如何修改一个被占用的管脚，将其修改为普通gpio

mao0504

评估板的F11_VOUT1_D0信号被用作了屏线的vd0_b0, 我们新设计的板子把这个管脚用作普通的GPIO去控制一个芯片，设备树里面没有找到F11_VOUT1_D0管脚的信息，GPIO8 0,地址0x4A0035dc等信息，

我在设备树里添加了新的节点，代码如下。
写了一个新的驱动，通过insmod安装，demoApp设置这个GPIO的高低变化，可以安装，应用的时候会报错，错误内容见后面的表格；
如果管脚设置为led7 ，CTRL_CORE_PAD_MCASP2_AXR2，GPIO6_8，同样的方法、流程就没有问题，可以控制led7的闪烁。


请问我还有做什么吗？

1. 
   
2. mygpio56 {
   
3.                 pinctrl-names = "default";
   
4.                 pinctrl-0 = <&mygpio56_user_gpio>;
   
5.                 status = "okay";
   
6.                   compatible = "gpio567";
   
7.                   mygpio568 {
   
8.                                label = "mygpio569";  
   
9.                                gpios = <&gpio8 0 GPIO_ACTIVE_LOW>;
   
10.                     
    
11.                             };
    
12. 
    
13.                };
    
14. 
    
15. mygpio56_user_gpio: mygpio56_user_gpio {
    
16.                 pinctrl-single,pins = <                
    
17.                          DRA7XX_CORE_IOPAD(0x35dc, MUX_MODE14 | PIN_OUTPUT_PULLUP) /* gpio8-0 spi */
    
18.                 >;
    
19.         };

复制代码

报错内容：

1. 
   
2. [15705.814706] ------------[ cut here ]------------
   
3. [15705.819357] WARNING: CPU: 0 PID: 1330 at drivers/bus/omap_l3_noc.c:147 l3_interrupt_handler+0x25c/0x36c
   
4. [15705.828790] 44000000.ocp:L3 Custom Error: MASTER MPU TARGET L4_PER1_P3 (Read): Data Access in User mode during Functional access
   
5. [15705.840402] Modules linked in: mygpio567(O) sha512_generic sha512_arm sha256_generic sha1_generic sha1_arm_neon sha1_arm md5 cbc xfrm_user xfrm4_tunnel ipcomp xfrm_ipcomp esp4 ah4 af_key xfrm_algo rfcomm bc_example(O) wlan btusb btrtl btbcm btintel xhci_plat_hcd pru_rproc pruss_intc xhci_hcd rpmsg_proto pruss bluetooth dwc3 udc_core rpmsg_rpc snd_soc_**_card snd_soc_**_card_utils pwm_fan snd_soc_omap_hdmi_audio pvrsrvkm(O) omap_aes_driver c_can_platform c_can omap_sham pruss_soc_bus can_dev omap_wdt ahci_platform libahci_platform libahci libata scsi_mod ti_vip ti_vpe ti_sc ti_csc ti_vpdma dwc3_omap extcon_core w1_therm ti_cal gpio_pisosr rtc_rx8010 ov5640_mipi omap_des ov5640 snd_soc_wm8960 omap_hdq wire spidev des_generic crypto_engine omap_remoteproc virtio_rpmsg_bus rpmsg_core remoteproc sch_fq_codel xr_usb_serial_common usbcore usb_common uio_module_drv(O) uio gdbserverproxy(O) cryptodev(O) cmemk(O) [last unloaded: gt911]
   
6. [15705.924154] CPU: 0 PID: 1330 Comm: hello Tainted: G      D W  O    4.9.41 #29
   
7. [15705.931319] Hardware name: Generic DRA72X (Flattened Device Tree)
   
8. [15705.937436] Backtrace:
   
9. [15705.939909] [<c020b2d8>] (dump_backtrace) from [<c020b594>] (show_stack+0x18/0x1c)
   
