Commit | Line | Data |
---|---|---|
2acb037f LW |
1 | /* |
2 | * Cortina Gemini Reset controller driver | |
3 | * Copyright (C) 2017 Linus Walleij <linus.walleij@linaro.org> | |
4 | * | |
5 | * This program is free software; you can redistribute it and/or modify | |
6 | * it under the terms of the GNU General Public License version 2 as | |
7 | * published by the Free Software Foundation. | |
8 | */ | |
9 | ||
10 | #include <linux/err.h> | |
11 | #include <linux/init.h> | |
12 | #include <linux/mfd/syscon.h> | |
13 | #include <linux/regmap.h> | |
14 | #include <linux/of.h> | |
15 | #include <linux/platform_device.h> | |
16 | #include <linux/reset-controller.h> | |
17 | #include <dt-bindings/reset/cortina,gemini-reset.h> | |
18 | ||
19 | /** | |
20 | * struct gemini_reset - gemini reset controller | |
21 | * @map: regmap to access the containing system controller | |
22 | * @rcdev: reset controller device | |
23 | */ | |
24 | struct gemini_reset { | |
25 | struct regmap *map; | |
26 | struct reset_controller_dev rcdev; | |
27 | }; | |
28 | ||
29 | #define GEMINI_GLOBAL_SOFT_RESET 0x0c | |
30 | ||
31 | #define to_gemini_reset(p) \ | |
32 | container_of((p), struct gemini_reset, rcdev) | |
33 | ||
34 | /* | |
35 | * This is a self-deasserting reset controller. | |
36 | */ | |
37 | static int gemini_reset(struct reset_controller_dev *rcdev, | |
38 | unsigned long id) | |
39 | { | |
40 | struct gemini_reset *gr = to_gemini_reset(rcdev); | |
41 | ||
42 | /* Manual says to always set BIT 30 (CPU1) to 1 */ | |
43 | return regmap_write(gr->map, | |
44 | GEMINI_GLOBAL_SOFT_RESET, | |
45 | BIT(GEMINI_RESET_CPU1) | BIT(id)); | |
46 | } | |
47 | ||
48 | static int gemini_reset_status(struct reset_controller_dev *rcdev, | |
49 | unsigned long id) | |
50 | { | |
51 | struct gemini_reset *gr = to_gemini_reset(rcdev); | |
52 | u32 val; | |
53 | int ret; | |
54 | ||
55 | ret = regmap_read(gr->map, GEMINI_GLOBAL_SOFT_RESET, &val); | |
56 | if (ret) | |
57 | return ret; | |
58 | ||
59 | return !!(val & BIT(id)); | |
60 | } | |
61 | ||
62 | static const struct reset_control_ops gemini_reset_ops = { | |
63 | .reset = gemini_reset, | |
64 | .status = gemini_reset_status, | |
65 | }; | |
66 | ||
67 | static int gemini_reset_probe(struct platform_device *pdev) | |
68 | { | |
69 | struct gemini_reset *gr; | |
70 | struct device *dev = &pdev->dev; | |
71 | struct device_node *np = dev->of_node; | |
72 | int ret; | |
73 | ||
74 | gr = devm_kzalloc(dev, sizeof(*gr), GFP_KERNEL); | |
75 | if (!gr) | |
76 | return -ENOMEM; | |
77 | ||
78 | gr->map = syscon_node_to_regmap(np); | |
79 | if (IS_ERR(gr->map)) { | |
80 | ret = PTR_ERR(gr->map); | |
81 | dev_err(dev, "unable to get regmap (%d)", ret); | |
82 | return ret; | |
83 | } | |
84 | gr->rcdev.owner = THIS_MODULE; | |
85 | gr->rcdev.nr_resets = 32; | |
86 | gr->rcdev.ops = &gemini_reset_ops; | |
87 | gr->rcdev.of_node = pdev->dev.of_node; | |
88 | ||
89 | ret = devm_reset_controller_register(&pdev->dev, &gr->rcdev); | |
90 | if (ret) | |
91 | return ret; | |
92 | ||
93 | dev_info(dev, "registered Gemini reset controller\n"); | |
94 | return 0; | |
95 | } | |
96 | ||
97 | static const struct of_device_id gemini_reset_dt_ids[] = { | |
98 | { .compatible = "cortina,gemini-syscon", }, | |
99 | { /* sentinel */ }, | |
100 | }; | |
101 | ||
102 | static struct platform_driver gemini_reset_driver = { | |
103 | .probe = gemini_reset_probe, | |
104 | .driver = { | |
105 | .name = "gemini-reset", | |
106 | .of_match_table = gemini_reset_dt_ids, | |
107 | .suppress_bind_attrs = true, | |
108 | }, | |
109 | }; | |
110 | builtin_platform_driver(gemini_reset_driver); |