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.smir...@gmail.com>
Reviewed-by: Daniel Lezcano <daniel.lezc...@linaro.org>
Tested-by: Lucas Stach <l.st...@pengutronix.de>
Cc: Chris Healy <cphe...@gmail.com>
Cc: Lucas Stach <l.st...@pengutronix.de>
Cc: Eduardo Valentin <edubez...@gmail.com>
Cc: Daniel Lezcano <daniel.lezc...@linaro.org>
Cc: Angus Ainslie (Purism) <an...@akkea.ca>
Cc: linux-...@nxp.com
Cc: linux...@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
---
drivers/thermal/qoriq_thermal.c | 19 ++++++++++++++++++-
1 file changed, 18 insertions(+), 1 deletion(-)
diff --git a/drivers/thermal/qoriq_thermal.c b/drivers/thermal/qoriq_thermal.c
index 5f964f806187..2f8c5feb1a25 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
*/
@@ -62,8 +63,24 @@ static int tmu_get_temp(void *p, int *temp)
struct qoriq_sensor *qsensor = p;
struct qoriq_tmu_data *qdata = qoriq_sensor_to_data(qsensor);
u32 val;
+ /*
+ * REGS_TRITSR(id) has the following layout:
+ *
+ * 31 ... 7 6 5 4 3 2 1 0
+ * V TEMP
+ *
+ * Where V bit signifies if the measurement is ready and is
+ * within sensor range. TEMP is an 8 bit value representing
+ * temperature in C.
+ */
+ if (regmap_read_poll_timeout(qdata->regmap,
+ REGS_TRITSR(qsensor->id),
+ val,
+ val & TRITSR_V,
+ USEC_PER_MSEC,
+ 10 * USEC_PER_MSEC))
+ return -ENODATA;
- regmap_read(qdata->regmap, REGS_TRITSR(qsensor->id), &val);
*temp = (val & 0xff) * 1000;
return 0;
--
2.21.0
