On Tue, Nov 12, 2024 at 4:02 PM Krishna chaitanya chundru
[off-list ref] wrote:

QPS615 is the PCIe switch which has one upstream and three downstream
ports. To one of the downstream ports ethernet MAC is connected as endpoint
device. Other two downstream ports are supposed to connect to external
device. One Host can connect to QPS615 by upstream port. QPS615 switch
needs to be configured after powering on and before PCIe link was up.

The PCIe controller driver already enables link training at the host side
even before qps615 driver probe happens, due to this when driver enables
power to the switch it participates in the link training and PCIe link
may come up before configuring the switch through i2c. To prevent the
host from participating in link training, disable link training on the
host side to ensure the link does not come up before the switch is
configured via I2C.

Based up on dt property and type of the port, qps615 is configured
through i2c.

Signed-off-by: Krishna chaitanya chundru <redacted>
---

Krishna,

This looks really good thanks.

One nit: I'd rename qps615_pwrctl_power_on() to something else as most
of its code does configure the switch, not power it up. Maybe
qps615_pwrctl_bring_up()?

With that and the build issue fixed:

Reviewed-by: Bartosz Golaszewski <redacted>

I'll test it once it compiles.

Bart