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  2. µ±Ç°Î»ÖÃ:Ê×Ò³ > ǶÈëʽÅàѵ > ǶÈëʽѧϰ > ½²Ê¦²©ÎÄ >
    ʵÀý½âÎölinuxÄÚºËI2CÌåϵ½á¹¹£¨2£©
    ʱ¼ä£º2018-08-16×÷Õߣº»ªÇåÔ¶¼û

    ËÄ¡¢ÔÚÄÚºËÀïдi2cÉ豸Çý¶¯µÄÁ½ÖÖ·½Ê½

    ÔÚ¡¶ÊµÀý½âÎölinuxÄÚºËI2CÌåϵ½á¹¹£¨1£©¡·Ò»ÎĽéÉÜÁËÀûÓÃ/dev/i2c-0ÔÚÓ¦ÓòãÍê³É¶Ôi2cÉ豸µÄ²Ù×÷£¬µ«ºÜ¶àʱºòÎÒÃÇ»¹ÊÇϰ¹ßΪi2cÉ豸ÔÚÄں˲ã±àдÇý¶¯³ÌÐò¡£Ä¿Ç°ÄÚºËÖ§³ÖÁ½ÖÖ±àдi2cÇý¶¯³ÌÐòµÄ·½Ê½¡£ÏÂÃæ·Ö±ð½éÉÜÕâÁ½ÖÖ·½Ê½µÄʵÏÖ¡£ÕâÀï·Ö±ð³ÆÕâÁ½ÖÖ·½Ê½Îª“Adapter·½Ê½£¨LEGACY£©”ºÍ“Probe·½Ê½£¨new style£©”¡£

    £¨1£© Adapter·½Ê½£¨LEGACY£©

    £¨ÏÂÃæµÄʵÀý´úÂëÊÇÔÚ2.6.27Äں˵Äpca953x.c»ù´¡ÉÏÐ޸ĵÄ£¬Ô­Ê¼´úÂë²ÉÓõÄÊDZ¾ÎĽ«ÒªÌÖÂ۵ĵÚ2ÖÖ·½Ê½£¬¼´Probe·½Ê½£©

    ¡ñ    ¹¹½¨i2c_driver

    static struct i2c_driver pca953x_driver = {
                    .driver = {
                                        .name= "pca953x", //Ãû³Æ
                                    },
                    .id= ID_PCA9555,//idºÅ
                    .attach_adapter= pca953x_attach_adapter, //µ÷ÓÃÊÊÅäÆ÷Á¬½ÓÉ豸
                    .detach_client= pca953x_detach_client,//ÈÃÉ豸ÍÑÀëÊÊÅäÆ÷
            };

    ¡ñ    ×¢²ái2c_driver

    static int __init pca953x_init(void)
            {
                    return i2c_add_driver(&pca953x_driver);
            }
            module_init(pca953x_init);

    ¡ñ    attach_adapter¶¯×÷

    Ö´ÐÐi2c_add_driver(&pca953x_driver)ºó»á£¬Èç¹ûÄÚºËÖÐÒѾ­×¢²áÁËi2cÊÊÅäÆ÷£¬Ôò˳Ðòµ÷ÓÃÕâЩÊÊÅäÆ÷À´Á¬½ÓÎÒÃǵÄi2cÉ豸¡£´Ë¹ý³ÌÊÇͨ¹ýµ÷ÓÃi2c_driverÖеÄattach_adapter·½·¨Íê³ÉµÄ¡£¾ßÌåʵÏÖÐÎʽÈçÏ£º

    static int pca953x_attach_adapter(struct i2c_adapter *adapter)
            {
                    return i2c_probe(adapter, &addr_data, pca953x_detect);
                    /*
                    adapter:ÊÊÅäÆ÷
                    addr_data:µØÖ·ÐÅÏ¢
                    pca953x_detect£ºÌ½²âµ½É豸ºóµ÷Óõĺ¯Êý
                    */
            }

    µØÖ·ÐÅÏ¢addr_dataÊÇÓÉÏÂÃæ´úÂëÖ¸¶¨µÄ¡£
            /* Addresses to scan */
            static unsigned short normal_i2c[] = {0x20,0x21,0x22,0x23,0x24,0x25,0x26,0x27,I2C_CLIENT_END};
            I2C_CLIENT_INSMOD;

