tpm/st33zp24/spi: Improve st33zp24_spi_evaluate_latency

Add check in st33zp24_spi_evaluate_latency helping to diagnose if the chip is present or in a bad state. Signed-off-by: Christophe Ricard <[email protected]> Reviewed-by: Jarkko Sakkinen <[email protected]> Signed-off-by: Jarkko Sakkinen <[email protected]>
jix · Jun 25, 2016 · 4ef2aa3 · 4ef2aa3
1 parent 300796c
commit 4ef2aa3
Showing 1 changed file with 5 additions and 0 deletions.
diff --git a/drivers/char/tpm/st33zp24/spi.c b/drivers/char/tpm/st33zp24/spi.c
@@ -214,6 +214,11 @@ static int st33zp24_spi_evaluate_latency(void *phy_id)
 						&data, 1);
 		latency++;
 	}
+	if (status < 0)
+		return status;
+	if (latency == MAX_SPI_LATENCY)
+		return -ENODEV;
+
 	return latency - 1;
 } /* evaluate_latency() */