Messages in this thread | | | Subject | Re: [PATCH 2/2] ARM: dts: imx6ul: Add imx6ul-tempmon | From | Leonard Crestez <> | Date | Fri, 9 Jun 2017 18:34:44 +0300 |
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On Fri, 2017-06-09 at 15:46 +0200, Lothar Waßmann wrote: > On Fri, 9 Jun 2017 13:58:15 +0300 Leonard Crestez wrote: > > On Thu, 2017-06-08 at 13:45 -0300, Fabio Estevam wrote: > > > On Thu, Jun 8, 2017 at 1:26 PM, Leonard Crestez wrote: > > > > + tempmon: tempmon { > > > > + compatible = "fsl,imx6ul-tempmon", "fsl,imx6sx-tempmon"; > > > > + interrupts = ; > > > > + fsl,tempmon = <&anatop>; > > > > + fsl,tempmon-data = <&ocotp>; > > > > + clocks = <&clks IMX6UL_CLK_PLL3_USB_OTG>; > > > Does the IMX6UL_CLK_PLL3_USB_OTG clock really control tempmon? Please > > > double check. > > Yes, as far as I can tell the tempmon block uses the 480 Mhz PLL3 clock > > directly. This is similar to other imx6 SOCs. This PLL is used for > > stuff like USB but not only that. My understanding is the _USB_OTG > > suffix is descriptive, similar to PLL4_AUDIO and PLL6_ENET. Other non- > > usb components use PLL3 (like UART) but through other gates/dividers. > > > > Setting this to IMX6UL_CLK_DUMMY will cause temperature reads to fail. > > Even if PLL3 usually ends up being constantly enabled because of uarts > > this is not true at imx_thermal_probe time (or uarts can be disabled). > > > Since the driver is accessing the OCOTP registers it definitely needs > the IMX6UL_CLK_OCOTP too! > I don't think so. OCOTP reads fuse values into shadows registers on chip reset and values seem to be available even if it's specific OCOTP clock is off. I think that clock is only required for writes or shadow updates.
In theory perhaps tempmon could be made to read ocotp through the imx- ocotp nvmem driver? It is not clear in what scenario this would actually be required.
This discussion is not specific to 6ul/6ull. There are other reads from ocotp which don't enable it's clock, for example imx6q_opp_check_speed_grading.
-- Regards, Leonard
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