    ×¢Ò⣺normal_i2cÀïµÄµØÖ·±ØÐëÊÇÄãi2cоƬµÄµØÖ·¡£·ñÔò½«ÎÞ·¨Õýȷ̽²âµ½É豸¡£¶øI2C_ CLIENT_INSMODÊÇÒ»¸öºê£¬Ëü»áÀûÓÃnormal_i2c¹¹½¨addr_data¡£

    ¡ñ    ¹¹½¨i2c_client£¬²¢×¢²á×Ö·ûÉ豸Çý¶¯

    i2c_probeÔÚ̽²âµ½Ä¿±êÉ豸ºó£¬ºóµ÷ÓÃpca953x_detect£¬²¢°Ñµ±Ê±µÄ̽²âµØÖ·address×÷Ϊ²ÎÊý´«Èë¡£

    static int pca953x_detect(struct i2c_adapter *adapter, int address, int kind)
            {
                    struct i2c_client *new_client;
                    struct pca953x_chip *chip; //É豸½á¹¹Ìå
                    int err = 0,result;
                    dev_t pca953x_dev=MKDEV(pca953x_major,0);//¹¹½¨É豸ºÅ£¬¸ù¾Ý¾ßÌåÇé¿öÉ趨£¬ÕâÀïÎÒÖ»¿¼ÂÇÁËnormal_i2cÖÐÖ»ÓÐÒ»¸öµØÖ·Æ¥ÅäµÄÇé¿ö¡£
                    if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA| I2C_FUNC_SMBUS_WORD_DATA))//Åж¨ÊÊÅäÆ÷ÄÜÁ¦
                    goto exit;
                    if (!(chip = kzalloc(sizeof(struct pca953x_chip), GFP_KERNEL))) {
                            err = -ENOMEM;
                            goto exit;
                    }
                    /****¹¹½¨i2c-client****/
                    chip->client=kzalloc(sizeof(struct i2c_client),GFP_KERNEL);
                    new_client = chip->client;
                    i2c_set_clientdata(new_client, chip);
                    new_client->addr = address;
                    new_client->adapter = adapter;
                    new_client->driver = &pca953x_driver;
                    new_client->flags = 0;
                    strlcpy(new_client->name, "pca953x", I2C_NAME_SIZE);
                    if ((err = i2c_attach_client(new_client)))//×¢²ái2c_client
                    goto exit_kfree;
                    if (err)
                    goto exit_detach;
                    if(pca953x_major)
                    {
                            result=register_chrdev_region(pca953x_dev,1,"pca953x");
                    }
                    else{
                            result=alloc_chrdev_region(&pca953x_dev,0,1,"pca953x");
                            pca953x_major=MAJOR(pca953x_dev);
                    }
                    if (result < 0) {
                            printk(KERN_NOTICE "Unable to get pca953x region, error %d\n", result);
                            return result;
                    }
                    pca953x_setup_cdev(chip,0); //×¢²á×Ö·ûÉ豸£¬´Ë´¦²»Ïê½â
                    return 0;
                    exit_detach:
                    i2c_detach_client(new_client);
            exit_kfree:
                    kfree(chip);
            exit:
                    return err;
            }

    i2c_check_functionalityÓÃÀ´Åж¨ÉèÅäÆ÷µÄÄÜÁ¦£¬ÕâÒ»µã·Ç³£ÖØÒª¡£ÄãÒ²¿ÉÒÔÖ±½Ó²é¿´¶ÔÓ¦ÉèÅäÆ÷µÄÄÜÁ¦£¬Èç

    static const struct i2c_algorithm smbus_algorithm = {
                    .smbus_xfer= i801_access,
                    .functionality= i801_func,
            };
            static u32 i801_func(struct i2c_adapter *adapter)
            {
                            return I2C_FUNC_SMBUS_QUICK | I2C_FUNC_SMBUS_BYTE |
                        I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA |
                    I2C_FUNC_SMBUS_BLOCK_DATA | I2C_FUNC_SMBUS_WRITE_I2C_BLOCK
                                    | (isich4 ? I2C_FUNC_SMBUS_HWPEC_CALC : 0);
            }

