On 10/12/2015 04:12 PM, Ladislav Michl wrote: > On Fri, Oct 09, 2015 at 11:45:17AM +0200, Rolf Peukert wrote: >> On 09.10.2015 02:54, Ladislav Michl wrote: >>> Hi there! >>> >>> on custom AM37x board running 2.6.37 this was enough to enable gpio 67: >>> echo 71 > /sys/class/gpio/export >>> echo out > /sys/class/gpio/gpio71/direction >>> echo 1 > /sys/class/gpio/gpio71/value >>> >>> However, with DT configured linux-4.2 compiled using omap2plus_defconfig >>> this no longer works. >> [...] >> >> Is some other device driver using these pins? Pins 70 and 71 could be >> DSS or UART1. Maybe you need to set them to "disabled" in your DT. > > Only UART2 is enabled. This should not make difference anyway, as it should > be matter of mux config and gpio settings. Working GPIO 82 is on the same > bank as GPIO 71 and to make it work from U-Boot only these registers need > to be touched: > => mw.l 0x480020DC 0x40004 > => mw.l 0x480020F4 0x40004 > => mw.l 0x49052034 0xFFF41F3F > => mw.l 0x4905203C <value> > First two writes are mux config, 3rd is direction and the last one is output. > Both GPIO 71 and 82 could be driven this way. But as long as kernel steps in, > GPIO 71 no longer works even if I use devmem utility to write relevant > registers. Just tried 3.19.8 and it does not work either, moving backward > to the past... >
I think You might need to check pin muxing in DT-file. if you have smth like dss_dpi_pins_cm_t35x: pinmux_dss_dpi_pins_cm_t35x { pinctrl-single,pins = < OMAP3_CORE1_IOPAD(0x20dc, PIN_OUTPUT | MUX_MODE0) /* dss_data0.dss_data0 */ OMAP3_CORE1_IOPAD(0x20de, PIN_OUTPUT | MUX_MODE0) /* dss_data1.dss_data1 */ ^^^^^ it will not work as gpio. OMAP3_CORE1_IOPAD(0x20e0, PIN_OUTPUT | MUX_MODE0) /* dss_data2.dss_data2 */ OMAP3_CORE1_IOPAD(0x20e2, PIN_OUTPUT | MUX_MODE0) /* dss_data3.dss_data3 */ OMAP3_CORE1_IOPAD(0x20e4, PIN_OUTPUT | MUX_MODE0) /* dss_data4.dss_data4 */ OMAP3_CORE1_IOPAD(0x20e6, PIN_OUTPUT | MUX_MODE0) /* dss_data5.dss_data5 */ >; }; -- regards, -grygorii -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html