From b2c98153f45fc17b9fcb241000f2d131ddea6030 Mon Sep 17 00:00:00 2001 From: Alexandru Ardelean Date: Thu, 26 Sep 2019 13:51:30 +0300 Subject: spi: introduce spi_delay struct as "value + unit" & spi_delay_exec() There are plenty of delays that have been introduced in SPI core. Most of them are in micro-seconds, some need to be in nano-seconds, and some in clock-cycles. For some of these delays (related to transfers & CS timing) it may make sense to have a `spi_delay` struct that abstracts these a bit. The important element of these delays [for unification] seems to be the `unit` of the delay. It looks like micro-seconds is good enough for most people, but every-once in a while, some delays seem to require other units of measurement. This change adds the `spi_delay` struct & a `spi_delay_exec()` function that processes a `spi_delay` object/struct to execute the delay. It's a copy of the `cs_change_delay` mechanism, but without the default for 10 uS. The clock-cycle delay unit is a bit special, as it needs to be bound to an `spi_transfer` object to execute. Signed-off-by: Alexandru Ardelean Link: https://lore.kernel.org/r/20190926105147.7839-3-alexandru.ardelean@analog.com Signed-off-by: Mark Brown --- include/linux/spi/spi.h | 18 +++++++++++++++--- 1 file changed, 15 insertions(+), 3 deletions(-) (limited to 'include/linux/spi/spi.h') diff --git a/include/linux/spi/spi.h b/include/linux/spi/spi.h index 27f6b046cf92..8f643de3197b 100644 --- a/include/linux/spi/spi.h +++ b/include/linux/spi/spi.h @@ -90,6 +90,21 @@ void spi_statistics_add_transfer_stats(struct spi_statistics *stats, #define SPI_STATISTICS_INCREMENT_FIELD(stats, field) \ SPI_STATISTICS_ADD_TO_FIELD(stats, field, 1) +/** + * struct spi_delay - SPI delay information + * @value: Value for the delay + * @unit: Unit for the delay + */ +struct spi_delay { +#define SPI_DELAY_UNIT_USECS 0 +#define SPI_DELAY_UNIT_NSECS 1 +#define SPI_DELAY_UNIT_SCK 2 + u16 value; + u8 unit; +}; + +extern int spi_delay_exec(struct spi_delay *_delay, struct spi_transfer *xfer); + /** * struct spi_device - Controller side proxy for an SPI slave device * @dev: Driver model representation of the device. @@ -887,9 +902,6 @@ struct spi_transfer { u16 delay_usecs; u16 cs_change_delay; u8 cs_change_delay_unit; -#define SPI_DELAY_UNIT_USECS 0 -#define SPI_DELAY_UNIT_NSECS 1 -#define SPI_DELAY_UNIT_SCK 2 u32 speed_hz; u16 word_delay; -- cgit v1.2.3-59-g8ed1b