On Wed, Apr 15, 2015 at 05:48:08PM +0200, Matthias Brugger wrote: > 2015-04-15 17:11 GMT+02:00 Matthias Brugger <matthias....@gmail.com>: > > 2015-04-14 13:57 GMT+02:00 Sascha Hauer <s.ha...@pengutronix.de>: > >> On Tue, Apr 14, 2015 at 01:01:30PM +0200, Matthias Brugger wrote: > >>> Hi Sascha, > >>> > >>> 2015-04-14 12:08 GMT+02:00 Sascha Hauer <s.ha...@pengutronix.de>: > >>> > Hi Matthias, > >>> > > >>> > On Tue, Apr 07, 2015 at 01:47:58PM +0200, Matthias Brugger wrote: > >>> >> Hi Sascha, > >>> >> > >>> >> > >>> >> 2015-03-31 20:16 GMT+02:00 Sascha Hauer <s.ha...@pengutronix.de>: > >>> >> > > >>> >> > The following changes since commit > >>> >> > 9eccca0843205f87c00404b663188b88eb248051: > >>> >> > > >>> >> > Linux 4.0-rc3 (2015-03-08 16:09:09 -0700) > >>> >> > > >>> >> > are available in the git repository at: > >>> >> > > >>> >> > git://git.pengutronix.de/git/imx/linux-2.6.git > >>> >> > tags/v4.0-clk-mediatek-v11 > >>> >> > > >>> >> > for you to fetch changes up to > >>> >> > ae9129219143cfdefe8b3a463deb8c5cb8955525: > >>> >> > > >>> >> > dt-bindings: ARM: Mediatek: Document devicetree bindings for > >>> >> > clock/reset controllers (2015-03-31 20:08:46 +0200) > >>> >> > > >>> >> > ---------------------------------------------------------------- > >>> >> > This patchset contains the initial common clock support for Mediatek > >>> >> > SoCs. > >>> >> > Mediatek SoC's clock architecture comprises of various PLLs, > >>> >> > dividers, muxes > >>> >> > and clock gates. > >>> >> > >>> >> I tried the patch set on my mt8135 eval board. I used the dts bindings > >>> >> from a former version of this set [1], but it does not boot the board > >>> >> (based on v4.0-rc7). > >>> >> Do you have any hint, what is happening, or are the bindings wrong? > >>> > > >>> > I just tried on a v4.0 with > >>> > - this series applied > >>> > - the dts patch applied (which is still up-to-date) > >>> > - multi_v7_defconfig > >>> > > >>> > And it still works. What do you mean with "does not boot the board"? No > >>> > console output? Could you try with earlyprintk? > >>> > >>> The probelms I see is, that with the clock patches, I'm not able to > >>> boot into a initramfs [1]. > >>> Whereas if I just comment topckgen and preicfg in the dts, I'm able to > >>> get the a serial console of my initramfs [2]. > >>> > >>> I wonder if you are able to get serial console from the initramfs with > >>> the clock patches + dts patch? > >> > >> So you get kernel messages but no output from initramfs? In this case > >> the kernel disables the unused clocks in a late_initcall. The UART > >> driver still uses the dummy clock provided in the dtsi, so the real > >> UART clk gets disabled in the initcall. Try passing clk_ignore_unused to > >> the kernel > > > > OK, I can boot to the initramfs with this kernel parameter, but it > > fails to boot, when I change the uart clock. I suppose that PERI_UART3 > > for debug port uart3 should be fine, but it looks like it doesn't > > work. > > I can see on the mt6589 datasheet that you have a register > > PERI_UART_CK_SOURCE_SEL where you can decide if you want a 26 MHz or a > > 52 MHz clock for the UART block. > > Does this register exists on mt8135? If so, why is it not implemented? > > I found that PERI_UARTx_CK is connected to axi_sel but should be > connected to uart_sel. Like this I'm able to reach to initramfs > console, but the baud rate values are screwed up. > As uart_sel is at 52 MHz, I suppose we need to change the entries in > PERI_UART_CK_SOURCE_SEL.
I just asked the Mediatek guys for clarification, lets see what they tell me. There is a PERI_UART_CK_SOURCE_SEL on MT8135/MT8173, I have no idea why this is not implemented. I also don't know where the clocks I can select in the PERI_UART_CK_SOURCE_SEL register are derived from. It's also unclear to me how the real UART clock topology looks like. Sascha -- Pengutronix e.K. | | Industrial Linux Solutions | http://www.pengutronix.de/ | Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 | -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
