Implementation of task 10 with gpio-enhanced chardev

10_chardev/CMakeLists.txt

@@ -0,0 +1,38 @@
+cmake_minimum_required(VERSION 3.21)
+project(ioctl_userspace_app)
+
+set(CMAKE_CXX_STANDARD 17)
+
+
+if(NOT EXISTS "${CMAKE_BINARY_DIR}/conan.cmake")
+  message(STATUS "Downloading conan.cmake from https://github.com/conan-io/cmake-conan")
+  file(DOWNLOAD "https://raw.githubusercontent.com/conan-io/cmake-conan/v0.16.1/conan.cmake"
+                "${CMAKE_BINARY_DIR}/conan.cmake"
+                EXPECTED_HASH SHA256=396e16d0f5eabdc6a14afddbcfff62a54a7ee75c6da23f32f7a31bc85db23484
+                TLS_VERIFY ON)
+endif()
+
+list(APPEND CMAKE_MODULE_PATH ${CMAKE_BINARY_DIR})
+list(APPEND CMAKE_PREFIX_PATH ${CMAKE_BINARY_DIR})
+
+include(${CMAKE_BINARY_DIR}/conan.cmake)
+
+conan_cmake_configure(REQUIRES
+                      fmt/8.0.1
+                      GENERATORS cmake_find_package
+                      IMPORTS "bin, *.dll -> ${CMAKE_CURRENT_BINARY_DIR}"
+                      IMPORTS "lib, *.dylib* -> ${CMAKE_CURRENT_BINARY_DIR}"
+                      OPTIONS fmt:header_only=True
+                      )
+
+conan_cmake_autodetect(settings)
+
+conan_cmake_install(PATH_OR_REFERENCE .
+                    BUILD missing
+                    PROFILE orange_zero_profile
+                    REMOTE conancenter
+                    SETTINGS ${settings})
+
+find_package(fmt REQUIRED)
+add_executable(${PROJECT_NAME} main.cpp)
+target_link_libraries(${PROJECT_NAME} PRIVATE fmt::fmt)

10_chardev/Makefile

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+KERNELDIR ?=/home/valenti/Development/Embedded/exercise8/build_orange_zero_image/build/linux-5.10.10/
+
+ifneq ($(KERNELRELEASE),)
+	obj-m := gpio_chardev.o
+else
+
+all:
+	$(MAKE) CFLAGS_MODULE="-DDEBUG -DORANGE_PI_ZERO" -C $(KERNELDIR) M=$(PWD) modules
+clean:
+	$(MAKE) -C $(KERNELDIR) M=$(PWD) clean
+endif

