[PATCH 0/2] mfd: rsmu_spi: fixes and new IC support

Matthew Bystrin
2026-04-21T09:00:52Z

Greetings!

First patch fixes Renesas 8A34002 SPI driver.

In my setup 8A34002 is connected to VisionFive2 via SPI. I've discovered that
upstream driver does not work:

[ 4.728771] 8a3400x-phc 8a3400x-phc.0.auto: 4.8.7, Id: 0x4002 HW Rev: 5 OTP Config Select: 0
[ 4.737389] 8a3400x-phc 8a3400x-phc.0.auto: requesting firmware 'idtcm.bin'
[ 4.744462] 8a3400x-phc 8a3400x-phc.0.auto: Direct firmware load for idtcm.bin failed with error -2
[ 4.753547] 8a3400x-phc 8a3400x-phc.0.auto: Failed at line 1273 in idtcm_load_firmware!
[ 4.761576] 8a3400x-phc 8a3400x-phc.0.auto: loading firmware failed with -2
[ 4.769411] 8a3400x-phc 8a3400x-phc.0.auto: No wait state: DPLL_SYS_STATE 0
[ 4.776374] 8a3400x-phc 8a3400x-phc.0.auto: Continuing while SYS APLL/DPLL is not locked
[ 4.785206] 8a3400x-phc 8a3400x-phc.0.auto: Unsupported MANUAL_REFERENCE: 0x00
[ 4.796930] 8a3400x-phc 8a3400x-phc.0.auto: PLL2 registered as ptp0

This being caused by a piece of code in rsmu_write_page_register() function:

if (reg < RSMU_CM_SCSR_BASE)
return 0;

All addresses in include/linux/mfd/idt8a340_reg.h are less than
RSMU_CM_SCSR_BASE so function was returning early, before any modifications to
the page register. Valid read of versions - is just a coincidence, because
default value of the page register is zero.

There were 2 separate patch series which have to be merged in one time: mfd and
ptp. The latter have been merged, the former[1] have not. As result we've got a
broken driver.

This patch can be reverted later when the second part will be ready (of course
if it is planned to do so). Any comments, Min? I could support with testing.

Also I've had a quick look into I2C part. It may also require the same kind of
fixes to work properly. But I didn't tested it. I could do some experiments and
return with patches later.

Second patch just adds support for 8A34002, which is compatible with 8A34001. As
I can see there is no need to update bindings, everything is already being done.

Link: https://lore.kernel.org/netdev/LV3P220MB1202F8E2FCCFBA2519B4966EA0192@LV3P220MB1202.NAMP220.PROD.OUTLOOK.COM/
Signed-off-by: Matthew Bystrin <dev.mbstr@gmail.com>

Matthew Bystrin (2):
mfd: rsmu_spi: fix page register setup
mfd: rsmu_spi: add 8a34002 support

drivers/mfd/rsmu_spi.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)

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2.53.0