10. [15705.947512]  r7:00000009 r6:60070193 r5:00000000 r4:c10229d0
    
11. [15705.953199] [<c020b57c>] (show_stack) from [<c04ace60>] (dump_stack+0x8c/0xa0)
    
12. [15705.960456] [<c04acdd4>] (dump_stack) from [<c022e4b8>] (__warn+0xec/0x104)
    
13. [15705.967448]  r7:00000009 r6:c0bcd6e0 r5:00000000 r4:ee413b40
    
14. [15705.973132] [<c022e3cc>] (__warn) from [<c022e510>] (warn_slowpath_fmt+0x40/0x48)
    
15. [15705.980649]  r9:00000006 r8:ef1dd2d0 r7:c0bcd54c r6:00000002 r5:c0bcd60c r4:c0bcd6b0
    
16. [15705.988428] [<c022e4d4>] (warn_slowpath_fmt) from [<c04dcd10>] (l3_interrupt_handler+0x25c/0x36c)
    
17. [15705.997337]  r3:ef1dd140 r2:c0bcd6b0
    
18. [15706.000926]  r4:80080003
    
19. [15706.003473] [<c04dcab4>] (l3_interrupt_handler) from [<c027fd20>] (__handle_irq_event_percpu+0xb4/0x138)
    
20. [15706.012995]  r10:c101a4af r9:ef1d1200 r8:00000017 r7:ee413c64 r6:00000000 r5:ef1d1200
    
21. [15706.020855]  r4:ef1dd640
    
22. [15706.023401] [<c027fc6c>] (__handle_irq_event_percpu) from [<c027fdc8>] (handle_irq_event_percpu+0x24/0x60)
    
23. [15706.033096]  r10:bf545360 r9:ee412000 r8:ef006000 r7:00000000 r6:c1008c34 r5:ef1d1200
    
24. [15706.040956]  r4:ef1d1200
    
25. [15706.043500] [<c027fda4>] (handle_irq_event_percpu) from [<c027fe44>] (handle_irq_event+0x40/0x64)
    
26. [15706.052409]  r5:ef1d1260 r4:ef1d1200
    
27. [15706.056002] [<c027fe04>] (handle_irq_event) from [<c02834f0>] (handle_fasteoi_irq+0xc0/0x190)
    
28. [15706.064563]  r7:00000000 r6:c1008c34 r5:ef1d1260 r4:ef1d1200
    
29. [15706.070247] [<c0283430>] (handle_fasteoi_irq) from [<c027ef48>] (generic_handle_irq+0x2c/0x3c)
    
30. [15706.078894]  r7:00000000 r6:00000000 r5:00000017 r4:c0e5cde0
    
31. [15706.084579] [<c027ef1c>] (generic_handle_irq) from [<c027f4d0>] (__handle_domain_irq+0x64/0xbc)
    
32. [15706.093316] [<c027f46c>] (__handle_domain_irq) from [<c02014a0>] (gic_handle_irq+0x40/0x7c)
    
33. [15706.101703]  r9:ee412000 r8:fa213000 r7:fa212000 r6:ee413d20 r5:fa21200c r4:c1003424
    
34. [15706.109479] [<c0201460>] (gic_handle_irq) from [<c020c138>] (__irq_svc+0x58/0x8c)
    
35. [15706.116993] Exception stack(0xee413d20 to 0xee413d68)
    
36. [15706.122066] 3d20: 00000000 fa053000 00000001 bf5459c0 bf545770 c103408c 00000038 c1034074
    
37. [15706.130278] 3d40: ee1a9b40 ed31d360 bf545360 ee413d7c ee413c30 ee413d70 c02c0f18 bf545054
    
38. [15706.138487] 3d60: 60070013 ffffffff
    
39. [15706.141990]  r9:ee412000 r8:ee1a9b40 r7:ee413d54 r6:ffffffff r5:60070013 r4:bf545054
    
40. [15706.149777] [<bf545020>] (mygpio_open [mygpio567]) from [<c05921bc>] (misc_open+0x15c/0x174)
    
