• imx6ull内置温度传感器实践1:输出一个采样

    前言

            先写代码，然后再一个问题，一个问题分析。不是应该先分析问题，再写代码吗？因为笨呗。分析不明白。只有看到现象，才能明白手册上说的是啥意思。   

            实例1 主要完成以下几个事情

            1 创建一个misc驱动

            2 在驱动中将寄存器remap过来，需要映射的寄存器的列表，不要怕，代码都有。

             3 配置寄存器的值，然后在1秒定时器中输出TEMP_CNT值

     

    一 使用到的函数

            映射和解除映射函数

            如下，ioremap其实是一个宏，但是宏看起来不好理解，所以，我就把它当成一个下面这样的函数来用，好理解，ioremap的返回值，可以作为iounmap的参数，ioremap的第一个参数paddr就是前面列表中的寄存器地址，例如0x20c 8180，它是32位寄存器，4个字节，所以参数byte_count传入4。

    1. #include 
    2. volatile void __iomem *ioremap(void *paddr,int byte_count);
    3. void iounmap (volatile void __iomem *addr)

    读寄存器函数

    u8 readb ( const volatile void __iomem * addr )
    u16 readw ( const volatile void __iomem * addr )
    u32 readl ( const volatile void __iomem * addr )
    readb 、 readw 和 readl 这三个函数分别对应 8bit 、 16bit 和 32bit 读操作，参数 addr 就是要
    读取写内存地址，返回值就是读取到的数据。

    写寄存器函数

    void writeb ( u8 value , volatile void __iomem * addr )
    void writew ( u16 value , volatile void __iomem * addr )
    void writel ( u32 value , volatile void __iomem * addr )
    writeb 、 writew 和 writel 这三个函数分别对应 8bit 、 16bit 和 32bit 写操作，参数 value 是要
    写入的数值， addr 是要写入的地址。

