ENGR00259189 thermal:mx6: Make sure thermal alarm working safely

The thermal sensor's value will be updated even it is power down,
as thermal sensor's clock source is from PLL3, so there is chance
that PLL3 is disabled before thermal driver is probed during kernel
boot up, so the value in thermal sensor can be incorrect in this
PLL3 disabled window.

Previous flow of thermal driver probe routine will enable PLL3
clock, then set the thermal alarm value and enable the alarm irq,
there is no delay or check about the thermal sensor's value, only
when the thermal sensor's value is correct, its alarm function
can be enabled. As adding delay in the probe routine is not a
good option, so we move the enabling of thermal alarm function
into the get temperature routine, as after the thermal value is
read, the alarm function is safe enough, as the thermal sensor
will be always working right after a read if its clock is enabled.

Signed-off-by: Anson Huang <b20788@freescale.com>

1 files changed, 5 insertions, 1 deletions

diff --git a/drivers/mxc/thermal/thermal.c b/drivers/mxc/thermal/thermal.c
index 2a29109d2861..39383e297216 100644
--- a/drivers/mxc/thermal/thermal.c
+++ b/drivers/mxc/thermal/thermal.c
@@ -338,6 +338,11 @@ static int anatop_thermal_get_temp(struct thermal_zone_device *thermal,
 	*temp = (cooling_device_disable && tz->temperature >= KELVIN_TO_CEL(TEMP_CRITICAL, KELVIN_OFFSET)) ?
 			KELVIN_TO_CEL(TEMP_CRITICAL - 1, KELVIN_OFFSET) : tz->temperature;
 
+	/* Set alarm threshold if necessary */
+	if ((__raw_readl(anatop_base + HW_ANADIG_TEMPSENSE0) &
+		BM_ANADIG_TEMPSENSE0_ALARM_VALUE) == 0)
+		anatop_update_alarm(raw_critical);
+
 	return 0;
 }
 
@@ -900,7 +905,6 @@ static int anatop_thermal_counting_ratio(unsigned int fuse_data)
 	/* Init default critical temp to set alarm */
 	raw_critical = raw_25c - ratio * (KELVIN_TO_CEL(TEMP_CRITICAL, KELVIN_OFFSET) - 25) / 100;
 	clk_enable(pll3_clk);
-	anatop_update_alarm(raw_critical);
 
 	return ret;
 }