Implement gpiomem for Debian. DEVMOD=0666

Signed-off-by: yi-hsin_hung <yi-hsin_hung@asus.com>
Change-Id: Ibda4c6071d0469e13a28d55884b4ce47c5ea4279

Author: yihsin-hung

arch/arm/boot/dts/rk3288-tinker-board.dts

@@ -200,6 +200,12 @@
 		regulator-boot-on;
 	};
 
+        rk3288_gpiomem: rk3288-gpiomem {
+                compatible = "rockchip,rk3288-gpiomem";
+                reg = <0x0 0xff750000 0x0 0x1000>;
+                status = "okay";
+        };
+
 	xin32k: xin32k {
 		compatible = "fixed-clock";
 		clock-frequency = <32768>;

arch/arm/configs/rockchip_linux_defconfig

@@ -3,6 +3,8 @@ CONFIG_DEFAULT_HOSTNAME="localhost"
 CONFIG_BOARDINFO=y
 CONFIG_SYSVIPC=y
 CONFIG_POSIX_MQUEUE=y
+CONFIG_RK_CHAR_DRIVERS=y
+CONFIG_RK3288_DEVGPIOMEM=y
 CONFIG_FHANDLE=y
 CONFIG_NO_HZ=y
 CONFIG_HIGH_RES_TIMERS=y

drivers/char/Kconfig

@@ -4,6 +4,7 @@
 
 menu "Character devices"
 
+source "drivers/char/rockchip/Kconfig"
 source "drivers/tty/Kconfig"
 
 config DEVMEM

drivers/char/Makefile

@@ -60,3 +60,4 @@ js-rtc-y = rtc.o
 
 obj-$(CONFIG_TILE_SROM)		+= tile-srom.o
 obj-$(CONFIG_XILLYBUS)		+= xillybus/
+obj-$(CONFIG_RK_CHAR_DRIVERS)  += rockchip/

drivers/char/rockchip/Kconfig

@@ -0,0 +1,16 @@
+#
+# Rockchip char driver config
+#
+
+menuconfig RK_CHAR_DRIVERS
+	bool "Rockchip Char Drivers"
+	help
+	  Rockchip's char drivers
+
+config RK3288_DEVGPIOMEM
+	tristate "/dev/gpiomem rootless GPIO access via mmap() on the RK3288"
+	default y
+	help
+		Provides users with root-free access to the GPIO registers
+		on the 3288. Calling mmap(/dev/gpiomem) will map the GPIO
+		register page to the user's pointer.

