diff options
| author | Alexandru Ardelean <alexandru.ardelean@analog.com> | 2019-09-26 13:51:35 +0300 |
|---|---|---|
| committer | Mark Brown <broonie@kernel.org> | 2019-10-15 11:44:10 +0100 |
| commit | 6c613f68aabf33385c01e949204ac5ed30887161 (patch) | |
| tree | 7c1d71fe3b8d7f6c63453a873c952c5719934895 /drivers/spi/spi-atmel.c | |
| parent | ec3fa72fa8404128771a095d5a56b738752ba9ff (diff) | |
spi: core,atmel: convert `word_delay_usecs` -> `word_delay` for spi_device
This change does a conversion from the `word_delay_usecs` -> `word_delay`
for the `spi_device` struct.
This allows users to specify inter-word delays in other unit types
(nano-seconds or clock cycles), depending on how users want.
The Atmel SPI driver is the only current user of the `word_delay_usecs`
field (from the `spi_device` struct).
So, it needed a slight conversion to use the `word_delay` as an `spi_delay`
struct.
In SPI core, the only required mechanism is to update the `word_delay`
information per `spi_transfer`. This requires a bit more logic than before,
because it needs that both delays be converted to a common unit
(nano-seconds) for comparison.
Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
Link: https://lore.kernel.org/r/20190926105147.7839-8-alexandru.ardelean@analog.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Diffstat (limited to 'drivers/spi/spi-atmel.c')
| -rw-r--r-- | drivers/spi/spi-atmel.c | 26 |
1 files changed, 24 insertions, 2 deletions
diff --git a/drivers/spi/spi-atmel.c b/drivers/spi/spi-atmel.c index 3ed5e663da6f..1471b049f99a 100644 --- a/drivers/spi/spi-atmel.c +++ b/drivers/spi/spi-atmel.c @@ -1149,12 +1149,31 @@ atmel_spi_pdc_interrupt(int irq, void *dev_id) return ret; } +static int atmel_word_delay_csr(struct spi_device *spi, struct atmel_spi *as) +{ + struct spi_delay *delay = &spi->word_delay; + u32 value = delay->value; + + switch (delay->unit) { + case SPI_DELAY_UNIT_NSECS: + value /= 1000; + break; + case SPI_DELAY_UNIT_USECS: + break; + default: + return -EINVAL; + } + + return (as->spi_clk / 1000000 * value) >> 5; +} + static int atmel_spi_setup(struct spi_device *spi) { struct atmel_spi *as; struct atmel_spi_device *asd; u32 csr; unsigned int bits = spi->bits_per_word; + int word_delay_csr; as = spi_master_get_devdata(spi->master); @@ -1178,11 +1197,14 @@ static int atmel_spi_setup(struct spi_device *spi) */ csr |= SPI_BF(DLYBS, 0); + word_delay_csr = atmel_word_delay_csr(spi, as); + if (word_delay_csr < 0) + return word_delay_csr; + /* DLYBCT adds delays between words. This is useful for slow devices * that need a bit of time to setup the next transfer. */ - csr |= SPI_BF(DLYBCT, - (as->spi_clk / 1000000 * spi->word_delay_usecs) >> 5); + csr |= SPI_BF(DLYBCT, word_delay_csr); asd = spi->controller_state; if (!asd) { |