Re: [PATCH 2/2] i3c: master: svc: fix probe failure when no i3c device exist

[Miquel Raynal]

Hi Frank,

Frank.Li@xxxxxxx wrote on Mon, 28 Aug 2023 15:25:02 -0400:

> If there are not i3c device, all ccc command will get NACK. Set

		no					NACKed?

> i3c_ccc_cmd::err as I3C_ERROR_M2.

This sentence should come last and be slightly more explicit.

> Return success when no i3c device found at svc_i3c_master_do_daa_locked().

Please explain why this is important/useful.

> Fixes: dd3c52846d59 ("i3c: master: svc: Add Silvaco I3C master driver")

Shall we consider a backport into stable kernels?

> Signed-off-by: Frank Li <Frank.Li@xxxxxxx>
> ---
>  drivers/i3c/master/svc-i3c-master.c | 13 +++++++++++--
>  1 file changed, 11 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/i3c/master/svc-i3c-master.c b/drivers/i3c/master/svc-i3c-master.c
> index 770b40e28015e..a5620103acb73 100644
> --- a/drivers/i3c/master/svc-i3c-master.c
> +++ b/drivers/i3c/master/svc-i3c-master.c
> @@ -789,6 +789,9 @@ static int svc_i3c_master_do_daa_locked(struct svc_i3c_master *master,
>  				 */
>  				break;
>  			} else if (SVC_I3C_MSTATUS_NACKED(reg)) {
> +				/* No I3C devices attached */
> +				if (dev_nb == 0)
> +					break;

\n ?

>  				/*
>  				 * A slave device nacked the address, this is
>  				 * allowed only once, DAA will be stopped and
> @@ -1263,11 +1266,17 @@ static int svc_i3c_master_send_ccc_cmd(struct i3c_master_controller *m,
>  {
>  	struct svc_i3c_master *master = to_svc_i3c_master(m);
>  	bool broadcast = cmd->id < 0x80;
> +	int ret;
>  
>  	if (broadcast)
> -		return svc_i3c_master_send_bdcast_ccc_cmd(master, cmd);
> +		ret = svc_i3c_master_send_bdcast_ccc_cmd(master, cmd);
>  	else
> -		return svc_i3c_master_send_direct_ccc_cmd(master, cmd);
> +		ret = svc_i3c_master_send_direct_ccc_cmd(master, cmd);
> +
> +	if (ret)
> +		cmd->err = I3C_ERROR_M2;
> +
> +	return ret;
>  }
>  
>  static int svc_i3c_master_priv_xfers(struct i3c_dev_desc *dev,


Thanks,
Miquèl