Re: [PATCH 0/3] adv748x: Add support for s2ram

[Sergei Shtylyov <sergei.shtylyov@gmail.com>]

On 22.11.2020 19:36, Niklas Söderlund wrote:

> This series enables usage of the ADV748x after the system have been
> suspended to ram. During s2ram the ADV748x may be powered down and thus
> lose its configuration from probe time. The configuration contains
> among other things the i2c slave address mappings for the different
> blocks inside the ADV748x. If this is lost the hardware listens to the
> "wrong" i2c addresses and becomes inaccessible.
> 
> Example trying to read the analog standard before and after s2ram with
> and without this this series.
> 
> Without this series,
> 
>    # subdev=$(grep -l "adv748x 4-0070 afe" /sys/class/video4linux/*/name | sed 's#.*video4linux\(.*\)/name#/dev\1#g')
>    # v4l2-ctl --get-detected-standard -d $subdev
>    Video Standard = 0x000000ff
>            PAL-B/B1/G/H/I/D/D1/K
>    # echo on > /sys/bus/i2c/drivers/bd9571mwv/*/bd9571mwv-regulator*/backup_mode
>    ** flipp SW23 off **

    flip?

>    # echo mem > /sys/power/state
>    ** flipp SW23 on **

    flip?

>    # v4l2-ctl --get-detected-standard -d $subdev
>    [  502.753723] adv748x 4-0070: error reading 63, 02
>    [  502.866437] adv748x 4-0070: error reading 63, 02
>    VIDIOC_QUERYSTD: failed: No such device or address
> 
> With this series,
> 
>    # subdev=$(grep -l "adv748x 4-0070 afe" /sys/class/video4linux/*/name | sed 's#.*video4linux\(.*\)/name#/dev\1#g')
>    # v4l2-ctl --get-detected-standard -d $subdev
>    Video Standard = 0x000000ff
>            PAL-B/B1/G/H/I/D/D1/K
>    # echo on > /sys/bus/i2c/drivers/bd9571mwv/*/bd9571mwv-regulator*/backup_mode
>    ** flipp SW23 off **
>    # echo mem > /sys/power/state
>    ** flipp SW23 on **

    Here as well...

>    # v4l2-ctl --get-detected-standard -d $subdev
>    Video Standard = 0x000000ff
>            PAL-B/B1/G/H/I/D/D1/K
[...]

MBR, Sergei