Linux-Media Archive on lore.kernel.org
 help / color / Atom feed
From: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
To: Dongchun Zhu <dongchun.zhu@mediatek.com>
Cc: linus.walleij@linaro.org, bgolaszewski@baylibre.com,
	mchehab@kernel.org, robh+dt@kernel.org, mark.rutland@arm.com,
	sakari.ailus@linux.intel.com, drinkcat@chromium.org,
	tfiga@chromium.org, matthias.bgg@gmail.com, bingbu.cao@intel.com,
	srv_heupstream@mediatek.com, linux-mediatek@lists.infradead.org,
	linux-arm-kernel@lists.infradead.org, sj.huang@mediatek.com,
	linux-media@vger.kernel.org, devicetree@vger.kernel.org,
	louis.kuo@mediatek.com, shengnan.wang@mediatek.com
Subject: Re: [V7, 2/2] media: i2c: dw9768: Add DW9768 VCM driver
Date: Mon, 8 Jun 2020 16:27:20 +0300
Message-ID: <20200608132720.GS2428291@smile.fi.intel.com> (raw)
In-Reply-To: <1591424358.8804.599.camel@mhfsdcap03>

On Sat, Jun 06, 2020 at 02:19:18PM +0800, Dongchun Zhu wrote:
> On Fri, 2020-06-05 at 15:46 +0300, Andy Shevchenko wrote:
> > On Fri, Jun 05, 2020 at 06:54:12PM +0800, Dongchun Zhu wrote:

...

> > > +	depends on I2C && VIDEO_V4L2
> > 
> > No compile test?
> > 
> 
> Sorry?
> Kconfig here is based on the current media tree master branch.
> It is also what the other similar drivers from Dongwoon do. 

COMPILE_TEST.
I dunno if it's established or not practice in media subsystem.

...

> > > +/*
> > > + * DW9768 requires waiting time (delay time) of t_OPR after power-up,
> > > + * or in the case of PD reset taking place.
> > > + */
> > > +#define DW9768_T_OPR_US				1000
> > > +#define DW9768_Tvib_MS_BASE10			(64 - 1)
> > > +#define DW9768_AAC_MODE_DEFAULT			2
> > 
> > > +#define DW9768_AAC_TIME_DEFAULT			0x20
> > 
> > Hex? Why not decimal?
> > 
> 
> There is one optional property 'dongwoon,aac-timing' defined in DT.
> I don't know whether you have noticed that.
> 
> 'DW9768_AAC_TIME_DEFAULT' is the value set to AACT[5:0] register.
> I thought the Hex unit should be proper as it is directly written to the
> Hex register.

I see. I would rather put it like (BIT(6) / 2) to show explicitly that we
choose half of the resolution.

...

> > > +	val = ((unsigned char)ret & ~mask) | (val & mask);
> > 
> > This cast is weird.
> > 
> 
> Thanks for the review, but this cast is using classical pattern from
> your suggestion on OV02A10 v5:
> https://patchwork.linuxtv.org/patch/59788/
> 
> So I wonder whether it is still required to be refined currently.
> Or what would it be supposed to do for the cast?

Okay, does it produce a warning w/o cast?
If yes, replace it at least to be the same type as mask and val.

...

> > > +	for ( ; val >= 0; val -= DW9768_MOVE_STEPS) {
> > > +		ret = dw9768_set_dac(dw9768, val);
> > > +		if (ret) {
> > > +			dev_err(&client->dev, "I2C write fail: %d", ret);
> > > +			return ret;
> > > +		}
> > > +		usleep_range(move_delay_us, move_delay_us + 1000);
> > > +	}
> > 
> > 
> > It will look more naturally in the multiplier kind of value.
> > 
> > 	unsigned int steps = DIV_ROUND_UP(...);
> > 
> > 	while (steps--) {
> > 		...(..., steps * ..._MOVE_STEPS);
> > 		...
> > 	}
> > 
> > but double check arithmetics.
> 
> The current coding style is actually updated with reference to your
> previous comments on DW9768 v3:
> https://patchwork.linuxtv.org/patch/61856/

I understand, but can you consider to go further and see if the proposal works?

-- 
With Best Regards,
Andy Shevchenko



  reply index

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-06-05 10:54 [V7, 0/2] media: i2c: Add support for " Dongchun Zhu
2020-06-05 10:54 ` [V7, 1/2] media: dt-bindings: media: i2c: Document DW9768 bindings Dongchun Zhu
2020-06-09 19:47   ` Rob Herring
2020-06-05 10:54 ` [V7, 2/2] media: i2c: dw9768: Add DW9768 VCM driver Dongchun Zhu
2020-06-05 12:14   ` Sakari Ailus
2020-06-05 13:02     ` Tomasz Figa
2020-06-05 13:37       ` Sakari Ailus
2020-06-06  6:24     ` Dongchun Zhu
2020-06-05 12:46   ` Andy Shevchenko
2020-06-05 13:10     ` Tomasz Figa
2020-06-06  6:19     ` Dongchun Zhu
2020-06-08 13:27       ` Andy Shevchenko [this message]
2020-06-09  3:45         ` Dongchun Zhu
2020-06-09 11:14           ` Andy Shevchenko
2020-06-10 12:58             ` Sakari Ailus
2020-06-05 13:44   ` Tomasz Figa
2020-06-06  6:42     ` Dongchun Zhu

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20200608132720.GS2428291@smile.fi.intel.com \
    --to=andriy.shevchenko@linux.intel.com \
    --cc=bgolaszewski@baylibre.com \
    --cc=bingbu.cao@intel.com \
    --cc=devicetree@vger.kernel.org \
    --cc=dongchun.zhu@mediatek.com \
    --cc=drinkcat@chromium.org \
    --cc=linus.walleij@linaro.org \
    --cc=linux-arm-kernel@lists.infradead.org \
    --cc=linux-media@vger.kernel.org \
    --cc=linux-mediatek@lists.infradead.org \
    --cc=louis.kuo@mediatek.com \
    --cc=mark.rutland@arm.com \
    --cc=matthias.bgg@gmail.com \
    --cc=mchehab@kernel.org \
    --cc=robh+dt@kernel.org \
    --cc=sakari.ailus@linux.intel.com \
    --cc=shengnan.wang@mediatek.com \
    --cc=sj.huang@mediatek.com \
    --cc=srv_heupstream@mediatek.com \
    --cc=tfiga@chromium.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

Linux-Media Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/linux-media/0 linux-media/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 linux-media linux-media/ https://lore.kernel.org/linux-media \
		linux-media@vger.kernel.org
	public-inbox-index linux-media

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kernel.vger.linux-media


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git