Re: [PATCH] media: i2c: imx412: Extend the power-on waiting time

[Wenmeng Liu]

On 12/22/2025 10:16 PM, Dave Stevenson wrote:
> Hi Wenmeng
>
> On Mon, 22 Dec 2025 at 12:20, Wenmeng Liu <wenmeng.liu@xxxxxxxxxxxxxxxx> wrote:
> > On 12/22/2025 8:11 PM, Dave Stevenson wrote:
> > > Hi Wenmeng & Sakari
> > >
> > > On Mon, 22 Dec 2025 at 09:35, Wenmeng Liu <wenmeng.liu@xxxxxxxxxxxxxxxx> wrote:
> > > > > > The Arducam IMX577 module requires a longer reset time than the 1000µs
> > > > > > configured in the current driver. Increase the wait time after power-on
> > > > > > to ensure proper initialization.
> > > > >
> > > > > Is this somehow specific to the Arducam module? If so, what's there in the
> > > > > module that requires this?
> > > >
> > > >
> > > > Yes, This issue occurred on the Arducam 22-pin IMX577 module.
> > > > I have tried changing the sequence of regulator, reset, and clock, and
> > > > found that this module must wait a sufficient amount of time after reset
> > > > before registers can be written (10 ms is a safe duration). This issue
> > > > did not occur when using other IMX577 modules.
> > >
> > > Is it the probe that fails, or starting streaming?
> > >
> > > Google has found me a datasheet for IMX577 at [1]. I'm hoping you have
> > > an official datasheet, so do correct the following if that has any
> > > updates.
> > > Section 7-2-2 on page 30 for the startup sequence.
> > >
> > > The sequence is meant to be regulators, INCK, and then XCLR. The
> > > driver does XCLR before clock, so that would appear to be wrong.
> > >
> > > It also states that T6 as the time from XCLR to being able to read the
> > > version register is min 0.6ms, but T7 as the time before you can send
> > > "Streaming Commmand" is min 8ms "To complete reading all parameters
> > > from NVM".
> > > That would be a difference between probe and start_streaming, although
> > > admittedly sending the mode and control setup I2C commands will take
> > > up some of that time.
> > >
> > > Plausibly the other set of modules don't have the NVM programmed and
> > > hence they are ready sooner. Either way I'd say that does mean the
> > > driver currently isn't following the defined power up sequence, and
> > > the patch looks reasonable for IMX577.
> > > However as this is a shared driver does IMX412 have this restriction
> > > too? I can't find a datasheet for that one to check. For the sake of
> > > ~9ms it's not going to make a huge difference though.
> > >
> > >     Dave
> > >
> > > [1] https://en.sunnywale.com/uploadfile/2021/1222/IMX577-AACK-C(Awin).pdf
> >
> > Hi Dave,
> >
> > this issue appears in the write register when streamon
> > imx412_write_regs.  poweron->streamon.
> >
> > static int imx412_start_streaming(struct imx412 *imx412)
> > {
> >           const struct imx412_reg_list *reg_list;
> >           int ret;
> >
> >           /* Write sensor mode registers */
> >           reg_list = &imx412->cur_mode->reg_list;
> >           ret = imx412_write_regs(imx412, reg_list->regs,
> >                                   reg_list->num_of_regs);
> >           if (ret) {
> >                   dev_err(imx412->dev, "fail to write initial registers\n");
> >                   return ret;
> >           }
> >
> >           /* Setup handler will write actual exposure and gain */
> >           ret =  __v4l2_ctrl_handler_setup(imx412->sd.ctrl_handler);
> >           if (ret) {
> >                   dev_err(imx412->dev, "fail to setup handler\n");
> >                   return ret;
> >           }
> >
> >           /* Delay is required before streaming*/
> >           usleep_range(7400, 8000);
> >
> >           /* Start streaming */
> >           ret = imx412_write_reg(imx412, IMX412_REG_MODE_SELECT,
> >                                  1, IMX412_MODE_STREAMING);
> >           if (ret) {
> >                   dev_err(imx412->dev, "fail to start streaming\n");
> >                   return ret;
> >           }
> >
> >           return 0;
> > }
> >   > but T7 as the time before you can send "Streaming Commmand" is min 8ms "
> > I think the usleep_range(7400, 8000) represents the 8ms duration
> > required by T7.
>
> I'd missed that one.
> If you've delayed for 10-12ms between coming out of reset and sending
> the first command, then does the Arducam module still require another
> 8ms here, or can that be removed as you've already complied with T7?
>
> Have you asked Arducam as to why their module takes longer? I can't
> find an IMX577 module listed on their product pages so presumably it's
> discontinued. There are a few links for a Luxonis Oak DepthAI board
> [1] which is made by Arducam and is using IMX577, so is it that one?
> Generally I've not encountered an issue with Arducam adding any weird
> delay circuits on their sensor boards.
>
>    Dave
>
> [1] https://shop.luxonis.com/products/oak-ffc-imx577-m12
>
> > Thanks,
> > Wenmeng

Hi Dave,

Based on my testing, moving usleep_range(7400, 8000); to the beginning 
of the imx412_start_streaming function allows the Arducam IMX577 module 
to work properly. In contrast, other IMX577 sensors do not require this 
delay. I believe this corresponds to the T7 timing requirement. I have 
not yet confirmed this with Arducam, and I plan to compare once I 
receive another type Arducam IMX577 sensor.

Thanks,
Wenmeng