41. [15706.158256] [<c0592060>] (misc_open) from [<c0333fc0>] (chrdev_open+0xac/0x190)
    
42. [15706.165596]  r10:ee1a9b40 r9:ee413ea8 r8:ef342300 r7:ee1a9b40 r6:ed31d360 r5:ef342300
    
43. [15706.173458]  r4:c0a3ec80 r3:c0592060
    
44. [15706.177051] [<c0333f14>] (chrdev_open) from [<c032d164>] (do_dentry_open.constprop.3+0x1ec/0x314)
    
45. [15706.185961]  r8:ee413f5c r7:c0333f14 r6:ee1a9b48 r5:ed31d360 r4:ee1a9b40
    
46. [15706.192691] [<c032cf78>] (do_dentry_open.constprop.3) from [<c032e0a4>] (vfs_open+0x48/0x78)
    
47. [15706.201165]  r9:ee413ea8 r8:ee413f5c r7:eec023b8 r6:00000002 r5:ee1a9b40 r4:ee413ea8
    
48. [15706.208944] [<c032e05c>] (vfs_open) from [<c033d1f4>] (path_openat+0x344/0xefc)
    
49. [15706.216283]  r5:00000000 r4:00000000
    
50. [15706.219875] [<c033ceb0>] (path_openat) from [<c033f134>] (do_filp_open+0x6c/0xd0)
    
51. [15706.227391]  r10:00000000 r9:ee412000 r8:c0207d84 r7:00000001 r6:ee413f5c r5:ee413ea8
    
52. [15706.235250]  r4:00000003
    
53. [15706.237795] [<c033f0c8>] (do_filp_open) from [<c032e458>] (do_sys_open+0x11c/0x1cc)
    
54. [15706.245483]  r7:fffff000 r6:ed384000 r5:ffffff9c r4:00000003
    
55. [15706.251167] [<c032e33c>] (do_sys_open) from [<c032e528>] (SyS_open+0x20/0x24)
    
56. [15706.258332]  r9:ee412000 r8:c0207d84 r7:00000005 r6:00000000 r5:00000000 r4:be9d3b38
    
57. [15706.266110] [<c032e508>] (SyS_open) from [<c0207be0>] (ret_fast_syscall+0x0/0x34)
    
58. [15706.273622] ---[ end trace 7e2b11ee0c31fa61 ]---
    
59. [15706.278569] Unhandled fault: asynchronous external abort (0x1211) at 0x00000000
    
60. [15706.285911] pgd = ee070680
    
61. [15706.288627] [00000000] *pgd=9fa38003, *pmd=00000000
    
62. [15706.305552] systemd[1]: systemd-journald.service: Failed with result 'core-dump'.
    
63. [15706.331909] systemd[1]: systemd-journald.service: Service has no hold-off time, scheduling restart.
    
64. [15706.353929] systemd[1]: Stopped Flush Journal to Persistent Storage.
    
65. [15706.360436] systemd[1]: Stopping Flush Journal to Persistent Storage...
    
66. [15706.381362] systemd[1]: Stopped Journal Service.
    
67. [15706.393271] systemd[1]: Starting Journal Service...
    
68. [15706.417041] systemd-journald[1334]: File /run/log/journal/b9d28430c5bb428b8c75daa70d99e56a/system.journal corrupted or uncleanly shut down, renaming and replacing.
    

复制代码

驱动源码：

1. #include <linux/slab.h>
   
2. 
   
3. #include <linux/device.h>
   
4. 
   
5. #include <linux/miscdevice.h>
   
6. 
   
7. #include <linux/device.h>
   
8. 
   
9. #include <linux/uaccess.h>
   
10. 
    
11. #include <linux/fb.h>
    
12. 
    
13. #include <linux/init.h>
    
14. 
    
15. #include <linux/module.h>
    
16. 
    
17. #include <linux/kernel.h>
    
18. 
    
