[S] Change in coreboot[master]: mb/siemens/mc_ehl2/devicetree.cb: Use RV3028 bus_speed instead of dum...

[Felix Held (Code Review)]

Felix Held has submitted this change. ( https://review.coreboot.org/c/coreboot/+/69544 )

Change subject: mb/siemens/mc_ehl2/devicetree.cb: Use RV3028 bus_speed instead of dummy i2c device
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mb/siemens/mc_ehl2/devicetree.cb: Use RV3028 bus_speed instead of dummy i2c device

Instead of creating a dummy I2C device in order to force Linux to
decrease the I2C bus speed, use the own 'bus_speed' field of RV3028
device config structure.

Linux should always set the bus speed to the speed of the slowest
device sitting on the bus. Hence the dummy device is not needed
here anymore.

BUG=none
TEST=See if the RV3028 RTC is visible and working (date/time can
be set/read) in Linux. At the time, a driver modification is needed
to add a match table for the "MCRY3028" ACPI HID. A proper kernel
patch is pending.

Change-Id: I6e269dc67d1fe2a6747fcf3bee224def7b553f08
Signed-off-by: Jan Samek 
Reviewed-on: https://review.coreboot.org/c/coreboot/+/69544
Reviewed-by: Paul Menzel 
Tested-by: build bot (Jenkins) 
Reviewed-by: Mario Scheithauer 
---
M src/mainboard/siemens/mc_ehl/variants/mc_ehl2/devicetree.cb
1 file changed, 29 insertions(+), 6 deletions(-)

Approvals:
  build bot (Jenkins): Verified
  Paul Menzel: Looks good to me, but someone else must approve
  Mario Scheithauer: Looks good to me, approved

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 3b54f24..4dd062c 100644
--- a/src/mainboard/siemens/mc_ehl/variants/mc_ehl2/devicetree.cb
+++ b/src/mainboard/siemens/mc_ehl/variants/mc_ehl2/devicetree.cb
@@ -147,6 +147,7 @@
    	device pci 15.1 on	    # I2C1
    		# Enable external RTC chip
    		chip drivers/i2c/rv3028c7
+				register "bus_speed" = "I2C_SPEED_STANDARD"
    			register "set_user_date" = "1"
    			register "user_year" = "04"
    			register "user_month" = "07"
@@ -156,12 +157,6 @@
    			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