238 lines
6.6 KiB
Diff
238 lines
6.6 KiB
Diff
From 512d9fadc272271e1e8e9bc81d445883940f81ca Mon Sep 17 00:00:00 2001
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From: Phil Elwell <phil@raspberrypi.com>
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Date: Mon, 11 Oct 2021 17:33:05 +0100
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Subject: [PATCH] char: vcio: Rewrite as a firmware node child
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The old vcio driver is a simple character device that manually locates
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the firmware driver. Initialising it before the firmware driver causes
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a failure, and no retries are attempted.
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Rewrite vcio as a platform driver that depends on a DT node for its
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instantiation and the location of the firmware driver, making use of
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the miscdevice framework to reduce the code size.
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N.B. Using miscdevice changes the udev SUBSYSTEM string, so a change
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to the companion udev rule is required in order to continue to set
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the correct device permissions, e.g.:
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KERNEL="vcio", GROUP="video", MODE="0660"
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See: https://github.com/raspberrypi/linux/issues/4620
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Signed-off-by: Phil Elwell <phil@raspberrypi.com>
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---
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drivers/char/broadcom/vcio.c | 133 ++++++++++++++++-------------------
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1 file changed, 62 insertions(+), 71 deletions(-)
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--- a/drivers/char/broadcom/vcio.c
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+++ b/drivers/char/broadcom/vcio.c
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@@ -1,6 +1,7 @@
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/*
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* Copyright (C) 2010 Broadcom
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* Copyright (C) 2015 Noralf Trønnes
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+ * Copyright (C) 2021 Raspberry Pi (Trading) Ltd.
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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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@@ -8,8 +9,6 @@
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*
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*/
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-#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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-
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#include <linux/cdev.h>
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#include <linux/device.h>
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#include <linux/fs.h>
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@@ -19,24 +18,22 @@
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#include <linux/slab.h>
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#include <linux/uaccess.h>
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#include <linux/compat.h>
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+#include <linux/miscdevice.h>
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#include <soc/bcm2835/raspberrypi-firmware.h>
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-#define MBOX_CHAN_PROPERTY 8
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-
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+#define MODULE_NAME "vcio"
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#define VCIO_IOC_MAGIC 100
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#define IOCTL_MBOX_PROPERTY _IOWR(VCIO_IOC_MAGIC, 0, char *)
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#ifdef CONFIG_COMPAT
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#define IOCTL_MBOX_PROPERTY32 _IOWR(VCIO_IOC_MAGIC, 0, compat_uptr_t)
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#endif
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-static struct {
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- dev_t devt;
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- struct cdev cdev;
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- struct class *class;
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+struct vcio_data {
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struct rpi_firmware *fw;
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-} vcio;
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+ struct miscdevice misc_dev;
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+};
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-static int vcio_user_property_list(void *user)
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+static int vcio_user_property_list(struct vcio_data *vcio, void *user)
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{
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u32 *buf, size;
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int ret;
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@@ -55,7 +52,7 @@ static int vcio_user_property_list(void
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}
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/* Strip off protocol encapsulation */
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- ret = rpi_firmware_property_list(vcio.fw, &buf[2], size - 12);
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+ ret = rpi_firmware_property_list(vcio->fw, &buf[2], size - 12);
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if (ret) {
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kfree(buf);
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return ret;
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@@ -87,9 +84,12 @@ static int vcio_device_release(struct in
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static long vcio_device_ioctl(struct file *file, unsigned int ioctl_num,
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unsigned long ioctl_param)
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{
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+ struct vcio_data *vcio = container_of(file->private_data,
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+ struct vcio_data, misc_dev);
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+
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switch (ioctl_num) {
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case IOCTL_MBOX_PROPERTY:
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- return vcio_user_property_list((void *)ioctl_param);
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+ return vcio_user_property_list(vcio, (void *)ioctl_param);
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default:
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pr_err("unknown ioctl: %x\n", ioctl_num);
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return -EINVAL;
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@@ -100,9 +100,12 @@ static long vcio_device_ioctl(struct fil
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static long vcio_device_compat_ioctl(struct file *file, unsigned int ioctl_num,
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unsigned long ioctl_param)
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{
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+ struct vcio_data *vcio = container_of(file->private_data,
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+ struct vcio_data, misc_dev);
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+
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switch (ioctl_num) {
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case IOCTL_MBOX_PROPERTY32:
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- return vcio_user_property_list(compat_ptr(ioctl_param));
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+ return vcio_user_property_list(vcio, compat_ptr(ioctl_param));
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default:
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pr_err("unknown ioctl: %x\n", ioctl_num);
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return -EINVAL;
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@@ -119,77 +122,65 @@ const struct file_operations vcio_fops =
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.release = vcio_device_release,
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};
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-static int __init vcio_init(void)
