diff options
| author | Werner Zeh <werner.zeh@siemens.com> | 2022-11-07 15:15:58 +0100 |
|---|---|---|
| committer | Felix Held <felix-coreboot@felixheld.de> | 2022-11-09 14:19:40 +0000 |
| commit | eda13db4e93bda57d73a5b71229588238b5e1e1b (patch) | |
| tree | 0e4d46c8a529410d6c93564b7770c36f0e03884b /src | |
| parent | 14612f698c1ec76555ebe4c89ca771795450dff1 (diff) | |
mb/siemens/mc_ehl2: Add dummy I2C devices to limit the I2C speed in OS
In Linux, the I2C speed defaults to 400 kHz if there is no device
registered in ACPI which requests a different speed. Due to board
limitations (layout, bus load), 400 kHz are too fast which results in a
timing violation. Therefore, add a dummy I2C device to both used I2C
buses (I2C1 and I2C2) with a speed of 100 kHz. This will limit the bus
speed in Linux accordingly.
Change-Id: I507c53c9ec7f763cef18903609231b1a66ed98fa
Signed-off-by: Werner Zeh <werner.zeh@siemens.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/69306
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Mario Scheithauer <mario.scheithauer@siemens.com>
Diffstat (limited to 'src')
| -rw-r--r-- | src/mainboard/siemens/mc_ehl/variants/mc_ehl2/devicetree.cb | 15 |
1 files changed, 14 insertions, 1 deletions
diff --git a/src/mainboard/siemens/mc_ehl/variants/mc_ehl2/devicetree.cb b/src/mainboard/siemens/mc_ehl/variants/mc_ehl2/devicetree.cb index 4109ec9157..d5d12777ec 100644 --- a/src/mainboard/siemens/mc_ehl/variants/mc_ehl2/devicetree.cb +++ b/src/mainboard/siemens/mc_ehl/variants/mc_ehl2/devicetree.cb @@ -144,8 +144,21 @@ chip soc/intel/elkhartlake register "cap_charge" = "CHARGE_OFF" device i2c 0x52 on end # RTC RV3028-C7 end + # Add dummy I2C device to limit BUS speed to 100 kHz in OS + chip drivers/i2c/generic + register "hid" = ""PRP0001"" + register "speed" = "I2C_SPEED_STANDARD" + device i2c 0x7f on end + end + end + device pci 15.2 on # I2C2 + # Add dummy I2C device to limit BUS speed to 100 kHz in OS + chip drivers/i2c/generic + register "hid" = ""PRP0001"" + register "speed" = "I2C_SPEED_STANDARD" + device i2c 0x7f on end + end end - device pci 15.2 on end # I2C2 device pci 15.3 on end # I2C3 device pci 16.0 hidden end # Management Engine Interface 1 |