From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0E14BC28CF8 for ; Sat, 13 Oct 2018 05:55:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B94A820895 for ; Sat, 13 Oct 2018 05:55:43 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org B94A820895 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=bootlin.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726309AbeJMNbb (ORCPT ); Sat, 13 Oct 2018 09:31:31 -0400 Received: from mail.bootlin.com ([62.4.15.54]:35278 "EHLO mail.bootlin.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726125AbeJMNbb (ORCPT ); Sat, 13 Oct 2018 09:31:31 -0400 Received: by mail.bootlin.com (Postfix, from userid 110) id EF667207A3; Sat, 13 Oct 2018 07:55:37 +0200 (CEST) Received: from bbrezillon (unknown [91.160.177.164]) by mail.bootlin.com (Postfix) with ESMTPSA id A3D6820717; Sat, 13 Oct 2018 07:55:37 +0200 (CEST) Date: Sat, 13 Oct 2018 07:55:37 +0200 From: Boris Brezillon To: Janusz Krzysztofik Cc: Miquel Raynal , Richard Weinberger , David Woodhouse , Brian Norris , Marek Vasut , linux-mtd@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2 1/2] mtd: rawnand: Provide helper for polling GPIO R/B pin Message-ID: <20181013075537.291e145f@bbrezillon> In-Reply-To: <20181012204101.26274-1-jmkrzyszt@gmail.com> References: <20181003120028.9257-1-jmkrzyszt@gmail.com> <20181012204101.26274-1-jmkrzyszt@gmail.com> X-Mailer: Claws Mail 3.15.0-dirty (GTK+ 2.24.31; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Janusz, On Fri, 12 Oct 2018 22:41:00 +0200 Janusz Krzysztofik wrote: > Each controller driver with access to NAND R/B pin over GPIO would have > to reimplement the polling loop otherwise. > > Signed-off-by: Janusz Krzysztofik > --- > Changelog: > v2: > New patch - v1 consisted of only one patch (the followning one) > > > drivers/mtd/nand/raw/nand_base.c | 38 ++++++++++++++++++++++++++++++++++++++ > include/linux/mtd/rawnand.h | 10 ++++++++++ > 2 files changed, 48 insertions(+) > > diff --git a/drivers/mtd/nand/raw/nand_base.c b/drivers/mtd/nand/raw/nand_base.c > index 05bd0779fe9b..ff1ac4a3c647 100644 > --- a/drivers/mtd/nand/raw/nand_base.c > +++ b/drivers/mtd/nand/raw/nand_base.c > @@ -45,6 +45,9 @@ > #include > #include > #include > +#ifdef CONFIG_GPIOLIB > +#include > +#endif The ifdef is not needed here, linux/gpio/consumer.h already has dummy wrappers when CONFIG_GPIOLIB is not enabled. > > #include "internals.h" > > @@ -531,6 +534,41 @@ int nand_soft_waitrdy(struct nand_chip *chip, unsigned long timeout_ms) > }; > EXPORT_SYMBOL_GPL(nand_soft_waitrdy); > > +#ifdef CONFIG_GPIOLIB > +/** > + * nand_gpio_waitrdy - Poll R/B GPIO pin until ready > + * @chip: NAND chip structure > + * @gpiod: GPIO descriptor of R/B pin > + * @timeout_ms: Timeout in ms > + * > + * Poll the R/B GPIO pin until it becomes ready. If that does not happen > + * whitin the specified timeout, -ETIMEDOUT is returned. > + * > + * This helper is intended to be used when the controller has access to the > + * NAND R/B pin over GPIO. > + * > + * Be aware that calling this helper from an ->exec_op() implementation means > + * ->exec_op() must be re-entrant. This is not true for this function: it does not call nand_exec_op(). > + * > + * Return 0 if the R/B pin indicates chip is ready, a negative error otherwise. > + */ > +int nand_gpio_waitrdy(struct nand_chip *chip, struct gpio_desc *gpiod, > + unsigned long timeout_ms) > +{ > + /* Wait until command is processed or timeout occurs */ > + timeout_ms = jiffies + msecs_to_jiffies(timeout_ms); > + do { > + if (gpiod_get_value_cansleep(gpiod)) > + return 0; > + > + cond_resched(); > + } while (time_before(jiffies, timeout_ms)); > + > + return gpiod_get_value_cansleep(gpiod) ? 0 : -ETIMEDOUT; > +}; > +EXPORT_SYMBOL_GPL(nand_gpio_waitrdy); > +#endif Hm, I don't see any other helpers defined in #ifdef blocks though most of them are optionals and are most of the time not used by drivers. Let's keep things consistent (at the expense of embedding unused code in nand.o) and remove the #ifdef here. If someone starts complaining about the size of the rawnand core, we'll consider doing that. > + > /** > * panic_nand_get_device - [GENERIC] Get chip for selected access > * @chip: the nand chip descriptor > diff --git a/include/linux/mtd/rawnand.h b/include/linux/mtd/rawnand.h > index e10b126e148f..09f0ed1345b1 100644 > --- a/include/linux/mtd/rawnand.h > +++ b/include/linux/mtd/rawnand.h > @@ -1346,4 +1346,14 @@ void nand_release(struct nand_chip *chip); > */ > int nand_soft_waitrdy(struct nand_chip *chip, unsigned long timeout_ms); > > +#ifdef CONFIG_GPIOLIB > +struct gpio_desc; > +/* > + * External helper for controller drivers that have to implement the WAITRDY > + * instruction and do have GPIO pin to check it. > + */ You can drop this comment, this is already explained in the kerneldoc header above the function def. > +int nand_gpio_waitrdy(struct nand_chip *chip, struct gpio_desc *gpiod, > + unsigned long timeout_ms); > +#endif > + > #endif /* __LINUX_MTD_RAWNAND_H */ Regards, Boris