19. #include <generated/autoconf.h>
    
20. 
    
21. #include <linux/platform_device.h>
    
22. 
    
23. #include <linux/fs.h>
    
24. 
    
25. #include <linux/ioctl.h>
    
26. 
    
27. #include <linux/types.h>
    
28. 
    
29. #include <linux/spinlock.h>
    
30. 
    
31. #include <linux/cdev.h>
    
32. 
    
33. #include <linux/of.h>
    
34. 
    
35. #include <asm/uaccess.h>
    
36. 
    
37. #include <asm/io.h>
    
38. 
    
39. #include <asm/atomic.h>
    
40. 
    
41. 
    
42. 
    
43. //#include "mt-plat/mtgpio.h"
    
44. 
    
45. #include <linux/types.h>
    
46. 
    
47. //#include <mt-plat/mt_gpio.h>
    
48. 
    
49. //#include <mt-plat/mt_gpio_core.h>
    
50. 
    
51. //#include <mach/gpio_const.h>
    
52. 
    
53. 
    
54. 
    
55. /* 生命函数定义 */
    
56. 
    
57. static int mygpio_probe(struct platform_device *pdev);
    
58. 
    
59. static int mygpio_remove(struct platform_device *pdev);
    
60. 
    
61. 
    
62. 
    
63. 
    
64. 
    
65. static const struct of_device_id mygpio_of_match[] = {
    
66. 
    
67.         { .compatible = "gpio567", },
    
68. 
    
69.         {},
    
70. 
    
71. };
    
72. 
    
73. 
    
74. 
    
75. static struct platform_driver mygpio_driver = {
    
76. 
    
77.         .remove = mygpio_remove,
    
78. 
    
79.         .probe = mygpio_probe,
    
80. 
    
81.         .driver = {
    
82. 
    
83.                         .name = "myGPIO",
    
84. 
    
85.                         .owner = THIS_MODULE,
    
86. 
    
87.                         .of_match_table = mygpio_of_match,
    
88. 
    
89.         },
    
90. 
    
91. };
    
92. 
    
93. 
    
94. 
    
95. 
    
96. 
    
97. #define GPIO_MUX_ADDR               0x4A0035dc
    
98. 
    
99. #define GPIO6_BASE_ADDR             0x48053000
    
100. 
     
101. #define GPIO_PIN_INDEX              0
     
102. 
     
103. 
     
104. 
     
105. #define GPIO_OE_OFFSET              0x134
     
106. 
     
107. #define GPIO_CLRDATAOUT_OFFSET      0x190
     
108. 
     
109. #define GPIO_SETDATAOUT_OFFSET      0x194
     
110. 
     
111. u32 reg_vir_addr;
     
112. 
     
113. static void config_gpio_muxmode(void)
     
114. 
     
115. {
     
116. 
     
117.     u32 reg_vir;
     
118. 
     
119.     printk("my_dev_muxmode\n");
     
120. 
     
121.    reg_vir = (u32)ioremap_nocache(GPIO_MUX_ADDR, 0x20);
     
122. 
     
123.    if (!reg_vir) {
     
124. 
     
125.         printk(": ctrl register remapping failed");                       
     
126. 
     
127.     }
     
128. 
     
129.     //__raw_writel(0xE, reg_vir +0);
     
130. 
     
131.     *(unsigned int *)(reg_vir)= 0x0e;//gpio
     
132. 
     
133. 
     
134. 
     
135.     iounmap((void *)reg_vir);
     
136. 
     
137. //
     
138. 
     
139. 
     
140. 
     
141. }
     
142. 
     
143. 
     
144. 
     
145. static int mygpio_open(struct inode *inode, struct file *file)
     
146. 
     
147. {
     
148. 
     
149.         printk("MyGPIO OPen. \r\n");
     
150. 
     
151.         (*( unsigned int *)(reg_vir_addr + GPIO_CLRDATAOUT_OFFSET)) |= 1 << GPIO_PIN_INDEX;
     
152. 
     
