From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.dev.rtsoft.ru (mail.dev.rtsoft.ru [213.79.90.226]) by ozlabs.org (Postfix) with SMTP id E73CDB7D04 for ; Wed, 27 Jan 2010 04:28:26 +1100 (EST) Date: Tue, 26 Jan 2010 20:28:24 +0300 From: Anton Vorontsov To: David Brownell Subject: Re: [PATCH 1/4] gpiolib: Introduce chip addition/removal notifier Message-ID: <20100126172824.GA20319@oksana.dev.rtsoft.ru> References: <20100125180957.GA5380@oksana.dev.rtsoft.ru> <20100125181100.GA13805@oksana.dev.rtsoft.ru> <201001252234.30169.david-b@pacbell.net> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 In-Reply-To: <201001252234.30169.david-b@pacbell.net> Cc: David Brownell , Dmitry Eremin-Solenikov , linux-kernel@vger.kernel.org, linuxppc-dev@ozlabs.org, Bill Gatliff , Andrew Morton Reply-To: avorontsov@ru.mvista.com List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Mon, Jan 25, 2010 at 10:34:29PM -0800, David Brownell wrote: > On Monday 25 January 2010, Anton Vorontsov wrote: > > > > +config GPIOLIB_NOTIFIER > > +       bool > > +       help > > +         This symbol is selected by subsystems that need to handle GPIO > > +         chips addition and removal. E.g., this is used for the > > +         OpenFirmware bindings. > > + > > I'm no huge fan of notifiers, but I suppose they have their place. > > However ... I don't see a lot of win to making this optional. OK, will remove it. > Just > inline the little two blocking_notifier_call_chain() calls directly, > making this a *LOT* simpler. I'd rather stay with gpio_call_chain() helper, it makes the code a little bit prettier, IMO. Compare this: --- a/drivers/gpio/gpiolib.c +++ b/drivers/gpio/gpiolib.c @@ -1103,6 +1107,9 @@ fail: pr_err("gpiochip_add: gpios %d..%d (%s) not registered\n", chip->base, chip->base + chip->ngpio - 1, chip->label ? : "generic"); + else + blocking_notifier_call_chain(&gpio_notifier, + GPIO_NOTIFY_CHIP_ADDED, chip); return status; } EXPORT_SYMBOL_GPL(gpiochip_add); @@ -1119,6 +1126,13 @@ int gpiochip_remove(struct gpio_chip *chip) int status = 0; unsigned id; + /* Ask external subsystems to release the chip. */ + status = blocking_notifier_call_chain(&gpio_notifier, + GPIO_NOTIFY_CHIP_REMOVE, chip); + status = notifier_to_errno(status); + if (status) + return status; + spin_lock_irqsave(&gpio_lock, flags); for (id = chip->base; id < chip->base + chip->ngpio; id++) { --- With the call_chain helper: --- a/drivers/gpio/gpiolib.c +++ b/drivers/gpio/gpiolib.c @@ -1029,6 +1030,16 @@ static inline void gpiochip_unexport(struct gpio_chip *chip) #endif /* CONFIG_GPIO_SYSFS */ +static int gpio_call_chain(struct gpio_chip *chip, enum gpio_notify_msg msg) +{ + int ret = blocking_notifier_call_chain(&gpio_notifier, msg, chip); + + return notifier_to_errno(ret); +} + /** * gpiochip_add() - register a gpio_chip * @chip: the chip to register, with chip->base initialized @@ -1103,6 +1114,9 @@ fail: pr_err("gpiochip_add: gpios %d..%d (%s) not registered\n", chip->base, chip->base + chip->ngpio - 1, chip->label ? : "generic"); + else + gpio_call_chain(chip, GPIO_NOTIFY_CHIP_ADDED); + return status; } EXPORT_SYMBOL_GPL(gpiochip_add); @@ -1119,6 +1133,11 @@ int gpiochip_remove(struct gpio_chip *chip) int status = 0; unsigned id; + /* Ask external subsystems to release the chip. */ + status = gpio_call_chain(chip, GPIO_NOTIFY_CHIP_REMOVE); + if (status) + return status; + spin_lock_irqsave(&gpio_lock, flags); for (id = chip->base; id < chip->base + chip->ngpio; id++) { --- Thanks!