linux-kernel - Re: [PATCH v3 4/4] media: i2c: ov2659: Use clk_{prepare_enable,disable

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Message-ID: <CAL9mu0LmZO38CvmRfBMvgJm6310eMY64tgTRw8kWKCPuGJReoA@mail.gmail.com>
Date:   Tue, 20 Apr 2021 14:45:47 +0800
From:   dillon min <dillon.minfei@...il.com>
To:     Krzysztof Kozlowski <krzysztof.kozlowski@...onical.com>,
        Rob Herring <robh+dt@...nel.org>,
        Shawn Guo <shawnguo@...nel.org>, krzk@...nel.org,
        linux@...pel-privat.de, s.riedmueller@...tec.de,
        matthias.schiffer@...tq-group.com, leoyang.li@....com,
        arnd@...db.de, olof@...om.net,
        Sascha Hauer <s.hauer@...gutronix.de>, kernel@...gutronix.de,
        festevam@...il.com, prabhakar.csengg@...il.com, mchehab@...nel.org
Cc:     "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" 
        <devicetree@...r.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Linux ARM <linux-arm-kernel@...ts.infradead.org>,
        linux-imx@....com, linux-media@...r.kernel.org
Subject: Re: [PATCH v3 4/4] media: i2c: ov2659: Use clk_{prepare_enable,disable_unprepare}()
 to set xvclk on/off

Hi All,

Just a gentle ping, hope some expert could take a look, thanks.

Best regards.
Dillon

On Thu, Apr 15, 2021 at 12:06 PM <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>
> ---
> v3: optimize commit message
>
>  drivers/media/i2c/ov2659.c | 24 ++++++++++++++++++------
>  1 file changed, 18 insertions(+), 6 deletions(-)
>
> 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
>