153.         (*( unsigned int *)(reg_vir_addr + GPIO_OE_OFFSET)) &= ~(1<<GPIO_PIN_INDEX);
     
154. 
     
155.         (*( unsigned int *)(reg_vir_addr + GPIO_SETDATAOUT_OFFSET)) |= 1 << GPIO_PIN_INDEX;
     
156. 
     
157.         return 0;
     
158. 
     
159. }
     
160. 
     
161. 
     
162. 
     
163. static ssize_t my_dev_write(struct file *file,const char __user *buf,size_t count,loff_t *offset)
     
164. 
     
165. {
     
166. 
     
167. #if 0
     
168. 
     
169.         int ret;
     
170. 
     
171.         ret = copy_from_user(&val,buf,count);
     
172. 
     
173.         if(ret<0)
     
174. 
     
175.         {
     
176. 
     
177.                 printk("ret=%d\n",ret);
     
178. 
     
179.                 return ret;
     
180. 
     
181.         }
     
182. 
     
183.         printk("my_dev_read\n");
     
184. 
     
185.        
     
186. 
     
187.         return 0;
     
188. 
     
189. #endif
     
190. 
     
191.         int ret,val;
     
192. 
     
193.         char temp[16];
     
194. 
     
195.         char status=0;
     
196. 
     
197.         memset(temp,0,16);
     
198. 
     
199. 
     
200. 
     
201.         ret=copy_from_user(temp,buf,count);
     
202. 
     
203.         if(ret<0)
     
204. 
     
205.         {
     
206. 
     
207.                 printk("ret=%d\n",ret);
     
208. 
     
209.                 status=-EFAULT;
     
210. 
     
211.                 goto err;
     
212. 
     
213.         }
     
214. 
     
215.         val=**_strtoul(temp,NULL,0);
     
216. 
     
217.         if(val >= 1)
     
218. 
     
219.         {
     
220. 
     
221.             *( unsigned int *)(reg_vir_addr + GPIO_SETDATAOUT_OFFSET) |= 1 << GPIO_PIN_INDEX;
     
222. 
     
223.                 //gpio_set_value(gpio_led_pin,1);
     
224. 
     
225.         }
     
226. 
     
227.         else
     
228. 
     
229.         {
     
230. 
     
231.              *( unsigned int *)(reg_vir_addr + GPIO_CLRDATAOUT_OFFSET)|= 1 << GPIO_PIN_INDEX;
     
232. 
     
233.                 //gpio_set_value(gpio_led_pin,0);       
     
234. 
     
235.          }
     
236. 
     
237. 
     
238. 
     
239.         if(!status)
     
240. 
     
241.                 status = count;
     
242. 
     
243. err:
     
244. 
     
245.         return status;
     
246. 
     
247. }
     
248. 
     
249. 
     
250. 
     
251. static int mygpio_release(struct inode *inode, struct file *file)
     
252. 
     
253. {
     
254. 
     
255.         printk("MyGPIO Release. \r\n");
     
256. 
     
257.        
     
258. 
     
259.         return 0;
     
260. 
     
261. }
     
262. 
     
263. 
     
264. 
     
265. static long mygpio_unlocked_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
     
266. 
     
267. {
     
268. 
     
269.         printk("MyGPIO Ioctl. \r\n");
     
270. 
     
271.        
     
272. 
     
273.         printk("MyGPIO cmd=%d \r\n", cmd);
     
274. 
     
275.        
     
276. 
     
277.         return 0;
     
278. 
     
279. }
     
280. 
     
281. 
     
282. 
     
283. static const struct file_operations mygpio_fops = {
     
284. 
     
285. /* .owner = THIS_MODULE, */
     
286. 
     
287.         .open = mygpio_open,
     
288. 
     
289.         .write        =my_dev_write,
     
290. 
     
291.         .release = mygpio_release,
     
292. 
     
