diff options
| author | Janusz Krzysztofik <jmkrzyszt@gmail.com> | 2018-10-15 22:41:28 +0300 |
|---|---|---|
| committer | Miquel Raynal <miquel.raynal@bootlin.com> | 2018-11-05 12:57:00 +0300 |
| commit | b0e137ad24b6cc36a4ab09558a401e124163eefb (patch) | |
| tree | 7f11d133ab8dfe72862727a67057cd4faff5c2c6 | |
| parent | 41d6f0d07d76257cf2d39071a439c7dd1da7271e (diff) | |
| download | linux-b0e137ad24b6cc36a4ab09558a401e124163eefb.tar.xz | |
mtd: rawnand: Provide helper for polling GPIO R/B pin
Each controller driver having access to NAND R/B pin over GPIO would
have to reimplement the polling loop otherwise.
Suggested-by: Boris Brezillon <boris.brezillon@bootlin.com>
Signed-off-by: Janusz Krzysztofik <jmkrzyszt@gmail.com>
Reviewed-by: Boris Brezillon <boris.brezillon@bootlin.com>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
| -rw-r--r-- | drivers/mtd/nand/raw/nand_base.c | 31 | ||||
| -rw-r--r-- | include/linux/mtd/rawnand.h | 4 |
2 files changed, 35 insertions, 0 deletions
diff --git a/drivers/mtd/nand/raw/nand_base.c b/drivers/mtd/nand/raw/nand_base.c index 05bd0779fe9b..0d5a2dc59b8d 100644 --- a/drivers/mtd/nand/raw/nand_base.c +++ b/drivers/mtd/nand/raw/nand_base.c @@ -45,6 +45,7 @@ #include <linux/io.h> #include <linux/mtd/partitions.h> #include <linux/of.h> +#include <linux/gpio/consumer.h> #include "internals.h" @@ -532,6 +533,36 @@ int nand_soft_waitrdy(struct nand_chip *chip, unsigned long timeout_ms) EXPORT_SYMBOL_GPL(nand_soft_waitrdy); /** + * 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. + * + * 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 R/B pin indicates chip is ready 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); + +/** * panic_nand_get_device - [GENERIC] Get chip for selected access * @chip: the nand chip descriptor * @mtd: MTD device structure diff --git a/include/linux/mtd/rawnand.h b/include/linux/mtd/rawnand.h index e10b126e148f..4e91a70ede10 100644 --- a/include/linux/mtd/rawnand.h +++ b/include/linux/mtd/rawnand.h @@ -1346,4 +1346,8 @@ void nand_release(struct nand_chip *chip); */ int nand_soft_waitrdy(struct nand_chip *chip, unsigned long timeout_ms); +struct gpio_desc; +int nand_gpio_waitrdy(struct nand_chip *chip, struct gpio_desc *gpiod, + unsigned long timeout_ms); + #endif /* __LINUX_MTD_RAWNAND_H */ |