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_new = 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>"); 143