xref: /openbmc/linux/drivers/reset/reset-lantiq.c (revision 41bbf704)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  *
4  *  Copyright (C) 2010 John Crispin <blogic@phrozen.org>
5  *  Copyright (C) 2013-2015 Lantiq Beteiligungs-GmbH & Co.KG
6  *  Copyright (C) 2016 Martin Blumenstingl <martin.blumenstingl@googlemail.com>
7  *  Copyright (C) 2017 Hauke Mehrtens <hauke@hauke-m.de>
8  */
9 
10 #include <linux/mfd/syscon.h>
11 #include <linux/module.h>
12 #include <linux/regmap.h>
13 #include <linux/reset-controller.h>
14 #include <linux/of_address.h>
15 #include <linux/of_platform.h>
16 #include <linux/platform_device.h>
17 #include <linux/property.h>
18 
19 #define LANTIQ_RCU_RESET_TIMEOUT	10000
20 
21 struct lantiq_rcu_reset_priv {
22 	struct reset_controller_dev rcdev;
23 	struct device *dev;
24 	struct regmap *regmap;
25 	u32 reset_offset;
26 	u32 status_offset;
27 };
28 
to_lantiq_rcu_reset_priv(struct reset_controller_dev * rcdev)29 static struct lantiq_rcu_reset_priv *to_lantiq_rcu_reset_priv(
30 	struct reset_controller_dev *rcdev)
31 {
32 	return container_of(rcdev, struct lantiq_rcu_reset_priv, rcdev);
33 }
34 
lantiq_rcu_reset_status(struct reset_controller_dev * rcdev,unsigned long id)35 static int lantiq_rcu_reset_status(struct reset_controller_dev *rcdev,
36 				   unsigned long id)
37 {
38 	struct lantiq_rcu_reset_priv *priv = to_lantiq_rcu_reset_priv(rcdev);
39 	unsigned int status = (id >> 8) & 0x1f;
40 	u32 val;
41 	int ret;
42 
43 	ret = regmap_read(priv->regmap, priv->status_offset, &val);
44 	if (ret)
45 		return ret;
46 
47 	return !!(val & BIT(status));
48 }
49 
lantiq_rcu_reset_status_timeout(struct reset_controller_dev * rcdev,unsigned long id,bool assert)50 static int lantiq_rcu_reset_status_timeout(struct reset_controller_dev *rcdev,
51 					   unsigned long id, bool assert)
52 {
53 	int ret;
54 	int retry = LANTIQ_RCU_RESET_TIMEOUT;
55 
56 	do {
57 		ret = lantiq_rcu_reset_status(rcdev, id);
58 		if (ret < 0)
59 			return ret;
60 		if (ret == assert)
61 			return 0;
62 		usleep_range(20, 40);
63 	} while (--retry);
64 
65 	return -ETIMEDOUT;
66 }
67 
lantiq_rcu_reset_update(struct reset_controller_dev * rcdev,unsigned long id,bool assert)68 static int lantiq_rcu_reset_update(struct reset_controller_dev *rcdev,
69 				   unsigned long id, bool assert)
70 {
71 	struct lantiq_rcu_reset_priv *priv = to_lantiq_rcu_reset_priv(rcdev);
72 	unsigned int set = id & 0x1f;
73 	u32 val = assert ? BIT(set) : 0;
74 	int ret;
75 
76 	ret = regmap_update_bits(priv->regmap, priv->reset_offset, BIT(set),
77 				 val);
78 	if (ret) {
79 		dev_err(priv->dev, "Failed to set reset bit %u\n", set);
80 		return ret;
81 	}
82 
83 
84 	ret = lantiq_rcu_reset_status_timeout(rcdev, id, assert);
85 	if (ret)
86 		dev_err(priv->dev, "Failed to %s bit %u\n",
87 			assert ? "assert" : "deassert", set);
88 
89 	return ret;
90 }
91 
lantiq_rcu_reset_assert(struct reset_controller_dev * rcdev,unsigned long id)92 static int lantiq_rcu_reset_assert(struct reset_controller_dev *rcdev,
93 			     unsigned long id)
94 {
95 	return lantiq_rcu_reset_update(rcdev, id, true);
96 }
97 
lantiq_rcu_reset_deassert(struct reset_controller_dev * rcdev,unsigned long id)98 static int lantiq_rcu_reset_deassert(struct reset_controller_dev *rcdev,
99 			       unsigned long id)
100 {
101 	return lantiq_rcu_reset_update(rcdev, id, false);
102 }
103 
