From mboxrd@z Thu Jan 1 00:00:00 1970 From: Grygorii Strashko Subject: Re: [PATCH] gpio: bcm-kona: lock IRQs when starting them Date: Thu, 21 Nov 2013 12:10:14 +0200 Message-ID: <528DDC06.9070405@ti.com> References: <1384867051-31066-1-git-send-email-linus.walleij@linaro.org> <528DCC8E.8060505@ti.com> Mime-Version: 1.0 Content-Type: text/plain; charset="ISO-8859-1"; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from comal.ext.ti.com ([198.47.26.152]:34403 "EHLO comal.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750782Ab3KUKNi (ORCPT ); Thu, 21 Nov 2013 05:13:38 -0500 In-Reply-To: Sender: linux-gpio-owner@vger.kernel.org List-Id: linux-gpio@vger.kernel.org To: Javier Martinez Canillas Cc: Markus Mayer , Linus Walleij , Linux GPIO List , Alexandre Courbot , Christian Daudt On 11/21/2013 11:50 AM, Javier Martinez Canillas wrote: > Hi, > > On Thu, Nov 21, 2013 at 10:04 AM, Grygorii Strashko > wrote: >> On 11/21/2013 03:21 AM, Markus Mayer wrote: >>> >>> Fixing Christian's e-mail address. >>> >>> On 20 November 2013 17:13, Markus Mayer wrote: >>>> >>>> On 19 November 2013 05:17, Linus Walleij >>>> wrote: >>>>> >>>>> This uses the new API for tagging GPIO lines as in use by >>>>> IRQs. This enforces a few semantic checks on how the underlying >>>>> GPIO line is used. >>>>> >>>>> Cc: Markus Mayer >>>>> Cc: Christian Daudt >>>>> Signed-off-by: Linus Walleij >>>>> --- >>>>> drivers/gpio/gpio-bcm-kona.c | 20 ++++++++++++++++++++ >>>>> 1 file changed, 20 insertions(+) >>>>> >>>>> diff --git a/drivers/gpio/gpio-bcm-kona.c b/drivers/gpio/gpio-bcm-kona.c >>>>> index 72c927dc3be1..dee6d03a7959 100644 >>>>> --- a/drivers/gpio/gpio-bcm-kona.c >>>>> +++ b/drivers/gpio/gpio-bcm-kona.c >>>>> @@ -449,12 +449,32 @@ static void bcm_kona_gpio_irq_handler(unsigned int >>>>> irq, struct irq_desc *desc) >>>>> chained_irq_exit(chip, desc); >>>>> } >>>>> >>>>> +static unsigned int bcm_kona_gpio_irq_startup(struct irq_data *d) >>>>> +{ >>>>> + struct bcm_kona_gpio *kona_gpio = irq_data_get_irq_chip_data(d); >>>>> + >>>>> + if (gpio_lock_as_irq(&kona_gpio->gpio_chip, d->hwirq)) >>>>> + dev_err(kona_gpio->gpio_chip.dev, >>>>> + "unable to lock HW IRQ %lu for IRQ\n", >>>>> + d->hwirq); >>>>> + return 0; >>>>> +} >>>>> + >>>>> +static void bcm_kona_gpio_irq_shutdown(struct irq_data *d) >>>>> +{ >>>>> + struct bcm_kona_gpio *kona_gpio = irq_data_get_irq_chip_data(d); >>>>> + >>>>> + gpio_unlock_as_irq(&kona_gpio->gpio_chip, d->hwirq); >>>>> +} >>>>> + >>>>> static struct irq_chip bcm_gpio_irq_chip = { >>>>> .name = "bcm-kona-gpio", >>>>> .irq_ack = bcm_kona_gpio_irq_ack, >>>>> .irq_mask = bcm_kona_gpio_irq_mask, >>>>> .irq_unmask = bcm_kona_gpio_irq_unmask, >>>>> .irq_set_type = bcm_kona_gpio_irq_set_type, >>>>> + .irq_startup = bcm_kona_gpio_irq_startup, >>>>> + .irq_shutdown = bcm_kona_gpio_irq_shutdown, >>>>> }; >>>>> >>>>> static struct __initconst of_device_id bcm_kona_gpio_of_match[] = { >>>>> -- >>>>> 1.8.3.1 >>>>> >>>> >>>> I don't know yet why, but as soon as I apply that patch, the cd-gpio >>>> interrupt doesn't seem to get triggered anymore. >>>> >>>> $ grep bcm-kona-gpio /proc/interrupts >>>> 270: 0 bcm-kona-gpio 14 3f1b0000.sdio cd >>>> >>>> The counter remains at 0. If I comment-out the irq_startup & >>>> irq_shutdown assignments to temporarily disable the new code, the >>>> interrupt counter increases again when I insert/remove an SD card. >> >> >> Possibly, you have the same problem as I explained here >> "[PATCH] gpio: lynxpoint: lock IRQs when starting them" >> http://comments.gmane.org/gmane.linux.kernel.gpio/1163 >> > > How about locking the GPIO as IRQ on the .irq_set_type function > handler instead of adding a .irq_startup? > > That's how we did on gpio-omap driver and it works pretty well. As for me - .irq_startup/.irq_shutdown are fit the best to do gpio lock, but they have to be implemented accordingly. Because .irq_startup()/.irq_shutdown() are called exactly when GPIO is requested/freed as opposed to .irq_set_type() which may be called any time and many times. Looks like, It will be enough to unmask/mask IRQ from bcm_kona_gpio_irq_startup/shutdown() for this driver. Regards, - grygorii