源码：
1 /*****************************************************************************
2 简 述：简单字符型驱动程序，手动静态分配设备号，手动创建设备节点
3 ******************************************************************************/
4 #include <linux/module.h>
5 #include <linux/moduleparam.h>
6 #include <linux/cdev.h>
7 #include <linux/fs.h>
8 #include <linux/wait.h>
9 #include <linux/poll.h>
10 #include <linux/sched.h>
11 #include <linux/irq.h>
12 #include <asm/irq.h>
13 #include <linux/interrupt.h>
14
15
16 #include <mach/map.h>
17 #include <mach/gpio.h>
18 #include <mach/regs-gpio.h>
19 #include <plat/gpio-cfg.h>
20
21 #include <linux/slab.h>
22
23 #define DEVICE_NAME "buttons"
24
25 struct button_desc {
26 int gpio;
27 int number;
28 char *name;
29 };
30
31 static struct button_desc buttons[] = {
32 { S5PV210_GPH2(0), 0, "KEY0" },
33 { S5PV210_GPH2(1), 1, "KEY1" },
34 { S5PV210_GPH2(2), 2, "KEY2" },
35 { S5PV210_GPH2(3), 3, "KEY3" },
36 { S5PV210_GPH3(0), 4, "KEY4" },
37 { S5PV210_GPH3(1), 5, "KEY5" },
38 { S5PV210_GPH3(2), 6, "KEY6" },
39 { S5PV210_GPH3(3), 7, "KEY7" },
40 };
41 #define OK (0)
42 #define ERROR (-1)
43
44 struct cdev *gDev;
45 struct file_operations *gFile;
46 dev_t devNum;
47 unsigned int subDevNum = 1;
48 int reg_major = 232;
49 int reg_minor = 0;
50
51
52 static irqreturn_t button_interrupt(int irq, void *dev_id)
53 {
54 struct button_desc *bdata = (struct button_desc *)dev_id;
55
56 int down;
57 unsigned tmp;
58
59 tmp = gpio_get_value(bdata->gpio);
60
61 /* active low */
62 down = !tmp;
63 printk("KEY %d: %08x\n", bdata->number, down);
64
65 return IRQ_HANDLED;
66 }
67
68 int butsOpen(struct inode *p, struct file *f)
69 {
70
71 int irq;
72 int i;
73 int err = 0;
74 printk(KERN_EMERG"butsOpen\r\n");
75 for (i = 0; i < ARRAY_SIZE(buttons); i++) {
76 if (!buttons[i].gpio)
77 continue;
78
79 irq = gpio_to_irq(buttons[i].gpio);
80 err = request_irq(irq, button_interrupt, IRQ_TYPE_EDGE_BOTH,
81 buttons[i].name, (void *)&buttons[i]);
82 if (err)
83 break;
84 }
85
86 if (err) {
87 i--;
88 for (; i >= 0; i--) {
89 if (!buttons[i].gpio)
90 continue;
91
92 irq = gpio_to_irq(buttons[i].gpio);
93 disable_irq(irq);
94 free_irq(irq, (void *)&buttons[i]);
95 }
96
97 return -EBUSY;
98 }
99 return 0;
100 }
101
102
103
104
105 int charDrvInit(void)
106 {
107
108 devNum = MKDEV(reg_major, reg_minor);
109
110 printk(KERN_EMERG"devNum is %d\r\n", devNum);
111 if(OK == register_chrdev_region(devNum, subDevNum, DEVICE_NAME))
112 {
113 printk(KERN_EMERG"register_chrdev_region ok\r\n");
114 }
115 else
116 {
117 printk(KERN_EMERG"register_chrdev_region error\r\n");
118 return ERROR;
119 }
120 /*if(OK == alloc_chrdev_region(&devNum, subDevNum, subDevNum,"test"))
121 {
122 printk(KERN_EMERG"register_chrdev_region ok\r\n");
123 }
124 else
125 {
126 printk(KERN_EMERG"register_chrdev_region error\r\n");
127 return ERROR;
128 }*/
129
130 gDev = kzalloc(sizeof(struct cdev), GFP_KERNEL);
131 gFile = kzalloc(sizeof(struct file_operations), GFP_KERNEL);
132
133 gFile->open = butsOpen;
134 //注册设备函数到file_operations结构体gFile
135
136 //gDev->owner = THIS_MODULE;
