From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-lj1-x243.google.com ([2a00:1450:4864:20::243]) by bombadil.infradead.org with esmtps (Exim 4.90_1 #2 (Red Hat Linux)) id 1gB4Ds-0001wK-MX for linux-mtd@lists.infradead.org; Fri, 12 Oct 2018 20:39:59 +0000 Received: by mail-lj1-x243.google.com with SMTP id v7-v6so12451211ljg.5 for ; Fri, 12 Oct 2018 13:39:37 -0700 (PDT) From: Janusz Krzysztofik To: Boris Brezillon , Miquel Raynal Cc: Richard Weinberger , David Woodhouse , Brian Norris , Marek Vasut , linux-mtd@lists.infradead.org, linux-kernel@vger.kernel.org, Janusz Krzysztofik Subject: [PATCH v2 1/2] mtd: rawnand: Provide helper for polling GPIO R/B pin Date: Fri, 12 Oct 2018 22:41:00 +0200 Message-Id: <20181012204101.26274-1-jmkrzyszt@gmail.com> In-Reply-To: <20181003120028.9257-1-jmkrzyszt@gmail.com> References: <20181003120028.9257-1-jmkrzyszt@gmail.com> List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , 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 #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. + * + * 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 + /** * 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. + */ +int nand_gpio_waitrdy(struct nand_chip *chip, struct gpio_desc *gpiod, + unsigned long timeout_ms); +#endif + #endif /* __LINUX_MTD_RAWNAND_H */ -- 2.16.4