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 const struct dev_pm_ops simple_pm_bus_pm_ops = {
113	RUNTIME_PM_OPS(simple_pm_bus_runtime_suspend, simple_pm_bus_runtime_resume, NULL)
114	NOIRQ_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend, pm_runtime_force_resume)
115};
116
117#define ONLY_BUS	((void *) 1) /* Match if the device is only a bus. */
118
119static const struct of_device_id simple_pm_bus_of_match[] = {
120	{ .compatible = "simple-pm-bus", },
121	{ .compatible = "simple-bus",	.data = ONLY_BUS },
122	{ .compatible = "simple-mfd",	.data = ONLY_BUS },
123	{ .compatible = "isa",		.data = ONLY_BUS },
124	{ .compatible = "arm,amba-bus",	.data = ONLY_BUS },
125	{ /* sentinel */ }
126};
127MODULE_DEVICE_TABLE(of, simple_pm_bus_of_match);
128
129static struct platform_driver simple_pm_bus_driver = {
130	.probe = simple_pm_bus_probe,
131	.remove = simple_pm_bus_remove,
132	.driver = {
133		.name = "simple-pm-bus",
134		.of_match_table = simple_pm_bus_of_match,
135		.pm = pm_ptr(&simple_pm_bus_pm_ops),
136	},
137};
138
139module_platform_driver(simple_pm_bus_driver);
140
141MODULE_DESCRIPTION("Simple Power-Managed Bus Driver");
142MODULE_AUTHOR("Geert Uytterhoeven <geert+renesas@glider.be>");