On Thu, Jun 9, 2016 at 10:08 AM,  <[email protected]> wrote:
>
> I've been trying to port the driver for a SPI rtc, the DS3234, from the 3.8
> kernel
> to a recent 4.4.  After minor changes the cape manager loads the dts file
> sucessfully,
> and the slot entry and /dev/rtc1 appear, but reading and writing to the
> clock fails.
>
> Checking the pins and pin groups it seems that 4.4 isn't enabling the pins
> group.
> In 3.8 I get:
> pin 100 (44e10990): 481a0000.spi (GPIO UNCLAIMED) function pinctrl_spi1_pins
> group pinctrl_spi1_pins
> pin 101 (44e10994): 481a0000.spi (GPIO UNCLAIMED) function pinctrl_spi1_pins
> group pinctrl_spi1_pins
> pin 102 (44e10998): 481a0000.spi (GPIO UNCLAIMED) function pinctrl_spi1_pins
> group pinctrl_spi1_pins
> pin 103 (44e1099c): 481a0000.spi (GPIO UNCLAIMED) function pinctrl_spi1_pins
> group pinctrl_spi1_pins
>
> and in 4.4 the pins are unclaimed by both GPIO and MUX.
>
> The uEnv.txt line is:
> optargs=bone_capemgr.enable_partno=BB-SPIDEV0,BB-SPI1CLK
> Loading SPIDEV1 in place of SPI1CLK produces the correct /dev/spidevN.N
> devices,
> but again these don't seem to be useable; the test programs in the kernel
> sources fail.
>
> The only change between the 3.8 and 4.4 setups is that the HDMI overlay has
> gone,
> and there seems no way to disable HDMI.  There's a note in one of Robert
> Nelson's
> pages that setting dtb=am335x-boneblack-overlay.dtb in uEnv.txt will achieve
> this,
> but checking the new u-boot code that doesn't seem likely, and checking the
> pins
> and pingroups shows no change.

Our u-boot patch looks for dtb=...

https://github.com/RobertCNelson/Bootloader-Builder/blob/master/patches/v2016.03/0001-am335x_evm-uEnv.txt-bootz-n-fixes.patch#L455-L458

Regards,

-- 
Robert Nelson
https://rcn-ee.com/

-- 
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