diff mbox series

[net] net: usb: smsc95xx: fix external PHY reset

Message ID 20221114131643.19450-1-alexandru.tachici@analog.com (mailing list archive)
State Superseded
Delegated to: Netdev Maintainers
Headers show
Series [net] net: usb: smsc95xx: fix external PHY reset | expand

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Context Check Description
netdev/tree_selection success Clearly marked for net
netdev/fixes_present success Fixes tag present in non-next series
netdev/subject_prefix success Link
netdev/cover_letter success Single patches do not need cover letters
netdev/patch_count success Link
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 1 this patch: 1
netdev/cc_maintainers success CCed 9 of 9 maintainers
netdev/build_clang success Errors and warnings before: 0 this patch: 0
netdev/module_param success Was 0 now: 0
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success Fixes tag looks correct
netdev/build_allmodconfig_warn success Errors and warnings before: 1 this patch: 1
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 16 lines checked
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0

Commit Message

Alexandru Tachici Nov. 14, 2022, 1:16 p.m. UTC
An external PHY needs settling time after power up or reser.
In the bind() function an mdio bus is registered. If at this point
the external PHY is still initialising, no valid PHY ID will be
read and on phy_find_first() the bind() function will fail.

If an external PHY is present, wait the maximum time specified
in 802.3 45.2.7.1.1.

Fixes: 05b35e7eb9a1 ("smsc95xx: add phylib support")
Signed-off-by: Alexandru Tachici <alexandru.tachici@analog.com>
---
 drivers/net/usb/smsc95xx.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

Comments

Russell King (Oracle) Nov. 14, 2022, 11:31 a.m. UTC | #1
On Mon, Nov 14, 2022 at 03:16:43PM +0200, Alexandru Tachici wrote:
> +	} else {
> +		/* Driver has no knowledge at this point about the external PHY.
> +		 * The 802.3 specifies that the reset process shall
> +		 * be completed within 0.5 s.
> +		 */
> +		fsleep(500000);
> +	}

It's slightly more code, but would it be better to do this in the
mdiobus reset() method?

Thanks.
Sergey Shtylyov Nov. 14, 2022, 11:43 a.m. UTC | #2
Hello!

On 11/14/22 4:16 PM, Alexandru Tachici wrote:

> An external PHY needs settling time after power up or reser.

   Reset? :-)

> In the bind() function an mdio bus is registered. If at this point
> the external PHY is still initialising, no valid PHY ID will be
> read and on phy_find_first() the bind() function will fail.
> 
> If an external PHY is present, wait the maximum time specified
> in 802.3 45.2.7.1.1.
> 
> Fixes: 05b35e7eb9a1 ("smsc95xx: add phylib support")
> Signed-off-by: Alexandru Tachici <alexandru.tachici@analog.com>

[...]

MBR, Sergey
diff mbox series

Patch

diff --git a/drivers/net/usb/smsc95xx.c b/drivers/net/usb/smsc95xx.c
index bfb58c91db04..5ed001c0cd56 100644
--- a/drivers/net/usb/smsc95xx.c
+++ b/drivers/net/usb/smsc95xx.c
@@ -1134,8 +1134,15 @@  static int smsc95xx_bind(struct usbnet *dev, struct usb_interface *intf)
 		goto free_mdio;
 
 	is_internal_phy = !(val & HW_CFG_PSEL_);
-	if (is_internal_phy)
+	if (is_internal_phy) {
 		pdata->mdiobus->phy_mask = ~(1u << SMSC95XX_INTERNAL_PHY_ID);
+	} else {
+		/* Driver has no knowledge at this point about the external PHY.
+		 * The 802.3 specifies that the reset process shall
+		 * be completed within 0.5 s.
+		 */
+		fsleep(500000);
+	}
 
 	pdata->mdiobus->priv = dev;
 	pdata->mdiobus->read = smsc95xx_mdiobus_read;