[feat] add gpio_virtual_driver

gpio/gpio_virtual/Makefile

@@ -0,0 +1,12 @@
+ARCH ?= arm
+CROSS_COMPILE ?= /home/jzh/work/study/weidongshan/100ask_stm32mp157_pro-sdk/ToolChain/arm-buildroot-linux-gnueabihf_sdk-buildroot/bin/arm-linux-
+KERN_DIR ?= /home/jzh/work/study/weidongshan/100ask_stm32mp157_pro-sdk/Linux-5.4
+
+all:
+	make -C $(KERN_DIR) M=`pwd` ARCH=$(ARCH) CROSS_COMPILE=$(CROSS_COMPILE) modules
+
+clean:
+	make -C $(KERN_DIR) M=`pwd` ARCH=$(ARCH) CROSS_COMPILE=$(CROSS_COMPILE) modules clean
+	rm -rf modules.order
+
+obj-m += gpio_virtual_driver.o

gpio/gpio_virtual/gpio_virtual.dts

@@ -0,0 +1,10 @@
+gpio_virtual: gpio_virtual_controller {
+        compatible = "jzh,gpio_virtual";
+        gpio-controller;
+        #gpio-cells = <2>;
+        ngpios = <4>;
+};
+myled {
+        compatible = "jzh,led_driver";
+        led-gpios = <&gpio_virtual 0 GPIO_ACTIVE_LOW>;
+};

gpio/gpio_virtual/gpio_virtual_driver.c

@@ -0,0 +1,106 @@
+#include <linux/module.h>
+#include <linux/err.h>
+#include <linux/init.h>
+#include <linux/io.h>
+#include <linux/mfd/syscon.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/of_address.h>
+#include <linux/gpio/driver.h>
+#include <linux/slab.h>
+#include <linux/regmap.h>
+
+static struct gpio_chip *g_gpio_virtual;
+static int g_gpio_val = 0;
+
+static int gpio_virtual_direction_output(struct gpio_chip *gc, unsigned offset, int val)
+{
+    printk("set pin %d as output %s\r\n", offset, val ? "high" : "low");
+    return 0;
+}
+
+static int gpio_virtual_direction_input(struct gpio_chip *gc, unsigned offset)
+{
+    printk("set pin %d as input\r\n", offset);
+    return 0;
+}
+
+static int gpio_virtual_get_value(struct gpio_chip *gc, unsigned offset)
+{
+    int val = (g_gpio_val & (1 << offset)) ? 1 : 0;
+    printk("get pin %d value %d\r\n", offset, val);
+    return val;
+}
+
+static void gpio_virtual_set_value(struct gpio_chip *gc, unsigned offset, int val)
+{
+    if (val) {
+        g_gpio_val |= (1 << offset);
+    } else {
+        g_gpio_val &= ~(1 << offset);
+    }
+    printk("set pin %d value %d\r\n", offset, val);
+}
+
+static int gpio_virtual_probe(struct platform_device *pdev)
+{
+    int ret;
+    uint32_t val;
+
+    printk("%s %s %d\r\n", __FILE__, __FUNCTION__, __LINE__);
+    g_gpio_virtual = devm_kzalloc(&pdev->dev, sizeof(*g_gpio_virtual), GFP_KERNEL);
+
+    g_gpio_virtual->label = pdev->name;
+    g_gpio_virtual->direction_output = gpio_virtual_direction_output;
+    g_gpio_virtual->direction_input = gpio_virtual_direction_input;
+    g_gpio_virtual->get = gpio_virtual_get_value;
+    g_gpio_virtual->set = gpio_virtual_set_value;
+
+    g_gpio_virtual->parent = &pdev->dev;
+    g_gpio_virtual->owner = THIS_MODULE;
+
+    g_gpio_virtual->base = -1;
+    ret = of_property_read_u32(pdev->dev.of_node, "ngpios", &val);
+    g_gpio_virtual->ngpio = val;
+
+    ret = devm_gpiochip_add_data(&pdev->dev, g_gpio_virtual, NULL);
+    return 0;
+}
+
+static int gpio_virtual_remove(struct platform_device *pdev)
+{
+    printk("%s %s %d\r\n", __FILE__, __FUNCTION__, __LINE__);
+    return 0;
+}
+
+static const struct of_device_id gpio_virtual_of_match[] = {
+    { .compatible = "jzh,gpio-virtual", },
+    {  },
+};
+
+static struct platform_driver gpio_virtual_driver = {
+    .probe = gpio_virtual_probe,
+    .remove = gpio_virtual_remove,
+    .driver = {
+        .name = "gpio-virtual",
+        .of_match_table = of_match_ptr(gpio_virtual_of_match),
+    },
+};
+
+static int __init gpio_virtual_init(void)
+{
+    printk("%s %s %d\r\n", __FILE__, __FUNCTION__, __LINE__);
+    return platform_driver_register(&gpio_virtual_driver);
+}
+
+static void __exit gpio_virtual_exit(void)
+{
+    printk("%s %s %d\r\n", __FILE__, __FUNCTION__, __LINE__);
+    platform_driver_unregister(&gpio_virtual_driver);
+}
+
+module_init(gpio_virtual_init);
+module_exit(gpio_virtual_exit);
+MODULE_DESCRIPTION("Virtual GPIO Driver");
+MODULE_AUTHOR("jzhgonha@163.com");
+MODULE_LICENSE("GPL");