Re: [PATCH 3/4] media: mt9m111: fix device power usage

From: Marco Felsch
Date: Fri Aug 19 2022 - 03:33:11 EST


Hi Jacopo,

On 22-08-19, Jacopo Mondi wrote:
> Hi Marco
>
> On Thu, Aug 18, 2022 at 04:47:11PM +0200, Marco Felsch wrote:
> > Currently the driver turn off the power after probe and toggle it during
> > .stream by using the .s_power callback. This is problematic since other
> > callbacks like .set_fmt accessing the hardware as well which will fail.
>
> Ouch!
>
> > So in the end the default format is the only supported format.
> >
> > Remove the hardware register access from the callbacks and instead sync
> > the state once right before the stream gets enabled to fix this.
>
> Where does it happen in this patch ?

during mt9m111_s_power which gets called by s_power() or after this
small series during s_stream().

> >
> > Signed-off-by: Marco Felsch <m.felsch@xxxxxxxxxxxxxx>
> > ---
> > drivers/media/i2c/mt9m111.c | 20 +++++++++++++-------
> > 1 file changed, 13 insertions(+), 7 deletions(-)
> >
> > diff --git a/drivers/media/i2c/mt9m111.c b/drivers/media/i2c/mt9m111.c
> > index 53c4dac4e4bd..cd74c408e110 100644
> > --- a/drivers/media/i2c/mt9m111.c
> > +++ b/drivers/media/i2c/mt9m111.c
> > @@ -481,8 +481,6 @@ static int mt9m111_set_selection(struct v4l2_subdev *sd,
> > width = min(mt9m111->width, rect.width);
> > height = min(mt9m111->height, rect.height);
> >
> > -
>
> Why in mainline I don't see these empty lines ?

Hm.. because I introduced this during my "media: mt9m111: fix subdev API
usage" patch.. Sorry.

> > - mt9m111_setup_geometry(mt9m111, &rect, width, height, mt9m111->fmt->code);
> > mt9m111->rect = rect;
> > mt9m111->width = width;
> > mt9m111->height = height;
> > @@ -611,7 +609,6 @@ static int mt9m111_set_pixfmt(struct mt9m111 *mt9m111,
> > if (mt9m111->pclk_sample == 0)
> > mask_outfmt2 |= MT9M111_OUTFMT_INV_PIX_CLOCK;
> >
> > -
> > mt9m111_reg_mask(client, context_a.output_fmt_ctrl2,
> > data_outfmt2, mask_outfmt2);
> > mt9m111_reg_mask(client, context_b.output_fmt_ctrl2,
> > @@ -678,9 +675,6 @@ static int mt9m111_set_fmt(struct v4l2_subdev *sd,
> > return 0;
> > }
> >
> > -
> > - mt9m111_setup_geometry(mt9m111, rect, mf->width, mf->height, mf->code);
> > - mt9m111_set_pixfmt(mt9m111, mf->code);
>
> Are we looking at two different versions of the driver ??
> https://elixir.bootlin.com/linux/latest/source/drivers/media/i2c/mt9m111.c#L684

Same here.

> > mt9m111->width = mf->width;
> > mt9m111->height = mf->height;
> > mt9m111->fmt = fmt;
> > @@ -743,6 +737,8 @@ mt9m111_find_mode(struct mt9m111 *mt9m111, unsigned int req_fps,
> > return mode;
> > }
> >
> > +static int mt9m111_s_power(struct v4l2_subdev *sd, int on);
> > +
> > #ifdef CONFIG_VIDEO_ADV_DEBUG
> > static int mt9m111_g_register(struct v4l2_subdev *sd,
> > struct v4l2_dbg_register *reg)
> > @@ -753,10 +749,14 @@ static int mt9m111_g_register(struct v4l2_subdev *sd,
> > if (reg->reg > 0x2ff)
> > return -EINVAL;
> >
> > + mt9m111_s_power(sd, 1);
> > +
> > val = mt9m111_reg_read(client, reg->reg);
> > reg->size = 2;
> > reg->val = (u64)val;
> >
> > + mt9m111_s_power(sd, 0);
> > +
> > if (reg->val > 0xffff)
> > return -EIO;
> >
> > @@ -771,9 +771,13 @@ static int mt9m111_s_register(struct v4l2_subdev *sd,
> > if (reg->reg > 0x2ff)
> > return -EINVAL;
> >
> > + mt9m111_s_power(sd, 1);
> > +
> > if (mt9m111_reg_write(client, reg->reg, reg->val) < 0)
> > return -EIO;
> >
> > + mt9m111_s_power(sd, 0);
> > +
> > return 0;
> > }
> > #endif
> > @@ -896,6 +900,9 @@ static int mt9m111_s_ctrl(struct v4l2_ctrl *ctrl)
> > struct mt9m111, hdl);
> > int ret;
> >
> > + if (!mt9m111->is_streaming)
> > + return 0;
> > +
> > switch (ctrl->id) {
> > case V4L2_CID_VFLIP:
> > ret = mt9m111_set_flip(mt9m111, ctrl->val,
> > @@ -927,7 +934,6 @@ static int mt9m111_s_ctrl(struct v4l2_ctrl *ctrl)
> > ret = -EINVAL;
> > }
> >
> > -
> > return ret;
> > }
> >
> > --
> > 2.30.2
> >
>