271 lines
6.5 KiB
C
271 lines
6.5 KiB
C
/*
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* cros_ec_dev - expose the Chrome OS Embedded Controller to userspace
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*
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* Copyright (C) 2013 The Chromium OS Authors
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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 as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#define pr_fmt(fmt) "cros_ec_dev: " fmt
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#include <linux/delay.h>
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#include <linux/device.h>
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#include <linux/fs.h>
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#include <linux/mfd/cros_ec.h>
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#include <linux/mfd/cros_ec_commands.h>
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#include <linux/mfd/cros_ec_dev.h>
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#include <linux/module.h>
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#include <linux/platform_device.h>
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#include <linux/printk.h>
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#include <linux/types.h>
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#include <linux/uaccess.h>
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#include "cros_ec_dev.h"
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/* Device variables */
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#define CROS_CLASS_NAME "chromeos"
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static struct cros_ec_device *ec;
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static struct class *cros_class;
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static int ec_major;
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/* Basic communication */
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static int ec_get_version(struct cros_ec_device *ec, char *str, int maxlen)
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{
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struct ec_response_get_version resp;
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static const char * const current_image_name[] = {
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"unknown", "read-only", "read-write", "invalid",
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};
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struct cros_ec_command msg = {
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.version = 0,
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.command = EC_CMD_GET_VERSION,
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.outdata = NULL,
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.outsize = 0,
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.indata = (uint8_t *)&resp,
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.insize = sizeof(resp),
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};
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int ret;
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ret = cros_ec_cmd_xfer(ec, &msg);
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if (ret < 0)
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return ret;
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if (msg.result != EC_RES_SUCCESS) {
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snprintf(str, maxlen,
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"%s\nUnknown EC version: EC returned %d\n",
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CROS_EC_DEV_VERSION, msg.result);
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return 0;
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}
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if (resp.current_image >= ARRAY_SIZE(current_image_name))
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resp.current_image = 3; /* invalid */
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snprintf(str, maxlen, "%s\n%s\n%s\n%s\n", CROS_EC_DEV_VERSION,
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resp.version_string_ro, resp.version_string_rw,
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current_image_name[resp.current_image]);
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return 0;
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}
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/* Device file ops */
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static int ec_device_open(struct inode *inode, struct file *filp)
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{
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return 0;
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}
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static int ec_device_release(struct inode *inode, struct file *filp)
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{
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return 0;
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}
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static ssize_t ec_device_read(struct file *filp, char __user *buffer,
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size_t length, loff_t *offset)
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{
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char msg[sizeof(struct ec_response_get_version) +
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sizeof(CROS_EC_DEV_VERSION)];
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size_t count;
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int ret;
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if (*offset != 0)
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return 0;
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ret = ec_get_version(ec, msg, sizeof(msg));
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if (ret)
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return ret;
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count = min(length, strlen(msg));
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if (copy_to_user(buffer, msg, count))
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return -EFAULT;
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*offset += count;
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return count;
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}
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/* Ioctls */
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static long ec_device_ioctl_xcmd(void __user *argp)
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{
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long ret;
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struct cros_ec_command s_cmd;
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uint8_t *user_indata;
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uint8_t buf[EC_PROTO2_MAX_PARAM_SIZE]; /* FIXME: crosbug.com/p/20820 */
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if (copy_from_user(&s_cmd, argp, sizeof(s_cmd)))
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return -EFAULT;
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if (s_cmd.outsize &&
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copy_from_user(&buf, (void __user *)s_cmd.outdata, sizeof(buf)))
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return -EFAULT;
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user_indata = s_cmd.indata;
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s_cmd.indata = buf;
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s_cmd.outdata = buf;
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ret = cros_ec_cmd_xfer(ec, &s_cmd);
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s_cmd.indata = user_indata;
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/* Only copy data to userland if data was received. */
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if (ret > 0 && s_cmd.insize) {
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unsigned size = ret;
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size = min(size, s_cmd.insize);
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if (copy_to_user((void __user *)s_cmd.indata, buf, size))
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return -EFAULT;
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}
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if (copy_to_user(argp, &s_cmd, sizeof(s_cmd)))
