#include <linux/kernel.h> #include <linux/init.h> #include <linux/module.h> #include <linux/slab.h> #include <linux/delay.h> #include <linux/mutex.h> #include <linux/sysfs.h> #include <linux/mod_devicetable.h> #include <linux/log2.h> #include <linux/bitops.h> #include <linux/jiffies.h> #include <linux/i2c.h> #include <linux/i2c/at24.h> #include <linux/fs.h> #include <asm/uaccess.h>
static struct i2c_client *at24_client;
static int major=0;
static struct class *cls;
static const struct i2c_device_id at24_ids[] = {
{"at24",8}, {}, };
MODULE_DEVICE_TABLE(i2c,at24_ids);
static ssize_t at24_read(struct file *file, char __user *buf, size_t len, loff_t *offset)
{ unsigned char address;
unsigned char data;
struct i2c_msg msg[2];
int ret;
if(len!=1) return -EINVAL; copy_from_user(&address,buf,1); msg[0].addr=at24_client->addr; msg[0].buf=&address; msg[0].len=1; msg[0].flags=0; msg[1].addr=at24_client->addr; msg[1].buf=&data; msg[1].len=1; msg[1].flags =I2C_M_RD; ret=i2c_transfer(at24_client->adapter,msg,2); if(ret==2) { copy_to_user(buf,&data,1); return 1; } else return -EIO; printk("read ! "); return 0; } static ssize_t at24_write(struct file *file, const char __user *buf, size_t len, loff_t *offset) { unsigned char val[2]; struct i2c_msg msg[1]; int ret; if(len!=2) return -EINVAL; copy_from_user(val,buf,2); msg[0].addr=at24_client->addr; msg[0].buf=val; msg[0].len=2; msg[0].flags=0; ret=i2c_transfer(at24_client->adapter,msg,1); if(ret==1) { return 2; } else return -EIO; printk("write ! "); return 0; }
static struct file_operations fop={ .owner =THIS_MODULE, .write =at24_write, .read =at24_read, }; static int at24_probe(struct i2c_client *client, const struct i2c_device_id *ids) { printk("probe ok! "); at24_client=client; major=register_chrdev(0,"at24",&fop); cls=class_create(THIS_MODULE,"at24"); device_create(cls,NULL,MKDEV(major,0),NULL,"at24"); return 0; } static int at24_remove(struct i2c_client *client) { kfree(at24_client); unregister_chrdev(major,"at24"); device_destroy(cls,MKDEV(major,0)); class_destroy(cls); printk("remove ok! "); return 0; }
static struct i2c_driver at24cx_driver = { .driver = { .name = "at24", .owner = THIS_MODULE, }, .probe = at24_probe, .remove = at24_remove, .id_table =at24_ids, };
static int at24cx_init(void) { return i2c_add_driver(&at24cx_driver); }
static void at24cx_exit(void) { i2c_del_driver(&at24cx_driver); } module_init(at24cx_init); module_exit(at24cx_exit); MODULE_LICENSE("GPL");
static struct at24_platform_data at24_i2c_info = {
.byte_len = 8, .page_size = 8, };
static struct i2c_board_info at24_i2c_devices[] =
{ { I2C_BOARD_INFO("at24", 0x50),
.platform_data = &at24_i2c_info, },
};