art-pi smart 里并没有实现ADC驱动，然而我自己又很需要使用ADC，所以只能自己补一个ADC驱动了。
主体程序都是仿照drv_pwm写的。
大佬说，驱动可以搬imxrt里面的，所以我就借用了rt-thread里的两个关键文件：
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fsl_adc.c和fsl_adc.h。具体目录参考图片。
怎么去理解fsl_xxx文件呢？类比的话就是STM32的HAL库的文件。
另外还有drv_adc.c和drv_adc.h
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也是搬过来的。
当然，换了MCU了，函数名字还是需要改改的。
放出源码，还有很多需要改良的地方的。
/*
* Copyright (c) 2006-2021, RT-Thread Development Team
*
* SPDX-License-Identifier: Apache-2.0
*
* Change Logs:
* Date Author Notes
* 2019-04-28 tyustli first version
*
*/
#include
#define RT_USING_ADC
#ifdef RT_USING_ADC
#define LOG_TAG "drv.adc"
#include
#include
#include
#include "fsl_adc.h"
#include "drv_adc.h"
#include
#include
static rt_err_t imx6ull_adc_enabled(struct rt_adc_device *device, rt_uint32_t channel, rt_bool_t enabled)
{
return RT_EOK;
}
static rt_err_t imx6ull_adc_convert(struct rt_adc_device *device, rt_uint32_t channel, rt_uint32_t *value)
{
adc_channel_config_t adc_channel;
ADC_Type *base;
base = (ADC_Type *)(device->parent.user_data);
adc_channel.channelNumber = channel;
adc_channel.enableInterruptOnConversionCompleted = 0;
ADC_SetChannelConfig(base, 0, &adc_channel);
while (0U == ADC_GetChannelStatusFlags(base, 0))
{
continue;
}
*value = ADC_GetChannelConversionValue(base, 0);
return RT_EOK;
}
static struct rt_adc_ops imx6ull_adc_ops =
{
.enabled = imx6ull_adc_enabled,
.convert = imx6ull_adc_convert,
};
int imx6ull_adc_gpio_init(void)
{
#ifdef BSP_USING_ADC1_1
do {
struct imx6ull_iomuxc gpio;
uint32_t pin_fun_id[5]={IOMUXC_GPIO1_IO01_GPIO1_IO01};
gpio.muxRegister = pin_fun_id[0];
gpio.muxMode = pin_fun_id[1];
gpio.inputRegister = pin_fun_id[2];
gpio.inputDaisy = pin_fun_id[3];
gpio.configRegister = pin_fun_id[4];
gpio.inputOnfield = 0;
gpio.configValue = IOMUXC_SW_PAD_CTL_PAD_DSE(2U) | IOMUXC_SW_PAD_CTL_PAD_SPEED(2U);
imx6ull_gpio_init(&gpio);
}while(0);
#endif
#ifdef BSP_USING_ADC1_2
do {
struct imx6ull_iomuxc gpio;
uint32_t pin_fun_id[5]={IOMUXC_GPIO1_IO02_GPIO1_IO02};
gpio.muxRegister = pin_fun_id[0];
gpio.muxMode = pin_fun_id[1];
gpio.inputRegister = pin_fun_id[2];
gpio.inputDaisy = pin_fun_id[3];
gpio.configRegister = pin_fun_id[4];
gpio.inputOnfield = 0;
gpio.configValue = IOMUXC_SW_PAD_CTL_PAD_DSE(2U) | IOMUXC_SW_PAD_CTL_PAD_SPEED(2U);
imx6ull_gpio_init(&gpio);
}while(0);
#endif
#ifdef BSP_USING_ADC1_3
do {
struct imx6ull_iomuxc gpio;
uint32_t pin_fun_id[5]={IOMUXC_GPIO1_IO03_GPIO1_IO03};
gpio.muxRegister = pin_fun_id[0];
gpio.muxMode = pin_fun_id[1];
gpio.inputRegister = pin_fun_id[2];
gpio.inputDaisy = pin_fun_id[3];
gpio.configRegister = pin_fun_id[4];
gpio.inputOnfield = 0;
gpio.configValue = IOMUXC_SW_PAD_CTL_PAD_DSE(2U) | IOMUXC_SW_PAD_CTL_PAD_SPEED(2U);
imx6ull_gpio_init(&gpio);
}while(0);
#endif
#ifdef BSP_USING_ADC1_4
do {
struct imx6ull_iomuxc gpio;
uint32_t pin_fun_id[5]={IOMUXC_GPIO1_IO04_GPIO1_IO04};
gpio.muxRegister = pin_fun_id[0];
gpio.muxMode = pin_fun_id[1];
gpio.inputRegister = pin_fun_id[2];
gpio.inputDaisy = pin_fun_id[3];
gpio.configRegister = pin_fun_id[4];