137 gFile->owner = THIS_MODULE;
138 cdev_init(gDev, gFile);
139 //在cdev结构体中添加指针指向file_operations结构体gFile
140 cdev_add(gDev, devNum, 3);
141 //建立设备号与cdev结构体联系
142 printk(KERN_EMERG"button driver initial done...\r\n");
143 return 0;
144 }
145
146 void __exit charDrvExit(void)
147 {
148 int i;
149
150 cdev_del(gDev);
151 unregister_chrdev_region(devNum, subDevNum);
152 return;
153 }
154 module_init(charDrvInit);
155 module_exit(charDrvExit);
156 MODULE_LICENSE("GPL");
View Code
1 int butsOpen(struct inode *p, struct file *f)
2 {
3
4 int irq;
5 int i;
6 int err = 0;
7 printk(KERN_EMERG"butsOpen\r\n");
8 for (i = 0; i < ARRAY_SIZE(buttons); i++) {
9 if (!buttons[i].gpio)
10 continue;
11
12 irq = gpio_to_irq(buttons[i].gpio);
13 err = request_irq(irq, button_interrupt, IRQ_TYPE_EDGE_BOTH,
14 buttons[i].name, (void *)&buttons[i]);
15 if (err)
16 break;
17 }
18
19 if (err) {
20 i--;
21 for (; i >= 0; i--) {
22 if (!buttons[i].gpio)
23 continue;
24
25 irq = gpio_to_irq(buttons[i].gpio);
26 disable_irq(irq);
27 free_irq(irq, (void *)&buttons[i]);
28 }
29
30 return -EBUSY;
31 }
32 return 0;
33 }
1 #define gpio_to_irq __gpio_to_irq
1 int __gpio_to_irq(unsigned gpio)
2 {
3 struct gpio_chip *chip;
4 chip = gpio_to_chip(gpio);
5 return chip->to_irq ? chip->to_irq(chip, gpio - chip->base) : -ENXIO;
6 }
1 static inline struct gpio_chip *gpio_to_chip(unsigned gpio)
2 {
3 return gpio_desc[gpio].chip;//此处的gpio_desc[gpio].chip实际完成赋值在gpio-s5pv210.c中的s5pv210_gpiolib_init(void)函数中实现
4 }
gpio_desc[gpio].chip实际完成赋值在gpio-s5pv210.c中的s5pv210_gpiolib_init(void)函数中的实现：
1 static __init int s5pv210_gpiolib_init(void)
2 {
3 struct s3c_gpio_chip *chip = s5pv210_gpio_4bit;
4 int nr_chips = ARRAY_SIZE(s5pv210_gpio_4bit);
5 int gpioint_group = 0;
6 int i = 0;
7
8 for (i = 0; i < nr_chips; i++, chip++) {
9 if (chip->config == NULL) {
10 chip->config = &gpio_cfg;
11 chip->group = gpioint_group++;
12 }
13 if (chip->base == NULL)
14 chip->base = S5PV210_BANK_BASE(i);
15 }
16
17 samsung_gpiolib_add_4bit_chips(s5pv210_gpio_4bit, nr_chips);
18 s5p_register_gpioint_bank(IRQ_GPIOINT, 0, S5P_GPIOINT_GROUP_MAXNR);
19
20 return 0;
21 }
1 static struct s3c_gpio_chip s5pv210_gpio_4bit[] = {
2 {
3 .chip = {
4 .base = S5PV210_GPA0(0),
5 .ngpio = S5PV210_GPIO_A0_NR,
6 .label = "GPA0",
7 },
8 }, {
9 .chip = {
10 .base = S5PV210_GPA1(0),
11 .ngpio = S5PV210_GPIO_A1_NR,
12 .label = "GPA1",
13 },
14 }, {
15 .chip = {
16 .base = S5PV210_GPB(0),
17 .ngpio = S5PV210_GPIO_B_NR,
18 .label = "GPB",
19 },
20 }, {
21 .chip = {
22 .base = S5PV210_GPC0(0),
23 .ngpio = S5PV210_GPIO_C0_NR,
24 .label = "GPC0",
25 },
26 }, {
27 .chip = {
28 .base = S5PV210_GPC1(0),
29 .ngpio = S5PV210_GPIO_C1_NR,
30 .label = "GPC1",
31 },
32 }, {
33 .chip = {
34 .base = S5PV210_GPD0(0),
35 .ngpio = S5PV210_GPIO_D0_NR,
36 .label = "GPD0",
37 },
38 }, {
39 .chip = {
40 .base = S5PV210_GPD1(0),
41 .ngpio = S5PV210_GPIO_D1_NR,
42 .label = "GPD1",
43 },
44 }, {
45 .chip = {
46 .base = S5PV210_GPE0(0),
47 .ngpio = S5PV210_GPIO_E0_NR,
48 .label = "GPE0",
49 },
50 }, {
51 .chip = {
