diff mbox series

[net-next,2/2] net: mdio-mux: be compatible with parent buses which only support C45

Message ID 20231213152712.320842-3-vladimir.oltean@nxp.com (mailing list archive)
State Accepted
Commit 10ad63da5c036b2fd61600b43217cfa9b4d66f52
Delegated to: Netdev Maintainers
Headers show
Series MDIO mux cleanup | expand

Checks

Context Check Description
netdev/series_format success Posting correctly formatted
netdev/tree_selection success Clearly marked for net-next
netdev/ynl success Generated files up to date; no warnings/errors; no diff in generated;
netdev/fixes_present success Fixes tag not required for -next series
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 1115 this patch: 1115
netdev/cc_maintainers success CCed 7 of 7 maintainers
netdev/build_clang success Errors and warnings before: 1142 this patch: 1142
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/deprecated_api success None detected
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success No Fixes tag
netdev/build_allmodconfig_warn success Errors and warnings before: 1142 this patch: 1142
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 12 lines checked
netdev/build_clang_rust success No Rust files in patch. Skipping build
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0

Commit Message

Vladimir Oltean Dec. 13, 2023, 3:27 p.m. UTC
After the mii_bus API conversion to a split read() / read_c45(), there
might be MDIO parent buses which only populate the read_c45() and
write_c45() function pointers but not the C22 variants.

We haven't seen these in the wild paired with MDIO multiplexers, but
Andrew points out we should treat the corner case.

Link: https://lore.kernel.org/netdev/4ccd7dc9-b611-48aa-865f-68d3a1327ce8@lunn.ch/
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
---
 drivers/net/mdio/mdio-mux.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

Comments

Andrew Lunn Dec. 13, 2023, 10:49 p.m. UTC | #1
On Wed, Dec 13, 2023 at 05:27:12PM +0200, Vladimir Oltean wrote:
> After the mii_bus API conversion to a split read() / read_c45(), there
> might be MDIO parent buses which only populate the read_c45() and
> write_c45() function pointers but not the C22 variants.
> 
> We haven't seen these in the wild paired with MDIO multiplexers, but
> Andrew points out we should treat the corner case.
> 
> Link: https://lore.kernel.org/netdev/4ccd7dc9-b611-48aa-865f-68d3a1327ce8@lunn.ch/
> Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>

Reviewed-by: Andrew Lunn <andrew@lunn.ch>

    Andrew
diff mbox series

Patch

diff --git a/drivers/net/mdio/mdio-mux.c b/drivers/net/mdio/mdio-mux.c
index e5dee7ad7c09..fe0e46bd7964 100644
--- a/drivers/net/mdio/mdio-mux.c
+++ b/drivers/net/mdio/mdio-mux.c
@@ -214,8 +214,10 @@  int mdio_mux_init(struct device *dev,
 		snprintf(cb->mii_bus->id, MII_BUS_ID_SIZE, "%s-%x.%x",
 			 cb->mii_bus->name, pb->parent_id, v);
 		cb->mii_bus->parent = dev;
-		cb->mii_bus->read = mdio_mux_read;
-		cb->mii_bus->write = mdio_mux_write;
+		if (parent_bus->read)
+			cb->mii_bus->read = mdio_mux_read;
+		if (parent_bus->write)
+			cb->mii_bus->write = mdio_mux_write;
 		if (parent_bus->read_c45)
 			cb->mii_bus->read_c45 = mdio_mux_read_c45;
 		if (parent_bus->write_c45)