Hello,

We are using a custom board where an ethernet switch device KSZ9896 is available. This family of devices can use several types of serial bus as management interface: mdio, i2c or SPI. Due to board design constraints and because we initially planned to use this device only from Linux, the SPI bus was used.

Luckily we are using a recent enough u-boot release where KSZ9477 driver is available... but only for the i2c interface. Indeed, unlike the kernel driver, the KSZ9477 driver doesn't use the regmap API to access the underlying bus since the regmap API is limited to direct memory access [1].

As a workaround, we duplicated the existing code to a new driver (KSZ9896_SPI) where all i2c related calls were replaced by SPI.

So far so good, we are able to use the KSZ9896 ethernet switch using SPI bus as the management interface on top of u-boot 2024.10-rc5 (and after fixing issues with the ethernet controller driver with fixed-link). dhcp and ping commands are working using one of the lan interface (lan1).

In order to upstream the KSZ9896 with SPI interface support and avoid any code duplication or #if#else... it seems u-boot needs regmap with (i2c, SPI, ...) bus support as explained in the first attempt [2] back in 2018.

Is there any pending patch series about regmap I could use to test with the KSZ9896 SPI driver?

[1] https://source.denx.de/u-boot/u-boot/-/blob/v2024.10-rc5/drivers/core/Kconfi... [2] https://lists.denx.de/pipermail/u-boot/2018-May/329392.html

Best regards, Romain

Romain Naour (1): net: ksz9477: add KSZ9896 switch support

drivers/net/ksz9477.c | 3 +++ 1 file changed, 3 insertions(+)