tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
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linux
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Simple Power-Managed Bus Driver
4 *
5 * Copyright (C) 2014-2015 Glider bvba
6 *
7 * This file is subject to the terms and conditions of the GNU General Public
8 * License. See the file "COPYING" in the main directory of this archive
9 * for more details.
10 */
11
12#include <linux/clk.h>
13#include <linux/module.h>
14#include <linux/of.h>
15#include <linux/of_device.h>
16#include <linux/of_platform.h>
17#include <linux/platform_device.h>
18#include <linux/pm_runtime.h>
19
20struct simple_pm_bus {
21 struct clk_bulk_data *clks;
22 int num_clks;
23};
24
25static int simple_pm_bus_probe(struct platform_device *pdev)
26{
27 const struct device *dev = &pdev->dev;
28 const struct of_dev_auxdata *lookup = dev_get_platdata(dev);
29 struct device_node *np = dev->of_node;
30 const struct of_device_id *match;
31 struct simple_pm_bus *bus;
32
33 /*
34 * Allow user to use driver_override to bind this driver to a
35 * transparent bus device which has a different compatible string
36 * that's not listed in simple_pm_bus_of_match. We don't want to do any
37 * of the simple-pm-bus tasks for these devices, so return early.
38 */
39 if (pdev->driver_override)
40 return 0;
41
42 match = of_match_device(dev->driver->of_match_table, dev);
43 /*
44 * These are transparent bus devices (not simple-pm-bus matches) that
45 * have their child nodes populated automatically. So, don't need to
46 * do anything more. We only match with the device if this driver is
47 * the most specific match because we don't want to incorrectly bind to
48 * a device that has a more specific driver.
49 */
50 if (match && match->data) {
51 if (of_property_match_string(np, "compatible", match->compatible) == 0)
52 return 0;
53 else
54 return -ENODEV;
55 }
56
57 bus = devm_kzalloc(&pdev->dev, sizeof(*bus), GFP_KERNEL);
58 if (!bus)
59 return -ENOMEM;
60
61 bus->num_clks = devm_clk_bulk_get_all(&pdev->dev, &bus->clks);
62 if (bus->num_clks < 0)
63 return dev_err_probe(&pdev->dev, bus->num_clks, "failed to get clocks\n");
64
65 dev_set_drvdata(&pdev->dev, bus);
66
67 dev_dbg(&pdev->dev, "%s\n", __func__);
68
69 pm_runtime_enable(&pdev->dev);
70
71 if (np)
72 of_platform_populate(np, NULL, lookup, &pdev->dev);
73
74 return 0;
75}
76
77static void simple_pm_bus_remove(struct platform_device *pdev)
78{
79 const void *data = of_device_get_match_data(&pdev->dev);
80
81 if (pdev->driver_override || data)
82 return;
83
84 dev_dbg(&pdev->dev, "%s\n", __func__);
85
86 pm_runtime_disable(&pdev->dev);
87}
88
89static int simple_pm_bus_runtime_suspend(struct device *dev)
90{
91 struct simple_pm_bus *bus = dev_get_drvdata(dev);
92
93 clk_bulk_disable_unprepare(bus->num_clks, bus->clks);
94
95 return 0;
96}
97
98static int simple_pm_bus_runtime_resume(struct device *dev)
99{
100 struct simple_pm_bus *bus = dev_get_drvdata(dev);
101 int ret;
102
103 ret = clk_bulk_prepare_enable(bus->num_clks, bus->clks);
104 if (ret) {
105 dev_err(dev, "failed to enable clocks: %d\n", ret);
106 return ret;
107 }
108
109 return 0;
110}
111
112static int simple_pm_bus_suspend(struct device *dev)
113{
114 struct simple_pm_bus *bus = dev_get_drvdata(dev);
115
116 if (!bus)
117 return 0;
118
119 return pm_runtime_force_suspend(dev);
120}
121
122static int simple_pm_bus_resume(struct device *dev)
123{
124 struct simple_pm_bus *bus = dev_get_drvdata(dev);
125
126 if (!bus)
127 return 0;
128
129 return pm_runtime_force_resume(dev);
130}
131
132static const struct dev_pm_ops simple_pm_bus_pm_ops = {
133 RUNTIME_PM_OPS(simple_pm_bus_runtime_suspend, simple_pm_bus_runtime_resume, NULL)
134 NOIRQ_SYSTEM_SLEEP_PM_OPS(simple_pm_bus_suspend, simple_pm_bus_resume)
135};
136
137#define ONLY_BUS ((void *) 1) /* Match if the device is only a bus. */
138
139static const struct of_device_id simple_pm_bus_of_match[] = {
140 { .compatible = "simple-pm-bus", },
141 { .compatible = "simple-bus", .data = ONLY_BUS },
142 { .compatible = "simple-mfd", .data = ONLY_BUS },
143 { .compatible = "isa", .data = ONLY_BUS },
144 { .compatible = "arm,amba-bus", .data = ONLY_BUS },
145 { /* sentinel */ }
146};
147MODULE_DEVICE_TABLE(of, simple_pm_bus_of_match);
148
149static struct platform_driver simple_pm_bus_driver = {
150 .probe = simple_pm_bus_probe,
151 .remove = simple_pm_bus_remove,
152 .driver = {
153 .name = "simple-pm-bus",
154 .of_match_table = simple_pm_bus_of_match,
155 .pm = pm_ptr(&simple_pm_bus_pm_ops),
156 },
157};
158
159module_platform_driver(simple_pm_bus_driver);
160
161MODULE_DESCRIPTION("Simple Power-Managed Bus Driver");
162MODULE_AUTHOR("Geert Uytterhoeven <geert+renesas@glider.be>");