xref: /openbmc/linux/drivers/reset/reset-tn48m.c (revision 5cd3921d)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Delta TN48M CPLD reset driver
4  *
5  * Copyright (C) 2021 Sartura Ltd.
6  *
7  * Author: Robert Marko <robert.marko@sartura.hr>
8  */
9 
10 #include <linux/device.h>
11 #include <linux/kernel.h>
12 #include <linux/mod_devicetable.h>
13 #include <linux/module.h>
14 #include <linux/platform_device.h>
15 #include <linux/regmap.h>
16 #include <linux/reset-controller.h>
17 
18 #include <dt-bindings/reset/delta,tn48m-reset.h>
19 
20 #define TN48M_RESET_REG		0x10
21 
22 #define TN48M_RESET_TIMEOUT_US	125000
23 #define TN48M_RESET_SLEEP_US	10
24 
25 struct tn48_reset_map {
26 	u8 bit;
27 };
28 
29 struct tn48_reset_data {
30 	struct reset_controller_dev rcdev;
31 	struct regmap *regmap;
32 };
33 
34 static const struct tn48_reset_map tn48m_resets[] = {
35 	[CPU_88F7040_RESET] = {0},
36 	[CPU_88F6820_RESET] = {1},
37 	[MAC_98DX3265_RESET] = {2},
38 	[PHY_88E1680_RESET] = {4},
39 	[PHY_88E1512_RESET] = {6},
40 	[POE_RESET] = {7},
41 };
42 
to_tn48_reset_data(struct reset_controller_dev * rcdev)43 static inline struct tn48_reset_data *to_tn48_reset_data(
44 			struct reset_controller_dev *rcdev)
45 {
46 	return container_of(rcdev, struct tn48_reset_data, rcdev);
47 }
48 
tn48m_control_reset(struct reset_controller_dev * rcdev,unsigned long id)49 static int tn48m_control_reset(struct reset_controller_dev *rcdev,
50 			       unsigned long id)
51 {
52 	struct tn48_reset_data *data = to_tn48_reset_data(rcdev);
53 	unsigned int val;
54 
55 	regmap_update_bits(data->regmap, TN48M_RESET_REG,
56 			   BIT(tn48m_resets[id].bit), 0);
57 
58 	return regmap_read_poll_timeout(data->regmap,
59 					TN48M_RESET_REG,
60 					val,
61 					val & BIT(tn48m_resets[id].bit),
62 					TN48M_RESET_SLEEP_US,
63 					TN48M_RESET_TIMEOUT_US);
64 }
65 
tn48m_control_status(struct reset_controller_dev * rcdev,unsigned long id)66 static int tn48m_control_status(struct reset_controller_dev *rcdev,
67 				unsigned long id)
68 {
69 	struct tn48_reset_data *data = to_tn48_reset_data(rcdev);
70 	unsigned int regval;
71 	int ret;
72 
73 	ret = regmap_read(data->regmap, TN48M_RESET_REG, &regval);
74 	if (ret < 0)
75 		return ret;
76 
77 	if (BIT(tn48m_resets[id].bit) & regval)
78 		return 0;
79 	else
80 		return 1;
81 }
82 
83 static const struct reset_control_ops tn48_reset_ops = {
84 	.reset		= tn48m_control_reset,
85 	.status		= tn48m_control_status,
86 };
87 
tn48m_reset_probe(struct platform_device * pdev)88 static int tn48m_reset_probe(struct platform_device *pdev)
89 {
90 	struct tn48_reset_data *data;
91 	struct regmap *regmap;
92 
93 	regmap = dev_get_regmap(pdev->dev.parent, NULL);
94 	if (!regmap)
95 		return -ENODEV;
96 
97 	data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
98 	if (!data)
99 		return -ENOMEM;
100 
101 	data->regmap = regmap;
102 
103 	data->rcdev.owner = THIS_MODULE;
104 	data->rcdev.ops = &tn48_reset_ops;
105 	data->rcdev.nr_resets = ARRAY_SIZE(tn48m_resets);
106 	data->rcdev.of_node = pdev->dev.of_node;
107 
108 	return devm_reset_controller_register(&pdev->dev, &data->rcdev);
109 }
110 
111 static const struct of_device_id tn48m_reset_of_match[] = {
112 	{ .compatible = "delta,tn48m-reset" },
113 	{ }
114 };
115 MODULE_DEVICE_TABLE(of, tn48m_reset_of_match);
116 
117 static struct platform_driver tn48m_reset_driver = {
118 	.driver = {
119 		.name = "delta-tn48m-reset",
120 		.of_match_table = tn48m_reset_of_match,
121 	},
122 	.probe = tn48m_reset_probe,
123 };
124 module_platform_driver(tn48m_reset_driver);
125 
126 MODULE_AUTHOR("Robert Marko <robert.marko@sartura.hr>");
127 MODULE_DESCRIPTION("Delta TN48M CPLD reset driver");
128 MODULE_LICENSE("GPL");
129