blob: b5e229f3c3d9b874d15035d944797464d97c2ad2 [file] [log] [blame]
Mika Westerberg701190f2013-01-18 13:46:00 +00001/*
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
20static 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
26static 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 */
71struct 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}