293.         .unlocked_ioctl = mygpio_unlocked_ioctl,
     
294. 
     
295. };
     
296. 
     
297. 
     
298. 
     
299. 
     
300. 
     
301. static struct miscdevice mygpio_device = {
     
302. 
     
303.         .minor = MISC_DYNAMIC_MINOR,                //动态设备号
     
304. 
     
305.         .name = "myGPIO",
     
306. 
     
307.         .fops = &mygpio_fops,
     
308. 
     
309. };
     
310. 
     
311. 
     
312. 
     
313. 
     
314. 
     
315. 
     
316. 
     
317. /* My GPIO probe */
     
318. 
     
319. static int mygpio_probe(struct platform_device *pdev)
     
320. 
     
321. {//
     
322. 
     
323.         int ret = 0;
     
324. 
     
325.         unsigned int outvalue[32];
     
326. 
     
327.        
     
328. 
     
329.         printk("MyGPIO Probe. \r\n");
     
330. 
     
331.        
     
332. 
     
333.         ret = misc_register(&mygpio_device);
     
334. 
     
335.         if (ret != 0 )
     
336. 
     
337.                 printk("myGPIO: mygpio_device register failed\n");
     
338. 
     
339.        
     
340. 
     
341.          struct device_node *dn;
     
342. 
     
343.          //1.通过节点名字查找指定的节点驱动程序里面调用of_get_address，提示没有？
     
344. 
     
345.          dn = of_find_node_by_name(NULL,"mygpio56");
     
346. 
     
347.          if(dn==NULL)
     
348. 
     
349.          {
     
350. 
     
351.               printk("of_find_node_by_name err \r\n");
     
352. 
     
353.          }
     
354. 
     
355.          else
     
356. 
     
357.          {
     
358. 
     
359.                   //of_find_node_by_name :mygpio56 /mygpio56 <NULL> mygpio568  compatible
     
360. 
     
361.          //   printk("of_find_node_by_name :%s %s %s  %s %s %s\r\n",dn->name,dn->full_name,dn->type,dn->child->name,dn->properties->name, dn->properties->next->name);
     
362. 
     
363. 
     
364. 
     
365.                 of_property_read_u32_array(dn->child,dn->child->properties->next->name,outvalue,3);
     
366. 
     
367.                 //读取属性中 u8、 u16、 u32 和 u64 类型的数组数据，比如大多数的 reg 属性都是数组数据
     
368. 
     
369. 
     
370. 
     
371.                  printk("%s {\n",dn->name);
     
372. 
     
373.                  printk("      %s = " %s " ;\n",dn->properties->name,dn->properties->value);
     
374. 
     
375.                  printk("      %s = " %s " ;\n",dn->properties->next->name,dn->properties->next->value);
     
376. 
     
377.                  printk("         %s {\n",dn->child->name);
     
378. 
     
379.                  printk("         %s = " %s " ;\n",dn->child->properties->name,dn->child->properties->value);         
     
380. 
     
381.                  printk("         %s = < %x %x %x > ;\n",dn->child->properties->next->name,outvalue[0],outvalue[1],outvalue[2]);
     
382. 
     
383.                  printk("};\n};\n");
     
384. 
     
385.          }
     
386. 
     
387.      ///    u64 size[1]; unsigned int flags[1];
     
388. 
     
389.        //  unsigned int *addr;
     
390. 
     
391.       //   addr = of_get_address(dn->child, 0, size, flags);
     
392. 
     
393.          //of_translate_address(dn->child, const __be32 *in_addr);
     
394. 
     
395.          //2. 通过 device_type 属性查找指定的节点,节点对应的 type 字符串，也就是 device_type 属性值。
     
396. 
     
397.          //struct device_node *of_find_node_by_type(struct device_node *from, const char *type)
     
398. 
     
399.         //3. 根据 device_type 和 compatible 这两个属性查找指定的节点  struct device_node *of_find_compatible_node(struct device_node *from,const char *type,const char *compatible)
     
400. 
     
