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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>
This commit is contained in:
Tao Xia 2021-05-13 16:02:02 +08:00 committed by Patrick Georgi
parent 0b7bc80eba
commit 35aafb3a2a
1 changed files with 6 additions and 0 deletions
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6
src/mainboard/google/dedede/variants/blipper/overridetree.cb
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@ -21,18 +21,24 @@ chip soc/intel/jasperlake
}, },
.i2c[0] = { .i2c[0] = {
.speed = I2C_SPEED_FAST, .speed = I2C_SPEED_FAST,
.rise_time_ns = 247,
.fall_time_ns = 11,
}, },
.i2c[1] = { .i2c[1] = {
.speed = I2C_SPEED_FAST, .speed = I2C_SPEED_FAST,
}, },
.i2c[2] = { .i2c[2] = {
.speed = I2C_SPEED_FAST, .speed = I2C_SPEED_FAST,
.rise_time_ns = 175,
.fall_time_ns = 20,
}, },
.i2c[3] = { .i2c[3] = {
.speed = I2C_SPEED_FAST, .speed = I2C_SPEED_FAST,
}, },
.i2c[4] = { .i2c[4] = {
.speed = I2C_SPEED_FAST, .speed = I2C_SPEED_FAST,
.rise_time_ns = 99,
.fall_time_ns = 7,
}, },
}" }"