Patrick Georgi has submitted this change. ( https://review.coreboot.org/c/coreboot/+/54249 )
Change subject: mb/google/dedede/var/blipper: Configure I2C times for touchpad/touchpanel/codec ......................................................................
mb/google/dedede/var/blipper: Configure I2C times for touchpad/touchpanel/codec
Configure I2C rise/fall time in device tree to ensure I2C CLK runs accurately at I2C_SPEED_FAST (<400 kHz).
Measured I2C frequency changes are just as below after tuning: touchpad: 434kHz ---> 391kHz touchpanel: 439kHz ---> 382kHz audio codec RT5682: 445kHz ---> 385kHz
BUG=b:187555396 BRANCH=dedede TEST=Build and check after tuning I2C clock is under 400 kHz
Signed-off-by: Tao Xia xiatao5@huaqin.corp-partner.google.com Change-Id: I8438e37be49f8a74f53fd8460110dac1a3f06993 Reviewed-on: https://review.coreboot.org/c/coreboot/+/54249 Tested-by: build bot (Jenkins) no-reply@coreboot.org Reviewed-by: Karthik Ramasubramanian kramasub@google.com --- M src/mainboard/google/dedede/variants/blipper/overridetree.cb 1 file changed, 6 insertions(+), 0 deletions(-)
Approvals: build bot (Jenkins): Verified Karthik Ramasubramanian: Looks good to me, approved
diff --git a/src/mainboard/google/dedede/variants/blipper/overridetree.cb b/src/mainboard/google/dedede/variants/blipper/overridetree.cb index df3f9dd..a5a7e48 100644 --- a/src/mainboard/google/dedede/variants/blipper/overridetree.cb +++ b/src/mainboard/google/dedede/variants/blipper/overridetree.cb @@ -21,18 +21,24 @@ }, .i2c[0] = { .speed = I2C_SPEED_FAST, + .rise_time_ns = 247, + .fall_time_ns = 11, }, .i2c[1] = { .speed = I2C_SPEED_FAST, }, .i2c[2] = { .speed = I2C_SPEED_FAST, + .rise_time_ns = 175, + .fall_time_ns = 20, }, .i2c[3] = { .speed = I2C_SPEED_FAST, }, .i2c[4] = { .speed = I2C_SPEED_FAST, + .rise_time_ns = 99, + .fall_time_ns = 7, }, }"