[v4,0/5] usb: typec: ucsi: ccg: add runtime pm support

Message

Ajay Gupta June 3, 2019, 5:05 p.m. UTC

Hi Heikki and Wolfram

These patches add support for runtime power management for UCSI CCGx driver.
I have tested them with NVIDIA GPU card which has i2c interface to talk to
CCG controller. I have added runtime pm support for the i2c bus driver as well.

Third version (v4) of patches fix comments from Wolfram on further refactoring
master_xfer() fucntion in i2c-nvidia-gpuc.c file. Also I have added comment on
why we need a stub gpu_i2c_suspend() for runtime pm to work correctly.

First patch refactors master_xfer() of i2c driver fixing comment from Wolfram.
Second and third patch add support for runtime pm in i2c bus driver and UCSI CCGx
driver.

Last two patches add workaround for an old version of ccg firmware
which has known issue of missing interrupt when a device is connected
to runtime resume the ccg controller. The workaround is needed because
if a GPU card doesn't get new firmware but gets new kernel then also it
should continue to work. The workaround is to request runtime resume of
i2c client which is UCSI Cypress CCGx driver. CCG driver will call the ISR
for any connector change event only if NVIDIA GPU has old CCG firmware with
the known issue.

All the five patches should go together since ucsi_ccg driver is dependent
on i2c driver for runtime pm wokaround. I would prefer it to go through
usb-tree since usb ucsi_ccg driver is the main driver getting runtime pm
functionality with the series.

Thanks
Ajay


Ajay Gupta (5):
  i2c: nvidia-gpu: refactor master_xfer
  i2c: nvidia-gpu: add runtime pm support
  usb: typec: ucsi: ccg: enable runtime pm support
  i2c: nvidia-gpu: resume ccgx i2c client
  usb: typec: ucsi: ccg: add runtime pm workaround

 drivers/i2c/busses/i2c-nvidia-gpu.c |  71 +++++++++++++----
 drivers/usb/typec/ucsi/ucsi.c       |  10 +++
 drivers/usb/typec/ucsi/ucsi.h       |   1 +
 drivers/usb/typec/ucsi/ucsi_ccg.c   | 118 +++++++++++++++++++++++++++-
 4 files changed, 179 insertions(+), 21 deletions(-)