S3C6410 PWM Buzzer Porting 移植

[keyword]: embedded system, s3c6410, Linx, Android, PWM, Buzzer

大家好，我是Shawn，从事这个行业7~8年一直在用CSDN这个平台作为技术参考，最近转入这个嵌入式行业，想通过这个平台结识更多的朋友.

 

Step1: Create linux driver.

The article suppose you have already created a pwn node (dev/pwm)under linux kernel.

 

Step2: Android HAL

 

1. create android.2.3.4/hardware/pwm/Android.mk

 

 

2. create android.2.3.4/hardware/pwm/include/pwm.h

 

 #include <hardware/hardware.h> #include <fcntl.h> #include <errno.h> #include <cutils/log.h> #include <cutils/atomic.h> /******************************************************************/ struct pwm_module_t { struct hw_module_t common; }; struct pwm_control_device_t { struct hw_device_t common; /* attributes */ int fd; /* supporting control APIs go here */ int (*stop_pwm)(struct pwm_control_device_t *dev, int32_t dummy); int (*set_freq)(struct pwm_control_device_t *dev, int32_t freq); }; /***************************************************************************/ struct pwm_control_context_t { struct pwm_control_device_t device; }; #define PWM_HARDWARE_MODULE_ID "pwm"

 

2. create android.2.3.4/hardware/pwm/include/pwm.c

#define LOG_TAG "ForlinxPWMStub" #include <hardware/hardware.h> #include <fcntl.h> #include <errno.h> #include <cutils/log.h> #include <cutils/atomic.h> #include <pwm.h> #define PWM_IOCTL_SET_FREQ 1 #define PWM_IOCTL_STOP 0 /*****************************************************************************/ int g_fd=0; int pwm_device_close(struct hw_device_t* device) { struct pwm_control_device_t* ctx = (struct pwm_control_device_t*)device; if (ctx) { free(ctx); } close(g_fd); return 0; } int stop_pwm(struct pwm_control_device_t *dev, int32_t dummy) { LOGI("PWM Stub: stop pwm"); ioctl(g_fd, PWM_IOCTL_STOP); //stop pwm(buzzer) return 0; } int set_freq(struct pwm_control_device_t *dev, int32_t freq) { if(freq > 0 ) { LOGI("PWM Stub: set frequency:%d", freq); ioctl(g_fd, PWM_IOCTL_SET_FREQ , freq);// set pwm frequency } else { LOGI("PWM Stub: Invalid frequency:%d", freq); } return 0; } static int pwm_device_open(const struct hw_module_t* module, const char* name, struct hw_device_t** device) { struct pwm_control_device_t *dev; dev = (struct pwm_control_device_t *)malloc(sizeof(*dev)); memset(dev, 0, sizeof(*dev)); dev->common.tag = HARDWARE_DEVICE_TAG; dev->common.version = 0; dev->common.module = (struct hw_module_t*)module; dev->common.close = pwm_device_close; dev->stop_pwm = stop_pwm; dev->set_freq = set_freq; *device = &dev->common; g_fd = open("/dev/pwm0", 0); if (g_fd < 0) { g_fd = open("/dev/pwm", 0); } if(g_fd<0) { LOGI("PWM Stub: open /dev/pwm failure."); }else { LOGI("PWM Stub: open /dev/pwm successful ."); } return 0; } static struct hw_module_methods_t pwm_module_methods = { open: pwm_device_open }; extern "C" const struct pwm_module_t HAL_MODULE_INFO_SYM = { common: { tag: HARDWARE_MODULE_TAG, version_major: 1, version_minor: 0, id: PWM_HARDWARE_MODULE_ID, name: "Sample PWM Stub", author: "Forlinx Open Source Project", methods: &pwm_module_methods, } /* supporting APIs go here */ };

 

Step3: