Hi Krzysztof, > On Mon, 11 Feb 2019 at 08:20, Lukasz Majewski <lu...@denx.de> wrote: > > > > Hi Krzysztof, > > > > > Detection of board type is done early - before power setup. In > > > case of Odroid XU3/XU4/HC1 family, the detection is done using > > > ADC which is supplied by LDO4/VDD_ADC regulator. This regulator > > > could be turned off (e.g. by kernel before reboot); If ADC is > > > used early, the regulators are not yet available and the > > > detection won't work. > > > > > > Try to detect the revision again, once power is brought up. > > > > > > This is necessary to fix the detection of Odroid HC1 after > > > reboot, if kernel turned off the LDO4 regulator. Otherwise the > > > board is not detected.... > > > > But such approach seems not to be the optimal one (as we perform > > detection twice - with default LDO4 enabled after power on and after > > soft reset). > > > > I would expect to enable the LDO4 regulator in the early code (I2C > > would be probably necessary) and then read ADC value properly once. > > > > (I also guess that the "work-by-chance" approach is caused by > > default settings of PMIC after power on). > > So basically you want to move the board detection after the > exynos_power_init()... maybe it is possible. The other way is to split > set_board_type() into OF part (for compatible and main board > difference) and revision detection (requiring ADC). Maybe it is > possible, but isn't it used before?
I do want to avoid making the detection twice; First time when we have the LDO4 enabled by default and the second time when it may happen that we do a soft reset from Linux (which disabled LDO4). > > > As fair as I remember, TI is able to read the EEPROM via I2C in the > > very early u-boot (MLO to be precise) code and then make the > > decision regarding the platform. > > > > Maybe it would be possible to do the same with Samsung? > > > > And another thought - if the set_board_type() can be called latter > > and it works - why cannot we move it to this latter point and > > execute exactly once? > > It is the same as previous idea... or I do not see the difference... > > Best regards, > Krzysztof Best regards, Lukasz Majewski -- DENX Software Engineering GmbH, Managing Director: Wolfgang Denk HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany Phone: (+49)-8142-66989-59 Fax: (+49)-8142-66989-80 Email: lu...@denx.de
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