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701190fd MW |
1 | /* |
2 | * Intel Low Power Subsystem clocks. | |
3 | * | |
4 | * Copyright (C) 2013, Intel Corporation | |
5 | * Authors: Mika Westerberg <mika.westerberg@linux.intel.com> | |
6 | * Heikki Krogerus <heikki.krogerus@linux.intel.com> | |
7 | * | |
8 | * This program is free software; you can redistribute it and/or modify | |
9 | * it under the terms of the GNU General Public License version 2 as | |
10 | * published by the Free Software Foundation. | |
11 | */ | |
12 | ||
13 | #include <linux/acpi.h> | |
14 | #include <linux/clk.h> | |
15 | #include <linux/clk-provider.h> | |
16 | #include <linux/err.h> | |
17 | #include <linux/io.h> | |
18 | #include <linux/module.h> | |
19 | ||
20 | static int clk_lpss_is_mmio_resource(struct acpi_resource *res, void *data) | |
21 | { | |
22 | struct resource r; | |
23 | return !acpi_dev_resource_memory(res, &r); | |
24 | } | |
25 | ||
26 | static acpi_status clk_lpss_find_mmio(acpi_handle handle, u32 level, | |
27 | void *data, void **retval) | |
28 | { | |
29 | struct resource_list_entry *rentry; | |
30 | struct list_head resource_list; | |
31 | struct acpi_device *adev; | |
32 | const char *uid = data; | |
33 | int ret; | |
34 | ||
35 | if (acpi_bus_get_device(handle, &adev)) | |
36 | return AE_OK; | |
37 | ||
38 | if (uid) { | |
39 | if (!adev->pnp.unique_id) | |
40 | return AE_OK; | |
41 | if (strcmp(uid, adev->pnp.unique_id)) | |
42 | return AE_OK; | |
43 | } | |
44 | ||
45 | INIT_LIST_HEAD(&resource_list); | |
46 | ret = acpi_dev_get_resources(adev, &resource_list, | |
47 | clk_lpss_is_mmio_resource, NULL); | |
48 | if (ret < 0) | |
49 | return AE_NO_MEMORY; | |
50 | ||
51 | list_for_each_entry(rentry, &resource_list, node) | |
52 | if (resource_type(&rentry->res) == IORESOURCE_MEM) { | |
53 | *(struct resource *)retval = rentry->res; | |
54 | break; | |
55 | } | |
56 | ||
57 | acpi_dev_free_resource_list(&resource_list); | |
58 | return AE_OK; | |
59 | } | |
60 | ||
61 | /** | |
62 | * clk_register_lpss_gate - register LPSS clock gate | |
63 | * @name: name of this clock gate | |
64 | * @parent_name: parent clock name | |
65 | * @hid: ACPI _HID of the device | |
66 | * @uid: ACPI _UID of the device (optional) | |
67 | * @offset: LPSS PRV_CLOCK_PARAMS offset | |
68 | * | |
69 | * Creates and registers LPSS clock gate. | |
70 | */ | |
71 | struct clk *clk_register_lpss_gate(const char *name, const char *parent_name, | |
72 | const char *hid, const char *uid, | |
73 | unsigned offset) | |
74 | { | |
75 | struct resource res = { }; | |
76 | void __iomem *mmio_base; | |
77 | acpi_status status; | |
78 | struct clk *clk; | |
79 | ||
80 | /* | |
81 | * First try to look the device and its mmio resource from the | |
82 | * ACPI namespace. | |
83 | */ | |
84 | status = acpi_get_devices(hid, clk_lpss_find_mmio, (void *)uid, | |
85 | (void **)&res); | |
86 | if (ACPI_FAILURE(status) || !res.start) | |
87 | return ERR_PTR(-ENODEV); | |
88 | ||
89 | mmio_base = ioremap(res.start, resource_size(&res)); | |
90 | if (!mmio_base) | |
91 | return ERR_PTR(-ENOMEM); | |
92 | ||
93 | clk = clk_register_gate(NULL, name, parent_name, 0, mmio_base + offset, | |
94 | 0, 0, NULL); | |
95 | if (IS_ERR(clk)) | |
96 | iounmap(mmio_base); | |
97 | ||
98 | return clk; | |
99 | } |