gpio.inputOnfield = 0;
gpio.configValue = IOMUXC_SW_PAD_CTL_PAD_DSE(2U) | IOMUXC_SW_PAD_CTL_PAD_SPEED(2U);
imx6ull_gpio_init(&gpio);
}while(0);
#endif
return 0;
}
int rt_hw_adc_init(void)
{
rt_err_t ret = RT_EOK;
imx6ull_adc_gpio_init();
#if defined(BSP_USING_ADC1_1) || defined(BSP_USING_ADC1_2) || defined(BSP_USING_ADC1_3) || defined(BSP_USING_ADC1_4)
static adc_config_t ADC1_config_value;
static struct rt_adc_device adc1_device;
ADC_Type *adc1_base;
adc1_base = (ADC_Type *)rt_ioremap((void*)ADC1, 0x1000);
ADC_GetDefaultConfig(&ADC1_config_value);
ADC_Init(adc1_base, &ADC1_config_value);
ADC_DoAutoCalibration(adc1_base);
ret = rt_hw_adc_register(&adc1_device, "adc1", &imx6ull_adc_ops, adc1_base);
if (ret != RT_EOK)
{
LOG_E("register adc1 device failed error code = %d
", ret);
}
#endif
return ret;
}
INIT_DEVICE_EXPORT(rt_hw_adc_init);
void set_adc_default(void *parameter)
{
int result = 0;
#ifdef BSP_USING_ADC1_1
do {
struct rt_adc_device *device = RT_NULL;
device = (struct rt_adc_device *)rt_device_find("adc1");
if (!device)
{
result = -RT_EIO;
return;
}
result = rt_adc_enable(device, 1);
result = rt_adc_read(device, 1);
rt_kprintf("adc ch1 read result is %d
",result);
} while(0);
#endif
#ifdef BSP_USING_ADC1_2
do {
struct rt_adc_device *device = RT_NULL;
device = (struct rt_adc_device *)rt_device_find("adc1");
if (!device)
{
result = -RT_EIO;
return;
}
result = rt_adc_enable(device, 2);
result = rt_adc_read(device, 2);
rt_kprintf("adc ch2 read result is %d
",result);
} while(0);
#endif
#ifdef BSP_USING_ADC1_3
do {
struct rt_adc_device *device = RT_NULL;
device = (struct rt_adc_device *)rt_device_find("adc1");
if (!device)
{
result = -RT_EIO;
return;
}
result = rt_adc_enable(device, 3);
result = rt_adc_read(device, 3);
rt_kprintf("adc ch3 read result is %d
",result);
} while(0);
#endif
#ifdef BSP_USING_ADC1_4
do {
struct rt_adc_device *device = RT_NULL;
device = (struct rt_adc_device *)rt_device_find("adc1");
if (!device)
{
result = -RT_EIO;
return;
}
result = rt_adc_enable(device, 4);
result = rt_adc_read(device, 4);
rt_kprintf("adc ch4 read result is %d
",result);
} while(0);
#endif
}
static int set_adc_init(void)
{
rt_thread_t tid = rt_thread_create("adc_loop", set_adc_default, RT_NULL, 1024, 16, 20);
RT_ASSERT(tid != RT_NULL);
rt_thread_startup(tid);
return(RT_EOK);
}
INIT_APP_EXPORT(set_adc_init);
#endif /* BSP_USING_ADC */
编译，烧录，运行，观察效果：
![]()
观察CH4，因为我改的是CH4
![]()
第一次运行，CH4接的是3.3V，第二次运行CH4接的是GND。AD值符合预期。 中间值也调试过，不过没有截图。
另外，还需要修改 修改driver下的kconfig，让人可以在menuconfig里使能ADC,我目前就只验证过ADC1的1-4通道。
menu "Select ADC Driver"
config RT_USING_ADC
bool "Enable ADC"
default n
if RT_USING_ADC
config BSP_USING_ADC1_1
bool "Enable ADC1 CH1"
default n
config BSP_USING_ADC1_2
bool "Enable ADC1 CH2"
default n
config BSP_USING_ADC1_3
bool "Enable ADC1 CH3"
default n
config BSP_USING_ADC1_4
bool "Enable ADC1 CH4"
default n
endif
endmenu
修改看着简单，中途碰过很多壁，都是大佬指导和仿照PWM写的。 测试环境是：imx6ull pro以及art-pi smart。（没错，两块板子都能跑，毫无违和感。）
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