LXR linux/drivers/bus/simple-pm-bus.c

   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");
  96