Hi Biju,
On Wed, Feb 14, 2024 at 08:25:16PM +0000, Biju Das wrote:
> Hi Wolfram,
>
> Thanks for the feedback.
>
> > -----Original Message-----
> > From: Wolfram Sang <wsa@xxxxxxxxxx>
> > Sent: Wednesday, February 14, 2024 8:31 AM
> > Subject: Re: [PATCH 1/2] media: i2c: ov5645: Move the register 0x3008 from
> > ov5645_global_init_setting
> >
> > Hi Biju,
> >
> > > I think it is different here. That 1 msec is delay associated with
> > > applying hardware power see [1]
> >
> > Okay, ack.
> >
> > > I will restore it.
> >
> > Thanks!
> >
> > I had meanwhile another thought. What if we kind of merge the two patches,
> > so the outcome is basically this:
> >
> > In ov5645_set_register_array:
> >
> > If (settings->reg == 0x3008 && settings->val == 0x82)
> > usleep_range(1000, 2000)
> >
> > ?
> >
> > Then, we don't need to split the array and we are also future proof if we
> > ever need to set the reset bit again somewhere else.
> >
> > Bonus points for replacing 0x82 with a define :)
> >
> > What do you think?
>
>
> OK, this will do check for all other registers.
>
> But from your power down clue and checking ov5640.c
> Looks like there are 2 registers changes values after writing.
>
> [1] 0x3008, 0x82-->0x80
> [2] 0x0601, 0x02-->0x00
>
> I think [1] is soft reset based on ov5640. Since there is a gpio based
> hardware reset available, we can safely remove soft reset[1] and like
> ov5640.c, if there is no gpio for reset, then do the soft reset[1].
I guess that would work. My understanding is that hard reset control is
mandatory for the device, so there really should be no need for soft reset
in the driver.
>
>
> Then add 1msec delay for power down/up(0x3008: 0x42,0x02) and 0x0601
> registers.
>
> With this looks like the Camera works ok @400kHz.
>
> The plans is to add a u8 variable for delay and enable delays for the above registers
> and add a check like below
>
> static int ov5645_set_register_array(struct ov5645 *ov5645,
> const struct reg_value *settings,
> unsigned int num_settings)
> {
> unsigned int i;
> int ret;
>
> for (i = 0; i < num_settings; ++i, ++settings) {
> ret = ov5645_write_reg(ov5645, settings->reg, settings->val);
> if (ret < 0)
> return ret;
>
> if (settings->delay_ms)
> usleep_range(1000 * settings->delay_ms, 2 * 1000 * settings->delay_ms);
I'd prefer checking the register address in the write function instead of
this if you really need it. But it seems you don't.
> }
>
> return 0;
> }
>
> Please share your thoughts on this approach.
>
> Cheers,
> Biju
--
Regards,
Sakari Ailus
