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![Iwona Winiarska](/assets/img/avatar_default.png)
PECI is an interface that may be used by different types of devices. Add a peci-cpu driver compatible with Intel processors. The driver is responsible for handling auxiliary devices that can subsequently be used by other drivers (e.g. hwmons). Reviewed-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com> Acked-by: Joel Stanley <joel@jms.id.au> Signed-off-by: Iwona Winiarska <iwona.winiarska@intel.com> Link: https://lore.kernel.org/r/20220208153639.255278-10-iwona.winiarska@intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
252 lines
5.2 KiB
C
252 lines
5.2 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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// Copyright (c) 2018-2021 Intel Corporation
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#include <linux/bitfield.h>
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#include <linux/peci.h>
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#include <linux/peci-cpu.h>
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#include <linux/slab.h>
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#include "internal.h"
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/*
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* PECI device can be removed using sysfs, but the removal can also happen as
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* a result of controller being removed.
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* Mutex is used to protect PECI device from being double-deleted.
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*/
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static DEFINE_MUTEX(peci_device_del_lock);
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#define REVISION_NUM_MASK GENMASK(15, 8)
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static int peci_get_revision(struct peci_device *device, u8 *revision)
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{
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struct peci_request *req;
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u64 dib;
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req = peci_xfer_get_dib(device);
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if (IS_ERR(req))
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return PTR_ERR(req);
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/*
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* PECI device may be in a state where it is unable to return a proper
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* DIB, in which case it returns 0 as DIB value.
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* Let's treat this as an error to avoid carrying on with the detection
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* using invalid revision.
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*/
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dib = peci_request_dib_read(req);
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if (dib == 0) {
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peci_request_free(req);
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return -EIO;
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}
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*revision = FIELD_GET(REVISION_NUM_MASK, dib);
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peci_request_free(req);
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return 0;
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}
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static int peci_get_cpu_id(struct peci_device *device, u32 *cpu_id)
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{
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struct peci_request *req;
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int ret;
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req = peci_xfer_pkg_cfg_readl(device, PECI_PCS_PKG_ID, PECI_PKG_ID_CPU_ID);
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if (IS_ERR(req))
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return PTR_ERR(req);
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ret = peci_request_status(req);
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if (ret)
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goto out_req_free;
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*cpu_id = peci_request_data_readl(req);
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out_req_free:
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peci_request_free(req);
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return ret;
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}
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static unsigned int peci_x86_cpu_family(unsigned int sig)
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{
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unsigned int x86;
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x86 = (sig >> 8) & 0xf;
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if (x86 == 0xf)
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x86 += (sig >> 20) & 0xff;
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return x86;
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}
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static unsigned int peci_x86_cpu_model(unsigned int sig)
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{
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unsigned int fam, model;
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fam = peci_x86_cpu_family(sig);
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model = (sig >> 4) & 0xf;
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if (fam >= 0x6)
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model += ((sig >> 16) & 0xf) << 4;
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return model;
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}
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static int peci_device_info_init(struct peci_device *device)
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{
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u8 revision;
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u32 cpu_id;
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int ret;
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ret = peci_get_cpu_id(device, &cpu_id);
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if (ret)
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return ret;
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device->info.family = peci_x86_cpu_family(cpu_id);
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device->info.model = peci_x86_cpu_model(cpu_id);
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ret = peci_get_revision(device, &revision);
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if (ret)
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return ret;
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device->info.peci_revision = revision;
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device->info.socket_id = device->addr - PECI_BASE_ADDR;
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return 0;
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}
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static int peci_detect(struct peci_controller *controller, u8 addr)
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{
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/*
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* PECI Ping is a command encoded by tx_len = 0, rx_len = 0.
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* We expect correct Write FCS if the device at the target address
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* is able to respond.
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*/
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struct peci_request req = { 0 };
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int ret;
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mutex_lock(&controller->bus_lock);
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ret = controller->ops->xfer(controller, addr, &req);
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mutex_unlock(&controller->bus_lock);
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return ret;
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}
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static bool peci_addr_valid(u8 addr)
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{
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return addr >= PECI_BASE_ADDR && addr < PECI_BASE_ADDR + PECI_DEVICE_NUM_MAX;
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}
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static int peci_dev_exists(struct device *dev, void *data)
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{
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struct peci_device *device = to_peci_device(dev);
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u8 *addr = data;
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if (device->addr == *addr)
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return -EBUSY;
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return 0;
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}
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int peci_device_create(struct peci_controller *controller, u8 addr)
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{
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struct peci_device *device;
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int ret;
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if (!peci_addr_valid(addr))
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return -EINVAL;
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/* Check if we have already detected this device before. */
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ret = device_for_each_child(&controller->dev, &addr, peci_dev_exists);
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if (ret)
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return 0;
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ret = peci_detect(controller, addr);
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if (ret) {
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/*
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* Device not present or host state doesn't allow successful
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* detection at this time.
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*/
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if (ret == -EIO || ret == -ETIMEDOUT)
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return 0;
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return ret;
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}
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device = kzalloc(sizeof(*device), GFP_KERNEL);
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if (!device)
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return -ENOMEM;
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device_initialize(&device->dev);
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device->addr = addr;
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device->dev.parent = &controller->dev;
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device->dev.bus = &peci_bus_type;
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device->dev.type = &peci_device_type;
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ret = peci_device_info_init(device);
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if (ret)
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goto err_put;
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ret = dev_set_name(&device->dev, "%d-%02x", controller->id, device->addr);
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if (ret)
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goto err_put;
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ret = device_add(&device->dev);
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if (ret)
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goto err_put;
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return 0;
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err_put:
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put_device(&device->dev);
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return ret;
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}
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void peci_device_destroy(struct peci_device *device)
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{
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mutex_lock(&peci_device_del_lock);
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if (!device->deleted) {
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device_unregister(&device->dev);
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device->deleted = true;
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}
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mutex_unlock(&peci_device_del_lock);
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}
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int __peci_driver_register(struct peci_driver *driver, struct module *owner,
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const char *mod_name)
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{
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driver->driver.bus = &peci_bus_type;
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driver->driver.owner = owner;
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driver->driver.mod_name = mod_name;
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if (!driver->probe) {
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pr_err("peci: trying to register driver without probe callback\n");
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return -EINVAL;
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}
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if (!driver->id_table) {
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pr_err("peci: trying to register driver without device id table\n");
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return -EINVAL;
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}
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return driver_register(&driver->driver);
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}
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EXPORT_SYMBOL_NS_GPL(__peci_driver_register, PECI);
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void peci_driver_unregister(struct peci_driver *driver)
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{
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driver_unregister(&driver->driver);
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}
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EXPORT_SYMBOL_NS_GPL(peci_driver_unregister, PECI);
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static void peci_device_release(struct device *dev)
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{
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struct peci_device *device = to_peci_device(dev);
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kfree(device);
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}
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struct device_type peci_device_type = {
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.groups = peci_device_groups,
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.release = peci_device_release,
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};
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