Re: [PATCH v2 1/3] media: mt9m111: add V4L2_CID_LINK_FREQ support

From: Laurent Pinchart
Date: Mon Sep 19 2022 - 08:55:43 EST


On Mon, Sep 19, 2022 at 12:42:15PM +0000, Sakari Ailus wrote:
> Hi Marco,
>
> On Fri, Sep 16, 2022 at 03:57:11PM +0200, Marco Felsch wrote:
> > Add support to report the link frequency.
> >
> > Signed-off-by: Marco Felsch <m.felsch@xxxxxxxxxxxxxx>
> > ---
> > The v1 of this small series can be found here:
> > https://lore.kernel.org/all/20220818144712.997477-1-m.felsch@xxxxxxxxxxxxxx/
> >
> > Thanks a lot to Jacopo for the review feedback on my v1.
> >
> > Changelog:
> >
> > v2:
> > - use V4L2_CID_LINK_FREQ instead of V4L2_CID_PIXEL_RATE
> > ---
> > drivers/media/i2c/mt9m111.c | 21 ++++++++++++++++++++-
> > 1 file changed, 20 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/media/i2c/mt9m111.c b/drivers/media/i2c/mt9m111.c
> > index afc86efa9e3e..52be1c310455 100644
> > --- a/drivers/media/i2c/mt9m111.c
> > +++ b/drivers/media/i2c/mt9m111.c
> > @@ -1249,6 +1249,8 @@ static int mt9m111_probe(struct i2c_client *client)
> > {
> > struct mt9m111 *mt9m111;
> > struct i2c_adapter *adapter = client->adapter;
> > + static s64 extclk_rate;
> > + struct v4l2_ctrl *ctrl;
> > int ret;
> >
> > if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_WORD_DATA)) {
> > @@ -1271,6 +1273,13 @@ static int mt9m111_probe(struct i2c_client *client)
> > if (IS_ERR(mt9m111->clk))
> > return PTR_ERR(mt9m111->clk);
> >
> > + ret = clk_prepare_enable(mt9m111->clk);
> > + if (ret < 0)
> > + return ret;
> > +
> > + extclk_rate = clk_get_rate(mt9m111->clk);
> > + clk_disable_unprepare(mt9m111->clk);
>
> I don't think you'll need to enable a clock to just get its frequency.
>
> > +
> > mt9m111->regulator = devm_regulator_get(&client->dev, "vdd");
> > if (IS_ERR(mt9m111->regulator)) {
> > dev_err(&client->dev, "regulator not found: %ld\n",
> > @@ -1285,7 +1294,7 @@ static int mt9m111_probe(struct i2c_client *client)
> > mt9m111->subdev.flags |= V4L2_SUBDEV_FL_HAS_DEVNODE |
> > V4L2_SUBDEV_FL_HAS_EVENTS;
> >
> > - v4l2_ctrl_handler_init(&mt9m111->hdl, 7);
> > + v4l2_ctrl_handler_init(&mt9m111->hdl, 8);
> > v4l2_ctrl_new_std(&mt9m111->hdl, &mt9m111_ctrl_ops,
> > V4L2_CID_VFLIP, 0, 1, 1, 0);
> > v4l2_ctrl_new_std(&mt9m111->hdl, &mt9m111_ctrl_ops,
> > @@ -1309,6 +1318,16 @@ static int mt9m111_probe(struct i2c_client *client)
> > BIT(V4L2_COLORFX_NEGATIVE) |
> > BIT(V4L2_COLORFX_SOLARIZATION)),
> > V4L2_COLORFX_NONE);
> > + /*
> > + * The extclk rate equals the link freq. if reg default values are used,

s/freq./frequency/

> > + * which is the case. This must be adapted as soon as we don't use the
> > + * default values anymore.
> > + */
> > + ctrl = v4l2_ctrl_new_int_menu(&mt9m111->hdl, &mt9m111_ctrl_ops,
> > + V4L2_CID_LINK_FREQ, 0, 0, &extclk_rate);
> > + if (ctrl)
> > + ctrl->flags |= V4L2_CTRL_FLAG_READ_ONLY;
> > +
> > mt9m111->subdev.ctrl_handler = &mt9m111->hdl;
> > if (mt9m111->hdl.error) {
> > ret = mt9m111->hdl.error;

--
Regards,

Laurent Pinchart