[经验]

【WaRP7试用体验】4.在Yocto框架添加驱动程序验证

2017-8-5 10:59:02

4050

  Yocto框架接触一段时间以后就会越来越感觉到它的优势。原有layer可以让我们非常方便的利用现有资源，各种模版也可以根据自己的需求任意添加需求，不论是应用程序，还是驱动程序，还是系统组件和驱动模块。
  前面的帖子尝试新添加应用程序和驱动模块，这次我们尝试在现在kernel里面新加一个驱动程序，并读取dts的一些属性设置。
1）源代码和dts相关
  kernel的根目录：warp7_yocto/build/tmp/work-shared/imx7s-warp/kernel-source
  c文件：drivers/char/unflattendts.c

#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#define unflattendts_tiP "unflattendts_tip"
int g_nNum = 0;
char unflattendts_string[64] = "unflattendts, unflattendts_show";
int unflattendts_major = 217;
int unflattendts_open(struct inode *inode, struct file *filep)
{
int nNum = 99;
printk("unflattendts_open nNum=%d g_nNum=%dn", nNum, g_nNum);
return 0;
}
static const struct file_operations unflattendts_fops = {
.owner = THIS_MODULE,
.open = unflattendts_open,
};
static ssize_t show_unf(struct device_driver *driver, char *buf)
{
if(NULL != buf)
{
/* Newline is not appended on purpose, for convenience of reader programs */
snprintf(buf, PAGE_SIZE, "%sn", unflattendts_string);
return strlen(buf);
}
return 0;
}
static DRIVER_ATTR(unflattendts, 0444, show_unf, NULL);
static struct attribute *unflattendts_attrs[] = {
&driver_attr_unflattendts.attr,
NULL,
};
static struct attribute_group unflattendts_group = {
.name = "unflattendts",
.attrs = unflattendts_attrs,
};
static const struct attribute_group *unflattendts_groups[] = {
&unflattendts_group,
NULL,
};
static int unflattendts_probe(struct platform_device *pdev)
{
int nNum;
int ret;
const char *m_string;
printk("-0000-unflattendts_proben");
if(NULL == pdev)
{
printk("unflattendts_probe: unflattendts_probe failed, pdev is NULLn");
return 0;
}
if(NULL == pdev->dev.of_node)
{
printk( "unflattendts_probe: unflattendts_probe failed, of_node is NULLn");
return 0;
}
/* unflattendts_TIP*/
if(of_property_read_bool(pdev->dev.of_node, unflattendts_TIP))
{
printk( "unflattendts_probe: dtsi<%s> is existingn", unflattendts_TIP);
}
if (of_property_read_u32(pdev->dev.of_node, "linux,code", &nNum))
{
printk(KERN_INFO "=11= nNum=%dn", nNum);
}
else
{
printk(KERN_INFO "=0101= nNum=%dn", nNum);
}
g_nNum = nNum;
if (of_property_read_string(pdev->dev.of_node, "linux,string", &m_string))
{
strcpy(unflattendts_string, m_string);
printk(KERN_INFO "=11= m_string=%s unflattendts_string=%sn", m_string, unflattendts_string);
}
else
{
printk(KERN_INFO "=12= m_string=%sn", m_string);
}
return 0;
}
static struct of_device_id unflattendts_info_match_table[] = {
{ .compatible = "fsl,unflattendts",},
{ },
};
static struct platform_driver unflattendts = {
.driver = {
.name = "unflattendts",
.owner = THIS_MODULE,
.of_match_table = unflattendts_info_match_table,
},
.probe = unflattendts_probe,
.remove = NULL,
};
static int __init unflattendts_init(void)
{
printk("unflattendts_initn");
return platform_driver_register(&unflattendts);
}
static void __exit unflattendts_exit(void)
{
platform_driver_unregister(&unflattendts);
printk("unflattendts_exitn");
}
module_init(unflattendts_init);
module_exit(unflattendts_exit);
MODULE_LICENSE("GPL");

复制代码

Makefile：driver/char
obj-$(CONFIG_UNFLATTENDTS) += unflattendts.o
imx_v7_defconfig：arch/arm/configs

CONFIG_UNFLATTENDTS=y

dts文件：arch/arm/boot/dts/imx7s-warp.dts

memory {
reg = <0x80000000 0x40000000>;
};
unflattendts {
compatible = "fsl,unflattendts";
#address-cells = <3>;
#size-cells = <1>;
unflattendts_tip;
linux,code = <20170111>;
linux,string = "NXP fsl";
};
gpio-keys {
compatible = "gpio-keys";
pinctrl-0 = <&pinctrl_gpio>;
autorepeat;
back {
label = "Back";
gpios = <&gpio7 1 GPIO_ACTIVE_HIGH>;
linux,code = ;
gpio-key,wakeup;
autorepeat;
};
};

复制代码

2）编译

bitbake linux-warp7 -c compile -f

复制代码

3）下载运行
unflattendts_init
-0000-unflattendts_probe
unflattendts_probe: dtsi is existing
=0101= nNum=20170111
=12= m_string=NXP fsl

后面尝试把开发板自带WIFI使能起来。