52 .base = S5PV210_GPE1(0),
53 .ngpio = S5PV210_GPIO_E1_NR,
54 .label = "GPE1",
55 },
56 }, {
57 .chip = {
58 .base = S5PV210_GPF0(0),
59 .ngpio = S5PV210_GPIO_F0_NR,
60 .label = "GPF0",
61 },
62 }, {
63 .chip = {
64 .base = S5PV210_GPF1(0),
65 .ngpio = S5PV210_GPIO_F1_NR,
66 .label = "GPF1",
67 },
68 }, {
69 .chip = {
70 .base = S5PV210_GPF2(0),
71 .ngpio = S5PV210_GPIO_F2_NR,
72 .label = "GPF2",
73 },
74 }, {
75 .chip = {
76 .base = S5PV210_GPF3(0),
77 .ngpio = S5PV210_GPIO_F3_NR,
78 .label = "GPF3",
79 },
80 }, {
81 .chip = {
82 .base = S5PV210_GPG0(0),
83 .ngpio = S5PV210_GPIO_G0_NR,
84 .label = "GPG0",
85 },
86 }, {
87 .chip = {
88 .base = S5PV210_GPG1(0),
89 .ngpio = S5PV210_GPIO_G1_NR,
90 .label = "GPG1",
91 },
92 }, {
93 .chip = {
94 .base = S5PV210_GPG2(0),
95 .ngpio = S5PV210_GPIO_G2_NR,
96 .label = "GPG2",
97 },
98 }, {
99 .chip = {
100 .base = S5PV210_GPG3(0),
101 .ngpio = S5PV210_GPIO_G3_NR,
102 .label = "GPG3",
103 },
104 }, {
105 .config = &gpio_cfg_noint,
106 .chip = {
107 .base = S5PV210_GPI(0),
108 .ngpio = S5PV210_GPIO_I_NR,
109 .label = "GPI",
110 },
111 }, {
112 .chip = {
113 .base = S5PV210_GPJ0(0),
114 .ngpio = S5PV210_GPIO_J0_NR,
115 .label = "GPJ0",
116 },
117 }, {
118 .chip = {
119 .base = S5PV210_GPJ1(0),
120 .ngpio = S5PV210_GPIO_J1_NR,
121 .label = "GPJ1",
122 },
123 }, {
124 .chip = {
125 .base = S5PV210_GPJ2(0),
126 .ngpio = S5PV210_GPIO_J2_NR,
127 .label = "GPJ2",
128 },
129 }, {
130 .chip = {
131 .base = S5PV210_GPJ3(0),
132 .ngpio = S5PV210_GPIO_J3_NR,
133 .label = "GPJ3",
134 },
135 }, {
136 .chip = {
137 .base = S5PV210_GPJ4(0),
138 .ngpio = S5PV210_GPIO_J4_NR,
139 .label = "GPJ4",
140 },
141 }, {
142 .config = &gpio_cfg_noint,
143 .chip = {
144 .base = S5PV210_MP01(0),
145 .ngpio = S5PV210_GPIO_MP01_NR,
146 .label = "MP01",
147 },
148 }, {
149 .config = &gpio_cfg_noint,
150 .chip = {
151 .base = S5PV210_MP02(0),
152 .ngpio = S5PV210_GPIO_MP02_NR,
153 .label = "MP02",
154 },
155 }, {
156 .config = &gpio_cfg_noint,
157 .chip = {
158 .base = S5PV210_MP03(0),
159 .ngpio = S5PV210_GPIO_MP03_NR,
160 .label = "MP03",
161 },
162 }, {
163 .config = &gpio_cfg_noint,
164 .chip = {
165 .base = S5PV210_MP04(0),
166 .ngpio = S5PV210_GPIO_MP04_NR,
167 .label = "MP04",
168 },
169 }, {
170 .config = &gpio_cfg_noint,
171 .chip = {
172 .base = S5PV210_MP05(0),
173 .ngpio = S5PV210_GPIO_MP05_NR,
174 .label = "MP05",
175 },
176 }, {
177 .base = (S5P_VA_GPIO + 0xC00),
178 .config = &gpio_cfg_noint,
179 .irq_base = IRQ_EINT(0),
180 .chip = {
181 .base = S5PV210_GPH0(0),
182 .ngpio = S5PV210_GPIO_H0_NR,
183 .label = "GPH0",
184 .to_irq = samsung_gpiolib_to_irq,
185 },
186 }, {
187 .base = (S5P_VA_GPIO + 0xC20),
188 .config = &gpio_cfg_noint,
189 .irq_base = IRQ_EINT(8),
190 .chip = {
191 .base = S5PV210_GPH1(0),
192 .ngpio = S5PV210_GPIO_H1_NR,
193 .label = "GPH1",
194 .to_irq = samsung_gpiolib_to_irq,
195 },
196 }, {
197 .base = (S5P_VA_GPIO + 0xC40),
198 .config = &gpio_cfg_noint,
199 .irq_base = IRQ_EINT(16),
200 .chip = {
201 .base = S5PV210_GPH2(0),
202 .ngpio = S5PV210_GPIO_H2_NR,
203 .label = "GPH2",
