diff mbox series

[net,v2,4/5] net: dsa: vsc73xx: allow phy resetting

Message ID 20240805211031.1689134-5-paweldembicki@gmail.com (mailing list archive)
State Superseded
Delegated to: Netdev Maintainers
Headers show
Series net: dsa: vsc73xx: fix MDIO bus access and PHY operations | expand

Checks

Context Check Description
netdev/series_format success Posting correctly formatted
netdev/tree_selection success Clearly marked for net
netdev/ynl success Generated files up to date; no warnings/errors; no diff in generated;
netdev/fixes_present success Fixes tag present in non-next series
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 29 this patch: 29
netdev/build_tools success No tools touched, skip
netdev/cc_maintainers success CCed 7 of 7 maintainers
netdev/build_clang success Errors and warnings before: 29 this patch: 29
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: 29 this patch: 29
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 17 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

Pawel Dembicki Aug. 5, 2024, 9:10 p.m. UTC 
Resetting the VSC73xx PHY was problematic because the MDIO bus, without
a busy check, read and wrote incorrect register values.

My investigation indicates that resetting the PHY only triggers changes
in configuration. However, improper register values written earlier
were only exposed after a soft reset.

The reset itself wasn't the issue; rather, the problem stemmed from
incorrect read and write operations.

A 'soft_reset' can now proceed normally. There are no reasons to keep
the VSC73xx from being reset.

This commit removes the reset blockade in the 'vsc73xx_phy_write'
function.

Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Florian Fainelli <florian.fainelli@broadcom.com>
Signed-off-by: Pawel Dembicki <paweldembicki@gmail.com>
---
v2:
  - improved commit description

This patch came from net-next series[0].
Changes since net-next:
  - rebased to netdev/main only

[0] https://patchwork.kernel.org/project/netdevbpf/patch/20240729210615.279952-6-paweldembicki@gmail.com/
---
 drivers/net/dsa/vitesse-vsc73xx-core.c | 11 -----------
 1 file changed, 11 deletions(-)
diff mbox series

Patch

diff --git a/drivers/net/dsa/vitesse-vsc73xx-core.c b/drivers/net/dsa/vitesse-vsc73xx-core.c
index a9378e0512d8..ac02927a153b 100644
--- a/drivers/net/dsa/vitesse-vsc73xx-core.c
+++ b/drivers/net/dsa/vitesse-vsc73xx-core.c
@@ -599,17 +599,6 @@  static int vsc73xx_phy_write(struct dsa_switch *ds, int phy, int regnum,
 	if (ret)
 		return ret;
 
-	/* It was found through tedious experiments that this router
-	 * chip really hates to have it's PHYs reset. They
-	 * never recover if that happens: autonegotiation stops
-	 * working after a reset. Just filter out this command.
-	 * (Resetting the whole chip is OK.)
-	 */
-	if (regnum == 0 && (val & BIT(15))) {
-		dev_info(vsc->dev, "reset PHY - disallowed\n");
-		return 0;
-	}
-
 	cmd = (phy << 21) | (regnum << 16) | val;
 	ret = vsc73xx_write(vsc, VSC73XX_BLOCK_MII, 0, 1, cmd);
 	if (ret)