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return -EFAULT;
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return ret;
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}
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static long ec_device_ioctl_readmem(void __user *argp)
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{
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struct cros_ec_readmem s_mem;
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char buf[EC_MEMMAP_SIZE];
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long num;
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/* Not every platform supports direct reads */
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if (!ec->cmd_readmem)
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return -ENOTTY;
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if (copy_from_user(&s_mem, argp, sizeof(s_mem)))
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return -EFAULT;
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num = ec->cmd_readmem(ec, s_mem.offset, s_mem.bytes, buf);
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if (num <= 0)
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return num;
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if (copy_to_user((void __user *)s_mem.buffer, buf, num))
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return -EFAULT;
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return num;
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}
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static long ec_device_ioctl(struct file *filp, unsigned int cmd,
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unsigned long arg)
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{
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void __user *argp = (void __user *)arg;
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if (_IOC_TYPE(cmd) != CROS_EC_DEV_IOC)
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return -ENOTTY;
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switch (cmd) {
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case CROS_EC_DEV_IOCXCMD:
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return ec_device_ioctl_xcmd(argp);
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break;
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case CROS_EC_DEV_IOCRDMEM:
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return ec_device_ioctl_readmem(argp);
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break;
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}
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return -ENOTTY;
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}
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/* FIXME: Handle 32-bit apps on 64-bit kernels */
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static long ec_device_compat_ioctl(struct file *filp, unsigned int cmd,
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unsigned long arg)
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{
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return -ENOTTY;
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}
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/* Module initialization */
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static const struct file_operations fops = {
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.open = ec_device_open,
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.release = ec_device_release,
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.read = ec_device_read,
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.unlocked_ioctl = ec_device_ioctl,
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.compat_ioctl = ec_device_compat_ioctl,
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};
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static int ec_device_probe(struct platform_device *pdev)
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{
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int retval = -ENOTTY;
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ec = dev_get_drvdata(pdev->dev.parent);
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cros_class = class_create(THIS_MODULE, CROS_CLASS_NAME);
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if (IS_ERR(cros_class)) {
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pr_err("failed to register device class\n");
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retval = PTR_ERR(cros_class);
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goto failed_class;
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}
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/* Let the kernel pick the major num for us */
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ec_major = register_chrdev(0, CROS_EC_DEV_NAME, &fops);
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if (ec_major < 0) {
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pr_err("failed to register device\n");
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retval = ec_major;
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goto failed_chrdevreg;
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}
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/* Instantiate it (and remember the EC) */
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ec->vdev = device_create(cros_class, NULL, MKDEV(ec_major, 0),
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ec, CROS_EC_DEV_NAME);
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if (IS_ERR(ec->vdev)) {
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pr_err("failed to create device\n");
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retval = PTR_ERR(ec->vdev);
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goto failed_devreg;
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}
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/* Initialize extra interfaces */
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ec_dev_sysfs_init(ec);
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ec_dev_lightbar_init(ec);
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return 0;
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failed_devreg:
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unregister_chrdev(ec_major, CROS_EC_DEV_NAME);
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failed_chrdevreg:
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class_destroy(cros_class);
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failed_class:
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return retval;
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}
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static int ec_device_remove(struct platform_device *pdev)
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{
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ec_dev_lightbar_remove(ec);
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ec_dev_sysfs_remove(ec);
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device_destroy(cros_class, MKDEV(ec_major, 0));
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unregister_chrdev(ec_major, CROS_EC_DEV_NAME);
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class_destroy(cros_class);
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return 0;
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}
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static struct platform_driver cros_ec_dev_driver = {
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.driver = {
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.name = "cros-ec-dev",
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.owner = THIS_MODULE,
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},
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.probe = ec_device_probe,
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.remove = ec_device_remove,
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};
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module_platform_driver(cros_ec_dev_driver);
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MODULE_AUTHOR("Bill Richardson <wfrichar@chromium.org>");
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MODULE_DESCRIPTION("Userspace interface to the Chrome OS Embedded Controller");
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MODULE_VERSION("1.0");
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MODULE_LICENSE("GPL");
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