Hello Krzysztof, On 04/18/2016 09:33 AM, Krzysztof Kozlowski wrote: > Driver did not provide default value for ramp delay for LDOs which lead > to warning in dmesg, e.g. on Odroid XU4: > > [ 1.486076] vdd_ldo9: ramp_delay not set > [ 1.506875] vddq_mmc2: ramp_delay not set > [ 1.523766] vdd_ldo15: ramp_delay not set > [ 1.544702] vdd_sd: ramp_delay not set > > The datasheet for all the S2MPS1x family is inconsistent here and does > not specify unambiguously the value of ramp delay for LDO. It mentions > 30 mV/us in one timing diagram but then omits it completely in LDO > regulator characteristics table (it is specified for bucks). > > However the vendor kernels for Galaxy S5 and Odroid XU3 use values of 12 > mV/us or 24 mV/us. > > Without the ramp delay value the consumers do not wait for voltage > settle after changing it. Although the proper value of ramp delay for > LDOs is unknown, it seems safer to use at least some value from > reference kernel than to leave it unset. > > Signed-off-by: Krzysztof Kozlowski <k.kozlowski@xxxxxxxxxxx> > Reviewed-by: Javier Martinez Canillas <javier@xxxxxxxxxxxxxxx> Best regards, -- Javier Martinez Canillas Open Source Group Samsung Research America -- To unsubscribe from this list: send the line "unsubscribe linux-samsung-soc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
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