tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1/*
2 * Simple Power-Managed Bus Driver
3 *
4 * Copyright (C) 2014-2015 Glider bvba
5 *
6 * This file is subject to the terms and conditions of the GNU General Public
7 * License. See the file "COPYING" in the main directory of this archive
8 * for more details.
9 */
10
11#include <linux/clk.h>
12#include <linux/module.h>
13#include <linux/of_platform.h>
14#include <linux/platform_device.h>
15#include <linux/pm_runtime.h>
16
17struct simple_pm_bus {
18 struct clk_bulk_data *clks;
19 int num_clks;
20};
21
22static int simple_pm_bus_probe(struct platform_device *pdev)
23{
24 const struct device *dev = &pdev->dev;
25 const struct of_dev_auxdata *lookup = dev_get_platdata(dev);
26 struct device_node *np = dev->of_node;
27 const struct of_device_id *match;
28 struct simple_pm_bus *bus;
29
30 /*
31 * Allow user to use driver_override to bind this driver to a
32 * transparent bus device which has a different compatible string
33 * that's not listed in simple_pm_bus_of_match. We don't want to do any
34 * of the simple-pm-bus tasks for these devices, so return early.
35 */
36 if (pdev->driver_override)
37 return 0;
38
39 match = of_match_device(dev->driver->of_match_table, dev);
40 /*
41 * These are transparent bus devices (not simple-pm-bus matches) that
42 * have their child nodes populated automatically. So, don't need to
43 * do anything more. We only match with the device if this driver is
44 * the most specific match because we don't want to incorrectly bind to
45 * a device that has a more specific driver.
46 */
47 if (match && match->data) {
48 if (of_property_match_string(np, "compatible", match->compatible) == 0)
49 return 0;
50 else
51 return -ENODEV;
52 }
53
54 bus = devm_kzalloc(&pdev->dev, sizeof(*bus), GFP_KERNEL);
55 if (!bus)
56 return -ENOMEM;
57
58 bus->num_clks = devm_clk_bulk_get_all(&pdev->dev, &bus->clks);
59 if (bus->num_clks < 0)
60 return dev_err_probe(&pdev->dev, bus->num_clks, "failed to get clocks\n");
61
62 dev_set_drvdata(&pdev->dev, bus);
63
64 dev_dbg(&pdev->dev, "%s\n", __func__);
65
66 pm_runtime_enable(&pdev->dev);
67
68 if (np)
69 of_platform_populate(np, NULL, lookup, &pdev->dev);
70
71 return 0;
72}
73
74static int simple_pm_bus_remove(struct platform_device *pdev)
75{
76 const void *data = of_device_get_match_data(&pdev->dev);
77
78 if (pdev->driver_override || data)
79 return 0;
80
81 dev_dbg(&pdev->dev, "%s\n", __func__);
82
83 pm_runtime_disable(&pdev->dev);
84 return 0;
85}
86
87static int simple_pm_bus_runtime_suspend(struct device *dev)
88{
89 struct simple_pm_bus *bus = dev_get_drvdata(dev);
90
91 clk_bulk_disable_unprepare(bus->num_clks, bus->clks);
92
93 return 0;
94}
95
96static int simple_pm_bus_runtime_resume(struct device *dev)
97{
98 struct simple_pm_bus *bus = dev_get_drvdata(dev);
99 int ret;
100
101 ret = clk_bulk_prepare_enable(bus->num_clks, bus->clks);
102 if (ret) {
103 dev_err(dev, "failed to enable clocks: %d\n", ret);
104 return ret;
105 }
106
107 return 0;
108}
109
110static const struct dev_pm_ops simple_pm_bus_pm_ops = {
111 RUNTIME_PM_OPS(simple_pm_bus_runtime_suspend, simple_pm_bus_runtime_resume, NULL)
112 NOIRQ_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend, pm_runtime_force_resume)
113};
114
115#define ONLY_BUS ((void *) 1) /* Match if the device is only a bus. */
116
117static const struct of_device_id simple_pm_bus_of_match[] = {
118 { .compatible = "simple-pm-bus", },
119 { .compatible = "simple-bus", .data = ONLY_BUS },
120 { .compatible = "simple-mfd", .data = ONLY_BUS },
121 { .compatible = "isa", .data = ONLY_BUS },
122 { .compatible = "arm,amba-bus", .data = ONLY_BUS },
123 { /* sentinel */ }
124};
125MODULE_DEVICE_TABLE(of, simple_pm_bus_of_match);
126
127static struct platform_driver simple_pm_bus_driver = {
128 .probe = simple_pm_bus_probe,
129 .remove = simple_pm_bus_remove,
130 .driver = {
131 .name = "simple-pm-bus",
132 .of_match_table = simple_pm_bus_of_match,
133 .pm = pm_ptr(&simple_pm_bus_pm_ops),
134 },
135};
136
137module_platform_driver(simple_pm_bus_driver);
138
139MODULE_DESCRIPTION("Simple Power-Managed Bus Driver");
140MODULE_AUTHOR("Geert Uytterhoeven <geert+renesas@glider.be>");
141MODULE_LICENSE("GPL v2");