hammer: enable large block reading on usb i2c passthru.

Originally, i2c passthru is limited to use I2C_XFER_SINGLE flag where
it can only read at most 255 bytes at a time.  For application that
requires larger i2c bus reading, we change the flag setting and the
command protocol.

TEST=old ./touchpad_updater still works (previous protocol)
TEST=new ./touchpad_updater can get more than 500 bytes per transaction
TEST=Debug message only print when -d assigned.
     ./touchpad_updater -d
TEST=Manually change #define CONFIG_USB_I2C_MAX_READ_COUNT (1024 - 6)
     to #define CONFIG_USB_I2C_MAX_READ_COUNT (1024 - 4) and trigger
     POWER_OF_TWO assertion.
BRANCH=none
BUG=b:35587174, b:63993891

Change-Id: Id75b11ea49ba89bab8e18af24d47219030c778c5
Signed-off-by: Chun-Ta Lin <itspeter@google.com>
Reviewed-on: https://chromium-review.googlesource.com/542716
Commit-Ready: Chun-ta Lin <itspeter@chromium.org>
Tested-by: Chun-ta Lin <itspeter@chromium.org>
Reviewed-by: Nicolas Boichat <drinkcat@chromium.org>

0 files changed, 0 insertions, 0 deletions