From: Niklas Söderlund <niklas.soderlund+renesas@xxxxxxxxxxxx> The .thermal_init needs to be delayed a short amount of time after setting REG_GEN3_CTSR to allow for the TEMP register to contain something useful. If it's not delayed theses warnings are common during boot: thermal thermal_zone0: failed to read out thermal zone (-5) thermal thermal_zone1: failed to read out thermal zone (-5) thermal thermal_zone2: failed to read out thermal zone (-5) The warnings are triggered by the first call to .get_temp while the TEMP register contains 0 and rcar_gen3_thermal_get_temp() returns -EIO since a TEMP value of 0 will result in a temperature reading which is out of specifications. Signed-off-by: Niklas Söderlund <niklas.soderlund+renesas@xxxxxxxxxxxx> --- drivers/thermal/rcar_gen3_thermal.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/thermal/rcar_gen3_thermal.c b/drivers/thermal/rcar_gen3_thermal.c index 7d78498..085daec 100644 --- a/drivers/thermal/rcar_gen3_thermal.c +++ b/drivers/thermal/rcar_gen3_thermal.c @@ -199,6 +199,8 @@ static void r8a7795_thermal_init(struct rcar_gen3_thermal_tsc *tsc) rcar_gen3_thermal_write(tsc, REG_GEN3_CTSR, CTSR_PONM | CTSR_AOUT | CTSR_THBGR | CTSR_VMEN | CTSR_VMST | CTSR_THSST); + + usleep_range(1000, 2000); } static void r8a7796_thermal_init(struct rcar_gen3_thermal_tsc *tsc) -- 2.10.2
