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_platform.h> 15 #include <linux/platform_device.h> 16 #include <linux/pm_runtime.h> 17 18 struct simple_pm_bus { 19 struct clk_bulk_data *clks; 20 int num_clks; 21 }; 22 23 static int simple_pm_bus_probe(struct platform_device *pdev) 24 { 25 const struct device *dev = &pdev->dev; 26 const struct of_dev_auxdata *lookup = dev_get_platdata(dev); 27 struct device_node *np = dev->of_node; 28 const struct of_device_id *match; 29 struct simple_pm_bus *bus; 30 31 /* 32 * Allow user to use driver_override to bind this driver to a 33 * transparent bus device which has a different compatible string 34 * that's not listed in simple_pm_bus_of_match. We don't want to do any 35 * of the simple-pm-bus tasks for these devices, so return early. 36 */ 37 if (pdev->driver_override) 38 return 0; 39 40 match = of_match_device(dev->driver->of_match_table, dev); 41 /* 42 * These are transparent bus devices (not simple-pm-bus matches) that 43 * have their child nodes populated automatically. So, don't need to 44 * do anything more. We only match with the device if this driver is 45 * the most specific match because we don't want to incorrectly bind to 46 * a device that has a more specific driver. 47 */ 48 if (match && match->data) { 49 if (of_property_match_string(np, "compatible", match->compatible) == 0) 50 return 0; 51 else 52 return -ENODEV; 53 } 54 55 bus = devm_kzalloc(&pdev->dev, sizeof(*bus), GFP_KERNEL); 56 if (!bus) 57 return -ENOMEM; 58 59 bus->num_clks = devm_clk_bulk_get_all(&pdev->dev, &bus->clks); 60 if (bus->num_clks < 0) 61 return dev_err_probe(&pdev->dev, bus->num_clks, "failed to get clocks\n"); 62 63 dev_set_drvdata(&pdev->dev, bus); 64 65 dev_dbg(&pdev->dev, "%s\n", __func__); 66 67 pm_runtime_enable(&pdev->dev); 68 69 if (np) 70 of_platform_populate(np, NULL, lookup, &pdev->dev); 71 72 return 0; 73 } 74 75 static int simple_pm_bus_remove(struct platform_device *pdev) 76 { 77 const void *data = of_device_get_match_data(&pdev->dev); 78 79 if (pdev->driver_override || data) 80 return 0; 81 82 dev_dbg(&pdev->dev, "%s\n", __func__); 83 84 pm_runtime_disable(&pdev->dev); 85 return 0; 86 } 87 88 static int simple_pm_bus_runtime_suspend(struct device *dev) 89 { 90 struct simple_pm_bus *bus = dev_get_drvdata(dev); 91 92 clk_bulk_disable_unprepare(bus->num_clks, bus->clks); 93 94 return 0; 95 } 96 97 static int simple_pm_bus_runtime_resume(struct device *dev) 98 { 99 struct simple_pm_bus *bus = dev_get_drvdata(dev); 100 int ret; 101 102 ret = clk_bulk_prepare_enable(bus->num_clks, bus->clks); 103 if (ret) { 104 dev_err(dev, "failed to enable clocks: %d\n", ret); 105 return ret; 106 } 107 108 return 0; 109 } 110 111 static const struct dev_pm_ops simple_pm_bus_pm_ops = { 112 RUNTIME_PM_OPS(simple_pm_bus_runtime_suspend, simple_pm_bus_runtime_resume, NULL) 113 NOIRQ_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend, pm_runtime_force_resume) 114 }; 115 116 #define ONLY_BUS ((void *) 1) /* Match if the device is only a bus. */ 117 118 static const struct of_device_id simple_pm_bus_of_match[] = { 119 { .compatible = "simple-pm-bus", }, 120 { .compatible = "simple-bus", .data = ONLY_BUS }, 121 { .compatible = "simple-mfd", .data = ONLY_BUS }, 122 { .compatible = "isa", .data = ONLY_BUS }, 123 { .compatible = "arm,amba-bus", .data = ONLY_BUS }, 124 { /* sentinel */ } 125 }; 126 MODULE_DEVICE_TABLE(of, simple_pm_bus_of_match); 127 128 static struct platform_driver simple_pm_bus_driver = { 129 .probe = simple_pm_bus_probe, 130 .remove = simple_pm_bus_remove, 131 .driver = { 132 .name = "simple-pm-bus", 133 .of_match_table = simple_pm_bus_of_match, 134 .pm = pm_ptr(&simple_pm_bus_pm_ops), 135 }, 136 }; 137 138 module_platform_driver(simple_pm_bus_driver); 139 140 MODULE_DESCRIPTION("Simple Power-Managed Bus Driver"); 141 MODULE_AUTHOR("Geert Uytterhoeven <geert+renesas@glider.be>"); 142