From: Tony Lindgren tony@atomide.com
[ Upstream commit 30d24faba0532d6972df79a1bf060601994b5873 ]
We can sometimes get bogus thermal shutdowns on omap4430 at least with droid4 running idle with a battery charger connected:
thermal thermal_zone0: critical temperature reached (143 C), shutting down
Dumping out the register values shows we can occasionally get a 0x7f value that is outside the TRM listed values in the ADC conversion table. And then we get a normal value when reading again after that. Reading the register multiple times does not seem help avoiding the bogus values as they stay until the next sample is ready.
Looking at the TRM chapter "18.4.10.2.3 ADC Codes Versus Temperature", we should have values from 13 to 107 listed with a total of 95 values. But looking at the omap4430_adc_to_temp array, the values are off, and the end values are missing. And it seems that the 4430 ADC table is similar to omap3630 rather than omap4460.
Let's fix the issue by using values based on the omap3630 table and just ignoring invalid values. Compared to the 4430 TRM, the omap3630 table has the missing values added while the TRM table only shows every second value.
Note that sometimes the ADC register values within the valid table can also be way off for about 1 out of 10 values. But it seems that those just show about 25 C too low values rather than too high values. So those do not cause a bogus thermal shutdown.
Fixes: 1a31270e54d7 ("staging: omap-thermal: add OMAP4 data structures") Cc: Merlijn Wajer merlijn@wizzup.org Cc: Pavel Machek pavel@ucw.cz Cc: Sebastian Reichel sebastian.reichel@collabora.com Signed-off-by: Tony Lindgren tony@atomide.com Signed-off-by: Daniel Lezcano daniel.lezcano@linaro.org Link: https://lore.kernel.org/r/20200706183338.25622-1-tony@atomide.com Signed-off-by: Sasha Levin sashal@kernel.org --- .../ti-soc-thermal/omap4-thermal-data.c | 23 ++++++++++--------- .../thermal/ti-soc-thermal/omap4xxx-bandgap.h | 10 +++++--- 2 files changed, 19 insertions(+), 14 deletions(-)
diff --git a/drivers/thermal/ti-soc-thermal/omap4-thermal-data.c b/drivers/thermal/ti-soc-thermal/omap4-thermal-data.c index d255d33da9eb3..02e71d461d5c5 100644 --- a/drivers/thermal/ti-soc-thermal/omap4-thermal-data.c +++ b/drivers/thermal/ti-soc-thermal/omap4-thermal-data.c @@ -49,20 +49,21 @@ static struct temp_sensor_data omap4430_mpu_temp_sensor_data = {
/* * Temperature values in milli degree celsius - * ADC code values from 530 to 923 + * ADC code values from 13 to 107, see TRM + * "18.4.10.2.3 ADC Codes Versus Temperature". */ static const int omap4430_adc_to_temp[OMAP4430_ADC_END_VALUE - OMAP4430_ADC_START_VALUE + 1] = { - -38000, -35000, -34000, -32000, -30000, -28000, -26000, -24000, -22000, - -20000, -18000, -17000, -15000, -13000, -12000, -10000, -8000, -6000, - -5000, -3000, -1000, 0, 2000, 3000, 5000, 6000, 8000, 10000, 12000, - 13000, 15000, 17000, 19000, 21000, 23000, 25000, 27000, 28000, 30000, - 32000, 33000, 35000, 37000, 38000, 40000, 42000, 43000, 45000, 47000, - 48000, 50000, 52000, 53000, 55000, 57000, 58000, 60000, 62000, 64000, - 66000, 68000, 70000, 71000, 73000, 75000, 77000, 78000, 80000, 82000, - 83000, 85000, 87000, 88000, 90000, 92000, 93000, 95000, 97000, 98000, - 100000, 102000, 103000, 105000, 107000, 109000, 111000, 113000, 115000, - 117000, 118000, 120000, 122000, 123000, + -40000, -38000, -35000, -34000, -32000, -30000, -28000, -26000, -24000, + -22000, -20000, -18500, -17000, -15000, -13500, -12000, -10000, -8000, + -6500, -5000, -3500, -1500, 0, 2000, 3500, 5000, 6500, 8500, 10000, + 12000, 13500, 15000, 17000, 19000, 21000, 23000, 25000, 27000, 28500, + 30000, 32000, 33500, 35000, 37000, 38500, 40000, 42000, 43500, 45000, + 47000, 48500, 50000, 52000, 53500, 55000, 57000, 58500, 60000, 62000, + 64000, 66000, 68000, 70000, 71500, 73500, 75000, 77000, 78500, 80000, + 82000, 83500, 85000, 87000, 88500, 90000, 92000, 93500, 95000, 97000, + 98500, 100000, 102000, 103500, 105000, 107000, 109000, 111000, 113000, + 115000, 117000, 118500, 120000, 122000, 123500, 125000, };
/* OMAP4430 data */ diff --git a/drivers/thermal/ti-soc-thermal/omap4xxx-bandgap.h b/drivers/thermal/ti-soc-thermal/omap4xxx-bandgap.h index 6f2de3a3356d4..86850082b24b9 100644 --- a/drivers/thermal/ti-soc-thermal/omap4xxx-bandgap.h +++ b/drivers/thermal/ti-soc-thermal/omap4xxx-bandgap.h @@ -67,9 +67,13 @@ * and thresholds for OMAP4430. */
-/* ADC conversion table limits */ -#define OMAP4430_ADC_START_VALUE 0 -#define OMAP4430_ADC_END_VALUE 127 +/* + * ADC conversion table limits. Ignore values outside the TRM listed + * range to avoid bogus thermal shutdowns. See omap4430 TRM chapter + * "18.4.10.2.3 ADC Codes Versus Temperature". + */ +#define OMAP4430_ADC_START_VALUE 13 +#define OMAP4430_ADC_END_VALUE 107 /* bandgap clock limits (no control on 4430) */ #define OMAP4430_MAX_FREQ 32768 #define OMAP4430_MIN_FREQ 32768