1 /*
2 * Copyright Intel Corporation (C) 2017. All Rights Reserved
3 *
4 * This program is free software; you can redistribute it and/or modify it
5 * under the terms and conditions of the GNU General Public License,
6 * version 2, as published by the Free Software Foundation.
7 *
8 * This program is distributed in the hope it will be useful, but WITHOUT
9 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
10 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
11 * more details.
12 *
13 * You should have received a copy of the GNU General Public License along with
14 * this program. If not, see <http://www.gnu.org/licenses/>.
15 *
16 * Reset driver for Altera Arria10 MAX5 System Resource Chip
17 *
18 * Adapted from reset-socfpga.c
19 */
20
21 #include <linux/err.h>
22 #include <linux/mfd/altera-a10sr.h>
23 #include <linux/module.h>
24 #include <linux/of.h>
25 #include <linux/platform_device.h>
26 #include <linux/reset-controller.h>
27
28 #include <dt-bindings/reset/altr,rst-mgr-a10sr.h>
29
30 struct a10sr_reset {
31 struct reset_controller_dev rcdev;
32 struct regmap *regmap;
33 };
34
to_a10sr_rst(struct reset_controller_dev * rc)35 static inline struct a10sr_reset *to_a10sr_rst(struct reset_controller_dev *rc)
36 {
37 return container_of(rc, struct a10sr_reset, rcdev);
38 }
39
a10sr_reset_shift(unsigned long id)40 static inline int a10sr_reset_shift(unsigned long id)
41 {
42 switch (id) {
43 case A10SR_RESET_ENET_HPS:
44 return 1;
45 case A10SR_RESET_PCIE:
46 case A10SR_RESET_FILE:
47 case A10SR_RESET_BQSPI:
48 case A10SR_RESET_USB:
49 return id + 11;
50 default:
51 return -EINVAL;
52 }
53 }
54
a10sr_reset_update(struct reset_controller_dev * rcdev,unsigned long id,bool assert)55 static int a10sr_reset_update(struct reset_controller_dev *rcdev,
56 unsigned long id, bool assert)
57 {
58 struct a10sr_reset *a10r = to_a10sr_rst(rcdev);
59 int offset = a10sr_reset_shift(id);
60 u8 mask = ALTR_A10SR_REG_BIT_MASK(offset);
61 int index = ALTR_A10SR_HPS_RST_REG + ALTR_A10SR_REG_OFFSET(offset);
62
63 return regmap_update_bits(a10r->regmap, index, mask, assert ? 0 : mask);
64 }
65
a10sr_reset_assert(struct reset_controller_dev * rcdev,unsigned long id)66 static int a10sr_reset_assert(struct reset_controller_dev *rcdev,
67 unsigned long id)
68 {
69 return a10sr_reset_update(rcdev, id, true);
70 }
71
a10sr_reset_deassert(struct reset_controller_dev * rcdev,unsigned long id)72 static int a10sr_reset_deassert(struct reset_controller_dev *rcdev,
73 unsigned long id)
74 {
75 return a10sr_reset_update(rcdev, id, false);
76 }
77
a10sr_reset_status(struct reset_controller_dev * rcdev,unsigned long id)78 static int a10sr_reset_status(struct reset_controller_dev *rcdev,
79 unsigned long id)
80 {
81 int ret;
82 struct a10sr_reset *a10r = to_a10sr_rst(rcdev);
83 int offset = a10sr_reset_shift(id);
84 u8 mask = ALTR_A10SR_REG_BIT_MASK(offset);
85 int index = ALTR_A10SR_HPS_RST_REG + ALTR_A10SR_REG_OFFSET(offset);
86 unsigned int value;
87
88 ret = regmap_read(a10r->regmap, index, &value);
89 if (ret < 0)
90 return ret;
91
92 return !!(value & mask);
93 }
94
95 static const struct reset_control_ops a10sr_reset_ops = {
96 .assert = a10sr_reset_assert,
97 .deassert = a10sr_reset_deassert,
98 .status = a10sr_reset_status,
99 };
100
a10sr_reset_probe(struct platform_device * pdev)101 static int a10sr_reset_probe(struct platform_device *pdev)
102 {
103 struct altr_a10sr *a10sr = dev_get_drvdata(pdev->dev.parent);
104 struct a10sr_reset *a10r;
105
106 a10r = devm_kzalloc(&pdev->dev, sizeof(struct a10sr_reset),
107 GFP_KERNEL);
108 if (!a10r)
109 return -ENOMEM;
110
111 a10r->rcdev.owner = THIS_MODULE;
112 a10r->rcdev.nr_resets = A10SR_RESET_NUM;
113 a10r->rcdev.ops = &a10sr_reset_ops;
114 a10r->rcdev.of_node = pdev->dev.of_node;
115 a10r->regmap = a10sr->regmap;
116
117 platform_set_drvdata(pdev, a10r);
118
119 return devm_reset_controller_register(&pdev->dev, &a10r->rcdev);
120 }
121
122 static const struct of_device_id a10sr_reset_of_match[] = {
123 { .compatible = "altr,a10sr-reset" },
124 { },
125 };
126 MODULE_DEVICE_TABLE(of, a10sr_reset_of_match);
127
128 static struct platform_driver a10sr_reset_driver = {
129 .probe = a10sr_reset_probe,
130 .driver = {
131 .name = "altr_a10sr_reset",
132 },
133 };
134 module_platform_driver(a10sr_reset_driver);
135
136 MODULE_AUTHOR("Thor Thayer <thor.thayer@linux.intel.com>");
137 MODULE_DESCRIPTION("Altera Arria10 System Resource Reset Controller Driver");
138 MODULE_LICENSE("GPL v2");
139
