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 <jmkrzyszt@xxxxxxxxx> --- 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 <linux/io.h> #include <linux/mtd/partitions.h> #include <linux/of.h> +#ifdef CONFIG_GPIOLIB +#include <linux/gpio/consumer.h> +#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 ______________________________________________________ Linux MTD discussion mailing list http://lists.infradead.org/mailman/listinfo/linux-mtd/