Re: [PATCH v2 12/12] ipu3-cio2: Add cio2-bridge to ipu3-cio2 driver

From: Andy Shevchenko <andy.shevchenko@gmail.com>
To: Daniel Scally <djrscally@gmail.com>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	ACPI Devel Maling List <linux-acpi@vger.kernel.org>,
	Linux Media Mailing List <linux-media@vger.kernel.org>,
	devel@acpica.org, "Rafael J. Wysocki" <rjw@rjwysocki.net>,
	Len Brown <lenb@kernel.org>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Yong Zhi <yong.zhi@intel.com>,
	Sakari Ailus <sakari.ailus@linux.intel.com>,
	Bingbu Cao <bingbu.cao@intel.com>,
	Tian Shu Qiu <tian.shu.qiu@intel.com>,
	Mauro Carvalho Chehab <mchehab@kernel.org>,
	Robert Moore <robert.moore@intel.com>,
	Erik Kaneda <erik.kaneda@intel.com>,
	Petr Mladek <pmladek@suse.com>,
	Steven Rostedt <rostedt@goodmis.org>,
	Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
	Rasmus Villemoes <linux@rasmusvillemoes.dk>,
	Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>,
	Jacopo Mondi <jacopo+renesas@jmondi.org>,
	kieran.bingham+renesas@ideasonboard.com,
	Linus Walleij <linus.walleij@linaro.org>,
	"Krogerus, Heikki" <heikki.krogerus@linux.intel.com>,
	Tsuchiya Yuto <kitakar@gmail.com>,
	jorhand@linux.microsoft.com
Subject: Re: [PATCH v2 12/12] ipu3-cio2: Add cio2-bridge to ipu3-cio2 driver
Date: Sat, 19 Dec 2020 20:52:29 +0200	[thread overview]
Message-ID: <CAHp75VcebKas4j-vByodicHxRMrO4jkaJToSUW3iLJC2+vY_iA@mail.gmail.com> (raw)
In-Reply-To: <e2b4c35f-5020-c332-d97a-8ba25be0e55e@gmail.com>

On Sat, Dec 19, 2020 at 2:25 AM Daniel Scally <djrscally@gmail.com> wrote:
> On 18/12/2020 21:17, Andy Shevchenko wrote:
> > On Thu, Dec 17, 2020 at 11:43:37PM +0000, Daniel Scally wrote:

...

> >> +    sensor->ep_properties[0] = PROPERTY_ENTRY_U32(sensor->prop_names.bus_type, 4);
> >
> > Does 4 has any meaning that can be described by #define ?
>
> It's V4L2_FWNODE_BUS_TYPE_CSI2_DPHY:
>
> https://elixir.bootlin.com/linux/latest/source/drivers/media/v4l2-core/v4l2-fwnode.c#L36
>
> That enum's not in an accessible header, but I can define it in this
> module's header

Maybe you can do a preparatory patch to make it visible to v4l2
drivers? (Like moving to one of v4l2 headers)

...

> >> +                    if (bridge->n_sensors >= CIO2_NUM_PORTS) {
> >> +                            dev_warn(&cio2->dev, "Exceeded available CIO2 ports\n");
> >
> >> +                            /* overflow i so outer loop ceases */
> >> +                            i = ARRAY_SIZE(cio2_supported_sensors);
> >> +                            break;
> >
> > Why not to create a new label below and assign ret here with probably comment
> > why it's not an error?
>
> Sure, I can do that, but since it wouldn't need any cleanup I could also
> just return 0 here as Laurent suggest (but with a comment explaining why
> that's ok as you say) - do you have a preference?

While it's a good suggestion it will bring a bit of inconsistency into
approach. Everywhere else in the function you are using the goto
approach.
So yes, I have a preference.

> >> +                    }

...

> >> +                    ret = cio2_bridge_read_acpi_buffer(adev, "SSDB",
> >> +                                                       &sensor->ssdb,
> >> +                                                       sizeof(sensor->ssdb));
> >> +                    if (ret < 0)
> >
> > if (ret) (because positive case can be returned just by next conditional).
>
> cio2_bridge_read_acpi_buffer() returns the buffer length on success at
> the moment, but I can change it to return 0 and have this be if (ret)

Please correct this somehow, because the next failure returns it
instead of error...

> >> +                            goto err_put_adev;
> >> +
> >> +                    if (sensor->ssdb.lanes > 4) {
> >> +                            dev_err(&adev->dev,
> >> +                                    "Number of lanes in SSDB is invalid\n");

...I'm even thinking that you have to assign ret here to something meaningful.

> >> +                            goto err_put_adev;
> >> +                    }

-- 
With Best Regards,
Andy Shevchenko