401.         //4 通过 of_device_id 匹配表来查找指定的节点  struct device_node *of_find_matching_node_and_match(struct device_node *from,const struct of_device_id *matches,const struct of_device_id **match)  matches： of_device_id 匹配表，也就是在此匹配表里面查找节点。  match： 找到的匹配的 of_device_id。
     
402. 
     
403.         return ret;
     
404. 
     
405. }
     
406. 
     
407. 
     
408. 
     
409. 
     
410. 
     
411. static int mygpio_remove(struct platform_device *pdev)
     
412. 
     
413. {
     
414. 
     
415.         int err;
     
416. 
     
417.        
     
418. 
     
419.         printk("MyGPIO remove. \r\n");
     
420. 
     
421. 
     
422. 
     
423.          misc_deregister(&mygpio_device);
     
424. 
     
425.        
     
426. 
     
427.         return err;
     
428. 
     
429. }
     
430. 
     
431. 
     
432. 
     
433. static int __init my_gpio_init(void)
     
434. 
     
435. {
     
436. 
     
437.         int ret = 0;
     
438. 
     
439.         printk("my_gpio_init. \r\n");
     
440. 
     
441.         printk("Register MyGPIO platform_driver  init. \r\n");
     
442. 
     
443. 
     
444. 
     
445.         reg_vir_addr = (u32)ioremap_nocache(GPIO6_BASE_ADDR, 0x800);
     
446. 
     
447.            if (!reg_vir_addr) {
     
448. 
     
449.                 printk(": ctrl addr remapping failed");                       
     
450. 
     
451.             }
     
452. 
     
453. 
     
454. 
     
455.         config_gpio_muxmode();
     
456. 
     
457. 
     
458. 
     
459.         ret = platform_driver_register(&mygpio_driver);
     
460. 
     
461.         if(ret != 0 )
     
462. 
     
463.                 printk("unable to register MyGPIO driver.\n");
     
464. 
     
465.        
     
466. 
     
467.         return ret;
     
468. 
     
469. }
     
470. 
     
471. 
     
472. 
     
473. /*---------------------------------------------------------------------------*/
     
474. 
     
475. static void __exit my_gpio_exit(void)
     
476. 
     
477. {
     
478. 
     
479.         printk("my_gpio_exit. \r\n");
     
480. 
     
481.         iounmap((void *)reg_vir_addr);
     
482. 
     
483. 
     
484. 
     
485.           platform_driver_unregister(&mygpio_driver);
     
486. 
     
487. }
     
488. 
     
489. 
     
490. 
     
491. subsys_initcall(my_gpio_init);
     
492. 
     
493. /*module_init(my_gpio_init);*/
     
494. 
     
495. module_exit(my_gpio_exit);
     
496. 
     
497. 
     
498. 
     
499. MODULE_AUTHOR("zue");
     
500. 
     
501. MODULE_DESCRIPTION("MY General Purpose Driver (GPIO)");
     
502. 
     
503. MODULE_LICENSE("GPL v2");
     
504. 
     
505. /*
     
506. 
     
507. insmod newled
     
508. 
     
509. [  148.740316] my_gpio_init.
     
510. 
     
511. [  148.748510] MyGPIO Probe.  compatible = "gpio567"; 匹配才执行
     
512. 
     
513. //
     
514. 
     
515. rmmod newled
     
516. 
     
517. [  208.688966] my_gpio_exit.
     
518. 
     
519. [  208.691893] MyGPIO remove.
     
520. 
     
521. 
     
522. 
     
523. app open-->open
     
524. 
     
525.     write-->write
     
526. 
     
527.     close--->release
     
528. 
     
529. 
     
530. 
     
531. 
     
532. 
     
533. */

复制代码

mao0504

&gpio8 {
        ti,no-reset-on-init;
};
这种操作不起作用呢，如果起作用，GPIO8对应的是屏显示，屏应该不显示内容才对