Thread (17 messages) 17 messages, 5 authors, 2021-09-01

Re: [PATCH v2] of: property: fw_devlink: Add support for "phy-handle" property

From: Saravana Kannan <hidden>
Date: 2021-08-23 18:13:48
Also in: linux-amlogic, linux-devicetree, lkml

On Mon, Aug 23, 2021 at 6:16 AM Andrew Lunn [off-list ref] wrote:
quoted hunk ↗ jump to hunk
On Mon, Aug 23, 2021 at 02:08:48PM +0200, Marek Szyprowski wrote:
quoted
Hi,

On 18.08.2021 04:17, Saravana Kannan wrote:
quoted
Allows tracking dependencies between Ethernet PHYs and their consumers.

Cc: Andrew Lunn <andrew@lunn.ch>
Cc: netdev@vger.kernel.org
Signed-off-by: Saravana Kannan <redacted>
This patch landed recently in linux-next as commit cf4b94c8530d ("of:
property: fw_devlink: Add support for "phy-handle" property"). It breaks
ethernet operation on my Amlogic-based ARM64 boards: Odroid C4
(arm64/boot/dts/amlogic/meson-sm1-odroid-c4.dts) and N2
(meson-g12b-odroid-n2.dts) as well as Khadas VIM3/VIM3l
(meson-g12b-a311d-khadas-vim3.dts and meson-sm1-khadas-vim3l.dts).

In case of OdroidC4 I see the following entries in the
/sys/kernel/debug/devices_deferred:

ff64c000.mdio-multiplexer
ff3f0000.ethernet

Let me know if there is anything I can check to help debugging this issue.
Hi Marek

Please try this. Completetly untested, not even compile teseted:
diff --git a/drivers/of/property.c b/drivers/of/property.c
index 0c0dc2e369c0..7c4e257c0a81 100644
--- a/drivers/of/property.c
+++ b/drivers/of/property.c
@@ -1292,6 +1292,7 @@ DEFINE_SIMPLE_PROP(resets, "resets", "#reset-cells")
 DEFINE_SIMPLE_PROP(leds, "leds", NULL)
 DEFINE_SIMPLE_PROP(backlight, "backlight", NULL)
 DEFINE_SIMPLE_PROP(phy_handle, "phy-handle", NULL)
+DEFINE_SIMPLE_PROP(mdio_parent_bus, "mdio-parent-bus", NULL);
 DEFINE_SUFFIX_PROP(regulators, "-supply", NULL)
 DEFINE_SUFFIX_PROP(gpio, "-gpio", "#gpio-cells")
@@ -1381,6 +1382,7 @@ static const struct supplier_bindings of_supplier_bindings[] = {
        { .parse_prop = parse_leds, },
        { .parse_prop = parse_backlight, },
        { .parse_prop = parse_phy_handle, },
+       { .parse_prop = parse_mdio_parent_bus, },
        { .parse_prop = parse_gpio_compat, },
        { .parse_prop = parse_interrupts, },
        { .parse_prop = parse_regulators, },
Looking at the code, I'm fairly certain that the device that
corresponds to a DT node pointed to by mdio-parent-bus will be a "bus"
device that's registered with the mdio_bus_class.

If my understanding is right, then Nak for this patch. It'll break a
lot of probes.

TL;DR is that stateful/managed device links don't make sense for
devices that are never probed/bound to a driver. I plan to improve
device links to try and accommodate these cases nicely, but that's in
my TO DO list. Until that's completed, this patch will break stuff.

-Saravana
Keyboard shortcuts
hback out one level
jnext message in thread
kprevious message in thread
ldrill in
Escclose help / fold thread tree
?toggle this help