2014-08-11 9:15 GMT+02:00 Linus Walleij <linus.walleij@xxxxxxxxxx>: > On Thu, Jul 31, 2014 at 6:42 PM, Matthias Brugger > <matthias.bgg@xxxxxxxxx> wrote: > >> We enable GTP6 which ungates the arch timer clock. Apart we write the >> frequency with which the timer is running in the CNTFREQ register. >> In the future this should be done in the bootloader. >> >> Signed-off-by: Matthias Brugger <matthias.bgg@xxxxxxxxx> > (...) > >> + if (of_machine_is_compatible("mediatek,mt6589")) { >> + /* set cntfreq register which is not done in bootloader */ >> + asm volatile("mcr p15, 0, %0, c14, c0, 0" : : "r" (13000000)); > > I guess this is for something like the ARM arch timer in > drivers/clocksource/arm_arch_timer.c > > Instead of doing this, use the DT property "clock-frequency" on > the ARM arch timer node, as that overrides the CP15 setting. > >> + >> + /* turn on GPT6 which ungates arch timer clocks */ >> + gpt_base = ioremap(GPT6_CON_MT65xx, 0x04); >> + } >> + >> + /* enabel clock and set to free-run */ >> + if (gpt_base) >> + writel(0x31, gpt_base); > > Why is this not done properly in the GPT driver (I guess > in drivers/clocksource/mtk_timer.c) instead of remapping > it and fiddling around in the machine? I didn't put it in the GPT driver, because that would mean, that you need to have the mtk_timer to be able to use the ARM arch timer. >From my understanding this are two independent blocks in the SoC. Apart from that, as stated in the commit message, this patch is a workaround until we have a bootloader which does this for us. Therefore I thought the init_time function would be the better place to do this. Thanks, Matthias > > If it only affects the mt6589 just add another compatible string > to that driver like "mediatek,mt6589-timer" as it properly reflects the > fact that this timer is slightly different on the 6589. > > Also use a #define for the magic constant 0x31. > > Yours, > Linus Walleij -- motzblog.wordpress.com -- 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