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| author | Joshua Yeong <joshua.yeong@starfivetech.com> | 2023-11-14 16:55:25 +0800 |
|---|---|---|
| committer | Alexandre Belloni <alexandre.belloni@bootlin.com> | 2023-11-16 23:37:56 +0100 |
| commit | 2aac0bf4ebc8e09941bb2a40c0ce725437d9a82c (patch) | |
| tree | de9a0af3a3e8586ee57615a4d0eb85b640b16e4f /drivers/i3c | |
| parent | 4afd72876942f2ab1e97e79082464a46ab40a485 (diff) | |
| download | lwn-2aac0bf4ebc8e09941bb2a40c0ce725437d9a82c.tar.gz lwn-2aac0bf4ebc8e09941bb2a40c0ce725437d9a82c.zip | |
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: 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>
Diffstat (limited to 'drivers/i3c')
| -rw-r--r-- | drivers/i3c/master.c | 12 |
1 files changed, 10 insertions, 2 deletions
diff --git a/drivers/i3c/master.c b/drivers/i3c/master.c index 95caa162706f..718b643cb54d 100644 --- a/drivers/i3c/master.c +++ b/drivers/i3c/master.c @@ -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; |