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