From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ray Jui Subject: Re: [RFT][PATCH 1/2] gpio: bcm-kona: Return error if requesting an already taken gpio Date: Fri, 10 Apr 2015 09:05:03 -0700 Message-ID: <5527F4AF.20304@broadcom.com> References: <1428629325.5384.1.camel@phoenix> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Return-path: Received: from mail-gw1-out.broadcom.com ([216.31.210.62]:62876 "EHLO mail-gw1-out.broadcom.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932827AbbDJQFG (ORCPT ); Fri, 10 Apr 2015 12:05:06 -0400 In-Reply-To: <1428629325.5384.1.camel@phoenix> Sender: linux-gpio-owner@vger.kernel.org List-Id: linux-gpio@vger.kernel.org To: Axel Lin , Linus Walleij Cc: Alexandre Courbot , bcm-kernel-feedback-list@broadcom.com, "linux-gpio@vger.kernel.org" Hi Axel, On 4/9/2015 6:28 PM, Axel Lin wrote: > If a gpio is already taken, .gpio_request should return error. Isn't the protection logic already there at the higher layer in gpiolib? Ray > > Signed-off-by: Axel Lin > --- > drivers/gpio/gpio-bcm-kona.c | 12 +++++++++--- > 1 file changed, 9 insertions(+), 3 deletions(-) > > diff --git a/drivers/gpio/gpio-bcm-kona.c b/drivers/gpio/gpio-bcm-kona.c > index b164ce8..632352d 100644 > --- a/drivers/gpio/gpio-bcm-kona.c > +++ b/drivers/gpio/gpio-bcm-kona.c > @@ -106,7 +106,7 @@ static void bcm_kona_gpio_lock_gpio(struct bcm_kona_gpio *kona_gpio, > spin_unlock_irqrestore(&kona_gpio->lock, flags); > } > > -static void bcm_kona_gpio_unlock_gpio(struct bcm_kona_gpio *kona_gpio, > +static int bcm_kona_gpio_unlock_gpio(struct bcm_kona_gpio *kona_gpio, > unsigned gpio) > { > u32 val; > @@ -116,10 +116,17 @@ static void bcm_kona_gpio_unlock_gpio(struct bcm_kona_gpio *kona_gpio, > spin_lock_irqsave(&kona_gpio->lock, flags); > > val = readl(kona_gpio->reg_base + GPIO_PWD_STATUS(bank_id)); > + if (!(val & BIT(gpio))) { > + spin_unlock_irqrestore(&kona_gpio->lock, flags); > + return -EBUSY; > + } > + > val &= ~BIT(gpio); > bcm_kona_gpio_write_lock_regs(kona_gpio->reg_base, bank_id, val); > > spin_unlock_irqrestore(&kona_gpio->lock, flags); > + > + return 0; > } > > static void bcm_kona_gpio_set(struct gpio_chip *chip, unsigned gpio, int value) > @@ -185,8 +192,7 @@ static int bcm_kona_gpio_request(struct gpio_chip *chip, unsigned gpio) > { > struct bcm_kona_gpio *kona_gpio = to_kona_gpio(chip); > > - bcm_kona_gpio_unlock_gpio(kona_gpio, gpio); > - return 0; > + return bcm_kona_gpio_unlock_gpio(kona_gpio, gpio); > } > > static void bcm_kona_gpio_free(struct gpio_chip *chip, unsigned gpio) >