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List:       linux-i2c
Subject:    [PATCH v2 12/12] i2c: pxa: fix i2c_pxa_wait_bus_not_busy() boundary condition
From:       Russell King <rmk+kernel () armlinux ! org ! uk>
Date:       2020-04-27 18:49:32
Message-ID: E1jT8ou-0002vu-Jj () rmk-PC ! armlinux ! org ! uk
[Download RAW message or body]

Fix i2c_pxa_wait_bus_not_busy()'s boundary conditions, so that a
coincidental success and timeout results in the function returning
success.

Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
---
 drivers/i2c/busses/i2c-pxa.c | 17 ++++++++++++-----
 1 file changed, 12 insertions(+), 5 deletions(-)

diff --git a/drivers/i2c/busses/i2c-pxa.c b/drivers/i2c/busses/i2c-pxa.c
index f0205c47286c..e6bc21ece5e0 100644
--- a/drivers/i2c/busses/i2c-pxa.c
+++ b/drivers/i2c/busses/i2c-pxa.c
@@ -416,19 +416,26 @@ static void i2c_pxa_abort(struct pxa_i2c *i2c)
 static int i2c_pxa_wait_bus_not_busy(struct pxa_i2c *i2c)
 {
 	int timeout = DEF_TIMEOUT;
+	u32 isr;
 
-	while (timeout-- && readl(_ISR(i2c)) & (ISR_IBB | ISR_UB)) {
-		if ((readl(_ISR(i2c)) & ISR_SAD) != 0)
+	while (1) {
+		isr = readl(_ISR(i2c));
+		if (!(isr & (ISR_IBB | ISR_UB)))
+			return 0;
+
+		if (isr & ISR_SAD)
 			timeout += 4;
 
+		if (!timeout--)
+			break;
+
 		msleep(2);
 		show_state(i2c);
 	}
 
-	if (timeout < 0)
-		show_state(i2c);
+	show_state(i2c);
 
-	return timeout < 0 ? I2C_RETRY : 0;
+	return I2C_RETRY;
 }
 
 static int i2c_pxa_wait_master(struct pxa_i2c *i2c)
-- 
2.20.1

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