1000字范文 > 高通MSM8909下Android 7.1.2的GPIO驱动配置记录

高通MSM8909下Android 7.1.2的GPIO驱动配置记录

时间：2021-04-12 08:56:34

需要修改的文件：

1. 修改设备树文件 kernel/arch/arm/boot/dts/qcom/msm8909-mtp.dtsi

在&soc下添加

test_gpio {compatible = "test_gpio";test_gpio,gpio0 = <&msm_gpio 0 0>;qcom,num-grp-pins = <1>;qcom,pin-func = <0>;pinctrl-names = "test_gpio";pinctrl-0 = <&sim8905_act>;label = "test_gpio";sim8905_act: active {drive-strength = <2>;bias-disable = <0>;};};

2. 在 kernel/drivers/misc 下添加 test_gpio.c文件

#include <linux/types.h>#include <linux/pm.h>#include <linux/gpio.h>#include <linux/slab.h>#include <linux/init.h>#include <linux/platform_device.h>#include <linux/fsl_devices.h>#include <asm/setup.h>#include <linux/of.h>#include <linux/of_gpio.h>#include <linux/stat.h>#include <linux/module.h>#include <linux/err.h>#include <linux/spinlock.h>#include <linux/err.h>#include <linux/regulator/consumer.h>int test_gpio0 = -1;static struct class * test_gpios_class = NULL;static struct device * test_gpio0_dev = NULL;#define CTL_POWER_ON "1"#define CTL_POWER_OFF "0"//此函数会在使用 cat命令时候自动调用static ssize_t test_gpio0_show(struct device *dev,struct device_attribute *attr, char *buf){int gpio_state = gpio_get_value(test_gpio0);sprintf(buf, "%d\n", gpio_state);return strlen(buf);}//此函数会在使用 echo 命令时候自动调用static ssize_t test_gpio0_store(struct device *dev, struct device_attribute *attr, const char *buf, size_t count){if(!strncmp(buf, CTL_POWER_ON, strlen(CTL_POWER_ON))) {gpio_set_value(test_gpio0, 1);} else if(!strncmp(buf, CTL_POWER_OFF, strlen(CTL_POWER_OFF))) {gpio_set_value(test_gpio0, 0);}return count;}static struct device_attribute test_gpio0_dev_attr = {.attr = {.name = "state",.mode = S_IRWXU|S_IRWXG|S_IRWXO,},.show = test_gpio0_show,.store = test_gpio0_store,};static int test_gpio_probe(struct platform_device *pdev){int ret = 0;printk("zc enter test_gpio_probe \n");//寻找设备树dts下的 "test_gpio,gpio0" 名称对应的GPIO口test_gpio0 = of_get_named_gpio(pdev->dev.of_node, "test_gpio,gpio0", 0);if (test_gpio0 < 0)printk("test_gpio0 is not available \n");//对应修改的dts的 labelret = gpio_request(test_gpio0, "test_gpio");if(0 != ret) {printk("gpio request %d failed.", test_gpio0);goto fail1;}//设置gpio为输出gpio_direction_output(test_gpio0, 0);//创建test_gpios节点test_gpios_class = class_create(THIS_MODULE, "test_gpios");if(IS_ERR(test_gpios_class)){ret = PTR_ERR(test_gpios_class);printk("Failed to create class.\n");return ret;}//创建test_gpio0 的驱动设备test_gpio0_dev=device_create(test_gpios_class, NULL, 0, NULL, "test_gpio0");if (IS_ERR(test_gpio0_dev)){ret = PTR_ERR(test_gpios_class);printk("Failed to create device(test_gpio0_dev)!\n");return ret;}//根据 test_gpio0_dev_attr 配置，生成相应的文件ret = device_create_file(test_gpio0_dev, & test_gpio0_dev_attr);if(ret){pr_err("%s: test_gpio0 creat sysfs failed\n",__func__);return ret;}printk("enter test_gpio_probe, ok \n");fail1:return ret;}static int test_gpio_remove(struct platform_device *pdev){device_destroy(test_gpios_class, 0);class_destroy(test_gpios_class);device_remove_file(test_gpio0_dev, & test_gpio0_dev_attr);return 0;}static int test_gpio_suspend(struct platform_device *pdev,pm_message_t state){return 0;}static int test_gpio_resume(struct platform_device *pdev){return 0;}static struct of_device_id test_gpio_dt_match[] = {{ .compatible = "test_gpio",},{ },};MODULE_DEVICE_TABLE(of, test_gpio_dt_match);//驱动的方法与函数对应static struct platform_driver gpio_power_driver = {.driver = {.name = "test_gpio",.owner = THIS_MODULE,.of_match_table = of_match_ptr(test_gpio_dt_match),},.probe = test_gpio_probe,.remove = test_gpio_remove,.suspend = test_gpio_suspend,.resume = test_gpio_resume,};static __init int gpio_power_init(void){return platform_driver_register(&gpio_power_driver);}static void __exit gpio_power_exit(void){platform_driver_unregister(&gpio_power_driver);}module_init(gpio_power_init);module_exit(gpio_power_exit);MODULE_LICENSE("GPL");MODULE_DESCRIPTION("test_gpio Driver");

3.修改 kernel/drivers/misc 下 Makefile 和 Kconfig 文件

在Kconfig文件最后endmenu前面添加config TEST_GPIOtristate "test_gpio"在Makefile文件最后添加obj-$(CONFIG_TEST_GPIO) += test_gpio.o

4. 修改 kernel/arch/arm/configs 下的msm8909-1gb_defconfig 文件

msm8909-1gb_defconfig这个文件是根据芯片型号和编译的版本来的，我的是在/device/qcom/msm8909/AndroidBoard.mk中定义。如下

ifeq ($(KERNEL_DEFCONFIG),)ifeq ($(TARGET_BUILD_VARIANT),user)KERNEL_DEFCONFIG := msm8909-1gb-perf_defconfigelseKERNEL_DEFCONFIG := msm8909-1gb_defconfigendifendif

user版本是选择msm8909-1gb-perf_defconfig，其余版本是msm8909-1gb_defconfig。

修改msm8909-1gb_defconfig如下

在文件最后添加CONFIG_TEST_GPIO=y

添加这个，才能把写的驱动编译进系统。