Merge tag 'orphan-handling-v5.12-rc1' of git://git.kernel.org/pub/scm/linux/kernel...
[linux-2.6-microblaze.git] / drivers / reset / reset-simple.c
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * Simple Reset Controller Driver
4  *
5  * Copyright (C) 2017 Pengutronix, Philipp Zabel <kernel@pengutronix.de>
6  *
7  * Based on Allwinner SoCs Reset Controller driver
8  *
9  * Copyright 2013 Maxime Ripard
10  *
11  * Maxime Ripard <maxime.ripard@free-electrons.com>
12  */
13
14 #include <linux/delay.h>
15 #include <linux/device.h>
16 #include <linux/err.h>
17 #include <linux/io.h>
18 #include <linux/of.h>
19 #include <linux/of_device.h>
20 #include <linux/platform_device.h>
21 #include <linux/reset-controller.h>
22 #include <linux/reset/reset-simple.h>
23 #include <linux/spinlock.h>
24
25 static inline struct reset_simple_data *
26 to_reset_simple_data(struct reset_controller_dev *rcdev)
27 {
28         return container_of(rcdev, struct reset_simple_data, rcdev);
29 }
30
31 static int reset_simple_update(struct reset_controller_dev *rcdev,
32                                unsigned long id, bool assert)
33 {
34         struct reset_simple_data *data = to_reset_simple_data(rcdev);
35         int reg_width = sizeof(u32);
36         int bank = id / (reg_width * BITS_PER_BYTE);
37         int offset = id % (reg_width * BITS_PER_BYTE);
38         unsigned long flags;
39         u32 reg;
40
41         spin_lock_irqsave(&data->lock, flags);
42
43         reg = readl(data->membase + (bank * reg_width));
44         if (assert ^ data->active_low)
45                 reg |= BIT(offset);
46         else
47                 reg &= ~BIT(offset);
48         writel(reg, data->membase + (bank * reg_width));
49
50         spin_unlock_irqrestore(&data->lock, flags);
51
52         return 0;
53 }
54
55 static int reset_simple_assert(struct reset_controller_dev *rcdev,
56                                unsigned long id)
57 {
58         return reset_simple_update(rcdev, id, true);
59 }
60
61 static int reset_simple_deassert(struct reset_controller_dev *rcdev,
62                                  unsigned long id)
63 {
64         return reset_simple_update(rcdev, id, false);
65 }
66
67 static int reset_simple_reset(struct reset_controller_dev *rcdev,
68                               unsigned long id)
69 {
70         struct reset_simple_data *data = to_reset_simple_data(rcdev);
71         int ret;
72
73         if (!data->reset_us)
74                 return -ENOTSUPP;
75
76         ret = reset_simple_assert(rcdev, id);
77         if (ret)
78                 return ret;
79
80         usleep_range(data->reset_us, data->reset_us * 2);
81
82         return reset_simple_deassert(rcdev, id);
83 }
84
85 static int reset_simple_status(struct reset_controller_dev *rcdev,
86                                unsigned long id)
87 {
88         struct reset_simple_data *data = to_reset_simple_data(rcdev);
89         int reg_width = sizeof(u32);
90         int bank = id / (reg_width * BITS_PER_BYTE);
91         int offset = id % (reg_width * BITS_PER_BYTE);
92         u32 reg;
93
94         reg = readl(data->membase + (bank * reg_width));
95
96         return !(reg & BIT(offset)) ^ !data->status_active_low;
97 }
98
99 const struct reset_control_ops reset_simple_ops = {
100         .assert         = reset_simple_assert,
101         .deassert       = reset_simple_deassert,
102         .reset          = reset_simple_reset,
103         .status         = reset_simple_status,
104 };
105 EXPORT_SYMBOL_GPL(reset_simple_ops);
106
107 /**
108  * struct reset_simple_devdata - simple reset controller properties
109  * @reg_offset: offset between base address and first reset register.
110  * @nr_resets: number of resets. If not set, default to resource size in bits.
111  * @active_low: if true, bits are cleared to assert the reset. Otherwise, bits
112  *              are set to assert the reset.
113  * @status_active_low: if true, bits read back as cleared while the reset is
114  *                     asserted. Otherwise, bits read back as set while the
115  *                     reset is asserted.
116  */
117 struct reset_simple_devdata {
118         u32 reg_offset;
119         u32 nr_resets;
120         bool active_low;
121         bool status_active_low;
122 };
123
124 #define SOCFPGA_NR_BANKS        8
125
126 static const struct reset_simple_devdata reset_simple_socfpga = {
127         .reg_offset = 0x20,
128         .nr_resets = SOCFPGA_NR_BANKS * 32,
129         .status_active_low = true,
130 };
131
132 static const struct reset_simple_devdata reset_simple_active_low = {
133         .active_low = true,
134         .status_active_low = true,
135 };
136
137 static const struct of_device_id reset_simple_dt_ids[] = {
138         { .compatible = "altr,stratix10-rst-mgr",
139                 .data = &reset_simple_socfpga },
140         { .compatible = "st,stm32-rcc", },
141         { .compatible = "allwinner,sun6i-a31-clock-reset",
142                 .data = &reset_simple_active_low },
143         { .compatible = "zte,zx296718-reset",
144                 .data = &reset_simple_active_low },
145         { .compatible = "aspeed,ast2400-lpc-reset" },
146         { .compatible = "aspeed,ast2500-lpc-reset" },
147         { .compatible = "bitmain,bm1880-reset",
148                 .data = &reset_simple_active_low },
149         { .compatible = "brcm,bcm4908-misc-pcie-reset",
150                 .data = &reset_simple_active_low },
151         { .compatible = "snps,dw-high-reset" },
152         { .compatible = "snps,dw-low-reset",
153                 .data = &reset_simple_active_low },
154         { /* sentinel */ },
155 };
156
157 static int reset_simple_probe(struct platform_device *pdev)
158 {
159         struct device *dev = &pdev->dev;
160         const struct reset_simple_devdata *devdata;
161         struct reset_simple_data *data;
162         void __iomem *membase;
163         struct resource *res;
164         u32 reg_offset = 0;
165
166         devdata = of_device_get_match_data(dev);
167
168         data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
169         if (!data)
170                 return -ENOMEM;
171
172         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
173         membase = devm_ioremap_resource(dev, res);
174         if (IS_ERR(membase))
175                 return PTR_ERR(membase);
176
177         spin_lock_init(&data->lock);
178         data->membase = membase;
179         data->rcdev.owner = THIS_MODULE;
180         data->rcdev.nr_resets = resource_size(res) * BITS_PER_BYTE;
181         data->rcdev.ops = &reset_simple_ops;
182         data->rcdev.of_node = dev->of_node;
183
184         if (devdata) {
185                 reg_offset = devdata->reg_offset;
186                 if (devdata->nr_resets)
187                         data->rcdev.nr_resets = devdata->nr_resets;
188                 data->active_low = devdata->active_low;
189                 data->status_active_low = devdata->status_active_low;
190         }
191
192         data->membase += reg_offset;
193
194         return devm_reset_controller_register(dev, &data->rcdev);
195 }
196
197 static struct platform_driver reset_simple_driver = {
198         .probe  = reset_simple_probe,
199         .driver = {
200                 .name           = "simple-reset",
201                 .of_match_table = reset_simple_dt_ids,
202         },
203 };
204 builtin_platform_driver(reset_simple_driver);