[v5,3/7] i3c: add actual_len in i3c_priv_xfer

Commit Message

Frank Li Nov. 30, 2023, 10:44 p.m. UTC

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 <[e-mail]>
Signed-off-by: Frank Li <[e-mail]>
---

Notes:
    change from v4 to v5
    - Add Miquel review tag

 include/linux/i3c/device.h | 2 ++
 1 file changed, 2 insertions(+)

Patch

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;