10_chardev/gpio_chardev.c

@@ -0,0 +1,261 @@
+#include <linux/init.h>
+#include <linux/fs.h>
+#include <linux/module.h>
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/uaccess.h>
+#include <linux/gpio.h>
+
+#include "gpio_chardev_ioctl.h"
+
+#define GPIO_NUMBER(port, bit) (32 * (port) + (bit))
+
+//https://elixir.bootlin.com/linux/latest/source/sound/core/hwdep.c#L248
+//https://elixir.bootlin.com/linux/latest/source/drivers/char/dsp56k.c#L503
+
+/*	https://linux-sunxi.org/Xunlong_Orange_Pi_PC#LEDs
+ *  Board config for OPI-PC:
+ *	LED GREEN (PL10): GPIO_11_10
+ *	LED RED   (PA15): GPIO_0_15  
+ *	BUTTON    (PG7) : GPIO_6_7
+ *
+ *  https://linux-sunxi.org/Xunlong_Orange_Pi_Zero#LEDs
+ *  Board config for OPI-Zero:
+ *	LED GREEN (PL10): GPIO_11_10 
+ *	LED RED   (PA17): GPIO_0_17 
+ *	BUTTON    (PA6) : GPIO_0_6
+ *  
+ */
+
+#ifdef ORANGE_PI_PC
+#error "Implement the necessary port mappings"
+#endif
+#ifdef ORANGE_PI_ZERO
+#define LED_GREEN GPIO_NUMBER(11, 10)
+#define LED_RED GPIO_NUMBER(0, 17)
+#define BUTTON GPIO_NUMBER(0, 6)
+#endif
+
+#define CLASS_NAME "gpio_chardev"
+#define DEVICE_NAME "gpio_dev"
+#define BUFFER_SIZE 1024
+
+static struct class *pdevice_class;
+static struct device *p_chardev;
+
+static int major;
+static int is_open;
+
+static int data_size;
+static unsigned char data_buffer[BUFFER_SIZE];
+
+static int led_red_gpio;
+static int led_green_gpio;
+
+static int dev_open(struct inode *inodep, struct file *filep)
+{
+	if (is_open) {
+		pr_err("gpio_chardev: already open\n");
+		return -EBUSY;
+	}
+
+	is_open = 1;
+	pr_info("gpio_chardev: device opened\n");
+	return 0;
+}
+
+static int dev_release(struct inode *inodep, struct file *filep)
+{
+	is_open = 0;
+	pr_info("gpio_chardev: device closed\n");
+	return 0;
+}
+
+static ssize_t dev_read(struct file *filep, char *buffer, size_t len,
+			loff_t *offset)
+{
+	int ret;
+
+	pr_info("gpio_chardev: read from file %s\n",
+		filep->f_path.dentry->d_iname);
+	pr_info("gpio_chardev: read from device %d:%d\n",
+		imajor(filep->f_inode), iminor(filep->f_inode));
+
+	if (len > data_size)
+		len = data_size;
+
+	ret = copy_to_user(buffer, data_buffer, len);
+	if (ret) {
+		pr_err("gpio_chardev: copy_to_user failed: %d\n", ret);
+		return -EFAULT;
+	}
+	data_size = 0; /* eof for cat */
+
+	pr_info("gpio_chardev: %zu bytes read\n", len);
+	return len;
+}
+
+static ssize_t dev_write(struct file *filep, const char *buffer, size_t len,
+			 loff_t *offset)
+{
+	int ret;
+
+	pr_info("gpio_chardev: write to file %s\n",
+		filep->f_path.dentry->d_iname);
+	pr_info("gpio_chardev: write to device %d:%d\n", imajor(filep->f_inode),
+		iminor(filep->f_inode));
+
+	data_size = len;
+	if (data_size > BUFFER_SIZE)
+		data_size = BUFFER_SIZE;
+
+	ret = copy_from_user(data_buffer, buffer, data_size);
+	if (ret) {
+		pr_err("gpio_chardev: copy_from_user failed: %d\n", ret);
+		return -EFAULT;
+	}
+
+	pr_info("gpio_chardev: %d bytes written\n", data_size);
+	return data_size;
+}
+
+static long dev_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
+{
+	void __user *argp = (void __user *)arg;
+
+	pr_info("Handled ioctl call CMD: %d  \n", cmd);
+
+	switch (cmd) {
+	case GPIO_CHARDEV_SET_VALUE: {
+
+		struct gpio_chardev_set_data gpio_data = {};
+
+		if (copy_from_user(&gpio_data, argp, sizeof(struct gpio_chardev_set_data)))
+			return -EFAULT;
+
+		if (gpio_data.gpio_num == led_green_gpio ||
+		    gpio_data.gpio_num == led_red_gpio) {
+			gpio_set_value(gpio_data.gpio_num,
+				       gpio_data.gpio_value);
+			return 0;
+		}
+		return -EINVAL;
