Driver-Support of I2C_M_RECV_LEN

Driver-Support of I2C_M_RECV_LEN

[Michael Post]

Hello,

in the documentation i found at
http://ww2.cs.fsu.edu/~rosentha/linux/2.6.26.5/docs/DocBook/kernel-api/re1222.html
the following sentence:

"Note that using this function requires that the client's adapter
support the I2C_FUNC_SMBUS_READ_BLOCK_DATA functionality. Not all
adapter drivers support this; its emulation through I2C messaging relies
on a specific mechanism (I2C_M_RECV_LEN) which may not be implemented."

The second sentence says that the mechanism I2C_M_RECV_LEN is not all
over implemented.

How i can figure out whether this mechanism will be provided of my driver?
What is the alternative of using the function i2c_smbus_read_block_data?

Thanks a lot for your support,

Michael Post

Re: Driver-Support of I2C_M_RECV_LEN

[Michael Post]

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Hello together,

Am 20.06.14 14:03, schrieb Michael Post:
> Hello,
> 
> in the documentation i found at 
> http://ww2.cs.fsu.edu/~rosentha/linux/2.6.26.5/docs/DocBook/kernel-api/re1222.html
>
> 
the following sentence:
> 
> "Note that using this function requires that the client's adapter 
> support the I2C_FUNC_SMBUS_READ_BLOCK_DATA functionality. Not all 
> adapter drivers support this; its emulation through I2C messaging
> relies on a specific mechanism (I2C_M_RECV_LEN) which may not be
> implemented."
> 
> The second sentence says that the mechanism I2C_M_RECV_LEN is not
> all over implemented.
> 
> How i can figure out whether this mechanism will be provided of my
> driver? What is the alternative of using the function
> i2c_smbus_read_block_data?
> 

does nobody has any clue or hints for me?
Maybe there is an other mailinglist i can ask?

Thanks a lot,

Michael
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Re: Driver-Support of I2C_M_RECV_LEN

[Michael Post]

Hello together,

Am 20.06.14 14:03, schrieb Michael Post:
> Hello,
> 
> in the documentation i found at
> http://ww2.cs.fsu.edu/~rosentha/linux/2.6.26.5/docs/DocBook/kernel-api/re1222.html
> the following sentence:
> 
> "Note that using this function requires that the client's adapter
> support the I2C_FUNC_SMBUS_READ_BLOCK_DATA functionality. Not all
> adapter drivers support this; its emulation through I2C messaging relies
> on a specific mechanism (I2C_M_RECV_LEN) which may not be implemented."
> 
> The second sentence says that the mechanism I2C_M_RECV_LEN is not all
> over implemented.
> 
> How i can figure out whether this mechanism will be provided of my driver?
> What is the alternative of using the function i2c_smbus_read_block_data?

does nobody has any clue or hints for me?
Maybe there is an other mailinglist i can ask?

Thanks a lot,

Michael

Re: Driver-Support of I2C_M_RECV_LEN

[Wolfram Sang]

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Hi,

> How i can figure out whether this mechanism will be provided of my driver?

Use i2c_get_functionality() and check for
I2C_FUNC_SMBUS_READ_BLOCK_DATA (or look at the source code).

> What is the alternative of using the function i2c_smbus_read_block_data?

That depends solely on your slave device. Check the documentation what
transfer types it supports and what alternatives are possible.

Regards,

   Wolfram

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