Does SPI1 need timer4 pin 8.07?

[Gaurav S]

Hello,

I am creating a custom cape which uses SPI1 with both cs0 and cs1 and uses multiple GPIO pins including 8.07 mapped as GPIO pin.. My prototype has been working without issues but I recently noticed a curious issue while parsing dmesg:

[   10.775173] pinctrl-single 44e10800.pinmux: pin 44e10890.0 already requested by ocp:gpio_helper; cannot claim for 481a0000.spi

[   10.786802] pinctrl-single 44e10800.pinmux: pin-36 (481a0000.spi) status -22

[   10.793955] pinctrl-single 44e10800.pinmux: could not request pin 36 (44e10890.0) from group MYTEST_GPIO  on device pinctrl-single

[   10.805516] omap2_mcspi 481a0000.spi: Error applying setting, reverse things back

where MYTEST_GPIO is:

__overlay__ {

                  my_example: MYTEST_GPIO {

pinctrl-single,pins = <

                                0x090 0x07  // P8_07 this seems to be the offending pin 

                                0x094 0x07  // P8_08 

   // few more pins not shown here

>;

 };

             };

The SPI overlay is:

bb_spi1_pins: pinmux_bb_spi1_pins {

pinctrl-single,pins = <

0x190 0x33 /* spi1_sclk, INPUT_PULLUP | MODE3 */

0x194 0x13 /* spi1_d0, OUTPUT_PULLUP | MODE3 */

0x19c 0x13 /* spi1_cs0, OUTPUT_PULLUP | MODE3 */

0x164 0x12 /* spi1_cs1 OUTPUT_PULLUP | MODE2 */

>;

};

I am not defining the use of a timer in the overlays. I understand SPI needs to generate a clock in master mode, though I am not sure if one of the timers is used for this purpose. However, I am not sure I understand why is the pin 8.07 physically required especially when I am mapping it as a GPIO pin. 

Some system information if it helps:

debian@beaglebone:~$ uname -a

Linux beaglebone 4.4.47-ti-r87 #1 SMP Mon Feb 6 22:21:49 UTC 2017 armv7l GNU/Linux

debian@beaglebone:~$ cat /sys/devices/platform/bone_capemgr/slots

 0: P---L-   0 4D 4.3 LCD CAPE- 4DCAPE-43T     ,00A1,4D SYSTEMS      ,BB-BONE-LCD4-01

 1: PF----  -1

 2: PF----  -1

 3: PF----  -1

 4: P-O-L-   1 Override Board Name,00A0,Override Manuf,MYTEST-SPIDEV1

 5: P-O-L-   2 Override Board Name,00A0,Override Manuf,MYTEST-GPIO

Any thoughts would be appreciated..

Thanks

Gaurav