drivers/bus/simple-pm-bus.c

   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
  20 struct simple_pm_bus {
  21         struct clk_bulk_data *clks;
  22         int num_clks;
  23 };
  24
  25 static 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
  77 static 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
  89 static 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
  98 static 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
 112 static 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
 119 static 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 };
 127 MODULE_DEVICE_TABLE(of, simple_pm_bus_of_match);
 128
 129 static 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
 139 module_platform_driver(simple_pm_bus_driver);
 140
 141 MODULE_DESCRIPTION("Simple Power-Managed Bus Driver");
 142 MODULE_AUTHOR("Geert Uytterhoeven <geert+renesas@glider.be>");