    ¡ñ    ×Ö·ûÇý¶¯µÄ¾ßÌåʵÏÖ

    struct file_operations pca953x_fops = {
                    .owner = THIS_MODULE,
                    .ioctl= pca953x_ioctl, 
                    .open= pca953x_open, 
                    .release =pca953x_release, 
            };

    ×Ö·ûÉ豸Çý¶¯±¾ÉíûÓÐʲôºÃ˵µÄ£¬ÕâÀïÖ÷ÒªÏë˵һÏ£¬ÈçºÎÔÚÇý¶¯Öе÷ÓÃi2cÉèÅäÆ÷°ïÎÒÃÇÍê³ÉÊý¾Ý´«Êä¡£

    ĿǰÉèÅäÆ÷Ö÷ÒªÖ§³ÖÁ½ÖÖ´«Êä·½·¨£ºsmbus_xferºÍmaster_xfer¡£Ò»°ãÀ´Ëµ£¬Èç¹ûÉèÅäÆ÷Ö§³ÖÁËmaster_xferÄÇôËüÒ²¿ÉÒÔÄ£ÄâÖ§³ÖsmbusµÄ´«Êä¡£µ«Èç¹ûֻʵÏÖsmbus_xfer£¬Ôò²»Ö§³ÖһЩi2cµÄ´«Êä¡£

    int (*master_xfer)(struct i2c_adapter *adap,struct i2c_msg *msgs,int num);
            int (*smbus_xfer) (struct i2c_adapter *adap, u16 addr,
                                                                                    unsigned short flags, char read_write,
                                                                    u8 command, int size, union i2c_smbus_data * data);

    master_xferÖеIJÎÊýÉèÖ㬺ÍÇ°ÃæµÄÓû§¿Õ¼ä±à³ÌÒ»Ö¡£ÏÖÔÚÖ»ÊÇÒªÔÚÇý¶¯Öй¹½¨Ïà¹ØµÄ²ÎÊýÈ»ºóµ÷ÓÃi2c_transferÀ´Íê³É´«Êä¼È¿É¡£

    int i2c_transfer(struct i2c_adapter * adap, struct i2c_msg *msgs, int num)

    smbus_xferÖеIJÎÊýÉèÖü°µ÷Ó÷½·¨ÈçÏ£º

    static int pca953x_write_reg(struct pca953x_chip *chip, int reg, uint16_t val)
            {
                    int ret;
                    ret = i2c_smbus_write_word_data(chip->client, reg << 1, val);
                    if (ret < 0) {
                                    dev_err(&chip->client->dev, "failed writing register\n");
                                            return -EIO;
                                    }
                    return 0;
            }

    ÉÏÃæº¯ÊýÍê³ÉÏòоƬµÄµØÖ·ÎªregµÄ¼Ä´æÆ÷дһ¸ö16bitµÄÊý¾Ý¡£i2c_smbus_write_word_dataµÄʵÏÖÈçÏ£º

    s32 i2c_smbus_write_word_data(struct i2c_client *client, u8 command, u16 value)
            {
                    union i2c_smbus_data data;
                    data.word = value;
                    return i2c_smbus_xfer(client->adapter,client->addr,client->flags,
                                                                            I2C_SMBUS_WRITE,command,
                                                                            I2C_SMBUS_WORD_DATA,&data);
            }

    ´ÓÖпÉÒÔ¿´³ösmbus´«ÊäÒ»¸ö16λÊý¾ÝµÄ·½·¨¡£ÆäËü²Ù×÷È磺×Ö·ûд¡¢×Ö·û¶Á¡¢×Ö¶Á¡¢¿é²Ù×÷µÈ£¬¿ÉÒԲο¼Äں˵Äi2c-core.cÖÐÌṩµÄ·½·¨¡£

    ¡ñ    ×¢Ïúi2c_driver

    static void __exit pca953x_exit(void)
            {
                    i2c_del_driver(&pca953x_driver);
            }
            module_exit(pca953x_exit);

