Kernel 4.4 and SPI

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.

Has anyone any ideas as to how to configure the pingroups under 4.4, or how to
initialise the device tree for SPI?

Thanks - C W Rose

$ cat /boot/uEnv.txt
. . .
uname_r=4.4.9-bone-rt-r10
#uuid=
#dtb=

##BeagleBone Black/Green dtb’s for v4.1.x (BeagleBone White just works…)

##BeagleBone Black: HDMI (Audio/Video) disabled:
#dtb=am335x-boneblack-emmc-overlay.dtb
. . .
##BeagleBone Black: HDMI (Audio/Video)/eMMC disabled:
#dtb=am335x-boneblack-overlay.dtb
. . .

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,

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/

Yes, I’ve added that patch (or one of the same name). I’m using the u-boot build described in one of your pages,
and built the new u-boot last week. I’ll run through the process again.

C W Rose

Hi C W Rose

Any news on this issue, I am trying to setup the SPI0 on a BBB with no success.

In uEnv I configured the cap-universal to enable and runned the config-pins to P9.17, P9.18, P9.21 and P9.22 as spi. No errors are reported but I see no clock or data being transfered on this pins…

Any help on this?

thanks

Nuno F.

quinta-feira, 9 de Junho de 2016 às 16:08:40 UTC+1, cwrse...@gmail.com escreveu:

My apologies, but it’s some time since I worked with the BBB and my knowledge is well
out of date. The group is your best source of help.

Will