[PATCH 09/12] thermal: qoriq: Do not report invalid temperature reading

[Andrey Smirnov <andrew.smirnov@gmail.com>]

Before returning measured temperature data to upper layer we need to
make sure that the reading was marked as "valid" to avoid reporting
bogus data.

Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
Cc: Chris Healy <cphealy@gmail.com>
Cc: Lucas Stach <l.stach@pengutronix.de>
Cc: Zhang Rui <rui.zhang@intel.com>
Cc: Eduardo Valentin <edubezval@gmail.com>
Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: linux-imx@nxp.com
Cc: linux-pm@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
---
 drivers/thermal/qoriq_thermal.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/thermal/qoriq_thermal.c b/drivers/thermal/qoriq_thermal.c
index 6478d7a8168f..3d520d3b2da4 100644
--- a/drivers/thermal/qoriq_thermal.c
+++ b/drivers/thermal/qoriq_thermal.c
@@ -37,6 +37,7 @@
 #define REGS_TRITSR(n)	(0x100 + 16 * (n)) /* Immediate Temperature
 					    * Site Register
 					    */
+#define TRITSR_V	BIT(31)
 #define REGS_TTRnCR(n)	(0xf10 + 4 * (n)) /* Temperature Range n
 					   * Control Register
 					   */
@@ -55,8 +56,10 @@ static int tmu_get_temp(void *p, int *temp)
 	struct qoriq_tmu_data *data = p;
 
 	regmap_read(data->regmap, REGS_TRITSR(data->sensor_id), &val);
-	*temp = (val & 0xff) * 1000;
+	if (!(val & TRITSR_V))
+		return -ENODATA;
 
+	*temp = (val & 0xff) * 1000;
 	return 0;
 }
 
-- 
2.20.1