[PATCH] i2c: ocores: Use read_poll_timeout_atomic to avoid false poll timeouts

[Martin Aberer]

Replace the manual polling loop in ocores_wait() with the kernel helper
read_poll_timeout_atomic(). This simplifies the code and ensures robust
timeout handling. By using this helper, we avoid spurious timeout errors
that could occur under high CPU load or preemption, as the macro handles
timing and condition checks atomically.

Signed-off-by: Martin Aberer <martin.aberer@xxxxxxxxxxxxx>
---
 drivers/i2c/busses/i2c-ocores.c | 24 +++++++++---------------
 1 file changed, 9 insertions(+), 15 deletions(-)

diff --git a/drivers/i2c/busses/i2c-ocores.c b/drivers/i2c/busses/i2c-ocores.c
index 0f67e57cdeff..df6ebf32d6e8 100644
--- a/drivers/i2c/busses/i2c-ocores.c
+++ b/drivers/i2c/busses/i2c-ocores.c
@@ -24,6 +24,7 @@
 #include <linux/io.h>
 #include <linux/log2.h>
 #include <linux/spinlock.h>
+#include <linux/iopoll.h>
 #include <linux/jiffies.h>
 
 /*
@@ -258,7 +259,7 @@ static void ocores_process_timeout(struct ocores_i2c *i2c)
  * @reg: register to query
  * @mask: bitmask to apply on register value
  * @val: expected result
- * @timeout: timeout in jiffies
+ * @timeout_us: timeout in microseconds
  *
  * Timeout is necessary to avoid to stay here forever when the chip
  * does not answer correctly.
@@ -267,21 +268,14 @@ static void ocores_process_timeout(struct ocores_i2c *i2c)
  */
 static int ocores_wait(struct ocores_i2c *i2c,
 		       int reg, u8 mask, u8 val,
-		       const unsigned long timeout)
+		       unsigned long timeout_us)
 {
-	unsigned long j;
+	u8 status;
 
-	j = jiffies + timeout;
-	while (1) {
-		u8 status = oc_getreg(i2c, reg);
-
-		if ((status & mask) == val)
-			break;
-
-		if (time_after(jiffies, j))
-			return -ETIMEDOUT;
-	}
-	return 0;
+	return read_poll_timeout_atomic(oc_getreg, status,
+					(status & mask) == val,
+					0, timeout_us, false,
+					i2c, reg);
 }
 
 /**
@@ -314,7 +308,7 @@ static int ocores_poll_wait(struct ocores_i2c *i2c)
 	 * once we are here we expect to get the expected result immediately
 	 * so if after 1ms we timeout then something is broken.
 	 */
-	err = ocores_wait(i2c, OCI2C_STATUS, mask, 0, msecs_to_jiffies(1));
+	err = ocores_wait(i2c, OCI2C_STATUS, mask, 0, 1000);
 	if (err)
 		dev_warn(i2c->adap.dev.parent,
 			 "%s: STATUS timeout, bit 0x%x did not clear in 1ms\n",
-- 
2.43.0