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+static int vcio_probe(struct platform_device *pdev)
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{
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- struct device_node *np;
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- static struct device *dev;
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- int ret;
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-
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- np = of_find_compatible_node(NULL, NULL,
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- "raspberrypi,bcm2835-firmware");
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- if (!of_device_is_available(np))
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- return -ENODEV;
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-
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- vcio.fw = rpi_firmware_get(np);
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- if (!vcio.fw)
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- return -ENODEV;
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-
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- ret = alloc_chrdev_region(&vcio.devt, 0, 1, "vcio");
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- if (ret) {
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- pr_err("failed to allocate device number\n");
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- return ret;
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- }
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-
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- cdev_init(&vcio.cdev, &vcio_fops);
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- vcio.cdev.owner = THIS_MODULE;
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- ret = cdev_add(&vcio.cdev, vcio.devt, 1);
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- if (ret) {
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- pr_err("failed to register device\n");
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- goto err_unregister_chardev;
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- }
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+ struct device *dev = &pdev->dev;
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+ struct device_node *np = dev->of_node;
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+ struct device_node *fw_node;
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+ struct rpi_firmware *fw;
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+ struct vcio_data *vcio;
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- /*
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- * Create sysfs entries
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- * 'bcm2708_vcio' is used for backwards compatibility so we don't break
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- * userspace. Raspian has a udev rule that changes the permissions.
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- */
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- vcio.class = class_create(THIS_MODULE, "bcm2708_vcio");
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- if (IS_ERR(vcio.class)) {
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- ret = PTR_ERR(vcio.class);
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- pr_err("failed to create class\n");
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- goto err_cdev_del;
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+ fw_node = of_get_parent(np);
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+ if (!fw_node) {
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+ dev_err(dev, "Missing firmware node\n");
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+ return -ENOENT;
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}
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- dev = device_create(vcio.class, NULL, vcio.devt, NULL, "vcio");
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- if (IS_ERR(dev)) {
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- ret = PTR_ERR(dev);
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- pr_err("failed to create device\n");
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- goto err_class_destroy;
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- }
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+ fw = rpi_firmware_get(fw_node);
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+ of_node_put(fw_node);
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+ if (!fw)
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+ return -EPROBE_DEFER;
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- return 0;
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+ vcio = devm_kzalloc(dev, sizeof(struct vcio_data), GFP_KERNEL);
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+ if (!vcio)
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+ return -ENOMEM;
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-err_class_destroy:
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- class_destroy(vcio.class);
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-err_cdev_del:
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- cdev_del(&vcio.cdev);
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-err_unregister_chardev:
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- unregister_chrdev_region(vcio.devt, 1);
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+ vcio->fw = fw;
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+ vcio->misc_dev.fops = &vcio_fops;
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+ vcio->misc_dev.minor = MISC_DYNAMIC_MINOR;
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+ vcio->misc_dev.name = "vcio";
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+ vcio->misc_dev.parent = dev;
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- return ret;
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+ return misc_register(&vcio->misc_dev);
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}
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-module_init(vcio_init);
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-static void __exit vcio_exit(void)
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+static int vcio_remove(struct platform_device *pdev)
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{
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- device_destroy(vcio.class, vcio.devt);
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- class_destroy(vcio.class);
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- cdev_del(&vcio.cdev);
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- unregister_chrdev_region(vcio.devt, 1);
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+ struct device *dev = &pdev->dev;
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+
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+ misc_deregister(dev_get_drvdata(dev));
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+ return 0;
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}
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-module_exit(vcio_exit);
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+
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+static const struct of_device_id vcio_ids[] = {
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+ { .compatible = "raspberrypi,vcio" },
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+ { }
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+};
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+MODULE_DEVICE_TABLE(of, vcio_ids);
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+
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+static struct platform_driver vcio_driver = {
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+ .driver = {
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+ .name = MODULE_NAME,
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+ .of_match_table = of_match_ptr(vcio_ids),
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+ },
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+ .probe = vcio_probe,
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+ .remove = vcio_remove,
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+};
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+
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+module_platform_driver(vcio_driver);
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MODULE_AUTHOR("Gray Girling");
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MODULE_AUTHOR("Noralf Trønnes");
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MODULE_DESCRIPTION("Mailbox userspace access");
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MODULE_LICENSE("GPL");
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+MODULE_ALIAS("platform:rpi-vcio");
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