Grant Likely schrieb: > On Fri, Jul 04, 2008 at 11:57:14AM +0200, Andre Schwarz wrote: > >> Sascha, Grant, >> >> I'm running on 2.6.26-rc6 with an MPC5200B based system. >> >> Looks like some (for me) crucial GPIO are touched during boot. >> Is this possible ? >> >> Of course I have compiled in GPIO-Lib and specified the GPIOs in the dts. >> But no access yet - I'd like to preserve the setup from u-boot... >> > > The GPIO driver only writes to the GPIO registers when a driver actually > requests to use them. At probe time, the gpio drivers read the current > values from the GPIO registers, so current config should be preserved. > > However, the gpiochip_dir hook explicitly sets the output value when it > is called. It may be that when you are claiming the GPIO line it is > getting set with a default (and wrong) value. > > Another possibility; have you verified that it is the GPIO regs getting > clobbered? Or is port_config getting changed on you? Which GPIO pins? > > g. >
The pin in question is PSC2_4, i.e. a wake-up GPIO. It is configured as push-pull output and driven high. Since it has an external pull-down resistor I can't say if it is driven low or re-configured as an input ... I removed GPIO Lib and the problem is gone. I'm not yet using it anyway under linux - they're mainly for system configuration (setting up muxes etc.). I'll dig into it when I have some time. thanks, Andre MATRIX VISION GmbH, Talstraße 16, DE-71570 Oppenweiler - Registergericht: Amtsgericht Stuttgart, HRB 271090 Geschäftsführer: Gerhard Thullner, Werner Armingeon, Uwe Furtner _______________________________________________ Linuxppc-dev mailing list [email protected] https://ozlabs.org/mailman/listinfo/linuxppc-dev
