+++ /dev/null
-From 09897ac552d99d483131bcf107866ac2dc51694f Mon Sep 17 00:00:00 2001
-From: Luke Wren <luke@raspberrypi.org>
-Date: Fri, 21 Aug 2015 23:14:48 +0100
-Subject: [PATCH] Add /dev/gpiomem device for rootless user GPIO access
-
-Signed-off-by: Luke Wren <luke@raspberrypi.org>
-
-bcm2835-gpiomem: Fix for ARCH_BCM2835 builds
-
-Build on ARCH_BCM2835, and fail to probe if no IO resource.
-
-See: https://github.com/raspberrypi/linux/issues/1154
----
- drivers/char/broadcom/Kconfig | 8 +
- drivers/char/broadcom/Makefile | 1 +
- drivers/char/broadcom/bcm2835-gpiomem.c | 258 ++++++++++++++++++++++++
- 3 files changed, 267 insertions(+)
- create mode 100644 drivers/char/broadcom/bcm2835-gpiomem.c
-
---- a/drivers/char/broadcom/Kconfig
-+++ b/drivers/char/broadcom/Kconfig
-@@ -16,3 +16,11 @@ config BCM2708_VCMEM
- Helper for videocore memory access and total size allocation.
-
- endif
-+
-+config BCM2835_DEVGPIOMEM
-+ tristate "/dev/gpiomem rootless GPIO access via mmap() on the BCM2835"
-+ default m
-+ help
-+ Provides users with root-free access to the GPIO registers
-+ on the 2835. Calling mmap(/dev/gpiomem) will map the GPIO
-+ register page to the user's pointer.
---- a/drivers/char/broadcom/Makefile
-+++ b/drivers/char/broadcom/Makefile
-@@ -1 +1,2 @@
- obj-$(CONFIG_BCM2708_VCMEM) += vc_mem.o
-+obj-$(CONFIG_BCM2835_DEVGPIOMEM)+= bcm2835-gpiomem.o
---- /dev/null
-+++ b/drivers/char/broadcom/bcm2835-gpiomem.c
-@@ -0,0 +1,258 @@
-+/**
-+ * GPIO memory device driver
-+ *
-+ * Creates a chardev /dev/gpiomem which will provide user access to
-+ * the BCM2835's GPIO registers when it is mmap()'d.
-+ * No longer need root for user GPIO access, but without relaxing permissions
-+ * on /dev/mem.
-+ *
-+ * Written by Luke Wren <luke@raspberrypi.org>
-+ * Copyright (c) 2015, Raspberry Pi (Trading) Ltd.
-+ *
-+ * Redistribution and use in source and binary forms, with or without
-+ * modification, are permitted provided that the following conditions
-+ * are met:
-+ * 1. Redistributions of source code must retain the above copyright
-+ * notice, this list of conditions, and the following disclaimer,
-+ * without modification.
-+ * 2. Redistributions in binary form must reproduce the above copyright
-+ * notice, this list of conditions and the following disclaimer in the
-+ * documentation and/or other materials provided with the distribution.
-+ * 3. The names of the above-listed copyright holders may not be used
-+ * to endorse or promote products derived from this software without
-+ * specific prior written permission.
-+ *
-+ * ALTERNATIVELY, this software may be distributed under the terms of the
-+ * GNU General Public License ("GPL") version 2, as published by the Free
-+ * Software Foundation.
