reset-starfive-jh7100.c

 1// SPDX-License-Identifier: GPL-2.0-or-later
 2/*
 3 * Reset driver for the StarFive JH7100 SoC
 4 *
 5 * Copyright (C) 2021 Emil Renner Berthing <kernel@esmil.dk>
 6 */
 7
 8#include <linux/mod_devicetable.h>
 9#include <linux/platform_device.h>
10
11#include "reset-starfive-jh71x0.h"
12
13#include <dt-bindings/reset/starfive-jh7100.h>
14
15/* register offsets */
16#define JH7100_RESET_ASSERT0	0x00
17#define JH7100_RESET_ASSERT1	0x04
18#define JH7100_RESET_ASSERT2	0x08
19#define JH7100_RESET_ASSERT3	0x0c
20#define JH7100_RESET_STATUS0	0x10
21#define JH7100_RESET_STATUS1	0x14
22#define JH7100_RESET_STATUS2	0x18
23#define JH7100_RESET_STATUS3	0x1c
24
25/*
26 * Writing a 1 to the n'th bit of the m'th ASSERT register asserts
27 * line 32m + n, and writing a 0 deasserts the same line.
28 * Most reset lines have their status inverted so a 0 bit in the STATUS
29 * register means the line is asserted and a 1 means it's deasserted. A few
30 * lines don't though, so store the expected value of the status registers when
31 * all lines are asserted.
32 */
33static const u32 jh7100_reset_asserted[4] = {
34	/* STATUS0 */
35	BIT(JH7100_RST_U74 % 32) |
36	BIT(JH7100_RST_VP6_DRESET % 32) |
37	BIT(JH7100_RST_VP6_BRESET % 32),
38	/* STATUS1 */
39	BIT(JH7100_RST_HIFI4_DRESET % 32) |
40	BIT(JH7100_RST_HIFI4_BRESET % 32),
41	/* STATUS2 */
42	BIT(JH7100_RST_E24 % 32),
43	/* STATUS3 */
44	0,
45};
46
47static int __init jh7100_reset_probe(struct platform_device *pdev)
48{
49	void __iomem *base = devm_platform_ioremap_resource(pdev, 0);
50
51	if (IS_ERR(base))
52		return PTR_ERR(base);
53
54	return reset_starfive_jh71x0_register(&pdev->dev, pdev->dev.of_node,
55					      base + JH7100_RESET_ASSERT0,
56					      base + JH7100_RESET_STATUS0,
57					      jh7100_reset_asserted,
58					      JH7100_RSTN_END,
59					      THIS_MODULE);
60}
61
62static const struct of_device_id jh7100_reset_dt_ids[] = {
63	{ .compatible = "starfive,jh7100-reset" },
64	{ /* sentinel */ }
65};
66
67static struct platform_driver jh7100_reset_driver = {
68	.driver = {
69		.name = "jh7100-reset",
70		.of_match_table = jh7100_reset_dt_ids,
71		.suppress_bind_attrs = true,
72	},
73};
74builtin_platform_driver_probe(jh7100_reset_driver, jh7100_reset_probe);