Commits
Keerthy committed 79010636174
thermal: ti-soc-thermal: dra7: Implement Workaround for Errata i814
Bandgap Temperature read Dtemp can be corrupted
DESCRIPTION
Read accesses to registers listed below can be corrupted due to
incorrect resynchronization between clock domains.
Read access to registers below can be corrupted :
• CTRL_CORE_DTEMP_MPU/GPU/CORE/DSPEVE/IVA_n (n = 0 to 4)
• CTRL_CORE_TEMP_SENSOR_MPU/GPU/CORE/DSPEVE/IVA_n
WORKAROUND
Multiple reads to CTRL_CORE_TEMP_SENSOR_MPU/GPU/CORE/DSPEVE/IVA[9:0]:
BGAP_DTEMPMPU/GPU/CORE/DSPEVE/IVA is needed to discard false value and
read right value:
1. Perform two successive reads to BGAP_DTEMP bit field.
(a) If read1 returns Val1 and read2 returns Val1, then
right value is Val1.
(b) If read1 returns Val1, read 2 returns Val2, a third
read is needed.
2. Perform third read
(a) If read3 returns Val2 then right value is Val2.
(b) If read3 returns Val3, then right value is Val3.
The above in gist means if val1 and val2 are the same then we can go
ahead with that value else we need a third read which will be right
since synchronization will be complete by then.
Signed-off-by: Keerthy <j-keerthy@ti.com>
Signed-off-by: Eduardo Valentin <edubezval@gmail.com>