How do I configure mmc0 to 208MHz on MCIMX6ULL-EVK?
‎04-12-2023
03:33 PM
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JohnKlug
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I am seeing:
root@imx6ullevk:~# cat /sys/kernel/debug/mmc0/ios
clock: 132000000 Hz
vdd: 21 (3.3 ~ 3.4 V)
bus mode: 2 (push-pull)
chip select: 0 (don't care)
power mode: 2 (on)
bus width: 2 (4 bits)
timing spec: 6 (sd uhs SDR104)
signal voltage: 1 (1.80 V)
driver type: 0 (driver type B)
How do I get the interface to use the 200MHz clock? What should I put in device tree?
3 Replies
‎04-17-2023
08:43 AM
761 Views
JohnKlug
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I mean the large SD card port on the EK board, which is capable of 1.8 or 3.3V.
This is what I did to create my repo:
repo init -u https://github.com/nxp-imx/imx-manifest.git -b imx-linux-kirkstone -m imx-5.15.71-2.2.0.xml
I did not change the kernel or device tree.
‎04-17-2023
12:01 AM
765 Views


NXP TechSupport
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Do you mean emmc or sd card here? Which version BSP are you using?
‎04-18-2023
09:39 AM
749 Views
JohnKlug
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The 132000000 is found in device tree here:
usdhc assigned-clock-rates
This found in change:
SDIO CLOCK CHANGE
Apparently due to a chip errata:
MLK-13188-2 dts: imx6ull: change the usdhc root clock to 396MHz
Due to the errata ERR010450 limit, this patch change the imx6ull usdhc root clock to 132MHz in soc related dts file, remove all the root clock setting in board dts file, after this patch, SDR104/HS200 work at 132MHz, DDR50/DDR52 work at 33MHz.
