1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Copyright (c) 2015, National Instruments Corp.
4 *
5 * Xilinx Zynq Reset controller driver
6 *
7 * Author: Moritz Fischer <moritz.fischer@ettus.com>
8 */
9
10 #include <linux/err.h>
11 #include <linux/io.h>
12 #include <linux/init.h>
13 #include <linux/mfd/syscon.h>
14 #include <linux/of.h>
15 #include <linux/platform_device.h>
16 #include <linux/reset-controller.h>
17 #include <linux/regmap.h>
18 #include <linux/types.h>
19
20 struct zynq_reset_data {
21 struct regmap *slcr;
22 struct reset_controller_dev rcdev;
23 u32 offset;
24 };
25
26 #define to_zynq_reset_data(p) \
27 container_of((p), struct zynq_reset_data, rcdev)
28
zynq_reset_assert(struct reset_controller_dev * rcdev,unsigned long id)29 static int zynq_reset_assert(struct reset_controller_dev *rcdev,
30 unsigned long id)
31 {
32 struct zynq_reset_data *priv = to_zynq_reset_data(rcdev);
33
34 int bank = id / BITS_PER_LONG;
35 int offset = id % BITS_PER_LONG;
36
37 pr_debug("%s: %s reset bank %u offset %u\n", KBUILD_MODNAME, __func__,
38 bank, offset);
39
40 return regmap_update_bits(priv->slcr,
41 priv->offset + (bank * 4),
42 BIT(offset),
43 BIT(offset));
44 }
45
zynq_reset_deassert(struct reset_controller_dev * rcdev,unsigned long id)46 static int zynq_reset_deassert(struct reset_controller_dev *rcdev,
47 unsigned long id)
48 {
49 struct zynq_reset_data *priv = to_zynq_reset_data(rcdev);
50
51 int bank = id / BITS_PER_LONG;
52 int offset = id % BITS_PER_LONG;
53
54 pr_debug("%s: %s reset bank %u offset %u\n", KBUILD_MODNAME, __func__,
55 bank, offset);
56
57 return regmap_update_bits(priv->slcr,
58 priv->offset + (bank * 4),
59 BIT(offset),
60 ~BIT(offset));
61 }
62
zynq_reset_status(struct reset_controller_dev * rcdev,unsigned long id)63 static int zynq_reset_status(struct reset_controller_dev *rcdev,
64 unsigned long id)
65 {
66 struct zynq_reset_data *priv = to_zynq_reset_data(rcdev);
67
68 int bank = id / BITS_PER_LONG;
69 int offset = id % BITS_PER_LONG;
70 int ret;
71 u32 reg;
72
73 pr_debug("%s: %s reset bank %u offset %u\n", KBUILD_MODNAME, __func__,
74 bank, offset);
75
76 ret = regmap_read(priv->slcr, priv->offset + (bank * 4), ®);
77 if (ret)
78 return ret;
79
80 return !!(reg & BIT(offset));
81 }
82
83 static const struct reset_control_ops zynq_reset_ops = {
84 .assert = zynq_reset_assert,
85 .deassert = zynq_reset_deassert,
86 .status = zynq_reset_status,
87 };
88
zynq_reset_probe(struct platform_device * pdev)89 static int zynq_reset_probe(struct platform_device *pdev)
90 {
91 struct resource *res;
92 struct zynq_reset_data *priv;
93
94 priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
95 if (!priv)
96 return -ENOMEM;
97
98 priv->slcr = syscon_regmap_lookup_by_phandle(pdev->dev.of_node,
99 "syscon");
100 if (IS_ERR(priv->slcr)) {
101 dev_err(&pdev->dev, "unable to get zynq-slcr regmap");
102 return PTR_ERR(priv->slcr);
103 }
104
105 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
106 if (!res) {
107 dev_err(&pdev->dev, "missing IO resource\n");
108 return -ENODEV;
109 }
110
111 priv->offset = res->start;
112
113 priv->rcdev.owner = THIS_MODULE;
114 priv->rcdev.nr_resets = resource_size(res) / 4 * BITS_PER_LONG;
115 priv->rcdev.ops = &zynq_reset_ops;
116 priv->rcdev.of_node = pdev->dev.of_node;
117
118 return devm_reset_controller_register(&pdev->dev, &priv->rcdev);
119 }
120
121 static const struct of_device_id zynq_reset_dt_ids[] = {
122 { .compatible = "xlnx,zynq-reset", },
123 { /* sentinel */ },
124 };
125
126 static struct platform_driver zynq_reset_driver = {
127 .probe = zynq_reset_probe,
128 .driver = {
129 .name = KBUILD_MODNAME,
130 .of_match_table = zynq_reset_dt_ids,
131 },
132 };
133 builtin_platform_driver(zynq_reset_driver);
134