linux-kernel - [PATCH v5] i2c: npcm: Add clock toggle recovery

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20250527022223.78371-1-mohammed.0.elbadry@gmail.com>
Date: Mon, 26 May 2025 19:22:23 -0700
From: Mohammed Elbadry <mohammed.0.elbadry@...il.com>
To: 
Cc: avifishman70@...il.com,
	tmaimon77@...il.com,
	tali.perry1@...il.com,
	venture@...gle.com,
	yuenn@...gle.com,
	benjaminfair@...gle.com,
	andi.shyti@...nel.org,
	openbmc@...ts.ozlabs.org,
	linux-i2c@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	Mukesh Kumar Savaliya <quic_msavaliy@...cinc.com>
Subject: [PATCH v5] i2c: npcm: Add clock toggle recovery

From: Tali Perry <tali.perry1@...il.com>

During init of the bus, the module checks that the bus is idle.
If one of the lines are stuck try to recover them first before failing.
Sometimes SDA and SCL are low if improper reset occurs (e.g., reboot).

Signed-off-by: Tali Perry <tali.perry1@...il.com>
Signed-off-by: Mohammed Elbadry <mohammed.0.elbadry@...il.com>
Reviewed-by: Mukesh Kumar Savaliya <quic_msavaliy@...cinc.com>
---
 drivers/i2c/busses/i2c-npcm7xx.c | 13 +++++++++----
 1 file changed, 9 insertions(+), 4 deletions(-)

diff --git a/drivers/i2c/busses/i2c-npcm7xx.c b/drivers/i2c/busses/i2c-npcm7xx.c
index de713b5747fe..0757a23dc1cd 100644
--- a/drivers/i2c/busses/i2c-npcm7xx.c
+++ b/drivers/i2c/busses/i2c-npcm7xx.c
@@ -2178,10 +2178,15 @@ static int npcm_i2c_init_module(struct npcm_i2c *bus, enum i2c_mode mode,
 
 	/* Check HW is OK: SDA and SCL should be high at this point. */
 	if ((npcm_i2c_get_SDA(&bus->adap) == 0) || (npcm_i2c_get_SCL(&bus->adap) == 0)) {
-		dev_err(bus->dev, "I2C%d init fail: lines are low\n", bus->num);
-		dev_err(bus->dev, "SDA=%d SCL=%d\n", npcm_i2c_get_SDA(&bus->adap),
-			npcm_i2c_get_SCL(&bus->adap));
-		return -ENXIO;
+		dev_warn(bus->dev, " I2C%d SDA=%d SCL=%d, attempting to recover\n", bus->num,
+				 npcm_i2c_get_SDA(&bus->adap), npcm_i2c_get_SCL(&bus->adap));
+		ret = npcm_i2c_recovery_tgclk(&bus->adap);
+		if (ret) {
+			dev_err(bus->dev, "I2C%d init fail: SDA=%d SCL=%d\n",
+				bus->num, npcm_i2c_get_SDA(&bus->adap),
+				npcm_i2c_get_SCL(&bus->adap));
+			return ret;
+		}
 	}
 
 	npcm_i2c_int_enable(bus, true);
-- 
2.39.5 (Apple Git-154)