From: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
To: Kieran Bingham <kieran.bingham@ideasonboard.com>, y@Mani-XPS-13-9360
Cc: kieran.bingham+renesas@ideasonboard.com,
linux-renesas-soc@vger.kernel.org, linux-media@vger.kernel.org,
devicetree@vger.kernel.org, linux-kernel@vger.kernel.org,
"Mauro Carvalho Chehab" <mchehab@kernel.org>,
"Laurent Pinchart" <laurent.pinchart@ideasonboard.com>,
"Jacopo Mondi" <jacopo@jmondi.org>,
"Niklas Söderlund" <niklas.soderlund@ragnatech.se>,
sakari.ailus@iki.fi, "Hans Verkuil" <hverkuil@xs4all.nl>,
"Hyun Kwon" <hyunk@xilinx.com>,
"Rob Herring" <robh+dt@kernel.org>,
"Jacopo Mondi" <jacopo+renesas@jmondi.org>,
"Laurent Pinchart" <laurent.pinchart+renesas@ideasonboard.com>,
"Niklas Söderlund" <niklas.soderlund+renesas@ragnatech.se>
Subject: Re: [PATCH v9 2/4] media: i2c: Add MAX9286 driver
Date: Thu, 14 May 2020 18:24:45 +0530 [thread overview]
Message-ID: <20200514125445.GH2877@Mani-XPS-13-9360> (raw)
In-Reply-To: <d4d0e298-b863-8c6e-c9d7-ba861a98359e@ideasonboard.com>
On Thu, May 14, 2020 at 01:27:01PM +0100, Kieran Bingham wrote:
> Hi Mani,
>
> On 14/05/2020 12:47, Kieran Bingham wrote:
> > On 14/05/2020 11:13, Manivannan Sadhasivam wrote:
> >> Hi Kieran,
> <snip>
>
> >>>>> +static int max9286_parse_dt(struct max9286_priv *priv)
> >>>>> +{
> >>>>> + struct device *dev = &priv->client->dev;
> >>>>> + struct device_node *i2c_mux;
> >>>>> + struct device_node *node = NULL;
> >>>>> + unsigned int i2c_mux_mask = 0;
> >>>>> +
> >>>>> + of_node_get(dev->of_node);
> >>>>
> >>>> Why this is needed?
> >>>
> >>> Hrm .. I recall adding it to solve dt reference balancing.
> >>>
> >>> I wish I'd added a comment at the time ... as I can't recall the details
> >>> now.
> >>>
> >>
> >> I understand that it is for the refcount balancing but I certainly don't see
> >> a need for it.
> >
> > I'll go through and try to validate this again now.
>
> Aha, that's why:
>
> * of_find_node_by_name - Find a node by its "name" property
> * @from: The node to start searching from or NULL; the node
> * you pass will not be searched, only the next one
> * will. Typically, you pass what the previous call
> * returned. of_node_put() will be called on @from.
> * @name: The name string to match against
>
> I'll add a comment to state that it is to balance the of_node_put during
> of_find_node_by_name().
>
Ah, right. I mostly use of_find_node_by_name() with NULL, so didn't realize
this.
And yeah, a comment would be helpful.
Thanks,
Mani
> --
> Kieran
>
>
> >>>>> + i2c_mux = of_find_node_by_name(dev->of_node, "i2c-mux");
> >>>>> + if (!i2c_mux) {
> >>>>> + dev_err(dev, "Failed to find i2c-mux node\n");
> >>>>> + of_node_put(dev->of_node);
> >>>>> + return -EINVAL;
> >>>>> + }
> >>>>> +
> >> [...]
> >>>>
> --
> Regards
> --
> Kieran
next prev parent reply other threads:[~2020-05-14 12:55 UTC|newest]
Thread overview: 41+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-12 15:51 [PATCH v9 0/4] MAX9286 GMSL Support (+RDACM20) Kieran Bingham
2020-05-12 15:51 ` [PATCH v9 1/4] dt-bindings: media: i2c: Add bindings for Maxim Integrated MAX9286 Kieran Bingham
2020-05-12 22:33 ` Rob Herring
2020-05-13 12:54 ` Jacopo Mondi
2020-05-14 9:43 ` [PATCH] fixup! dt-bindings: media: i2c: Add bindings for Maxima Integrated MAX9286 Kieran Bingham
2020-05-14 10:20 ` Jacopo Mondi
2020-05-12 22:36 ` [PATCH v9 1/4] dt-bindings: media: i2c: Add bindings for Maxim " Rob Herring
2020-05-13 12:28 ` Jacopo Mondi
2020-05-12 15:51 ` [PATCH v9 2/4] media: i2c: Add MAX9286 driver Kieran Bingham
2020-05-12 17:40 ` Manivannan Sadhasivam
2020-05-14 9:53 ` Kieran Bingham
2020-05-14 9:59 ` Manivannan Sadhasivam
2020-05-14 10:05 ` Kieran Bingham
2020-05-12 18:17 ` Manivannan Sadhasivam
2020-05-14 10:02 ` Kieran Bingham
2020-05-14 10:13 ` Manivannan Sadhasivam
2020-05-14 11:47 ` Kieran Bingham
2020-05-14 11:59 ` Geert Uytterhoeven
2020-05-14 12:48 ` Manivannan Sadhasivam
2020-05-14 13:50 ` Kieran Bingham
2020-05-14 11:47 ` Kieran Bingham
2020-05-14 12:27 ` Kieran Bingham
2020-05-14 12:54 ` Manivannan Sadhasivam [this message]
2020-05-16 21:51 ` Sakari Ailus
2020-05-18 11:45 ` Kieran Bingham
2020-05-18 12:38 ` Jacopo Mondi
2020-05-18 13:09 ` Kieran Bingham
2020-05-18 16:11 ` [PATCH] fixes! [max9286]: Validate link formats Kieran Bingham
2020-05-18 18:44 ` Kieran Bingham
2020-05-19 8:13 ` Sakari Ailus
2020-05-19 7:56 ` Jacopo Mondi
2020-05-19 9:00 ` Kieran Bingham
2020-05-19 8:10 ` [PATCH v9 2/4] media: i2c: Add MAX9286 driver Sakari Ailus
2020-05-19 8:55 ` Kieran Bingham
2020-05-19 9:03 ` Sakari Ailus
2020-05-20 0:50 ` Laurent Pinchart
2020-05-26 8:54 ` Sakari Ailus
2020-05-12 15:51 ` [PATCH v9 3/4] dt-bindings: media: i2c: Add bindings for IMI RDACM2x Kieran Bingham
2020-05-12 15:51 ` [PATCH v9 4/4] media: i2c: Add RDACM20 driver Kieran Bingham
2020-05-16 22:36 ` Sakari Ailus
2020-05-18 7:35 ` Jacopo Mondi
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