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12#include <linux/mfd/syscon.h>
13#include <linux/module.h>
14#include <linux/regmap.h>
15#include <linux/reset-controller.h>
16#include <linux/of_address.h>
17#include <linux/of_platform.h>
18#include <linux/platform_device.h>
19#include <linux/property.h>
20
21#define LANTIQ_RCU_RESET_TIMEOUT 10000
22
23struct lantiq_rcu_reset_priv {
24 struct reset_controller_dev rcdev;
25 struct device *dev;
26 struct regmap *regmap;
27 u32 reset_offset;
28 u32 status_offset;
29};
30
31static struct lantiq_rcu_reset_priv *to_lantiq_rcu_reset_priv(
32 struct reset_controller_dev *rcdev)
33{
34 return container_of(rcdev, struct lantiq_rcu_reset_priv, rcdev);
35}
36
37static int lantiq_rcu_reset_status(struct reset_controller_dev *rcdev,
38 unsigned long id)
39{
40 struct lantiq_rcu_reset_priv *priv = to_lantiq_rcu_reset_priv(rcdev);
41 unsigned int status = (id >> 8) & 0x1f;
42 u32 val;
43 int ret;
44
45 ret = regmap_read(priv->regmap, priv->status_offset, &val);
46 if (ret)
47 return ret;
48
49 return !!(val & BIT(status));
50}
51
52static int lantiq_rcu_reset_status_timeout(struct reset_controller_dev *rcdev,
53 unsigned long id, bool assert)
54{
55 int ret;
56 int retry = LANTIQ_RCU_RESET_TIMEOUT;
57
58 do {
59 ret = lantiq_rcu_reset_status(rcdev, id);
60 if (ret < 0)
61 return ret;
62 if (ret == assert)
63 return 0;
64 usleep_range(20, 40);
65 } while (--retry);
66
67 return -ETIMEDOUT;
68}
69
70static int lantiq_rcu_reset_update(struct reset_controller_dev *rcdev,
71 unsigned long id, bool assert)
72{
73 struct lantiq_rcu_reset_priv *priv = to_lantiq_rcu_reset_priv(rcdev);
74 unsigned int set = id & 0x1f;
75 u32 val = assert ? BIT(set) : 0;
76 int ret;
77
78 ret = regmap_update_bits(priv->regmap, priv->reset_offset, BIT(set),
79 val);
80 if (ret) {
81 dev_err(priv->dev, "Failed to set reset bit %u\n", set);
82 return ret;
83 }
84
85
86 ret = lantiq_rcu_reset_status_timeout(rcdev, id, assert);
87 if (ret)
88 dev_err(priv->dev, "Failed to %s bit %u\n",
89 assert ? "assert" : "deassert", set);
90
91 return ret;
92}
93
94static int lantiq_rcu_reset_assert(struct reset_controller_dev *rcdev,
95 unsigned long id)
96{
97 return lantiq_rcu_reset_update(rcdev, id, true);
98}
99
100static int lantiq_rcu_reset_deassert(struct reset_controller_dev *rcdev,
101 unsigned long id)
102{
103 return lantiq_rcu_reset_update(rcdev, id, false);
104}
105
106static int lantiq_rcu_reset_reset(struct reset_controller_dev *rcdev,
107 unsigned long id)
108{
109 int ret;
110
111 ret = lantiq_rcu_reset_assert(rcdev, id);
112 if (ret)
113 return ret;
114
115 return lantiq_rcu_reset_deassert(rcdev, id);
116}
117
118static const struct reset_control_ops lantiq_rcu_reset_ops = {
119 .assert = lantiq_rcu_reset_assert,
120 .deassert = lantiq_rcu_reset_deassert,
121 .status = lantiq_rcu_reset_status,
122 .reset = lantiq_rcu_reset_reset,
123};
124
125static int lantiq_rcu_reset_of_parse(struct platform_device *pdev,
126 struct lantiq_rcu_reset_priv *priv)
127{
128 struct device *dev = &pdev->dev;
129 const __be32 *offset;
130
131 priv->regmap = syscon_node_to_regmap(dev->of_node->parent);
132 if (IS_ERR(priv->regmap)) {
133 dev_err(&pdev->dev, "Failed to lookup RCU regmap\n");
134 return PTR_ERR(priv->regmap);
135 }
136
137 offset = of_get_address(dev->of_node, 0, NULL, NULL);
138 if (!offset) {
139 dev_err(&pdev->dev, "Failed to get RCU reset offset\n");
140 return -ENOENT;
141 }
142 priv->reset_offset = __be32_to_cpu(*offset);
143
144 offset = of_get_address(dev->of_node, 1, NULL, NULL);
145 if (!offset) {
146 dev_err(&pdev->dev, "Failed to get RCU status offset\n");
147 return -ENOENT;
148 }
149 priv->status_offset = __be32_to_cpu(*offset);
150
151 return 0;
152}
153
154static int lantiq_rcu_reset_xlate(struct reset_controller_dev *rcdev,
155 const struct of_phandle_args *reset_spec)
156{
157 unsigned int status, set;
158
159 set = reset_spec->args[0];
160 status = reset_spec->args[1];
161
162 if (set >= rcdev->nr_resets || status >= rcdev->nr_resets)
163 return -EINVAL;
164
165 return (status << 8) | set;
166}
167
168static int lantiq_rcu_reset_probe(struct platform_device *pdev)
169{
170 struct lantiq_rcu_reset_priv *priv;
171 int err;
172
173 priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
174 if (!priv)
175 return -ENOMEM;
176
177 priv->dev = &pdev->dev;
178 platform_set_drvdata(pdev, priv);
179
180 err = lantiq_rcu_reset_of_parse(pdev, priv);
181 if (err)
182 return err;
183
184 priv->rcdev.ops = &lantiq_rcu_reset_ops;
185 priv->rcdev.owner = THIS_MODULE;
186 priv->rcdev.of_node = pdev->dev.of_node;
187 priv->rcdev.nr_resets = 32;
188 priv->rcdev.of_xlate = lantiq_rcu_reset_xlate;
189 priv->rcdev.of_reset_n_cells = 2;
190
191 return reset_controller_register(&priv->rcdev);
192}
193
194static const struct of_device_id lantiq_rcu_reset_dt_ids[] = {
195 { .compatible = "lantiq,danube-reset", },
196 { .compatible = "lantiq,xrx200-reset", },
197 { },
198};
199MODULE_DEVICE_TABLE(of, lantiq_rcu_reset_dt_ids);
200
201static struct platform_driver lantiq_rcu_reset_driver = {
202 .probe = lantiq_rcu_reset_probe,
203 .driver = {
204 .name = "lantiq-reset",
205 .of_match_table = lantiq_rcu_reset_dt_ids,
206 },
207};
208module_platform_driver(lantiq_rcu_reset_driver);
209
210MODULE_AUTHOR("Martin Blumenstingl <martin.blumenstingl@googlemail.com>");
211MODULE_DESCRIPTION("Lantiq XWAY RCU Reset Controller Driver");
212MODULE_LICENSE("GPL");
213
