linux/drivers/clk/x86/clk-lpss.c

100 lines
2.5 KiB
C

/*
* Intel Low Power Subsystem clocks.
*
* Copyright (C) 2013, Intel Corporation
* Authors: Mika Westerberg <mika.westerberg@linux.intel.com>
* Heikki Krogerus <heikki.krogerus@linux.intel.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/acpi.h>
#include <linux/clk.h>
#include <linux/clk-provider.h>
#include <linux/err.h>
#include <linux/io.h>
#include <linux/module.h>
static int clk_lpss_is_mmio_resource(struct acpi_resource *res, void *data)
{
struct resource r;
return !acpi_dev_resource_memory(res, &r);
}
static acpi_status clk_lpss_find_mmio(acpi_handle handle, u32 level,
void *data, void **retval)
{
struct resource_list_entry *rentry;
struct list_head resource_list;
struct acpi_device *adev;
const char *uid = data;
int ret;
if (acpi_bus_get_device(handle, &adev))
return AE_OK;
if (uid) {
if (!adev->pnp.unique_id)
return AE_OK;
if (strcmp(uid, adev->pnp.unique_id))
return AE_OK;
}
INIT_LIST_HEAD(&resource_list);
ret = acpi_dev_get_resources(adev, &resource_list,
clk_lpss_is_mmio_resource, NULL);
if (ret < 0)
return AE_NO_MEMORY;
list_for_each_entry(rentry, &resource_list, node)
if (resource_type(&rentry->res) == IORESOURCE_MEM) {
*(struct resource *)retval = rentry->res;
break;
}
acpi_dev_free_resource_list(&resource_list);
return AE_OK;
}
/**
* clk_register_lpss_gate - register LPSS clock gate
* @name: name of this clock gate
* @parent_name: parent clock name
* @hid: ACPI _HID of the device
* @uid: ACPI _UID of the device (optional)
* @offset: LPSS PRV_CLOCK_PARAMS offset
*
* Creates and registers LPSS clock gate.
*/
struct clk *clk_register_lpss_gate(const char *name, const char *parent_name,
const char *hid, const char *uid,
unsigned offset)
{
struct resource res = { };
void __iomem *mmio_base;
acpi_status status;
struct clk *clk;
/*
* First try to look the device and its mmio resource from the
* ACPI namespace.
*/
status = acpi_get_devices(hid, clk_lpss_find_mmio, (void *)uid,
(void **)&res);
if (ACPI_FAILURE(status) || !res.start)
return ERR_PTR(-ENODEV);
mmio_base = ioremap(res.start, resource_size(&res));
if (!mmio_base)
return ERR_PTR(-ENOMEM);
clk = clk_register_gate(NULL, name, parent_name, 0, mmio_base + offset,
0, 0, NULL);
if (IS_ERR(clk))
iounmap(mmio_base);
return clk;
}