diff options
| -rw-r--r-- | drivers/spi/spi.c | 51 | ||||
| -rw-r--r-- | include/linux/spi/spi.h | 18 |
2 files changed, 66 insertions, 3 deletions
diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c index 7ba981cdb86b..7499a4efbaba 100644 --- a/drivers/spi/spi.c +++ b/drivers/spi/spi.c @@ -1106,6 +1106,57 @@ static void _spi_transfer_delay_ns(u32 ns) } } +static int _spi_delay_to_ns(struct spi_delay *_delay, struct spi_transfer *xfer) +{ + u32 delay = _delay->value; + u32 unit = _delay->unit; + u32 hz; + + if (!delay) + return 0; + + switch (unit) { + case SPI_DELAY_UNIT_USECS: + delay *= 1000; + break; + case SPI_DELAY_UNIT_NSECS: /* nothing to do here */ + break; + case SPI_DELAY_UNIT_SCK: + /* clock cycles need to be obtained from spi_transfer */ + if (!xfer) + return -EINVAL; + /* if there is no effective speed know, then approximate + * by underestimating with half the requested hz + */ + hz = xfer->effective_speed_hz ?: xfer->speed_hz / 2; + if (!hz) + return -EINVAL; + delay *= DIV_ROUND_UP(1000000000, hz); + break; + default: + return -EINVAL; + } + + return delay; +} + +int spi_delay_exec(struct spi_delay *_delay, struct spi_transfer *xfer) +{ + int delay; + + if (!_delay) + return -EINVAL; + + delay = _spi_delay_to_ns(_delay, xfer); + if (delay < 0) + return delay; + + _spi_transfer_delay_ns(delay); + + return 0; +} +EXPORT_SYMBOL_GPL(spi_delay_exec); + static void _spi_transfer_cs_change_delay(struct spi_message *msg, struct spi_transfer *xfer) { 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 @@ -91,6 +91,21 @@ void spi_statistics_add_transfer_stats(struct spi_statistics *stats, 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. * @controller: SPI controller used with 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; |