-+ *
-+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
-+ * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
-+ * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
-+ * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
-+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
-+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
-+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
-+ * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
-+ * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
-+ * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
-+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
-+ */
-+
-+#include <linux/kernel.h>
-+#include <linux/module.h>
-+#include <linux/of.h>
-+#include <linux/platform_device.h>
-+#include <linux/mm.h>
-+#include <linux/slab.h>
-+#include <linux/cdev.h>
-+#include <linux/pagemap.h>
-+#include <linux/io.h>
-+
-+#define DEVICE_NAME "bcm2835-gpiomem"
-+#define DRIVER_NAME "gpiomem-bcm2835"
-+#define DEVICE_MINOR 0
-+
-+struct bcm2835_gpiomem_instance {
-+ unsigned long gpio_regs_phys;
-+ struct device *dev;
-+};
-+
-+static struct cdev bcm2835_gpiomem_cdev;
-+static dev_t bcm2835_gpiomem_devid;
-+static struct class *bcm2835_gpiomem_class;
-+static struct device *bcm2835_gpiomem_dev;
-+static struct bcm2835_gpiomem_instance *inst;
-+
-+
-+/****************************************************************************
-+*
-+* GPIO mem chardev file ops
-+*
-+***************************************************************************/
-+
-+static int bcm2835_gpiomem_open(struct inode *inode, struct file *file)
-+{
-+ int dev = iminor(inode);
-+ int ret = 0;
-+
-+ if (dev != DEVICE_MINOR) {
-+ dev_err(inst->dev, "Unknown minor device: %d", dev);
-+ ret = -ENXIO;
-+ }
-+ return ret;
-+}
-+
-+static int bcm2835_gpiomem_release(struct inode *inode, struct file *file)
-+{
-+ int dev = iminor(inode);
-+ int ret = 0;
-+
-+ if (dev != DEVICE_MINOR) {
-+ dev_err(inst->dev, "Unknown minor device %d", dev);
-+ ret = -ENXIO;
-+ }
-+ return ret;
-+}
-+
-+static const struct vm_operations_struct bcm2835_gpiomem_vm_ops = {
-+#ifdef CONFIG_HAVE_IOREMAP_PROT
-+ .access = generic_access_phys
-+#endif
-+};
-+
-+static int bcm2835_gpiomem_mmap(struct file *file, struct vm_area_struct *vma)
-+{
-+ /* Ignore what the user says - they're getting the GPIO regs
-+ whether they like it or not! */
-+ unsigned long gpio_page = inst->gpio_regs_phys >> PAGE_SHIFT;
-+
-+ vma->vm_page_prot = phys_mem_access_prot(file, gpio_page,
-+ PAGE_SIZE,
-+ vma->vm_page_prot);
-+ vma->vm_ops = &bcm2835_gpiomem_vm_ops;
-+ if (remap_pfn_range(vma, vma->vm_start,
-+ gpio_page,
-+ PAGE_SIZE,
-+ vma->vm_page_prot)) {
-+ return -EAGAIN;
-+ }
-+ return 0;
-+}
-+
-+static const struct file_operations
-+bcm2835_gpiomem_fops = {
-+ .owner = THIS_MODULE,
-+ .open = bcm2835_gpiomem_open,
-+ .release = bcm2835_gpiomem_release,
-+ .mmap = bcm2835_gpiomem_mmap,
-+};
-+
-+
-+ /****************************************************************************
-+*
-+* Probe and remove functions
-+*
-+***************************************************************************/
-+
-+
-+static int bcm2835_gpiomem_probe(struct platform_device *pdev)
-+{
-+ int err;
-+ void *ptr_err;
-+ struct device *dev = &pdev->dev;
