Hello Jernej, On Sat, Aug 24, 2019 at 11:09:49PM +0200, Jernej Škrabec wrote: > > Visually? > > > > That would explain why it doesn't work for you. The mainline RTC driver > > disables auto-switch feature, and if your board doesn't have a crystal for > > LOSC, RTC will not generate a clock for the RTC. > > > > H6's dtsi describes by default a situatiuon with external 32k crystal > > oscillator. See ext_osc32k node. That's incorrect for your board if it > > doesn't have the crystal. You need to fix this in the DTS for your board > > instead of patching the driver. > > I see that reparenting is supported, but I'm not sure how to fix that in DT. > Any suggestion? You may try removing the clocks property from rtc node. > > > > The driver has parent clock selection logic in case the LOSC crystal is not > > used. > > > > Your patch enables automatic detection of LOSC failure and RTC changes clock > > to LOSC automatically, despite what's described in the DTS. That may fix > > the issue, but is not the correct solution. > > > > Registers on my board look like this (external 32k osc is used) for > > reference: > > > > LOSC_CTRL_REG[7000000]: 8011 > > KEY_FIELD ??? (0) > > LOSC_AUTO_SWT_BYPASS EN (1) > > LOSC_AUTO_SWT_EN DIS (0) > > EXT_LOSC_EN EN (1) > > EXT_LOSC_GSM LOW (0) > > BATTERY_DIR DISCHARGE (0) > > LOSC_SRC_SEL EXT32k (1) > > > > LOSC_AUTO_SWT_STA_REG[7000004]: 1 > > EXT_LOSC_STA OK (0) > > LOSC_AUTO_SWT_PEND NOEFF (0) > > LOSC_SRC_SEL_STA EXT32K (1) > > > > In my case LOSC_CTRL_REG has value 0x4010 and LOSC_AUTO_SWT_STA_REG > has value 0x4, so there is issue with external crystal (it's missing) and RTC > switched to internal one. > > BTW, what's wrong with automatic switching? Why is it disabled? It always was disabled on mainline (bit 14 was set to 0 even before my patch). H6 just probably has another extra undocummented bit, that's needed to disables it properly. You probably don't want a glitch to switch your RTC from high-precision clock to a low precision one possibly without any indication in the userspace or a kernel log. Regardless of all this, DTS needs to have a correct description of the HW, which means if RTC module is not connected to the 32.757kHz crystal/clock, clocks property should be empty. regards, o. > Best regards, > Jernej > > > regards, > > o. > > > > > > The real issue probably is that the mainline driver is missing this: > > > > > > > > https://megous.com/git/linux/tree/drivers/rtc/rtc-sunxi.c?h=h6-4.9-bsp#n > > > > 650 > > > > > > Not sure what you mean by that. ext vs. int source selection? > > > > > > > > > > > > Best regards, > > > Jernej > > > > > > > regards, > > > > > > > > o. > > > >