drivers/char/rockchip/Makefile

@@ -0,0 +1 @@
+obj-$(CONFIG_RK3288_DEVGPIOMEM)+= rk3288-gpiomem.o

drivers/char/rockchip/rk3288-gpiomem.c

@@ -0,0 +1,308 @@
+/**
+ * GPIO memory device driver
+ *
+ * Creates a chardev /dev/gpiomem which will provide user access to
+ * the rk3288'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.
+ */
+
+/*
+ * Ported to rk3288 from Jorg Wolff, 2017
+*/
+
+#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 "rk3288-gpiomem"
+#define DRIVER_NAME "gpiomem-rk3288"
+#define DEVICE_MINOR 0
+
+struct rk3288_gpiomem_instance {
+	unsigned long gpio_regs_phys;
+	struct device *dev;
+};
+
+static struct cdev rk3288_gpiomem_cdev;
+static dev_t rk3288_gpiomem_devid;
+static struct class *rk3288_gpiomem_class;
+static struct device *rk3288_gpiomem_dev;
+static struct rk3288_gpiomem_instance *inst;
+
+
+/****************************************************************************
+*
+*   GPIO mem chardev file ops
+*
+***************************************************************************/
+
+static int rk3288_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 rk3288_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 rk3288_gpiomem_vm_ops = {
+#ifdef CONFIG_HAVE_IOREMAP_PROT
+	.access = generic_access_phys
+#endif
+};
+
+static int address_is_allowed(unsigned long pfn, unsigned long size)
+{
+    unsigned long address = pfn << PAGE_SHIFT;
+
+    dev_info(inst->dev, "address_is_allowed.pfn: 0x%08lx", address);
+
+    switch(address) {
+
+        case 0xff750000:
+        case 0xff760000:
+        case 0xff780000:
+        case 0xff790000:
+        case 0xff7a0000:
+        case 0xff7b0000:
+        case 0xff7c0000:
+        case 0xff7d0000:
+        case 0xff7e0000:
+        case 0xff7f0000:
+        case 0xff7f2000:
+        case 0xff770000:
+        case 0xff730000:
+        case 0xff680000:
+            dev_info(inst->dev, "address_is_allowed.return 1");
+            return 1;
+            break; 
+        default :
+            dev_info(inst->dev, "address_is_allowed.return 0");
+	        return 0;
+    }
+}
+
+static int rk3288_gpiomem_mmap(struct file *file, struct vm_area_struct *vma)
+{
+
+    size_t size;
+
+	size = vma->vm_end - vma->vm_start;
+
+
+	if (!address_is_allowed(vma->vm_pgoff, size))
+		return -EPERM;
+
+	vma->vm_page_prot = phys_mem_access_prot(file, vma->vm_pgoff,
+						 size,
+						 vma->vm_page_prot);
+
+	vma->vm_ops =  &rk3288_gpiomem_vm_ops;
+
+	/* Remap-pfn-range will mark the range VM_IO */
+	if (remap_pfn_range(vma,
+			    vma->vm_start,
+			    vma->vm_pgoff,
+			    size,
+			    vma->vm_page_prot)) {
+		return -EAGAIN;
+	}
+
+	return 0;
+}
+
+static const struct file_operations
+rk3288_gpiomem_fops = {
+	.owner = THIS_MODULE,
+	.open = rk3288_gpiomem_open,
+	.release = rk3288_gpiomem_release,
+	.mmap = rk3288_gpiomem_mmap,
+};
+
+static int rk3288_gpiomem_dev_uevent(struct device *dev, struct kobj_uevent_env *env)
+{
+    add_uevent_var(env, "DEVMODE=%#o", 0666);
+    return 0;
+}
+
+/****************************************************************************
+*
+*   Probe and remove functions
+*
+***************************************************************************/
+
+
+static int rk3288_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 rk3288_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(&rk3288_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(&rk3288_gpiomem_cdev, &rk3288_gpiomem_fops);
+	rk3288_gpiomem_cdev.owner = THIS_MODULE;
+	err = cdev_add(&rk3288_gpiomem_cdev, rk3288_gpiomem_devid, 1);
+	if (err != 0) {
+		dev_err(inst->dev, "unable to register device");
+		goto failed_cdev_add;
+	}
+
+	/* Create sysfs entries */
+
+	rk3288_gpiomem_class = class_create(THIS_MODULE, DEVICE_NAME);
+	ptr_err = rk3288_gpiomem_class;
+	if (IS_ERR(ptr_err))
+		goto failed_class_create;
+	rk3288_gpiomem_class->dev_uevent = rk3288_gpiomem_dev_uevent;
+	rk3288_gpiomem_dev = device_create(rk3288_gpiomem_class, NULL,
+					rk3288_gpiomem_devid, NULL,
+					"gpiomem");
+	ptr_err = rk3288_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(rk3288_gpiomem_class);
+failed_class_create:
+	cdev_del(&rk3288_gpiomem_cdev);
+	err = PTR_ERR(ptr_err);
+failed_cdev_add:
+	unregister_chrdev_region(rk3288_gpiomem_devid, 1);
+failed_alloc_chrdev:
+failed_get_resource:
+	kfree(inst);
+failed_inst_alloc:
+	dev_err(inst->dev, "could not load rk3288_gpiomem");
+	return err;
+}
+
+static int rk3288_gpiomem_remove(struct platform_device *pdev)
+{
+	struct device *dev = inst->dev;
+
+	kfree(inst);
+	device_destroy(rk3288_gpiomem_class, rk3288_gpiomem_devid);
+	class_destroy(rk3288_gpiomem_class);
+	cdev_del(&rk3288_gpiomem_cdev);
+	unregister_chrdev_region(rk3288_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 rk3288_gpiomem_of_match[] = {
+	{.compatible = "rockchip,rk3288-gpiomem",},
+	{ /* sentinel */ },
+};
+
+MODULE_DEVICE_TABLE(of, rk3288_gpiomem_of_match);
+
+static struct platform_driver rk3288_gpiomem_driver = {
+	.probe = rk3288_gpiomem_probe,
+	.remove = rk3288_gpiomem_remove,
+	.driver = {
+		   .name = DRIVER_NAME,
+		   .owner = THIS_MODULE,
+		   .of_match_table = rk3288_gpiomem_of_match,
+		   },
+};
+
+module_platform_driver(rk3288_gpiomem_driver);
+
+MODULE_ALIAS("platform:gpiomem-rk3288");
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("gpiomem driver for accessing GPIO from userspace");
+MODULE_AUTHOR("Luke Wren <luke@raspberrypi.org>");