Messages in this thread | | | Date | Tue, 16 Oct 2007 01:24:28 +0800 | From | "Bryan Wu" <> | Subject | Re: [PATCH try #3] Input/Joystick Driver: add support AD7142 joystick driver |
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On 10/15/07, Dmitry Torokhov <dmitry.torokhov@gmail.com> wrote: > Hi Bryan, > > On 10/15/07, Bryan Wu <bryan.wu@analog.com> wrote: > > + > > +static int ad7142_thread(void *nothing) > > +{ > > + do { > > + wait_for_completion(&ad7142_completion); > > + ad7142_decode(); > > + enable_irq(CONFIG_BFIN_JOYSTICK_IRQ_PFX); > > + } while (!kthread_should_stop()); > > + > > No, this is not going to work well: > - you at least need to reinitialize the completion before enabling > IRQ, otherwise you will spin in a very tight loop > - if noone would touch the joystick ad7142_clsoe would() block > infinitely because noone would signal the completion and > ad7142_thread() would never stop. > > Completion is just not a good abstraction here... Please use work > abstraction and possibly a separate workqueue.
Yes, I agree with you now, although I have a little concern about the possibility of big delay introduced by workqueue.
> > > + > > + ad7142_task = kthread_run(ad7142_thread, NULL, "ad7142_task"); > > + if (IS_ERR(ad7142_task)) { > > + printk(KERN_ERR "serio: Failed to start kseriod\n"); > > kseriod?
My fault, I did't notice this copy words from other driver.
> > > + return PTR_ERR(ad7142_task); > > + } > > + return 0; > > +} > > + > > +static void ad7142_close(struct input_dev *dev) > > +{ > > Don't you need to write something over i2c to tell the device to shut > down? As it is now I expect the device to continue raising its IRQ > until kernel decides that it is unhandled and should be ignored. > I am not sure here, should do some investigate of the hardware datasheet.
> > + free_irq(CONFIG_BFIN_JOYSTICK_IRQ_PFX, ad7142_interrupt); > > Ok, so you freeing IRQ here, but it is allocated in ad7142_probe(). > What happen if you try to open device after it was closed? > Yes, it should be move to ad7142_detach_client()
> > + kthread_stop(ad7142_task); > > +} > > + > > +static int __init ad7142_init(void) > > +{ > > + return i2c_add_driver(&ad7142_driver); > > +} > > + > > +static void __exit ad7142_exit(void) > > +{ > > + i2c_del_driver(&ad7142_driver); > > + input_unregister_device(ad7142_dev); > > input_unregister_device() should be in ad7142_detach_client? I am not > sure i2c - there seems to be 2 interface styles and you probably need > to use the new one. I am CC-inj Jean on this. > Yes, no need input_unregister_device() here.
Thanks a lot for you kindly review. I will resend update patch later.
Best Regards, -Bryan Wu - 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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