From: "Bryan Wu" <cooloney.lkml@gmail.com>
To: "Dmitry Torokhov" <dmitry.torokhov@gmail.com>
Cc: bryan.wu@analog.com, "Andrey Panin" <pazke@donpac.ru>,
"Roel Kluin" <12o3l@tiscali.nl>,
"Ahmed S. Darwish" <darwish.07@gmail.com>,
linux-input@atrey.karlin.mff.cuni.cz,
linux-joystick@atrey.karlin.mff.cuni.cz,
linux-kernel@vger.kernel.org, akpm@linux-foundation.org,
"Jean Delvare" <khali@linux-fr.org>
Subject: Re: [PATCH try #3] Input/Joystick Driver: add support AD7142 joystick driver
Date: Tue, 16 Oct 2007 01:24:28 +0800 [thread overview]
Message-ID: <386072610710151024s13e9c16qd7c974cde8000a9@mail.gmail.com> (raw)
In-Reply-To: <d120d5000710150848t1993b0aavbbc0cd7971e3ef3e@mail.gmail.com>
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
next prev parent reply other threads:[~2007-10-15 17:24 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-10-15 14:47 [PATCH try #3] Input/Joystick Driver: add support AD7142 joystick driver Bryan Wu
2007-10-15 15:48 ` Dmitry Torokhov
2007-10-15 17:24 ` Bryan Wu [this message]
2007-10-15 17:40 ` Dmitry Torokhov
2007-10-16 5:51 ` Bryan Wu
2007-10-16 16:53 ` Dmitry Torokhov
2007-10-15 18:27 ` Ahmed S. Darwish
2007-10-16 6:08 ` Bryan Wu
2007-10-16 16:40 ` Ahmed S. Darwish
2007-10-15 19:35 ` Jean Delvare
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