204 .to_irq = samsung_gpiolib_to_irq,
205 },
206 }, {
207 .base = (S5P_VA_GPIO + 0xC60),
208 .config = &gpio_cfg_noint,
209 .irq_base = IRQ_EINT(24),
210 .chip = {
211 .base = S5PV210_GPH3(0),
212 .ngpio = S5PV210_GPIO_H3_NR,
213 .label = "GPH3",
214 .to_irq = samsung_gpiolib_to_irq,
215 },
216 },
217 };
struct s3c_gpio_chip s5pv210_gpio_4bit[]
1 void __init samsung_gpiolib_add_4bit_chips(struct s3c_gpio_chip *chip,
2 int nr_chips)
3 {
4 for (; nr_chips > 0; nr_chips--, chip++) {
5 samsung_gpiolib_add_4bit(chip);
6 s3c_gpiolib_add(chip);
7 }
8 }
1 __init void s3c_gpiolib_add(struct s3c_gpio_chip *chip)
2 {
3 struct gpio_chip *gc = &chip->chip;//将struct s3c_gpio_chip结构体成员结构体chip赋值给struct gpio_chip结构体局部变量gc
4 int ret;
5
6 BUG_ON(!chip->base);
7 BUG_ON(!gc->label);
8 BUG_ON(!gc->ngpio);
9
10 spin_lock_init(&chip->lock);
11
12 if (!gc->direction_input)
13 gc->direction_input = s3c_gpiolib_input;
14 if (!gc->direction_output)
15 gc->direction_output = s3c_gpiolib_output;
16 if (!gc->set)
17 gc->set = s3c_gpiolib_set;
18 if (!gc->get)
19 gc->get = s3c_gpiolib_get;
20
21 #ifdef CONFIG_PM
22 if (chip->pm != NULL) {
23 if (!chip->pm->save || !chip->pm->resume)
24 printk(KERN_ERR "gpio: %s has missing PM functions\n",
25 gc->label);
26 } else
27 printk(KERN_ERR "gpio: %s has no PM function\n", gc->label);
28 #endif
29
30 /* gpiochip_add() prints own failure message on error. */
31 ret = gpiochip_add(gc);
32 if (ret >= 0)
33 s3c_gpiolib_track(chip);
34 }
1 int gpiochip_add(struct gpio_chip *chip)
2 {
3 unsigned long flags;
4 int status = 0;
5 unsigned id;
6 int base = chip->base;
7
8 if ((!gpio_is_valid(base) || !gpio_is_valid(base + chip->ngpio - 1))
9 && base >= 0) {
10 status = -EINVAL;
11 goto fail;
12 }
13
14 spin_lock_irqsave(&gpio_lock, flags);
15
16 if (base < 0) {
17 base = gpiochip_find_base(chip->ngpio);
18 if (base < 0) {
19 status = base;
20 goto unlock;
21 }
22 chip->base = base;
23 }
24
25 /* these GPIO numbers must not be managed by another gpio_chip */
26 for (id = base; id < base + chip->ngpio; id++) {
27 if (gpio_desc[id].chip != NULL) {
28 status = -EBUSY;
29 break;
30 }
31 }
32 if (status == 0) {
33 for (id = base; id < base + chip->ngpio; id++) {
34 gpio_desc[id].chip = chip;//在这里gpio_desc[id].chip和struct s3c_gpio_chip建立联系
35
36 /* REVISIT: most hardware initializes GPIOs as
37 * inputs (often with pullups enabled) so power
38 * usage is minimized. Linux code should set the
39 * gpio direction first thing; but until it does,
40 * we may expose the wrong direction in sysfs.
41 */
42 gpio_desc[id].flags = !chip->direction_input
43 ? (1 << FLAG_IS_OUT)
44 : 0;
45 }
46 }
47
48 of_gpiochip_add(chip);
49
50 unlock:
51 spin_unlock_irqrestore(&gpio_lock, flags);
52
53 if (status)
54 goto fail;
55
56 status = gpiochip_export(chip);
57 if (status)
58 goto fail;
59
60 return 0;
61 fail:
62 /* failures here can mean systems won't boot... */
63 pr_err("gpiochip_add: gpios %d..%d (%s) failed to register\n",
64 chip->base, chip->base + chip->ngpio - 1,
65 chip->label ? : "generic");
66 return status;
67 }