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/module.h>
12#include <linux/of_platform.h>
13#include <linux/platform_device.h>
14#include <linux/pm_runtime.h>
15
16static int simple_pm_bus_probe(struct platform_device *pdev)
17{
18	const struct device *dev = &pdev->dev;
19	const struct of_dev_auxdata *lookup = dev_get_platdata(dev);
20	struct device_node *np = dev->of_node;
21	const struct of_device_id *match;
22
23	/*
24	 * Allow user to use driver_override to bind this driver to a
25	 * transparent bus device which has a different compatible string
26	 * that's not listed in simple_pm_bus_of_match. We don't want to do any
27	 * of the simple-pm-bus tasks for these devices, so return early.
28	 */
29	if (pdev->driver_override)
30		return 0;
31
32	match = of_match_device(dev->driver->of_match_table, dev);
33	/*
34	 * These are transparent bus devices (not simple-pm-bus matches) that
35	 * have their child nodes populated automatically.  So, don't need to
36	 * do anything more. We only match with the device if this driver is
37	 * the most specific match because we don't want to incorrectly bind to
38	 * a device that has a more specific driver.
39	 */
40	if (match && match->data) {
41		if (of_property_match_string(np, "compatible", match->compatible) == 0)
42			return 0;
43		else
44			return -ENODEV;
45	}
46
47	dev_dbg(&pdev->dev, "%s\n", __func__);
48
49	pm_runtime_enable(&pdev->dev);
50
51	if (np)
52		of_platform_populate(np, NULL, lookup, &pdev->dev);
53
54	return 0;
55}
56
57static int simple_pm_bus_remove(struct platform_device *pdev)
58{
59	const void *data = of_device_get_match_data(&pdev->dev);
60
61	if (pdev->driver_override || data)
62		return 0;
63
64	dev_dbg(&pdev->dev, "%s\n", __func__);
65
66	pm_runtime_disable(&pdev->dev);
67	return 0;
68}
69
70#define ONLY_BUS	((void *) 1) /* Match if the device is only a bus. */
71
72static const struct of_device_id simple_pm_bus_of_match[] = {
73	{ .compatible = "simple-pm-bus", },
74	{ .compatible = "simple-bus",	.data = ONLY_BUS },
75	{ .compatible = "simple-mfd",	.data = ONLY_BUS },
76	{ .compatible = "isa",		.data = ONLY_BUS },
77	{ .compatible = "arm,amba-bus",	.data = ONLY_BUS },
78	{ /* sentinel */ }
79};
80MODULE_DEVICE_TABLE(of, simple_pm_bus_of_match);
81
82static struct platform_driver simple_pm_bus_driver = {
83	.probe = simple_pm_bus_probe,
84	.remove = simple_pm_bus_remove,
85	.driver = {
86		.name = "simple-pm-bus",
87		.of_match_table = simple_pm_bus_of_match,
88	},
89};
90
91module_platform_driver(simple_pm_bus_driver);
92
93MODULE_DESCRIPTION("Simple Power-Managed Bus Driver");
94MODULE_AUTHOR("Geert Uytterhoeven <geert+renesas@glider.be>");
95MODULE_LICENSE("GPL v2");