    本次实例，我们使用writel 和readl ；

    二 实例代码

    1. #include 
    2. #include 
    3. #include 
    4. #include 
    5. #include 
    6. #include 
    7. #include 
    8. #include 
    9. #include 
    10. #include 
    11. #include 
    12. #include 
    13. #include 
    14.  
    15. #define DEBUG_TEMP(format,...)	printk("%s,%d:"format"\n",	\
    16. 	__func__,__LINE__,##__VA_ARGS__)
    17.  
    18. /* 寄存器物理地址 */
    19. #define		TEMPMON_TEMPSENSE0 		(0x020C8180)
    20. #define		TEMPMON_TEMPSENSE0_SET	(0x020C8184)
    21. #define		TEMPMON_TEMPSENSE0_CLR	(0x020C8188)
    22. #define		TEMPMON_TEMPSENSE0_TOG	(0x020C818C)
    23.  
    24. #define		TEMPMON_TEMPSENSE1 		(0x020C8190)
    25. #define		TEMPMON_TEMPSENSE1_SET	(0x020C8184)
    26. #define		TEMPMON_TEMPSENSE1_CLR	(0x020C8198)
    27. #define		TEMPMON_TEMPSENSE1_TOG	(0x020C819C)
    28.  
    29. #define		TEMPMON_TEMPSENSE2 		(0x020C8290)
    30. #define		TEMPMON_TEMPSENSE2_SET	(0x020C8294)
    31. #define		TEMPMON_TEMPSENSE2_CLR	(0x020C8298)
    32. #define		TEMPMON_TEMPSENSE2_TOG	(0x020C829C)
    33.  
    34.  /* 映射后的寄存器虚拟地址指针 */
    35. static void __iomem *IMX6U_TEMPMON_TEMPSENSE0;
    36. static void __iomem *IMX6U_TEMPMON_TEMPSENSE0_SET;
    37. static void __iomem *IMX6U_TEMPMON_TEMPSENSE0_CLR;
    38. static void __iomem *IMX6U_TEMPMON_TEMPSENSE0_TOG;
    39.  
    40. static void __iomem *IMX6U_TEMPMON_TEMPSENSE1;
    41. static void __iomem *IMX6U_TEMPMON_TEMPSENSE1_SET;
    42. static void __iomem *IMX6U_TEMPMON_TEMPSENSE1_CLR;
    43. static void __iomem *IMX6U_TEMPMON_TEMPSENSE1_TOG;
    44.  
    45. static void __iomem *IMX6U_TEMPMON_TEMPSENSE2;
    46. static void __iomem *IMX6U_TEMPMON_TEMPSENSE2_SET;
    47. static void __iomem *IMX6U_TEMPMON_TEMPSENSE2_CLR;
    48. static void __iomem *IMX6U_TEMPMON_TEMPSENSE2_TOG;
    49.  
    50. struct temperature_register{
    51. 	void __iomem *ctrl;
    52. 	void __iomem *set;
    53. 	void __iomem *clr;
    54. 	void __iomem *tog;
    55. };
    56.  
    57. struct _temperature_sensor_{
    58. 	struct miscdevice misc;
    59. 	struct file_operations fops;
    60. 	struct temperature_register reg[3];
    61. 	struct timer_list timer;
    62. };
    63.  
    64. #define IMX6U_TEMPMON_TEMPSENSE(num)	(IMX6U_TEMPMON_TEMPSENSE##num)
    65. #define IMX6U_TEMPMON_TEMPSENSE_XXX(num,text)	(IMX6U_TEMPMON_TEMPSENSE##num##text)
    66.  
    67. static int imx_temperature_monitor_init(struct _temperature_sensor_ *p)
    68. {
    69. 	int i = 0;
    70. 	u32 val;
    71. 	IMX6U_TEMPMON_TEMPSENSE0 = ioremap(TEMPMON_TEMPSENSE0,4);
    72. 	IMX6U_TEMPMON_TEMPSENSE0_SET = ioremap(TEMPMON_TEMPSENSE0_SET,4);
    73. 	IMX6U_TEMPMON_TEMPSENSE0_CLR = ioremap(TEMPMON_TEMPSENSE0_CLR,4);
    74. 	IMX6U_TEMPMON_TEMPSENSE0_TOG = ioremap(TEMPMON_TEMPSENSE0_TOG,4);
    75.  
    76. 	DEBUG_TEMP("%p",IMX6U_TEMPMON_TEMPSENSE0);
    77. 	DEBUG_TEMP("%p",IMX6U_TEMPMON_TEMPSENSE0_SET);
    78. 	DEBUG_TEMP("%p",IMX6U_TEMPMON_TEMPSENSE0_CLR);
    79. 	DEBUG_TEMP("%p",IMX6U_TEMPMON_TEMPSENSE0_TOG);
    80.  
    81. 	IMX6U_TEMPMON_TEMPSENSE1 = ioremap(TEMPMON_TEMPSENSE1,4);
    82. 	IMX6U_TEMPMON_TEMPSENSE1_SET = ioremap(TEMPMON_TEMPSENSE1_SET,4);
    83. 	IMX6U_TEMPMON_TEMPSENSE1_CLR = ioremap(TEMPMON_TEMPSENSE1_CLR,4);
    84. 	IMX6U_TEMPMON_TEMPSENSE1_TOG = ioremap(TEMPMON_TEMPSENSE1_TOG,4);
    85.  
    86. 	DEBUG_TEMP("%p",IMX6U_TEMPMON_TEMPSENSE1);
    87. 	DEBUG_TEMP("%p",IMX6U_TEMPMON_TEMPSENSE1_SET);
    88. 	DEBUG_TEMP("%p",IMX6U_TEMPMON_TEMPSENSE1_CLR);
    89. 	DEBUG_TEMP("%p",IMX6U_TEMPMON_TEMPSENSE1_TOG);
    90.  
    91. 	IMX6U_TEMPMON_TEMPSENSE2 = ioremap(TEMPMON_TEMPSENSE2,4);
    92. 	IMX6U_TEMPMON_TEMPSENSE2_SET = ioremap(TEMPMON_TEMPSENSE2_SET,4);
    93. 	IMX6U_TEMPMON_TEMPSENSE2_CLR = ioremap(TEMPMON_TEMPSENSE2_CLR,4);
    94. 	IMX6U_TEMPMON_TEMPSENSE2_TOG = ioremap(TEMPMON_TEMPSENSE2_TOG,4);
    95.  
    96. 	DEBUG_TEMP("%p",IMX6U_TEMPMON_TEMPSENSE2);
    97. 	DEBUG_TEMP("%p",IMX6U_TEMPMON_TEMPSENSE2_SET);
    98. 	DEBUG_TEMP("%p",IMX6U_TEMPMON_TEMPSENSE2_CLR);
    99. 	DEBUG_TEMP("%p",IMX6U_TEMPMON_TEMPSENSE2_TOG);
