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

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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



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