Debugging and analysis of the implementation of mymsg and myprintk under proc in imx257

21 static struct class *drv_class = NULL;

22 static struct class_device *drv_class_dev = NULL;

twenty three

24 //Register base address;

25 static unsigned long base_iomux; //iomux base address 0X 43FA C000 - 0X 43FA FFFF

26 static unsigned long base_gpio3; //gpio3 0X 53FA 4000 - 0X 53FA 7FFF

27 //MUX_CTL mode selection configuration register

28 #define MUX_CTL (*(volatile unsigned long *)(base_iomux + 0x0060))

29 //PAD_CTL GPIO common function settings

30 #define PAD_CTL (*(volatile unsigned long *)(base_iomux + 0x0270))

31 //GPIO DR data register DR

32 #define DR_GPIO3 (*(volatile unsigned long *)(base_gpio3 + 0x0000))

33 // GPIO GDIR direction control register GDIR

34 #define GDIR_GPIO3 (*(volatile unsigned long *)(base_gpio3 + 0x0004))

35

36

37 extern int myprintk(const char *fmt, ...);

38

39 static int key_open(struct inode *inode, struct file *file)

40 {

41 myprintk("<0>function open!nn");

42 return 0;

43 }

44

45 static int key_read(struct file *filp, char __user *buff, size_t count, loff_t *offp)

46 {

47 return 0;

48 }

49

50 static ssize_t key_write(struct file *file, const char __user *buf, size_t count, loff_t * ppos)

51 {

52 myprintk("<0>function write!nn");

53 return 1;

54 }

55

56 static int key_release(struct inode *inode, struct file *filp)

57 {

58 myprintk("<0>function write!nn");

59 return 0;

60 }

61

62 static int key_ioctl(struct inode *inode,struct file *flip,unsigned int command,unsigned long arg)

63 {

64 myprintk("<0>function ioctl!nn");

65 return 0;

66 }

67 static struct file_operations key_fops = {

68 .owner = THIS_MODULE, /* This is a macro that pushes to the __this_module variable that is automatically created when compiling the module*/

69 .open = key_open,

70 .read = key_read,

71 .write = key_write,

72.release= key_release,

73 .ioctl = key_ioctl,

74 };

75

76 void gpio_addr(void){

77 myprintk("<0>addr base_iomux : %x n",base_iomux);

78 myprintk("<0>addr base_gpio3 : %x n",base_gpio3);

79 myprintk("<0>addr MUX_CTL : %x n",&MUX_CTL);

80 myprintk("<0>addr PAD_CTL : %x n",&PAD_CTL);

81 myprintk("<0>addr GDIR_GPIO3 : %x n",&GDIR_GPIO3);

82 myprintk("<0>addr DR_GPIO3 : %x n",&DR_GPIO3);

83 }

84

85 void led_on_off(void){

86 ssleep(1);

87 DR_GPIO3 |= (0x01 << 23); //Set GPIO2_23 to 1

88 ssleep(1);

89 DR_GPIO3 &= ~(0x01 << 23); // Clear GPIO2_23

90 ssleep(1);

91 DR_GPIO3 |= (0x01 << 23); //Set GPIO2_23 to 1

92 ssleep(1);

93 DR_GPIO3 &= ~(0x01 << 23); // Clear GPIO2_23

94 ssleep(1);

95 DR_GPIO3 |= (0x01 << 23); //Set GPIO2_23 to 1

96 ssleep(1);

97 DR_GPIO3 &= ~(0x01 << 23); // Clear GPIO2_23

98 ssleep(1);

99 DR_GPIO3 |= (0x01 << 23); //Set GPIO2_23 to 1

100 ssleep(1);

101 DR_GPIO3 &= ~(0x01 << 23); //Clear GPIO2_23

102 ssleep(1);

103 DR_GPIO3 |= (0x01 << 23); //Set GPIO2_23 to 1

104 }

105

106 static int __init key_irq_init(void)

107 {

108 myprintk("<0>nHello,this is %s module!nn",Driver_NAME);

109 //register and mknod

110 major = register_chrdev(0,Driver_NAME,&key_fops);

111 drv_class = class_create(THIS_MODULE,Driver_NAME);

112 drv_class_dev = device_create(drv_class,NULL,MKDEV(major,0),NULL,DEVICE_NAME); /*/dev/key_query*/

113

114 //IO port application ioremap can directly access these addresses through pointers

115 base_iomux = ioremap(0x43FAC000,0xFFF);

116 base_gpio3 = ioremap(0x53FA4000,0xFFF);

117

118 //MUX_CTL

119 MUX_CTL &= ~(0x07 << 0);

120 MUX_CTL |= (0X05 << 0); //Set to ALT5 GPIO3_23 ERR_LED

121 //PAD_CTL

122 PAD_CTL &= ~(0x01<<13 | 0x01<<3 | 0x03<<1 | 0x01<<0); //1.8v does not require pull-up or pull-down CMOS output slew rate

123 //GDIR_GPIO3 is configured as output mode

124 GDIR_GPIO3 &= ~(0x01 << 23);

125 GDIR_GPIO3 |= (0x01 << 23); //Configure to output mode

126

127 //DR_GPIO3 is configured as output 0 to light up ERR_LED

128 DR_GPIO3 &= ~(0x01 << 23); // Clear GPIO2_23

129 DR_GPIO3 &= ~(0x01 << 23); // Clear GPIO2_23

130 gpio_addr();

131 led_on_off();

132 return 0;

133 }

134

135 static void __exit key_irq_exit(void)

136 {

137 gpio_addr();

138 myprintk("<0>nGoodbye,%s!nn",Driver_NAME);

139 led_on_off();

140

141 unregister_chrdev(major,Driver_NAME);

142 device_unregister(drv_class_dev);

143 class_destroy(drv_class);

144

145 //Release IO port

146 iounmap(base_iomux);

147 iounmap(base_gpio3);

148 }

149

150

151 /* These two lines specify the driver's initialization function and uninstallation function*/

152 module_init(key_irq_init);

153 module_exit(key_irq_exit);

154

155 /* Describes some information about the driver, not required*/

156 MODULE_AUTHOR("Lover Cher");

157 MODULE_VERSION("0.1.0");

158 MODULE_DESCRIPTION("IMX257 key Driver");

159 MODULE_LICENSE("GPL");

OK, it's done.

The advantage of doing this is that we can concentrate the printing information of a certain driver in a certain file, so that the printing information will not be affected by other drivers, which is convenient for subsequent debugging.