platform/chrome: Add Chrome OS EC userspace device interface
This patch adds a device interface to access the Chrome OS Embedded Controller from user-space. Signed-off-by: Bill Richardson <wfrichar@chromium.org> Reviewed-by: Simon Glass <sjg@google.com> Signed-off-by: Javier Martinez Canillas <javier.martinez@collabora.co.uk> Reviewed-by: Gwendal Grignou <gwendal@chromium.org> Tested-by: Gwendal Grignou <gwendal@chromium.org> Reviewed-by: Gwendal Grignou <gwendal@chromium.org> Signed-off-by: Olof Johansson <olof@lixom.net>
This commit is contained in:
Bill Richardson
Olof Johansson
parent
ec2f33ab58
commit
e7c256fbfb
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@ -321,6 +321,7 @@ Code Seq#(hex) Include File Comments
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0xDB 00-0F drivers/char/mwave/mwavepub.h
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0xDD 00-3F ZFCP device driver see drivers/s390/scsi/
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<mailto:aherrman@de.ibm.com>
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0xEC 00-01 drivers/platform/chrome/cros_ec_dev.h ChromeOS EC driver
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0xF3 00-3F drivers/usb/misc/sisusbvga/sisusb.h sisfb (in development)
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<mailto:thomas@winischhofer.net>
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0xF4 00-1F video/mbxfb.h mbxfb
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@ -4,7 +4,7 @@
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menuconfig CHROME_PLATFORMS
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bool "Platform support for Chrome hardware"
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depends on X86
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depends on X86 || ARM
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---help---
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Say Y here to get to see options for platform support for
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various Chromebooks and Chromeboxes. This option alone does
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@ -16,8 +16,7 @@ if CHROME_PLATFORMS
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config CHROMEOS_LAPTOP
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tristate "Chrome OS Laptop"
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depends on I2C
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depends on DMI
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depends on I2C && DMI && X86
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---help---
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This driver instantiates i2c and smbus devices such as
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light sensors and touchpads.
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@ -27,6 +26,7 @@ config CHROMEOS_LAPTOP
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config CHROMEOS_PSTORE
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tristate "Chrome OS pstore support"
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depends on X86
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---help---
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This module instantiates the persistent storage on x86 ChromeOS
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devices. It can be used to store away console logs and crash
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@ -38,6 +38,14 @@ config CHROMEOS_PSTORE
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If you have a supported Chromebook, choose Y or M here.
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The module will be called chromeos_pstore.
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config CROS_EC_CHARDEV
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tristate "Chrome OS Embedded Controller userspace device interface"
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depends on MFD_CROS_EC
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---help---
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This driver adds support to talk with the ChromeOS EC from userspace.
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If you have a supported Chromebook, choose Y or M here.
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The module will be called cros_ec_dev.
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config CROS_EC_LPC
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tristate "ChromeOS Embedded Controller (LPC)"
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@ -1,4 +1,5 @@
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obj-$(CONFIG_CHROMEOS_LAPTOP) += chromeos_laptop.o
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obj-$(CONFIG_CHROMEOS_PSTORE) += chromeos_pstore.o
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obj-$(CONFIG_CROS_EC_CHARDEV) += cros_ec_dev.o
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obj-$(CONFIG_CROS_EC_LPC) += cros_ec_lpc.o
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@ -0,0 +1,268 @@
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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/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 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 = { 0 },
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.outsize = 0,
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.indata = { 0 },
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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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resp = (struct ec_response_get_version *)msg.indata;
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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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filp->private_data = container_of(inode->i_cdev,
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struct cros_ec_device, cdev);
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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_device *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_device *ec, void __user *arg)
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{
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long ret;
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struct cros_ec_command s_cmd = { };
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if (copy_from_user(&s_cmd, arg, sizeof(s_cmd)))
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return -EFAULT;
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ret = cros_ec_cmd_xfer(ec, &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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return ret;
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if (copy_to_user(arg, &s_cmd, sizeof(s_cmd)))
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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_readmem(struct cros_ec_device *ec, void __user *arg)
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{
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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->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->cmd_readmem(ec, s_mem.offset, s_mem.bytes, 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_device *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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};
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static int ec_device_probe(struct platform_device *pdev)
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{
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struct cros_ec_device *ec = dev_get_drvdata(pdev->dev.parent);
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int retval = -ENOTTY;
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dev_t devno = MKDEV(ec_major, 0);
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/* Instantiate it (and remember the EC) */
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cdev_init(&ec->cdev, &fops);
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retval = cdev_add(&ec->cdev, devno, 1);
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if (retval) {
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dev_err(&pdev->dev, ": failed to add character device\n");
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return retval;
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}
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ec->vdev = device_create(cros_class, NULL, devno, ec,
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CROS_EC_DEV_NAME);
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if (IS_ERR(ec->vdev)) {
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retval = PTR_ERR(ec->vdev);
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dev_err(&pdev->dev, ": failed to create device\n");
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cdev_del(&ec->cdev);
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return retval;
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}
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return 0;
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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_device *ec = dev_get_drvdata(pdev->dev.parent);
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device_destroy(cros_class, MKDEV(ec_major, 0));
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cdev_del(&ec->cdev);
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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-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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cros_class = class_create(THIS_MODULE, "chromeos");
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if (IS_ERR(cros_class)) {
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pr_err(CROS_EC_DEV_NAME ": failed to register device class\n");
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return PTR_ERR(cros_class);
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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_destroy(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_destroy(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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@ -0,0 +1,47 @@
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/*
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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) 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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#ifndef _CROS_EC_DEV_H_
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#define _CROS_EC_DEV_H_
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#include <linux/ioctl.h>
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#include <linux/types.h>
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#include <linux/mfd/cros_ec.h>
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#define CROS_EC_DEV_NAME "cros_ec"
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#define CROS_EC_DEV_VERSION "1.0.0"
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/*
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* @offset: within EC_LPC_ADDR_MEMMAP region
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* @bytes: number of bytes to read. zero means "read a string" (including '\0')
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* (at most only EC_MEMMAP_SIZE bytes can be read)
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* @buffer: where to store the result
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* ioctl returns the number of bytes read, negative on error
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*/
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struct cros_ec_readmem {
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uint32_t offset;
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uint32_t bytes;
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uint8_t buffer[EC_MEMMAP_SIZE];
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};
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#define CROS_EC_DEV_IOC 0xEC
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#define CROS_EC_DEV_IOCXCMD _IOWR(CROS_EC_DEV_IOC, 0, struct cros_ec_command)
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#define CROS_EC_DEV_IOCRDMEM _IOWR(CROS_EC_DEV_IOC, 1, struct cros_ec_readmem)
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#endif /* _CROS_EC_DEV_H_ */
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