366 lines
8.6 KiB
C
366 lines
8.6 KiB
C
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/*
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* cros_ec_dev - expose the Chrome OS Embedded Controller to user-space
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*
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* Copyright (C) 2014 Google, Inc.
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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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#include <linux/fs.h>
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#include <linux/module.h>
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#include <linux/platform_device.h>
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#include <linux/slab.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_MAX_DEV 128
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static int ec_major;
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static const struct attribute_group *cros_ec_groups[] = {
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&cros_ec_attr_group,
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&cros_ec_lightbar_attr_group,
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&cros_ec_vbc_attr_group,
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NULL,
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};
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static struct class cros_class = {
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.owner = THIS_MODULE,
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.name = "chromeos",
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.dev_groups = cros_ec_groups,
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};
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/* Basic communication */
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static int ec_get_version(struct cros_ec_dev *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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int ret;
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msg = kmalloc(sizeof(*msg) + sizeof(*resp), GFP_KERNEL);
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if (!msg)
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return -ENOMEM;
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msg->version = 0;
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msg->command = EC_CMD_GET_VERSION + ec->cmd_offset;
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msg->insize = sizeof(*resp);
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msg->outsize = 0;
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ret = cros_ec_cmd_xfer(ec->ec_dev, msg);
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if (ret < 0)
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goto exit;
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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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ret = -EINVAL;
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goto exit;
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}
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resp = (struct ec_response_get_version *)msg->data;
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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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ret = 0;
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exit:
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kfree(msg);
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return ret;
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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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struct cros_ec_dev *ec = container_of(inode->i_cdev,
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struct cros_ec_dev, cdev);
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filp->private_data = ec;
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nonseekable_open(inode, filp);
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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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struct cros_ec_dev *ec = filp->private_data;
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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(struct cros_ec_dev *ec, void __user *arg)
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{
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long ret;
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struct cros_ec_command u_cmd;
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struct cros_ec_command *s_cmd;
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if (copy_from_user(&u_cmd, arg, sizeof(u_cmd)))
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return -EFAULT;
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if ((u_cmd.outsize > EC_MAX_MSG_BYTES) ||
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(u_cmd.insize > EC_MAX_MSG_BYTES))
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return -EINVAL;
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s_cmd = kmalloc(sizeof(*s_cmd) + max(u_cmd.outsize, u_cmd.insize),
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GFP_KERNEL);
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if (!s_cmd)
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return -ENOMEM;
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if (copy_from_user(s_cmd, arg, sizeof(*s_cmd) + u_cmd.outsize)) {
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ret = -EFAULT;
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goto exit;
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}
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if (u_cmd.outsize != s_cmd->outsize ||
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u_cmd.insize != s_cmd->insize) {
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ret = -EINVAL;
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goto exit;
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}
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s_cmd->command += ec->cmd_offset;
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ret = cros_ec_cmd_xfer(ec->ec_dev, s_cmd);
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/* Only copy data to userland if data was received. */
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if (ret < 0)
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goto exit;
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if (copy_to_user(arg, s_cmd, sizeof(*s_cmd) + s_cmd->insize))
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ret = -EFAULT;
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exit:
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kfree(s_cmd);
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return ret;
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}
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static long ec_device_ioctl_readmem(struct cros_ec_dev *ec, void __user *arg)
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{
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struct cros_ec_device *ec_dev = ec->ec_dev;
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struct cros_ec_readmem s_mem = { };
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long num;
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/* Not every platform supports direct reads */
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if (!ec_dev->cmd_readmem)
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return -ENOTTY;
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if (copy_from_user(&s_mem, arg, sizeof(s_mem)))
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return -EFAULT;
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num = ec_dev->cmd_readmem(ec_dev, s_mem.offset, s_mem.bytes,
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s_mem.buffer);
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if (num <= 0)
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return num;
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if (copy_to_user((void __user *)arg, &s_mem, sizeof(s_mem)))
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return -EFAULT;
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return 0;
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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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struct cros_ec_dev *ec = filp->private_data;
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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(ec, (void __user *)arg);
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case CROS_EC_DEV_IOCRDMEM:
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return ec_device_ioctl_readmem(ec, (void __user *)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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#ifdef CONFIG_COMPAT
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.compat_ioctl = ec_device_ioctl,
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#endif
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};
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static void __remove(struct device *dev)
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{
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struct cros_ec_dev *ec = container_of(dev, struct cros_ec_dev,
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class_dev);
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kfree(ec);
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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 = -ENOMEM;
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struct device *dev = &pdev->dev;
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struct cros_ec_platform *ec_platform = dev_get_platdata(dev);
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dev_t devno = MKDEV(ec_major, pdev->id);
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struct cros_ec_dev *ec = kzalloc(sizeof(*ec), GFP_KERNEL);
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if (!ec)
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return retval;
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dev_set_drvdata(dev, ec);
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ec->ec_dev = dev_get_drvdata(dev->parent);
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ec->dev = dev;
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ec->cmd_offset = ec_platform->cmd_offset;
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device_initialize(&ec->class_dev);
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cdev_init(&ec->cdev, &fops);
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/*
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* Add the character device
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* Link cdev to the class device to be sure device is not used
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* before unbinding it.
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*/
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ec->cdev.kobj.parent = &ec->class_dev.kobj;
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retval = cdev_add(&ec->cdev, devno, 1);
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if (retval) {
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dev_err(dev, ": failed to add character device\n");
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goto cdev_add_failed;
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}
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/*
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* Add the class device
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* Link to the character device for creating the /dev entry
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* in devtmpfs.
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*/
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ec->class_dev.devt = ec->cdev.dev;
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ec->class_dev.class = &cros_class;
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ec->class_dev.parent = dev;
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ec->class_dev.release = __remove;
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retval = dev_set_name(&ec->class_dev, "%s", ec_platform->ec_name);
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if (retval) {
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dev_err(dev, "dev_set_name failed => %d\n", retval);
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goto set_named_failed;
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}
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retval = device_add(&ec->class_dev);
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if (retval) {
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dev_err(dev, "device_register failed => %d\n", retval);
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goto dev_reg_failed;
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}
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return 0;
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dev_reg_failed:
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set_named_failed:
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dev_set_drvdata(dev, NULL);
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cdev_del(&ec->cdev);
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cdev_add_failed:
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kfree(ec);
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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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struct cros_ec_dev *ec = dev_get_drvdata(&pdev->dev);
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cdev_del(&ec->cdev);
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device_unregister(&ec->class_dev);
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return 0;
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}
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static const struct platform_device_id cros_ec_id[] = {
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{ "cros-ec-ctl", 0 },
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{ /* sentinel */ },
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};
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MODULE_DEVICE_TABLE(platform, cros_ec_id);
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static struct platform_driver cros_ec_dev_driver = {
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.driver = {
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.name = "cros-ec-ctl",
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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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static int __init cros_ec_dev_init(void)
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{
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int ret;
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dev_t dev = 0;
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ret = class_register(&cros_class);
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if (ret) {
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pr_err(CROS_EC_DEV_NAME ": failed to register device class\n");
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return ret;
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}
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/* Get a range of minor numbers (starting with 0) to work with */
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ret = alloc_chrdev_region(&dev, 0, CROS_MAX_DEV, CROS_EC_DEV_NAME);
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if (ret < 0) {
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pr_err(CROS_EC_DEV_NAME ": alloc_chrdev_region() failed\n");
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goto failed_chrdevreg;
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}
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ec_major = MAJOR(dev);
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/* Register the driver */
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ret = platform_driver_register(&cros_ec_dev_driver);
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if (ret < 0) {
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pr_warn(CROS_EC_DEV_NAME ": can't register driver: %d\n", ret);
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goto failed_devreg;
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}
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return 0;
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failed_devreg:
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unregister_chrdev_region(MKDEV(ec_major, 0), CROS_MAX_DEV);
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failed_chrdevreg:
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class_unregister(&cros_class);
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return ret;
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}
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static void __exit cros_ec_dev_exit(void)
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{
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platform_driver_unregister(&cros_ec_dev_driver);
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unregister_chrdev(ec_major, CROS_EC_DEV_NAME);
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class_unregister(&cros_class);
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}
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module_init(cros_ec_dev_init);
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module_exit(cros_ec_dev_exit);
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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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