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.
Reviewed-by: Miquel Raynal <miquel.raynal@xxxxxxxxxxx>
Signed-off-by: Frank Li <Frank.Li@xxxxxxx>
---
Notes:
change from v4 to v5
- Add Miquel review tag
include/linux/i3c/device.h | 2 ++
1 file changed, 2 insertions(+)
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;
--
2.34.1
