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i3c: Add fallback method for GETMXDS CCC

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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: Joshua Yeong <joshua.yeong@starfivetech.com>
Reviewed-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/r/20231114085525.6271-2-joshua.yeong@starfivetech.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
This commit is contained in:
Joshua Yeong 2023-11-14 16:55:25 +08:00 • committed by Alexandre Belloni
parent 4afd728769
commit 2aac0bf4eb
1 changed files with 10 additions and 2 deletions
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8
drivers/i3c/master.c
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@ -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); i3c_ccc_cmd_init(&cmd, true, I3C_CCC_GETMXDS, &dest, 1);
ret = i3c_master_send_ccc_cmd_locked(master, &cmd); ret = i3c_master_send_ccc_cmd_locked(master, &cmd);
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) if (ret)
goto out; goto out;
}
if (dest.payload.len != 2 && dest.payload.len != 5) { if (dest.payload.len != 2 && dest.payload.len != 5) {
ret = -EIO; ret = -EIO;