    ¡ñ    detach_client¶¯×÷

    ˳Ðòµ÷ÓÃÄÚºËÖÐ×¢²áµÄÊÊÅäÆ÷À´¶Ï¿ªÎÒÃÇ×¢²á¹ýµÄi2cÉ豸¡£´Ë¹ý³Ìͨ¹ýµ÷ÓÃi2c_driverÖеÄattach_adapter·½·¨Íê³ÉµÄ¡£¾ßÌåʵÏÖÐÎʽÈçÏ£º

    static int pca953x_detach_client(struct i2c_client *client)
            {
                    int err;
                    struct pca953x_chip *data;
                    if ((err = i2c_detach_client(client)))//¶Ï¿ªi2c_client
                    return err;
                    data=i2c_get_clientdata(client);
                    cdev_del(&(data->cdev));
                    unregister_chrdev_region(MKDEV(pca953x_major, 0), 1);
                    kfree(data->client);
                    kfree(data);
                    return 0;
            }

    £¨2£© Probe·½Ê½£¨new style£©

    ¡ñ    ¹¹½¨i2c_driver

    ºÍLEGACY·½Ê½Ò»Ñù£¬Ò²ÐèÒª¹¹½¨i2c_driver£¬µ«ÊÇÄÚÈÝÓÐËù²»Í¬¡£

    static struct i2c_driver pca953x_driver = {
                    .driver = {
                            .name= "pca953x",
                            },
                            .probe= pca953x_probe, //µ±ÓÐi2c_clientºÍi2c_driverÆ¥Åäʱµ÷ÓÃ
                            .remove= pca953x_remove,//×¢Ïúʱµ÷ÓÃ
                            .id_table= pca953x_id,//Æ¥Å乿Ôò
            };

    ¡ñ    ×¢²ái2c_driver

    static int __init pca953x_init(void)
            {
                    return i2c_add_driver(&pca953x_driver);
            }
            module_init(pca953x_init);

    ÔÚ×¢²ái2c_driverµÄ¹ý³ÌÖУ¬Êǽ«driver×¢²áµ½ÁËi2c_bus_typeµÄ×ÜÏßÉÏ¡£´Ë×ÜÏߵį¥Å乿ÔòÊÇ£º

    static const struct i2c_device_id *i2c_match_id(const struct i2c_device_id *id,
                                                                                                    const struct i2c_client *client)
            {
                    while (id->name[0]) {
                            if (strcmp(client->name, id->name) == 0)
                                    return id;
                            id++;
                    }
                    return NULL;
            }

    ¿ÉÒÔ¿´³öÊÇÀûÓÃi2c_clientµÄÃû³ÆºÍid_tableÖеÄÃû³Æ×öÆ¥ÅäµÄ¡£±¾Çý¶¯ÖеÄid_tableΪ

    static const struct i2c_device_id pca953x_id[] = {
                    { "pca9534", 8, },
                    { "pca9535", 16, },
                    { "pca9536", 4, },
                    { "pca9537", 4, },
                    { "pca9538", 8, },
                    { "pca9539", 16, },
                    { "pca9554", 8, },
                    { "pca9555", 16, },
                    { "pca9557", 8, },
                    { "max7310", 8, },
                    { }
            };

    ¿´µ½ÏÖÔÚÎÒÃÇÓ¦¸Ã»áÓÐÕâÑùµÄÒÉÎÊ£¬ÔÚAdapterģʽÖУ¬i2c_clientÊÇÎÒÃÇ×Ô¼º¹¹Ôì³öÀ´µÄ£¬¶øÏÖÔÚµÄi2c_clientÊÇ´ÓÄÄÀ´µÄÄØ£¿¿´¿´ÏÂÃæµÄ½âÊÍ

