Am 29.09.2014 um 19:13 schrieb Mark Brown: > On Mon, Sep 29, 2014 at 08:38:51AM +0200, Stefan Wahren wrote: > >> I'm searching for a good regulator implementation example. >> Does it apply to ti-abb-regulator.c and twl-regulator.c? > Possibly. But bear in mind that it's important to understand the > hardware you're trying to support. The question refer more to the devicetree binding and it's implementation. > >>> This really needs a comment to explain what on earth is going on here - >>> the whole thing with writing the same thing twice with two delays is >>> more than a little odd. It looks like the driver is trying to busy wait >>> in cases where the change happens quickly but the comments about "fast" >>> and "normal" mode make this unclear. >> The regulator driver polls for the DC_OK bit in the power status register. >> Quote for reference manual (p. 935): "High when switching DC-DC >> converter control loop has stabilized after a voltage target change." >> The two loops comes from the different regulator modes >> (REGULATOR_MODE_FAST, REGULATOR_MODE_NORMAL). >> In REGULATOR_MODE_FAST the voltage steping is disabled and changing >> voltage should be fast. In REGULATOR_MODE_NORMAL voltage steping is >> enabled and it's take a while for reaching the target voltage. > I don't think you've fully understood what the different modes mean > here, that's not normally how a buck convertor works. The different > modes would typically control the ability of the regulator to respond > quickly to changes in load without drifting off regulation, fast mode > makes the regulator less efficient but more responsive to load changes > (probably marginally with modern regulators). It should have relatively > little to do with the ability to ramp the voltage and certainly not on > the scale there. > >> Do you see more a problem with the two different loops or the redundant >> register write? > Both. The code right now just looks really obscure. That leads me to the conclusion to drop both mode functions. My intention is to get the cpufreq-cpu0 aka cpufreq-dt working on i.MX28, not to build up the complete power system. @Fabio, @Shawn: What is your opinion? Best regards Stefan -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