lantiq_rcu_reset_reset(struct reset_controller_dev * rcdev,unsigned long id)104 static int lantiq_rcu_reset_reset(struct reset_controller_dev *rcdev,
105 			    unsigned long id)
106 {
107 	int ret;
108 
109 	ret = lantiq_rcu_reset_assert(rcdev, id);
110 	if (ret)
111 		return ret;
112 
113 	return lantiq_rcu_reset_deassert(rcdev, id);
114 }
115 
116 static const struct reset_control_ops lantiq_rcu_reset_ops = {
117 	.assert = lantiq_rcu_reset_assert,
118 	.deassert = lantiq_rcu_reset_deassert,
119 	.status = lantiq_rcu_reset_status,
120 	.reset	= lantiq_rcu_reset_reset,
121 };
122 
lantiq_rcu_reset_of_parse(struct platform_device * pdev,struct lantiq_rcu_reset_priv * priv)123 static int lantiq_rcu_reset_of_parse(struct platform_device *pdev,
124 			       struct lantiq_rcu_reset_priv *priv)
125 {
126 	struct device *dev = &pdev->dev;
127 	const __be32 *offset;
128 
129 	priv->regmap = syscon_node_to_regmap(dev->of_node->parent);
130 	if (IS_ERR(priv->regmap)) {
131 		dev_err(&pdev->dev, "Failed to lookup RCU regmap\n");
132 		return PTR_ERR(priv->regmap);
133 	}
134 
135 	offset = of_get_address(dev->of_node, 0, NULL, NULL);
136 	if (!offset) {
137 		dev_err(&pdev->dev, "Failed to get RCU reset offset\n");
138 		return -ENOENT;
139 	}
140 	priv->reset_offset = __be32_to_cpu(*offset);
141 
142 	offset = of_get_address(dev->of_node, 1, NULL, NULL);
143 	if (!offset) {
144 		dev_err(&pdev->dev, "Failed to get RCU status offset\n");
145 		return -ENOENT;
146 	}
147 	priv->status_offset = __be32_to_cpu(*offset);
148 
149 	return 0;
150 }
151 
lantiq_rcu_reset_xlate(struct reset_controller_dev * rcdev,const struct of_phandle_args * reset_spec)152 static int lantiq_rcu_reset_xlate(struct reset_controller_dev *rcdev,
153 				  const struct of_phandle_args *reset_spec)
154 {
155 	unsigned int status, set;
156 
157 	set = reset_spec->args[0];
158 	status = reset_spec->args[1];
159 
160 	if (set >= rcdev->nr_resets || status >= rcdev->nr_resets)
161 		return -EINVAL;
162 
163 	return (status << 8) | set;
164 }
165 
lantiq_rcu_reset_probe(struct platform_device * pdev)166 static int lantiq_rcu_reset_probe(struct platform_device *pdev)
167 {
168 	struct lantiq_rcu_reset_priv *priv;
169 	int err;
170 
171 	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
172 	if (!priv)
173 		return -ENOMEM;
174 
175 	priv->dev = &pdev->dev;
176 
177 	err = lantiq_rcu_reset_of_parse(pdev, priv);
178 	if (err)
179 		return err;
180 
181 	priv->rcdev.ops = &lantiq_rcu_reset_ops;
182 	priv->rcdev.owner = THIS_MODULE;
183 	priv->rcdev.of_node = pdev->dev.of_node;
184 	priv->rcdev.nr_resets = 32;
185 	priv->rcdev.of_xlate = lantiq_rcu_reset_xlate;
186 	priv->rcdev.of_reset_n_cells = 2;
187 
188 	return devm_reset_controller_register(&pdev->dev, &priv->rcdev);
189 }
190 
191 static const struct of_device_id lantiq_rcu_reset_dt_ids[] = {
192 	{ .compatible = "lantiq,danube-reset", },
193 	{ .compatible = "lantiq,xrx200-reset", },
194 	{ },
195 };
196 MODULE_DEVICE_TABLE(of, lantiq_rcu_reset_dt_ids);
197 
198 static struct platform_driver lantiq_rcu_reset_driver = {
199 	.probe	= lantiq_rcu_reset_probe,
200 	.driver = {
201 		.name		= "lantiq-reset",
202 		.of_match_table	= lantiq_rcu_reset_dt_ids,
203 	},
204 };
205 module_platform_driver(lantiq_rcu_reset_driver);
206 
207 MODULE_AUTHOR("Martin Blumenstingl <martin.blumenstingl@googlemail.com>");
208 MODULE_DESCRIPTION("Lantiq XWAY RCU Reset Controller Driver");
209