Re: [PATCH v2 2/3] media: Add lane checks for Cadence CSI2RX

[Jan Kotas]

> On 9 Sep 2019, at 09:51, Sakari Ailus <sakari.ailus@xxxxxx> wrote:
> 
> 
> On Mon, Sep 09, 2019 at 07:41:21AM +0000, Jan Kotas wrote:
>> 
>> 
>> Hello Sakari,
>> 
>> Thanks for your reply.
>>> On 6 Sep 2019, at 09:54, Sakari Ailus <sakari.ailus@xxxxxx> wrote:
>>> 
>>> Hi Jan,
>>> 
>>> Thanks for the patchset.
>>> 
>>> On Thu, Sep 05, 2019 at 11:56:00AM +0100, Jan Kotas wrote:
>>>> /*
>>>> * Driver for Cadence MIPI-CSI2 RX Controller v1.3
>>>> *
>>>> - * Copyright (C) 2017 Cadence Design Systems Inc.
>>>> + * Copyright (C) 2017-2019 Cadence Design Systems Inc.
>>>> */
>>>> 
>>>> +	for (i = 0; i < csi2rx->num_lanes; i++) {
>>>> +		if (csi2rx->lanes[i] < 1) {
>>> 
>>> Do you need this? v4l2_fwnode_parse_endpoint() already has a more thorough
>>> check for the lane numbers.
>> 
>> I looked at the source code of v4l2_fwnode_endpoint_parse_csi2_bus
>> and this particular case doesnât seem to be checked.
> 
> Not specifically, since 0 is a valid lane number.
> 
> However, the driver only appears to be using the information on how many
> lanes there are. If the hardware doesn't support lane routing, then this is
> all you need. Otherwise additional checks should be added in case there are
> limitations how the lanes can be routed.

The CSI2RX v1.3 does support that (CSI2RX_STATIC_CFG_REG)
and assumes the first data lane has number 1.

Regrads,
Jan

> -- 
> Sakari Ailus