Messages in this thread | | | Date | Wed, 10 Aug 2011 11:29:09 +0900 | Subject | Re: kernel panic with simple driver | From | "Murali K. Vemuri" <> |
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On Wed, Aug 10, 2011 at 11:16 AM, Greg KH <greg@kroah.com> wrote: > On Wed, Aug 10, 2011 at 10:33:28AM +0900, Murali K. Vemuri wrote: >> There is no concurrent access to the timer. The design is that: >> 1.Driver provides an IOCTL for start / stop >> 2. when the driver receives START IOCTL, it toggles some GPIOs to ON / OFF. >> 3. the GPIOs will be ON for 500 MSec and OFF for 500 MSec. >> 4. Two successive START IOCTLs will not be honored. >> 5. There is only one application that uses these IOCTLs >> 6. When I receive a STOP IOCTL, I am doing : >> if (timer_pending (&my_timer)) >> del_timer(&my_timer); > > What kind of driver is this? For what type of hardware? > > Can't you control the gpios from userspace with out any need to write a > kernel driver? >
This driver is meant for controlling some LEDs. The CPU is OMAP 3530 and the OS is Android. From the user space, I could not control the GPIOs directly, and thus I ended up supporting in the form of a simple driver. I agree that these are better done from the user space, but as much as I google'd studied, I could not find any better way to implement this.
If anyone has more info, that is also highly appreciated. Thanks Murali
> thanks, > > greg k-h > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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