+	} break;
+	case GPIO_CHARDEV_READ_BUTTON_VALUE: {
+		struct gpio_chardev_get_data gpio_data = {};
+
+		if (copy_from_user(&gpio_data, argp, sizeof(struct gpio_chardev_get_data)))
+			return -EFAULT;
+
+		if (gpio_data.gpio_num == BUTTON) {
+			int button_value = gpio_get_value(BUTTON);
+
+			gpio_data.gpio_value = button_value;
+			return copy_to_user(argp, &gpio_data, sizeof(struct gpio_chardev_get_data));
+		}
+		return -EINVAL;
+	} break;
+	default:
+		return -EINVAL;
+	}
+	return 0;
+}
+
+static int led_gpio_init(int gpio, int *led_gpio)
+{
+	int res;
+
+	res = gpio_direction_output(gpio, 0);
+	if (res != 0)
+		return res;
+
+	*led_gpio = gpio;
+	return 0;
+}
+static int button_gpio_init(int gpio)
+{
+	int res;
+
+	res = gpio_request(gpio, "Onboard user button");
+	if (res != 0)
+		return res;
+
+	res = gpio_direction_input(gpio);
+	if (res != 0)
+		goto err_input;
+
+	return 0;
+
+err_input:
+	gpio_free(gpio);
+	return res;
+}
+
+static void button_gpio_deinit(int button_gpio)
+{
+	gpio_free(button_gpio);
+	pr_info("Deinit GPIO%d\n", button_gpio);
+}
+static struct file_operations fops = {
+	.open = dev_open,
+	.release = dev_release,
+	.read = dev_read,
+	.write = dev_write,
+	.unlocked_ioctl = dev_ioctl,
+};
+
+static int __init charedev_mod_init(void)
+{
+	major = register_chrdev(0, DEVICE_NAME, &fops);
+	if (major < 0) {
+		pr_err("register_chrdev failed: %d\n", major);
+		return major;
+	}
+	pr_info("gpio_chardev: register_chrdev ok, major = %d\n", major);
+
+	pdevice_class = class_create(THIS_MODULE, CLASS_NAME);
+	if (IS_ERR(pdevice_class)) {
+		unregister_chrdev(major, DEVICE_NAME);
+		pr_err("gpio_chardev: class_create failed\n");
+		return PTR_ERR(pdevice_class);
+	}
+	pr_info("gpio_chardev: device class created successfully\n");
+
+	p_chardev = device_create(pdevice_class, NULL, MKDEV(major, 0), NULL,
+				  CLASS_NAME "0");
+	if (IS_ERR(p_chardev)) {
+		class_destroy(pdevice_class);
+		unregister_chrdev(major, DEVICE_NAME);
+		pr_err("chrdev: device_create failed\n");
+		return PTR_ERR(p_chardev);
+	}
+	pr_info("gpio_chardev: device node created successfully\n");
+
+	led_gpio_init(LED_GREEN, &led_green_gpio);
+	led_gpio_init(LED_RED, &led_red_gpio);
+	button_gpio_init(BUTTON);
+
+	pr_info("gpio_chardev: module loaded\n");
+	return 0;
+}
+
+static void __exit chardev_mod_exit(void)
+{
+	button_gpio_deinit(BUTTON);
+	gpio_free(led_red_gpio);
+	gpio_free(led_green_gpio);
+
+	device_destroy(pdevice_class, MKDEV(major, 0));
+	class_destroy(pdevice_class);
+	unregister_chrdev(major, DEVICE_NAME);
+
+	pr_info("gpio_chardev: module exited\n");
+}
+
+module_init(charedev_mod_init);
+module_exit(chardev_mod_exit);
+
+MODULE_AUTHOR("Valentyn Korniienko <valentyn.korniienko1@nure.ua>");
+MODULE_DESCRIPTION("Character device with IOCTL support for GPIOs");
+MODULE_LICENSE("GPL");
+MODULE_VERSION("0.1");

10_chardev/gpio_chardev_ioctl.h

@@ -0,0 +1,31 @@
+#ifndef GPIO_CHARDEV_IOCTL_H
+#define GPIO_CHARDEV_IOCTL_H
+
+#if defined(__cplusplus)
+extern "C" {
+#endif
+
+
+// https://elixir.bootlin.com/linux/latest/source/arch/m68k/include/asm/dsp56k.h#L31
+
+struct gpio_chardev_set_data {
+	int gpio_num;
+	int gpio_value;
+};
+
+struct gpio_chardev_get_data {
+	int gpio_num;
+	int gpio_value;
+};
+
+#define GPIO_CHARDEV_IOCTL_BASE 'f'
+
+#define GPIO_CHARDEV_SET_VALUE _IOW(GPIO_CHARDEV_IOCTL_BASE,0x00,struct gpio_chardev_set_data)
+#define GPIO_CHARDEV_READ_BUTTON_VALUE _IOR(GPIO_CHARDEV_IOCTL_BASE,0x01,struct gpio_chardev_get_data)
+
+
+#if defined(__cplusplus)
+}
+#endif
+
+#endif