1 | /* |
2 | * Copyright (C) 2014 Marvell Technology Group Ltd. |
3 | * |
4 | * Marvell Berlin reset driver |
5 | * |
6 | * Antoine Tenart <antoine.tenart@free-electrons.com> |
7 | * Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com> |
8 | * |
9 | * This file is licensed under the terms of the GNU General Public |
10 | * License version 2. This program is licensed "as is" without any |
11 | * warranty of any kind, whether express or implied. |
12 | */ |
13 | |
14 | #include <linux/delay.h> |
15 | #include <linux/io.h> |
16 | #include <linux/mfd/syscon.h> |
17 | #include <linux/module.h> |
18 | #include <linux/of.h> |
19 | #include <linux/of_address.h> |
20 | #include <linux/platform_device.h> |
21 | #include <linux/regmap.h> |
22 | #include <linux/reset-controller.h> |
23 | #include <linux/slab.h> |
24 | #include <linux/types.h> |
25 | |
26 | #define BERLIN_MAX_RESETS 32 |
27 | |
28 | #define to_berlin_reset_priv(p) \ |
29 | container_of((p), struct berlin_reset_priv, rcdev) |
30 | |
31 | struct berlin_reset_priv { |
32 | struct regmap *regmap; |
33 | struct reset_controller_dev rcdev; |
34 | }; |
35 | |
36 | static int berlin_reset_reset(struct reset_controller_dev *rcdev, |
37 | unsigned long id) |
38 | { |
39 | struct berlin_reset_priv *priv = to_berlin_reset_priv(rcdev); |
40 | int offset = id >> 8; |
41 | int mask = BIT(id & 0x1f); |
42 | |
43 | regmap_write(map: priv->regmap, reg: offset, val: mask); |
44 | |
45 | /* let the reset be effective */ |
46 | udelay(10); |
47 | |
48 | return 0; |
49 | } |
50 | |
51 | static const struct reset_control_ops berlin_reset_ops = { |
52 | .reset = berlin_reset_reset, |
53 | }; |
54 | |
55 | static int berlin_reset_xlate(struct reset_controller_dev *rcdev, |
56 | const struct of_phandle_args *reset_spec) |
57 | { |
58 | unsigned int offset, bit; |
59 | |
60 | offset = reset_spec->args[0]; |
61 | bit = reset_spec->args[1]; |
62 | |
63 | if (bit >= BERLIN_MAX_RESETS) |
64 | return -EINVAL; |
65 | |
66 | return (offset << 8) | bit; |
67 | } |
68 | |
69 | static int berlin2_reset_probe(struct platform_device *pdev) |
70 | { |
71 | struct device_node *parent_np = of_get_parent(node: pdev->dev.of_node); |
72 | struct berlin_reset_priv *priv; |
73 | |
74 | priv = devm_kzalloc(dev: &pdev->dev, size: sizeof(*priv), GFP_KERNEL); |
75 | if (!priv) |
76 | return -ENOMEM; |
77 | |
78 | priv->regmap = syscon_node_to_regmap(np: parent_np); |
79 | of_node_put(node: parent_np); |
80 | if (IS_ERR(ptr: priv->regmap)) |
81 | return PTR_ERR(ptr: priv->regmap); |
82 | |
83 | priv->rcdev.owner = THIS_MODULE; |
84 | priv->rcdev.ops = &berlin_reset_ops; |
85 | priv->rcdev.of_node = pdev->dev.of_node; |
86 | priv->rcdev.of_reset_n_cells = 2; |
87 | priv->rcdev.of_xlate = berlin_reset_xlate; |
88 | |
89 | return reset_controller_register(rcdev: &priv->rcdev); |
90 | } |
91 | |
92 | static const struct of_device_id berlin_reset_dt_match[] = { |
93 | { .compatible = "marvell,berlin2-reset" }, |
94 | { }, |
95 | }; |
96 | MODULE_DEVICE_TABLE(of, berlin_reset_dt_match); |
97 | |
98 | static struct platform_driver berlin_reset_driver = { |
99 | .probe = berlin2_reset_probe, |
100 | .driver = { |
101 | .name = "berlin2-reset" , |
102 | .of_match_table = berlin_reset_dt_match, |
103 | }, |
104 | }; |
105 | module_platform_driver(berlin_reset_driver); |
106 | |
107 | MODULE_AUTHOR("Antoine Tenart <antoine.tenart@free-electrons.com>" ); |
108 | MODULE_AUTHOR("Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>" ); |
109 | MODULE_DESCRIPTION("Synaptics Berlin reset controller" ); |
110 | MODULE_LICENSE("GPL" ); |
111 | |