Commit 2aac0bf4 authored by Joshua Yeong's avatar Joshua Yeong Committed by Alexandre Belloni

i3c: Add fallback method for GETMXDS CCC

Some I3C hardware will report error when an incorrect length is received from
device. GETMXDS CCC are available in 2 formats: without turnaround time (format
1) and with turnaround time (format 2). There is no mechanics to determine which
format is supported by device. So in case sending GETMXDS CCC format 2 resulted
in a failure, try sending GETMXDS CCC format 1 instead.
Signed-off-by: default avatarJoshua Yeong <joshua.yeong@starfivetech.com>
Reviewed-by: default avatarMiquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/r/20231114085525.6271-2-joshua.yeong@starfivetech.comSigned-off-by: default avatarAlexandre Belloni <alexandre.belloni@bootlin.com>
parent 4afd7287
......@@ -1130,8 +1130,16 @@ static int i3c_master_getmxds_locked(struct i3c_master_controller *master,
i3c_ccc_cmd_init(&cmd, true, I3C_CCC_GETMXDS, &dest, 1);
ret = i3c_master_send_ccc_cmd_locked(master, &cmd);
if (ret)
goto out;
if (ret) {
/*
* Retry when the device does not support max read turnaround
* while expecting shorter length from this CCC command.
*/
dest->payload.len -= 3;
ret = i3c_master_send_ccc_cmd_locked(master, &cmd);
if (ret)
goto out;
}
if (dest.payload.len != 2 && dest.payload.len != 5) {
ret = -EIO;
......
Markdown is supported
0%
or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment