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(matches: 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, propname: "compatible" , string: match->compatible) == 0) |
52 | return 0; |
53 | else |
54 | return -ENODEV; |
55 | } |
56 | |
57 | bus = devm_kzalloc(dev: &pdev->dev, size: sizeof(*bus), GFP_KERNEL); |
58 | if (!bus) |
59 | return -ENOMEM; |
60 | |
61 | bus->num_clks = devm_clk_bulk_get_all(dev: &pdev->dev, clks: &bus->clks); |
62 | if (bus->num_clks < 0) |
63 | return dev_err_probe(dev: &pdev->dev, err: bus->num_clks, fmt: "failed to get clocks\n" ); |
64 | |
65 | dev_set_drvdata(dev: &pdev->dev, data: bus); |
66 | |
67 | dev_dbg(&pdev->dev, "%s\n" , __func__); |
68 | |
69 | pm_runtime_enable(dev: &pdev->dev); |
70 | |
71 | if (np) |
72 | of_platform_populate(root: np, NULL, lookup, parent: &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(dev: &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(dev: &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(num_clks: bus->num_clks, 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(num_clks: bus->num_clks, 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 | |