From c9646693ae34a757ee7c98cf13291428b49f11a1 Mon Sep 17 00:00:00 2001 From: Lukas Wunner Date: Thu, 12 May 2022 10:42:02 +0200 Subject: [PATCH] usbnet: smsc95xx: Don't clear read-only PHY interrupt [ Upstream commit 93307b4f8595c9ffb5d35b60c10d7bd85bbc7ffc ] Upon receiving data from the Interrupt Endpoint, the SMSC LAN95xx driver attempts to clear the signaled interrupts by writing "all ones" to the Interrupt Status Register. However the driver only ever enables a single type of interrupt, namely the PHY Interrupt. And according to page 119 of the LAN950x datasheet, its bit in the Interrupt Status Register is read-only. There's no other way to clear it than in a separate PHY register: https://www.microchip.com/content/dam/mchp/documents/UNG/ProductDocuments/DataSheets/LAN950x-Data-Sheet-DS00001875D.pdf Consequently, writing "all ones" to the Interrupt Status Register is pointless and can be dropped. Tested-by: Oleksij Rempel # LAN9514/9512/9500 Tested-by: Ferry Toth # LAN9514 Signed-off-by: Lukas Wunner Reviewed-by: Andrew Lunn Signed-off-by: David S. Miller Signed-off-by: Sasha Levin --- drivers/net/usb/smsc95xx.c | 4 ---- 1 file changed, 4 deletions(-) diff --git a/drivers/net/usb/smsc95xx.c b/drivers/net/usb/smsc95xx.c index 4e39e43450848..c330891688807 100644 --- a/drivers/net/usb/smsc95xx.c +++ b/drivers/net/usb/smsc95xx.c @@ -570,10 +570,6 @@ static int smsc95xx_link_reset(struct usbnet *dev) unsigned long flags; int ret; - ret = smsc95xx_write_reg(dev, INT_STS, INT_STS_CLEAR_ALL_); - if (ret < 0) - return ret; - spin_lock_irqsave(&pdata->mac_cr_lock, flags); if (pdata->phydev->duplex != DUPLEX_FULL) { pdata->mac_cr &= ~MAC_CR_FDPX_; -- 2.39.5