-+ struct resource *ioresource;
-+
-+ /* Allocate buffers and instance data */
-+
-+ inst = kzalloc(sizeof(struct bcm2835_gpiomem_instance), GFP_KERNEL);
-+
-+ if (!inst) {
-+ err = -ENOMEM;
-+ goto failed_inst_alloc;
-+ }
-+
-+ inst->dev = dev;
-+
-+ ioresource = platform_get_resource(pdev, IORESOURCE_MEM, 0);
-+ if (ioresource) {
-+ inst->gpio_regs_phys = ioresource->start;
-+ } else {
-+ dev_err(inst->dev, "failed to get IO resource");
-+ err = -ENOENT;
-+ goto failed_get_resource;
-+ }
-+
-+ /* Create character device entries */
-+
-+ err = alloc_chrdev_region(&bcm2835_gpiomem_devid,
-+ DEVICE_MINOR, 1, DEVICE_NAME);
-+ if (err != 0) {
-+ dev_err(inst->dev, "unable to allocate device number");
-+ goto failed_alloc_chrdev;
-+ }
-+ cdev_init(&bcm2835_gpiomem_cdev, &bcm2835_gpiomem_fops);
-+ bcm2835_gpiomem_cdev.owner = THIS_MODULE;
-+ err = cdev_add(&bcm2835_gpiomem_cdev, bcm2835_gpiomem_devid, 1);
-+ if (err != 0) {
-+ dev_err(inst->dev, "unable to register device");
-+ goto failed_cdev_add;
-+ }
-+
-+ /* Create sysfs entries */
-+
-+ bcm2835_gpiomem_class = class_create(THIS_MODULE, DEVICE_NAME);
-+ ptr_err = bcm2835_gpiomem_class;
-+ if (IS_ERR(ptr_err))
-+ goto failed_class_create;
-+
-+ bcm2835_gpiomem_dev = device_create(bcm2835_gpiomem_class, NULL,
-+ bcm2835_gpiomem_devid, NULL,
-+ "gpiomem");
-+ ptr_err = bcm2835_gpiomem_dev;
-+ if (IS_ERR(ptr_err))
-+ goto failed_device_create;
-+
-+ dev_info(inst->dev, "Initialised: Registers at 0x%08lx",
-+ inst->gpio_regs_phys);
-+
-+ return 0;
-+
-+failed_device_create:
-+ class_destroy(bcm2835_gpiomem_class);
-+failed_class_create:
-+ cdev_del(&bcm2835_gpiomem_cdev);
-+ err = PTR_ERR(ptr_err);
-+failed_cdev_add:
-+ unregister_chrdev_region(bcm2835_gpiomem_devid, 1);
-+failed_alloc_chrdev:
-+failed_get_resource:
-+ kfree(inst);
-+failed_inst_alloc:
-+ dev_err(inst->dev, "could not load bcm2835_gpiomem");
-+ return err;
-+}
-+
-+static int bcm2835_gpiomem_remove(struct platform_device *pdev)
-+{
-+ struct device *dev = inst->dev;
-+
-+ kfree(inst);
-+ device_destroy(bcm2835_gpiomem_class, bcm2835_gpiomem_devid);
-+ class_destroy(bcm2835_gpiomem_class);
-+ cdev_del(&bcm2835_gpiomem_cdev);
-+ unregister_chrdev_region(bcm2835_gpiomem_devid, 1);
-+
-+ dev_info(dev, "GPIO mem driver removed - OK");
-+ return 0;
-+}
-+
-+ /****************************************************************************
-+*
-+* Register the driver with device tree
-+*
-+***************************************************************************/
-+
-+static const struct of_device_id bcm2835_gpiomem_of_match[] = {
-+ {.compatible = "brcm,bcm2835-gpiomem",},
-+ { /* sentinel */ },
-+};
-+
-+MODULE_DEVICE_TABLE(of, bcm2835_gpiomem_of_match);
-+
-+static struct platform_driver bcm2835_gpiomem_driver = {
-+ .probe = bcm2835_gpiomem_probe,
-+ .remove = bcm2835_gpiomem_remove,
-+ .driver = {
-+ .name = DRIVER_NAME,
-+ .owner = THIS_MODULE,
-+ .of_match_table = bcm2835_gpiomem_of_match,
-+ },
-+};
-+
-+module_platform_driver(bcm2835_gpiomem_driver);
-+
-+MODULE_ALIAS("platform:gpiomem-bcm2835");
-+MODULE_LICENSE("GPL");
-+MODULE_DESCRIPTION("gpiomem driver for accessing GPIO from userspace");
-+MODULE_AUTHOR("Luke Wren <luke@raspberrypi.org>");
projects / openwrt / staging / chunkeey.git / blobdiff