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From:   Piyush Malgujar <pmalgujar@marvell.com>
To:     <linux-i2c@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
        <andi.shyti@kernel.org>, <rric@kernel.org>
CC:     <cchavva@marvell.com>, <sgarapati@marvell.com>,
        <jannadurai@marvell.com>, Piyush Malgujar <pmalgujar@marvell.com>
Subject: [PATCH v2 3/4] i2c: octeon: Handle watchdog timeout
Date:   Fri, 28 Jul 2023 05:00:03 -0700
Message-ID: <20230728120004.19680-4-pmalgujar@marvell.com>
In-Reply-To: <20230728120004.19680-1-pmalgujar@marvell.com>
References: <20230728120004.19680-1-pmalgujar@marvell.com>
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From: Suneel Garapati <sgarapati@marvell.com>

Status code 0xF0 refers to expiry of TWSI controller
access watchdog and needs bus monitor reset using MODE
register.

Signed-off-by: Suneel Garapati <sgarapati@marvell.com>
Signed-off-by: Piyush Malgujar <pmalgujar@marvell.com>
Acked-by: Andi Shyti <andi.shyti@kernel.org>
---
 drivers/i2c/busses/i2c-octeon-core.c | 8 ++++++++
 drivers/i2c/busses/i2c-octeon-core.h | 4 ++++
 2 files changed, 12 insertions(+)

diff --git a/drivers/i2c/busses/i2c-octeon-core.c b/drivers/i2c/busses/i2c-octeon-core.c
index 6636719ca8f005056230620e2cee19de7154e024..0c89d8d640424356f1ea4f7da11d528631ae7efd 100644
--- a/drivers/i2c/busses/i2c-octeon-core.c
+++ b/drivers/i2c/busses/i2c-octeon-core.c
@@ -178,6 +178,7 @@ static int octeon_i2c_hlc_wait(struct octeon_i2c *i2c)
 static int octeon_i2c_check_status(struct octeon_i2c *i2c, int final_read)
 {
 	u8 stat;
+	u64 mode;
 
 	/*
 	 * This is ugly... in HLC mode the status is not in the status register
@@ -240,6 +241,13 @@ static int octeon_i2c_check_status(struct octeon_i2c *i2c, int final_read)
 	case STAT_RXADDR_NAK:
 	case STAT_AD2W_NAK:
 		return -ENXIO;
+
+	case STAT_WDOG_TOUT:
+		mode = __raw_readq(i2c->twsi_base + MODE(i2c));
+		/* Set BUS_MON_RST to reset bus monitor */
+		mode |= BUS_MON_RST_MASK;
+		octeon_i2c_writeq_flush(mode, i2c->twsi_base + MODE(i2c));
+		return -EIO;
 	default:
 		dev_err(i2c->dev, "unhandled state: %d\n", stat);
 		return -EIO;
diff --git a/drivers/i2c/busses/i2c-octeon-core.h b/drivers/i2c/busses/i2c-octeon-core.h
index e89f041550ace5f7cbcdd94146d0193abe51d466..e53fe60a41b7feb7ccc081cc671cec7be00c5a97 100644
--- a/drivers/i2c/busses/i2c-octeon-core.h
+++ b/drivers/i2c/busses/i2c-octeon-core.h
@@ -72,6 +72,7 @@
 #define STAT_SLAVE_ACK		0xC8
 #define STAT_AD2W_ACK		0xD0
 #define STAT_AD2W_NAK		0xD8
+#define STAT_WDOG_TOUT		0xF0
 #define STAT_IDLE		0xF8
 
 /* TWSI_INT values */
@@ -106,6 +107,9 @@ struct octeon_i2c_reg_offset {
 /* Set REFCLK_SRC and HS_MODE in TWSX_MODE register */
 #define TWSX_MODE_HS_MASK	(BIT(4) | BIT(0))
 
+/* Set BUS_MON_RST to reset bus monitor */
+#define BUS_MON_RST_MASK	BIT(3)
+
 struct octeon_i2c {
 	wait_queue_head_t queue;
 	struct i2c_adapter adap;
-- 
2.17.1