| Message ID | 20231129221225.387952-4-Frank.Li@nxp.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | i3c: master: some improvment for i3c master | expand |
Hi Frank, Frank.Li@nxp.com wrote on Wed, 29 Nov 2023 17:12:22 -0500: > In MIPI I3C Specification: > > "Ninth Bit of SDR Target Returned (Read) Data as End-of-Data: In I2C, the > ninth Data bit from Target to Controller is an ACK by the Controller. By > contrast, in I3C this bit allows the Target to end a Read, and allows the > Controller to Abort a Read. In SDR terms, the ninth bit of Read data is > referred to as the T-Bit (for ‘Transition’)" > > I3C allow devices early terminate data transfer. So need "actual_len" field > to indicate how much get by i3c_priv_xfer. > > Signed-off-by: Frank Li <Frank.Li@nxp.com> Reviewed-by: Miquel Raynal <miquel.raynal@bootlin.com> Thanks, Miquèl
diff --git a/include/linux/i3c/device.h b/include/linux/i3c/device.h index 90fa83464f003..ef6217da8253b 100644 --- a/include/linux/i3c/device.h +++ b/include/linux/i3c/device.h @@ -54,6 +54,7 @@ enum i3c_hdr_mode { * struct i3c_priv_xfer - I3C SDR private transfer * @rnw: encodes the transfer direction. true for a read, false for a write * @len: transfer length in bytes of the transfer + * @actual_len: actual length in bytes are transferred by the controller * @data: input/output buffer * @data.in: input buffer. Must point to a DMA-able buffer * @data.out: output buffer. Must point to a DMA-able buffer @@ -62,6 +63,7 @@ enum i3c_hdr_mode { struct i3c_priv_xfer { u8 rnw; u16 len; + u16 actual_len; union { void *in; const void *out;
In MIPI I3C Specification: "Ninth Bit of SDR Target Returned (Read) Data as End-of-Data: In I2C, the ninth Data bit from Target to Controller is an ACK by the Controller. By contrast, in I3C this bit allows the Target to end a Read, and allows the Controller to Abort a Read. In SDR terms, the ninth bit of Read data is referred to as the T-Bit (for ‘Transition’)" I3C allow devices early terminate data transfer. So need "actual_len" field to indicate how much get by i3c_priv_xfer. Signed-off-by: Frank Li <Frank.Li@nxp.com> --- include/linux/i3c/device.h | 2 ++ 1 file changed, 2 insertions(+)