linux-kernel - Re: [PATCH V3 3/3] media: i2c: gc5035: Add GC5035 image sensor driver

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Date:   Thu, 3 Sep 2020 09:30:42 +0300
From:   Sakari Ailus <sakari.ailus@...ux.intel.com>
To:     Tomasz Figa <tfiga@...omium.org>
Cc:     Xingyu Wu <wuxy@...land.com.cn>,
        Mauro Carvalho Chehab <mchehab@...nel.org>,
        Rob Herring <robh+dt@...nel.org>,
        "David S. Miller" <davem@...emloft.net>,
        "shawnx.tu" <shawnx.tu@...el.com>,
        Hans Verkuil <hverkuil-cisco@...all.nl>,
        "dave.stevenson" <dave.stevenson@...pberrypi.com>,
        Manivannan Sadhasivam <manivannan.sadhasivam@...aro.org>,
        Cao Bing Bu <bingbu.cao@...el.com>,
        Nicolas Boichat <drinkcat@...omium.org>,
        Linux Media Mailing List <linux-media@...r.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        linux-devicetree <devicetree@...r.kernel.org>,
        Dongchun Zhu <dongchun.zhu@...iatek.com>,
        Sj Huang <sj.huang@...iatek.com>,
        darfur_liu <darfur_liu@...reinc.com>,
        "hao.he7" <hao.he7@...il.com>,
        何浩B03205 <hao.he@...land.com.cn>
Subject: Re: [PATCH V3 3/3] media: i2c: gc5035: Add GC5035 image sensor driver

Hi Tomasz,

On Thu, Sep 03, 2020 at 12:59:20AM +0200, Tomasz Figa wrote:
> Hi Sakari,
> 
> On Mon, Aug 31, 2020 at 7:41 PM Sakari Ailus
> <sakari.ailus@...ux.intel.com> wrote:
> >
> > Hi Xingyu,
> >
> > Thanks for the update. I've got a few more comments below.
> >
> > Do you happen to have some insight on what the OTP data contains and what
> > does the driver do with it?
> >
> > At least in principle the OTP data may be programmed for the customer so
> > the same sensor could contain something else what the driver expects to
> > find there.
> >
> 
> Thanks for the review. For anything without my reply, assume fixed. :)
> 
> As far as I can see, the data is being read from an area that is
> supposed to be reserved for Galaxycore, so I'd assume it doesn't
> depend on the customer.

Sounds good.

> 
> [snip]
> > > diff --git a/drivers/media/i2c/Kconfig b/drivers/media/i2c/Kconfig
> > > index da11036..aeaf594 100644
> > > --- a/drivers/media/i2c/Kconfig
> > > +++ b/drivers/media/i2c/Kconfig
> > > @@ -712,6 +712,18 @@ config VIDEO_APTINA_PLL
> > >  config VIDEO_SMIAPP_PLL
> > >       tristate
> > >
> > > +config VIDEO_GC5035
> > > +     tristate "Galaxycore GC5035 sensor support"
> > > +     depends on I2C && VIDEO_V4L2
> > > +     select MEDIA_CONTROLLER
> > > +     select VIDEO_V4L2_SUBDEV_API
> >
> > Add:
> >
> >         V4L2_FWNODE
> >         OF
> 
> This driver doesn't depend on OF. It uses the firmware-independent
> property access API. (v4 I sent actually uses device_property_*()).

Yes, this is even better.

> 
> [snip]
> > > +static int __gc5035_power_on(struct gc5035 *gc5035)
> > > +{
> > > +     struct device *dev = &gc5035->client->dev;
> > > +     int i, ret;
> > > +
> > > +     ret = clk_prepare_enable(gc5035->xvclk);
> > > +     if (ret < 0) {
> > > +             dev_err(dev, "Failed to enable xvclk\n");
> > > +             return ret;
> > > +     }
> > > +
> > > +     gpiod_set_value_cansleep(gc5035->reset_gpio, 1);
> > > +
> > > +     for (i = 0; i < GC5035_NUM_SUPPLIES; i++) {
> > > +             ret = regulator_enable(gc5035->supplies[i].consumer);
> > > +             if (ret) {
> > > +                     dev_err(dev, "Failed to enable %s: %d\n",
> > > +                             gc5035->supplies[i].supply, ret);
> > > +                     goto disable_reg_clk;
> >
> > Please use regulator_bulk_enable() here, and regulator_bulk_disable()
> > below.
> >
> 
> This actually needs to have one of the regulators (iovdd) enabled
> before the other ones, but regulator_bulk_enable() is async. In v4 I
> used regulator_enable() for iovdd and regulator_bulk_enable() for the
> other two for optimal sequencing.

Ack.

-- 
Sakari Ailus