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 */
33 static 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
jh7100_reset_probe(struct platform_device * pdev)47 static 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
62 static const struct of_device_id jh7100_reset_dt_ids[] = {
63 { .compatible = "starfive,jh7100-reset" },
64 { /* sentinel */ }
65 };
66
67 static 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 };
74 builtin_platform_driver_probe(jh7100_reset_driver, jh7100_reset_probe);
75