linux-kernel - Re: [PATCH v4 4/4] media: i2c: ov2659: Use clk_{prepare_enable,disable

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Message-ID: <CAL9mu0LJ1txew9iL89YchmXyx78oecAUhcJ-U14NsWgehF2SQw@mail.gmail.com>
Date:   Mon, 3 May 2021 22:11:47 +0800
From:   dillon min <dillon.minfei@...il.com>
To:     "Lad, Prabhakar" <prabhakar.csengg@...il.com>
Cc:     Fabio Estevam <festevam@...il.com>,
        Shawn Guo <shawnguo@...nel.org>,
        Stefan Riedmueller <s.riedmueller@...tec.de>,
        Matthias Schiffer <matthias.schiffer@...tq-group.com>,
        leoyang.li@....com, Arnd Bergmann <arnd@...db.de>,
        Olof Johansson <olof@...om.net>,
        Sascha Hauer <s.hauer@...gutronix.de>,
        Sascha Hauer <kernel@...gutronix.de>,
        Mauro Carvalho Chehab <mchehab@...nel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski@...onical.com>,
        Krzysztof Kozlowski <krzk@...nel.org>,
        Rob Herring <robh+dt@...nel.org>,
        Oleksij Rempel <linux@...pel-privat.de>,
        "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" 
        <devicetree@...r.kernel.org>, LKML <linux-kernel@...r.kernel.org>,
        LAK <linux-arm-kernel@...ts.infradead.org>,
        NXP Linux Team <linux-imx@....com>,
        linux-media <linux-media@...r.kernel.org>
Subject: Re: [PATCH v4 4/4] media: i2c: ov2659: Use clk_{prepare_enable,disable_unprepare}()
 to set xvclk on/off

Hi Prabhakar,

Thanks for the reminder.

On Mon, May 3, 2021 at 8:24 PM Lad, Prabhakar
<prabhakar.csengg@...il.com> wrote:
>
> Hi Dillon,
>
> Thank you for the patch.
>
> On Wed, Apr 21, 2021 at 4:49 AM <dillon.minfei@...il.com> wrote:
> >
> > From: dillon min <dillon.minfei@...il.com>
> >
> > On some platform(imx6q), xvclk might not switch on in advance,
> > also for power save purpose, xvclk should not be always on.
> > so, add clk_prepare_enable(), clk_disable_unprepare() in driver
> > side to set xvclk on/off at proper stage.
> >
> > Add following changes:
> > - add 'struct clk *clk;' in 'struct ov2659 {}'
> > - enable xvclk in ov2659_power_on()
> > - disable xvclk in ov2659_power_off()
> >
> > Signed-off-by: dillon min <dillon.minfei@...il.com>
> s / dillon min /Dillon Min (unless you prefer in lower case) ?

Thanks, I haven't noticed it yet, and will change to a higher case in
the next submission.

Best regards.
Dillon
>
> > ---
> > v4: no changes
> >
> >  drivers/media/i2c/ov2659.c | 24 ++++++++++++++++++------
> >  1 file changed, 18 insertions(+), 6 deletions(-)
> >
> Acked-by: Lad Prabhakar <prabhakar.csengg@...il.com>
>
> Cheers,
> Prabhakar
>
> > diff --git a/drivers/media/i2c/ov2659.c b/drivers/media/i2c/ov2659.c
> > index 42f64175a6df..fb78a1cedc03 100644
> > --- a/drivers/media/i2c/ov2659.c
> > +++ b/drivers/media/i2c/ov2659.c
> > @@ -204,6 +204,7 @@ struct ov2659 {
> >         struct i2c_client *client;
> >         struct v4l2_ctrl_handler ctrls;
> >         struct v4l2_ctrl *link_frequency;
> > +       struct clk *clk;
> >         const struct ov2659_framesize *frame_size;
> >         struct sensor_register *format_ctrl_regs;
> >         struct ov2659_pll_ctrl pll;
> > @@ -1270,6 +1271,8 @@ static int ov2659_power_off(struct device *dev)
> >
> >         gpiod_set_value(ov2659->pwdn_gpio, 1);
> >
> > +       clk_disable_unprepare(ov2659->clk);
> > +
> >         return 0;
> >  }
> >
> > @@ -1278,9 +1281,17 @@ static int ov2659_power_on(struct device *dev)
> >         struct i2c_client *client = to_i2c_client(dev);
> >         struct v4l2_subdev *sd = i2c_get_clientdata(client);
> >         struct ov2659 *ov2659 = to_ov2659(sd);
> > +       int ret;
> >
> >         dev_dbg(&client->dev, "%s:\n", __func__);
> >
> > +       ret = clk_prepare_enable(ov2659->clk);
> > +       if (ret) {
> > +               dev_err(&client->dev, "%s: failed to enable clock\n",
> > +                       __func__);
> > +               return ret;
> > +       }
> > +
> >         gpiod_set_value(ov2659->pwdn_gpio, 0);
> >
> >         if (ov2659->resetb_gpio) {
> > @@ -1425,7 +1436,6 @@ static int ov2659_probe(struct i2c_client *client)
> >         const struct ov2659_platform_data *pdata = ov2659_get_pdata(client);
> >         struct v4l2_subdev *sd;
> >         struct ov2659 *ov2659;
> > -       struct clk *clk;
> >         int ret;
> >
> >         if (!pdata) {
> > @@ -1440,11 +1450,11 @@ static int ov2659_probe(struct i2c_client *client)
> >         ov2659->pdata = pdata;
> >         ov2659->client = client;
> >
> > -       clk = devm_clk_get(&client->dev, "xvclk");
> > -       if (IS_ERR(clk))
> > -               return PTR_ERR(clk);
> > +       ov2659->clk = devm_clk_get(&client->dev, "xvclk");
> > +       if (IS_ERR(ov2659->clk))
> > +               return PTR_ERR(ov2659->clk);
> >
> > -       ov2659->xvclk_frequency = clk_get_rate(clk);
> > +       ov2659->xvclk_frequency = clk_get_rate(ov2659->clk);
> >         if (ov2659->xvclk_frequency < 6000000 ||
> >             ov2659->xvclk_frequency > 27000000)
> >                 return -EINVAL;
> > @@ -1506,7 +1516,9 @@ static int ov2659_probe(struct i2c_client *client)
> >         ov2659->frame_size = &ov2659_framesizes[2];
> >         ov2659->format_ctrl_regs = ov2659_formats[0].format_ctrl_regs;
> >
> > -       ov2659_power_on(&client->dev);
> > +       ret = ov2659_power_on(&client->dev);
> > +       if (ret < 0)
> > +               goto error;
> >
> >         ret = ov2659_detect(sd);
> >         if (ret < 0)
> > --
> > 2.7.4
> >