Omap3 : I2c Driver I2C_M_RECV_LEN support

Omap3 : I2c Driver I2C_M_RECV_LEN support

[Romeo Enrico]

Hi,
In Order to implement the communication between an Omap3530 configured 
as master and a custom device configured as slave, I need to be able to 
configure the size of readings dynamically according to the first byte 
sent by the slave.
Checking kernel I found that in include/linux/i2c.h is declared the 
I2C_M_RECV_LEN flag for the "struct i2c_msg" which should be what I'm 
looking for... But I have not found an implementation of this feature in 
the Omap I2c driver.

Can anyone confirm that the I2C_M_RECV_LEN is not actually supported by 
the Omap I2c driver ?

Best Regards
Enrico

Re: Omap3 : I2c Driver I2C_M_RECV_LEN support

[Jean Delvare]

Hi Enrico,

On Wed, 17 Feb 2010 11:55:28 +0100, Romeo Enrico wrote:
> In Order to implement the communication between an Omap3530 configured 
> as master and a custom device configured as slave, I need to be able to 
> configure the size of readings dynamically according to the first byte 
> sent by the slave.
> Checking kernel I found that in include/linux/i2c.h is declared the 
> I2C_M_RECV_LEN flag for the "struct i2c_msg" which should be what I'm 
> looking for...

This is correct. This mechanism is used for the SMBus Block Read
transaction.

> But I have not found an implementation of this feature in 
> the Omap I2c driver.
> 
> Can anyone confirm that the I2C_M_RECV_LEN is not actually supported by 
> the Omap I2c driver ?

Looking at the source code of the i2c-omap driver in Linus' kernel, I
can confirm there is no support. You might want to check for updates in
the omap tree though, or even ask on an omap-specific list: someone
might have already implemented it but not pushed it to mainstream yet.

-- 
Jean Delvare