    ¡ñ    ×¢²ái2c_board_info

    ¶ÔÓÚProbeģʽ£¬Í¨³£ÔÚÆ½Ì¨´úÂëÖÐÒªÍê³Éi2c_board_infoµÄ×¢²á¡£·½·¨ÈçÏ£º

    static struct i2c_board_info __initdata test_i2c_devices[] = {
                    {
                            I2C_BOARD_INFO("pca9555", 0x27),//pca9555ΪоƬÃû³Æ£¬0x27ΪоƬµØÖ·
                            .platform_data = &pca9555_data,
                    }, {
                            I2C_BOARD_INFO("mt9v022", 0x48),
                            .platform_data = &iclink[0], /* With extender */
                    }, {
                            I2C_BOARD_INFO("mt9m001", 0x5d),
                            .platform_data = &iclink[0], /* With extender */
                    },
            };
            i2c_register_board_info(0, test_i2c_devices,ARRAY_SIZE(test_i2c_devices)); //×¢²á

    i2c_client¾ÍÊÇÔÚ×¢²á¹ý³ÌÖй¹½¨µÄ¡£µ«ÓÐÒ»µãÐèҪעÒâµÄÊÇi2c_register_board_info²¢Ã»ÓÐEXPORT_SYMBOL¸øÄ£¿éʹÓá£

    ¡ñ    ×Ö·ûÇý¶¯×¢²á

    ÔÚProbe·½Ê½Ï£¬Ìí¼Ó×Ö·ûÇý¶¯µÄλÖÃÔÚpca953x_probeÖС£

    static int __devinit pca953x_probe(struct i2c_client *client,const struct i2c_device_id *id)
            {
                            ……
                            /****×Ö·ûÉ豸Çý¶¯×¢²áλÖÃ****/
                            ……
                            return 0;
            }

    ¡ñ    ×¢Ïúi2c_driver

    static void __exit pca953x_exit(void)
            {
                    i2c_del_driver(&pca953x_driver);
            }
            module_exit(pca953x_exit);

    ¡ñ    ×¢Ïú×Ö·ûÉ豸Çý¶¯

    ÔÚProbe·½Ê½Ï£¬×¢Ïú×Ö·ûÇý¶¯µÄλÖÃÔÚpca953x_removeÖС£

    static int __devinit pca953x_remove (struct i2c_client *client)
            {
                    ……
                    /****×Ö·ûÉ豸Çý¶¯×¢ÏúµÄλÖÃ****/
                    ……
                    return 0;
            }

    ¡ñ    I2CÉ豸µÄÊý¾Ý½»»¥·½·¨(¼´£ºµ÷ÓÃÊÊÅäÆ÷²Ù×÷É豸µÄ·½·¨)ºÍAdapter·½Ê½ÏÂÏàͬ¡£


    ·¢±íÆÀÂÛ

    È«¹ú×Éѯµç»°£º400-611-6270£¬Ë«ÐÝÈÕ¼°½Ú¼ÙÈÕÇëÖµçÖµ°àÊÖ»ú£º15010390966

    ÔÚÏß×Éѯ£º ²ÜÀÏʦQQ£¨3337544669£©£¬ ÐìÀÏʦQQ£¨1462495461£©£¬ ÁõÀÏʦ QQ£¨3108687497£©

    ÆóÒµÅàѵǢ̸רÏߣº010-82600901£¬ÔºÐ£ºÏ×÷Ǣ̸רÏߣº010-82600350£¬ÔÚÏß×Éѯ£ºQQ£¨248856300£©

    Copyright 2004-2018 »ªÇåÔ¶¼û½ÌÓý¼¯ÍÅ °æÈ¨ËùÓÐ £¬¾©ICP±¸16055225ºÅ£¬¾©¹«º£Íø°²±¸11010802025203ºÅ

    welcome¹º²ÊÖÐÐÄ : 0px 0px 10px; list-style-type: none; font-family: Arial, Helvetica, sans-serif; font-size: 15px; color: rgb(102, 102, 102); line-height: 24px; text-indent: 28px;"> £¨1£© Adapter·½Ê½£¨LEGACY£©

    £¨ÏÂÃæµÄʵÀý´úÂëÊÇÔÚ2.6.27Äں˵Äpca953x.c»ù´¡ÉÏÐ޸ĵÄ£¬Ô­Ê¼´úÂë²ÉÓõÄÊDZ¾ÎĽ«ÒªÌÖÂ۵ĵÚ2ÖÖ·½Ê½£¬¼´Probe·½Ê½£©

