[PATCH net v1 1/1] lan78xx: enable auto speed configuration for LAN7850 if no EEPROM is detected

[PATCH net v1 1/1] lan78xx: enable auto speed configuration for LAN7850 if no EEPROM is detected

[Oleksij Rempel]

Same as LAN7800, LAN7850 can be used without EEPROM. If EEPROM is not
present or not flashed, LAN7850 will fail to sync the speed detected by the PHY
with the MAC. In case link speed is 100Mbit, it will accidentally work,
otherwise no data can be transferred.

Better way would be to implement link_up callback, or set auto speed
configuration unconditionally. But this changes would be more intrusive.
So, for now, set it only if no EEPROM is found.

Fixes: e69647a19c87 ("lan78xx: Set ASD in MAC_CR when EEE is enabled.")
Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
---
 drivers/net/usb/lan78xx.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/net/usb/lan78xx.c b/drivers/net/usb/lan78xx.c
index 106282612bc2..7d7e185d7fae 100644
--- a/drivers/net/usb/lan78xx.c
+++ b/drivers/net/usb/lan78xx.c
@@ -3033,7 +3033,8 @@ static int lan78xx_reset(struct lan78xx_net *dev)
 	if (dev->chipid == ID_REV_CHIP_ID_7801_)
 		buf &= ~MAC_CR_GMII_EN_;
 
-	if (dev->chipid == ID_REV_CHIP_ID_7800_) {
+	if (dev->chipid == ID_REV_CHIP_ID_7800_ ||
+	    dev->chipid == ID_REV_CHIP_ID_7850_) {
 		ret = lan78xx_read_raw_eeprom(dev, 0, 1, &sig);
 		if (!ret && sig != EEPROM_INDICATOR) {
 			/* Implies there is no external eeprom. Set mac speed */
-- 
2.39.2

Re: [PATCH net v1 1/1] lan78xx: enable auto speed configuration for LAN7850 if no EEPROM is detected

[patchwork-bot+netdevbpf]

Hello:

This patch was applied to netdev/net.git (main)
by Jakub Kicinski <kuba@kernel.org>:

On Thu, 22 Feb 2024 13:38:38 +0100 you wrote:
> Same as LAN7800, LAN7850 can be used without EEPROM. If EEPROM is not
> present or not flashed, LAN7850 will fail to sync the speed detected by the PHY
> with the MAC. In case link speed is 100Mbit, it will accidentally work,
> otherwise no data can be transferred.
> 
> Better way would be to implement link_up callback, or set auto speed
> configuration unconditionally. But this changes would be more intrusive.
> So, for now, set it only if no EEPROM is found.
> 
> [...]

Here is the summary with links:
  - [net,v1,1/1] lan78xx: enable auto speed configuration for LAN7850 if no EEPROM is detected
    https://git.kernel.org/netdev/net/c/0e67899abfbf

You are awesome, thank you!
-- 
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