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authorMartin Sperl <kernel@martin.sperl.org>2019-02-23 08:49:50 +0000
committerMark Brown <broonie@kernel.org>2019-05-08 18:30:01 +0900
commitd5864e5bed96db7230da45463d6ae7af5b3b4399 (patch)
tree5f88ca741879905a3740c8c8ffdc19cbec25f369 /drivers/spi
parent0ff2de8bb163551ec4230a5a6f3c40c1f6adec4f (diff)
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spi: core: allow defining time that cs is deasserted as a multiple of SCK
Support setting a delay between cs assert and deassert as a multiple of spi clock length. Signed-off-by: Martin Sperl <kernel@martin.sperl.org> Signed-off-by: Mark Brown <broonie@kernel.org>
Diffstat (limited to 'drivers/spi')
-rw-r--r--drivers/spi/spi.c8
1 files changed, 8 insertions, 0 deletions
diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
index 7e8ffe3fdc00..cfa3c3decb8a 100644
--- a/drivers/spi/spi.c
+++ b/drivers/spi/spi.c
@@ -1111,6 +1111,7 @@ static void _spi_transfer_cs_change_delay(struct spi_message *msg,
{
u32 delay = xfer->cs_change_delay;
u32 unit = xfer->cs_change_delay_unit;
+ u32 hz;
/* return early on "fast" mode - for everything but USECS */
if (!delay && unit != SPI_DELAY_UNIT_USECS)
@@ -1126,6 +1127,13 @@ static void _spi_transfer_cs_change_delay(struct spi_message *msg,
break;
case SPI_DELAY_UNIT_NSECS: /* nothing to do here */
break;
+ case SPI_DELAY_UNIT_SCK:
+ /* 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;
+ delay *= DIV_ROUND_UP(1000000000, hz);
+ break;
default:
dev_err_once(&msg->spi->dev,
"Use of unsupported delay unit %i, using default of 10us\n",