset_control_ops hi3660_reset_ops = {
 60	.reset    = hi3660_reset_dev,
 61	.assert   = hi3660_reset_assert,
 62	.deassert = hi3660_reset_deassert,
 63};
 64
 65static int hi3660_reset_xlate(struct reset_controller_dev *rcdev,
 66			      const struct of_phandle_args *reset_spec)
 67{
 68	unsigned int offset, bit;
 69
 70	offset = reset_spec->args[0];
 71	bit = reset_spec->args[1];
 72
 73	return (offset << 8) | bit;
 74}
 75
 76static int hi3660_reset_probe(struct platform_device *pdev)
 77{
 78	struct hi3660_reset_controller *rc;
 79	struct device_node *np = pdev->dev.of_node;
 80	struct device *dev = &pdev->dev;
 81
 82	rc = devm_kzalloc(dev, sizeof(*rc), GFP_KERNEL);
 83	if (!rc)
 84		return -ENOMEM;
 85
 86	rc->map = syscon_regmap_lookup_by_phandle(np, "hisilicon,rst-syscon");
 87	if (rc->map == ERR_PTR(-ENODEV)) {
 88		/* fall back to the deprecated compatible */
 89		rc->map = syscon_regmap_lookup_by_phandle(np,
 90							  "hisi,rst-syscon");
 91	}
 92	if (IS_ERR(rc->map)) {
 93		return dev_err_probe(dev, PTR_ERR(rc->map),
 94			"failed to get hisilicon,rst-syscon\n");
 95	}
 96
 97	rc->rst.ops = &hi3660_reset_ops,
 98	rc->rst.of_node = np;
 99	rc->rst.of_reset_n_cells = 2;
100	rc->rst.of_xlate = hi3660_reset_xlate;
101
102	return reset_controller_register(&rc->rst);
103}
104
105static const struct of_device_id hi3660_reset_match[] = {
106	{ .compatible = "hisilicon,hi3660-reset", },
107	{},
108};
109MODULE_DEVICE_TABLE(of, hi3660_reset_match);
110
111static struct platform_driver hi3660_reset_driver = {
112	.probe = hi3660_reset_probe,
113	.driver = {
114		.name = "hi3660-reset",
115		.of_match_table = hi3660_reset_match,
116	},
117};
118
119static int __init hi3660_reset_init(void)
120{
121	return platform_driver_register(&hi3660_reset_driver);
122}
123arch_initcall(hi3660_reset_init);
124
125MODULE_LICENSE("GPL");
126MODULE_ALIAS("platform:hi3660-reset");
127MODULE_DESCRIPTION("HiSilicon Hi3660 Reset Driver");