    100.  
    101. 	p->reg[0].ctrl = IMX6U_TEMPMON_TEMPSENSE(0);
    102. 	p->reg[0].set = IMX6U_TEMPMON_TEMPSENSE_XXX(0,_SET);
    103. 	p->reg[0].clr = IMX6U_TEMPMON_TEMPSENSE_XXX(0,_CLR);
    104. 	p->reg[0].tog = IMX6U_TEMPMON_TEMPSENSE_XXX(0,_TOG);
    105.  
    106. 	p->reg[1].ctrl = IMX6U_TEMPMON_TEMPSENSE(1);
    107. 	p->reg[1].set = IMX6U_TEMPMON_TEMPSENSE_XXX(1,_SET);
    108. 	p->reg[1].clr = IMX6U_TEMPMON_TEMPSENSE_XXX(1,_CLR);
    109. 	p->reg[1].tog = IMX6U_TEMPMON_TEMPSENSE_XXX(1,_TOG);
    110.  
    111. 	p->reg[2].ctrl = IMX6U_TEMPMON_TEMPSENSE(2);
    112. 	p->reg[2].set = IMX6U_TEMPMON_TEMPSENSE_XXX(2,_SET);
    113. 	p->reg[2].clr = IMX6U_TEMPMON_TEMPSENSE_XXX(2,_CLR);
    114. 	p->reg[2].tog = IMX6U_TEMPMON_TEMPSENSE_XXX(2,_TOG);
    115.  
    116. 	for(i = 0;i < 3;i++){
    117. 		DEBUG_TEMP("p->reg[%d].ctrl = %p",i,p->reg[i].ctrl);
    118. 		DEBUG_TEMP("p->reg[%d].set = %p",i,p->reg[i].set);
    119. 		DEBUG_TEMP("p->reg[%d].clr = %p",i,p->reg[i].clr);
    120. 		DEBUG_TEMP("p->reg[%d].tog = %p",i,p->reg[i].tog);
    121. 	}
    122. 	DEBUG_TEMP("");
    123. 	DEBUG_TEMP("");
    124. 	for(i = 0;i < 3;i++){
    125. 		DEBUG_TEMP("p->reg[%d].ctrl = %08x",i,readl(p->reg[i].ctrl));
    126. 		DEBUG_TEMP("p->reg[%d].set = %08x",i,readl(p->reg[i].set));
    127. 		DEBUG_TEMP("p->reg[%d].clr = %08x",i,readl(p->reg[i].clr));
    128. 		DEBUG_TEMP("p->reg[%d].tog = %08x",i,readl(p->reg[i].tog));
    129. 	}
    130.  
    131. 	writel(1 << 0,p->reg[0].clr);
    132. 	writel(2 << 0,p->reg[0].clr);
    133. 	writel(1 << 1,p->reg[0].set);
    134.  
    135. 	
    136. 	writel(1,p->reg[1].clr);
    137. 	return 0;
    138. }
    139. static long imx_temperature_unlocked_ioctl (
    140. 	struct file *file, unsigned int cmd, unsigned long arg)
    141. {
    142. 	DEBUG_TEMP("");
    143. 	return 0;
    144. }
    145. struct _temperature_sensor_ imx_temperature_sensor = {
    146. 	.fops = {
    147. 		.owner = THIS_MODULE,
    148. 		.unlocked_ioctl = imx_temperature_unlocked_ioctl,
    149. 	},
    150. 	.misc = {
    151. 		.name = "imx_temp",
    152. 		.minor = MISC_DYNAMIC_MINOR,
    153. 	},
    154. };
    155. void temperature_timer_function(unsigned long arg)
    156. {
    157. 	struct _temperature_sensor_ *p = (struct _temperature_sensor_ *)arg;
    158. 	u32 val = readl(p->reg[0].ctrl);
    159. 	static int last_val = 0;
    160.  
    161. 	while(1){
    162. 		if((val & 0x04) == 0){
    163. 			break;
    164. 		}
    165. 		
    166. 		DEBUG_TEMP("val = %08x,%d,%d,temperature = %d",val,val-last_val,(val&0xfff00000)>>20,(val&0xfff00)>>8);
    167. 		last_val = val;
    168. 		
    169. 		writel(1 << 0,p->reg[0].clr);
    170. 		writel(2 << 0,p->reg[0].clr);
    171. 		writel(1 << 1,p->reg[0].set);
    172. 		break;
    173. 	}
    174. 	mod_timer(&p->timer,msecs_to_jiffies(1000) + jiffies);
    175. }
    176. static int __init temperature_init(void)
    177. {
    178. 	struct _temperature_sensor_ *p = &imx_temperature_sensor;
    179. 	p->misc.fops = &p->fops;
    180. 	imx_temperature_monitor_init(p);
    181. 	
    182. 	
    183. 	if(misc_register(&p->misc) != 0){
    184. 		DEBUG_TEMP("misc_register error");
    185. 		return -EINVAL;
    186. 	}
    187. 	init_timer(&p->timer);
    188. 	p->timer.data = (unsigned long)p;
    189. 	p->timer.function = temperature_timer_function;
    190. 	mod_timer(&p->timer,msecs_to_jiffies(1000) + jiffies);
    191. 	DEBUG_TEMP("");
    192. 	return 0;
    193. }
    194. static void __exit temperature_exit(void)
    195. {
    196. 	struct _temperature_sensor_ *p = &imx_temperature_sensor;
    197. 	int i = 0;
    198. 	del_timer_sync(&p->timer);
    199. 	for(i = 0;i < 3;i++){
    200. 		iounmap(p->reg[i].ctrl);
    201. 		iounmap(p->reg[i].set);
    202. 		iounmap(p->reg[i].clr);
    203. 		iounmap(p->reg[i].tog);
    204. 	}
    205. 	
    206. 	misc_deregister(&p->misc);
    207. 	DEBUG_TEMP("");
    208. }
    209. module_init(temperature_init);
    210. module_exit(temperature_exit);
    211. MODULE_LICENSE("GPL");
    212.

