Hi Sascha,
On Mon, Mar 25, 2024 at 11:39:46AM +0100, Sascha Hauer wrote:
> Hi Tomas,
>
> Thanks for the patch. Looks mostly fine, but this needs fixing:
>
> On Wed, Mar 20, 2024 at 01:55:38PM +0100, Tomas Marek wrote:
> > +static int efi_i2c_xfer(struct i2c_adapter *adapter,
> > + struct i2c_msg *msg, int nmsgs)
> > +{
> > + struct efi_i2c_priv *i2c_priv = adapter_to_efi_i2c_priv(adapter);
> > + int i, ret;
> > +
> > + for (i = nmsgs; i > 0; i--, msg++) {
> > + ret = efi_i2c_message_xfer(i2c_priv, msg);
> > + if (ret)
> > + return ret;
> > + }
>
> Each of the messages should start with a (repeated) start bit and only
> the last message should be followed by a stop bit. By separating the
> full message into segments and pushing each segment into EFI separately
> you would instead send a stop bit after each segment, see the comment
> above EFI_I2C_REQUEST_PACKET:
>
> ///
> /// I2C device request
> ///
> /// The EFI_I2C_REQUEST_PACKET describes a single I2C transaction. The
> /// transaction starts with a start bit followed by the first operation
> /// in the operation array. Subsequent operations are separated with
> /// repeated start bits and the last operation is followed by a stop bit
> /// which concludes the transaction. Each operation is described by one
> /// of the elements in the Operation array.
> ///
>
> Instead you have to compile all nmsgs into a single EFI_I2C_REQUEST_PACKET
> and push it into EFI as a single request.
I see. You are right. I will fix.
Best regards
Tomas
>
> Sascha
>
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