    ¡ñ    ¹¹½¨i2c_driver

    static struct i2c_driver pca953x_driver = {
                    .driver = {
                                        .name= "pca953x", //Ãû³Æ
                                    },
                    .id= ID_PCA9555,//idºÅ
                    .attach_adapter= pca953x_attach_adapter, //µ÷ÓÃÊÊÅäÆ÷Á¬½ÓÉ豸
                    .detach_client= pca953x_detach_client,//ÈÃÉ豸ÍÑÀëÊÊÅäÆ÷
            };

    ¡ñ    ×¢²ái2c_driver

    static int __init pca953x_init(void)
            {
                    return i2c_add_driver(&pca953x_driver);
            }
            module_init(pca953x_init);

    ¡ñ    attach_adapter¶¯×÷

    Ö´ÐÐi2c_add_driver(&pca953x_driver)ºó»á£¬Èç¹ûÄÚºËÖÐÒѾ­×¢²áÁËi2cÊÊÅäÆ÷£¬Ôò˳Ðòµ÷ÓÃÕâЩÊÊÅäÆ÷À´Á¬½ÓÎÒÃǵÄi2cÉ豸¡£´Ë¹ý³ÌÊÇͨ¹ýµ÷ÓÃi2c_driverÖеÄattach_adapter·½·¨Íê³ÉµÄ¡£¾ßÌåʵÏÖÐÎʽÈçÏ£º

    static int pca953x_attach_adapter(struct i2c_adapter *adapter)
            {
                    return i2c_probe(adapter, &addr_data, pca953x_detect);
                    /*
                    adapter:ÊÊÅäÆ÷
                    addr_data:µØÖ·ÐÅÏ¢
                    pca953x_detect£ºÌ½²âµ½É豸ºóµ÷Óõĺ¯Êý
                    */
            }

    µØÖ·ÐÅÏ¢addr_dataÊÇÓÉÏÂÃæ´úÂëÖ¸¶¨µÄ¡£
            /* Addresses to scan */
            static unsigned short normal_i2c[] = {0x20,0x21,0x22,0x23,0x24,0x25,0x26,0x27,I2C_CLIENT_END};
            I2C_CLIENT_INSMOD;

    ×¢Ò⣺normal_i2cÀïµÄµØÖ·±ØÐëÊÇÄãi2cоƬµÄµØÖ·¡£·ñÔò½«ÎÞ·¨Õýȷ̽²âµ½É豸¡£¶øI2C_ CLIENT_INSMODÊÇÒ»¸öºê£¬Ëü»áÀûÓÃnormal_i2c¹¹½¨addr_data¡£

    ¡ñ    ¹¹½¨i2c_client£¬²¢×¢²á×Ö·ûÉ豸Çý¶¯

    i2c_probeÔÚ̽²âµ½Ä¿±êÉ豸ºó£¬ºóµ÷ÓÃpca953x_detect£¬²¢°Ñµ±Ê±µÄ̽²âµØÖ·address×÷Ϊ²ÎÊý´«Èë¡£

    static int pca953x_detect(struct i2c_adapter *adapter, int address, int kind)
            {
                    struct i2c_client *new_client;
                    struct pca953x_chip *chip; //É豸½á¹¹Ìå
                    int err = 0,result;
                    dev_t pca953x_dev=MKDEV(pca953x_major,0);//¹¹½¨É豸ºÅ£¬¸ù¾Ý¾ßÌåÇé¿öÉ趨£¬ÕâÀïÎÒÖ»¿¼ÂÇÁËnormal_i2cÖÐÖ»ÓÐÒ»¸öµØÖ·Æ¥ÅäµÄÇé¿ö¡£
                    if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA| I2C_FUNC_SMBUS_WORD_DATA))//Åж¨ÊÊÅäÆ÷ÄÜÁ¦
                    goto exit;
                    if (!(chip = kzalloc(sizeof(struct pca953x_chip), GFP_KERNEL))) {
                            err = -ENOMEM;
                            goto exit;
                    }
                    /****¹¹½¨i2c-client****/
                    chip->client=kzalloc(sizeof(struct i2c_client),GFP_KERNEL);
                    new_client = chip->client;
                    i2c_set_clientdata(new_client, chip);
                    new_client->addr = address;
                    new_client->adapter = adapter;
                    new_client->driver = &pca953x_driver;
                    new_client->flags = 0;