    Makefile

    1. export ARCH=arm
    2. export CROSS_COMPILE=arm-linux-gnueabihf-
    3. KERN_DIR = /home/lkmao/imx/linux/linux-imx
    4.  
    5. FILE_NAME=temperature
    6. obj-m += $(FILE_NAME).o
    7.  
    8. all:
    9.     make -C $(KERN_DIR) M=$(shell pwd) modules
    10.     sudo cp $(FILE_NAME).ko /big/nfsroot/buildrootfs/home/root/
    11.     sudo scp $(FILE_NAME).ko root@192.168.0.3:/home/root/
    12. .PHONY:clean
    13. clean:
    14.     make -C $(KERN_DIR) M=$(shell pwd) clean
    15.     rm app -rf

    测试结果

    1. [ 1428.046419] temperature_timer_function,166:val = 49a4d006,256,1178,temperature = 1232
    2. [ 1429.046419] temperature_timer_function,166:val = 49a4cf06,-256,1178,temperature = 1231
    3. [ 1430.046420] temperature_timer_function,166:val = 49a4cf06,0,1178,temperature = 1231
    4. [ 1431.046419] temperature_timer_function,166:val = 49a4cf06,0,1178,temperature = 1231
    5. [ 1432.046418] temperature_timer_function,166:val = 49a4d006,256,1178,temperature = 1232
    6. [ 1433.046425] temperature_timer_function,166:val = 49a4d006,0,1178,temperature = 1232
    7. [ 1434.046415] temperature_timer_function,166:val = 49a4cf06,-256,1178,temperature = 1231
    8. [ 1435.046418] temperature_timer_function,166:val = 49a4cf06,0,1178,temperature = 1231
    9. [ 1436.046420] temperature_timer_function,166:val = 49a4cf06,0,1178,temperature = 1231
    10. [ 1437.046420] temperature_timer_function,166:val = 49a4cf06,0,1178,temperature = 1231
    11. [ 1438.046419] temperature_timer_function,166:val = 49a4cf06,0,1178,temperature = 1231
    12. [ 1439.046418] temperature_timer_function,166:val = 49a4cf06,0,1178,temperature = 1231
    13. [ 1440.046419] temperature_timer_function,166:val = 49a4cf06,0,1178,temperature = 1231
    14. [ 1441.046421] temperature_timer_function,166:val = 49a4cf06,0,1178,temperature = 1231

    小结

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  • 原文地址：https://blog.csdn.net/yueni_zhao/article/details/127889836