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197858b6 GF |
1 | // SPDX-License-Identifier: GPL-2.0 |
2 | /* | |
3 | * Copyright (C) STMicroelectronics 2018 - All Rights Reserved | |
4 | * Author: Gabriel Fernandez <gabriel.fernandez@st.com> for STMicroelectronics. | |
5 | */ | |
6 | ||
7 | #include <linux/device.h> | |
8 | #include <linux/err.h> | |
9 | #include <linux/io.h> | |
10 | #include <linux/of.h> | |
11 | #include <linux/platform_device.h> | |
12 | #include <linux/reset-controller.h> | |
13 | ||
14 | #define CLR_OFFSET 0x4 | |
15 | ||
16 | struct stm32_reset_data { | |
17 | struct reset_controller_dev rcdev; | |
18 | void __iomem *membase; | |
19 | }; | |
20 | ||
21 | static inline struct stm32_reset_data * | |
22 | to_stm32_reset_data(struct reset_controller_dev *rcdev) | |
23 | { | |
24 | return container_of(rcdev, struct stm32_reset_data, rcdev); | |
25 | } | |
26 | ||
27 | static int stm32_reset_update(struct reset_controller_dev *rcdev, | |
28 | unsigned long id, bool assert) | |
29 | { | |
30 | struct stm32_reset_data *data = to_stm32_reset_data(rcdev); | |
31 | int reg_width = sizeof(u32); | |
32 | int bank = id / (reg_width * BITS_PER_BYTE); | |
33 | int offset = id % (reg_width * BITS_PER_BYTE); | |
34 | void __iomem *addr; | |
35 | ||
36 | addr = data->membase + (bank * reg_width); | |
37 | if (!assert) | |
38 | addr += CLR_OFFSET; | |
39 | ||
40 | writel(BIT(offset), addr); | |
41 | ||
42 | return 0; | |
43 | } | |
44 | ||
45 | static int stm32_reset_assert(struct reset_controller_dev *rcdev, | |
46 | unsigned long id) | |
47 | { | |
48 | return stm32_reset_update(rcdev, id, true); | |
49 | } | |
50 | ||
51 | static int stm32_reset_deassert(struct reset_controller_dev *rcdev, | |
52 | unsigned long id) | |
53 | { | |
54 | return stm32_reset_update(rcdev, id, false); | |
55 | } | |
56 | ||
57 | static int stm32_reset_status(struct reset_controller_dev *rcdev, | |
58 | unsigned long id) | |
59 | { | |
60 | struct stm32_reset_data *data = to_stm32_reset_data(rcdev); | |
61 | int reg_width = sizeof(u32); | |
62 | int bank = id / (reg_width * BITS_PER_BYTE); | |
63 | int offset = id % (reg_width * BITS_PER_BYTE); | |
64 | u32 reg; | |
65 | ||
66 | reg = readl(data->membase + (bank * reg_width)); | |
67 | ||
68 | return !!(reg & BIT(offset)); | |
69 | } | |
70 | ||
71 | static const struct reset_control_ops stm32_reset_ops = { | |
72 | .assert = stm32_reset_assert, | |
73 | .deassert = stm32_reset_deassert, | |
74 | .status = stm32_reset_status, | |
75 | }; | |
76 | ||
77 | static const struct of_device_id stm32_reset_dt_ids[] = { | |
78 | { .compatible = "st,stm32mp1-rcc"}, | |
79 | { /* sentinel */ }, | |
80 | }; | |
81 | ||
82 | static int stm32_reset_probe(struct platform_device *pdev) | |
83 | { | |
84 | struct device *dev = &pdev->dev; | |
85 | struct stm32_reset_data *data; | |
86 | void __iomem *membase; | |
87 | struct resource *res; | |
88 | ||
89 | data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL); | |
90 | if (!data) | |
91 | return -ENOMEM; | |
92 | ||
93 | res = platform_get_resource(pdev, IORESOURCE_MEM, 0); | |
94 | membase = devm_ioremap_resource(dev, res); | |
95 | if (IS_ERR(membase)) | |
96 | return PTR_ERR(membase); | |
97 | ||
98 | data->membase = membase; | |
99 | data->rcdev.owner = THIS_MODULE; | |
100 | data->rcdev.nr_resets = resource_size(res) * BITS_PER_BYTE; | |
101 | data->rcdev.ops = &stm32_reset_ops; | |
102 | data->rcdev.of_node = dev->of_node; | |
103 | ||
104 | return devm_reset_controller_register(dev, &data->rcdev); | |
105 | } | |
106 | ||
107 | static struct platform_driver stm32_reset_driver = { | |
108 | .probe = stm32_reset_probe, | |
109 | .driver = { | |
110 | .name = "stm32mp1-reset", | |
111 | .of_match_table = stm32_reset_dt_ids, | |
112 | }, | |
113 | }; | |
114 | ||
115 | builtin_platform_driver(stm32_reset_driver); |