From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from rv-out-0506.google.com (rv-out-0506.google.com [209.85.198.226]) by ozlabs.org (Postfix) with ESMTP id CDAC5DDDAC for ; Wed, 11 Feb 2009 20:41:03 +1100 (EST) Received: by rv-out-0506.google.com with SMTP id f6so66910rvb.9 for ; Wed, 11 Feb 2009 01:41:01 -0800 (PST) MIME-Version: 1.0 In-Reply-To: <1234343703.9778.13.camel@localhost> References: <1234343703.9778.13.camel@localhost> Date: Wed, 11 Feb 2009 15:11:01 +0530 Message-ID: Subject: Re: request_irq return errno 38 From: Vijay Nikam To: michael@ellerman.id.au Content-Type: text/plain; charset=ISO-8859-1 Cc: linuxppc-dev@ozlabs.org List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Thanks for your prompt reply ... I am using kernel version 2.6.20 ... May I know what raw IRQ means ? ? ? and what is the reason I cant map raw_irq_number ??? Kindly please acknowledge ... thank you ... Kind Regards, Vijay Nikam On 2/11/09, Michael Ellerman wrote: > On Wed, 2009-02-11 at 14:13 +0530, Vijay Nikam wrote: > > Hello All, > > > > I have mpc8313erdb evaluation board and currently I am writing GPIO > > driver. Actually it is just simple test driver. > > > > I did the irq_request in the driver init function, as request_irq > > returns zero (0) if successful, otherwise -1 on error and errno > > indicates the error. But when I load or insert the module using insmod > > request_irq return with Return Value -38. I checked in errno.h file in > > asm-generic and 38 means ENOSYS - Function not implemented. > > Following is irq_request code: > > ---------------------- > > ret = request_irq(74, interrupt_handler, SA_INTERRUPT | SA_SHIRQ , > > "gpio", &mydev); > > if(ret) > > printk(KERN_INFO "Error in request_irq, value return = %d \n", ret); > > ---------------------- > > NOTE: 74 is the Interrupt ID Number for GPIO Interrupt. this > > information is from Processor User Manual. > > > > Following is the handler: > > --------------------- > > static int interrupt_handler(int irqn, void *dev_id) > > { > > printk(KERN_INFO "Enter in interrupt handler\n"); > > return IRQ_HANDLED; > > } > > -------------------- > > > > Usually request_irq return EBUSY, EINVAL but in my case it returns > > ENOSYS (errno 38). I tried to look information for this errno in > > interrupt context but could not able to find anything useful or > > understable. Could anyone please let me know why this specific errno > > 38 generated in request_irq ? ? ? and what are the possiblities for > > resolving this error ? ? ? > > You don't mention what kernel version you're using. But you might be > hitting the check in __setup_irq(): > > if (desc->chip == &no_irq_chip) > return -ENOSYS; > > > That would make sense because you're trying to map a raw irq number, > which doesn't work. You first need to call irq_create_mapping(), like: > > int virq; > virq = irq_create_mapping(NULL, 74); > rc = request_irq(virq, ...); > > > cheers > > -- > Michael Ellerman > OzLabs, IBM Australia Development Lab > > wwweb: http://michael.ellerman.id.au > phone: +61 2 6212 1183 (tie line 70 21183) > > We do not inherit the earth from our ancestors, > we borrow it from our children. - S.M.A.R.T Person > >