From: Jeff Epler <jepler@unpythonic.net>
To: linux-rt-users@vger.kernel.org
Subject: [PATCH 3/4] spidev: actually use synchronous transfers
Date: Mon, 1 Sep 2014 09:30:34 -0500 [thread overview]
Message-ID: <1409581835-70814-4-git-send-email-jepler@unpythonic.net> (raw)
In-Reply-To: <1409581835-70814-1-git-send-email-jepler@unpythonic.net>
this reduces a source of latency
---
drivers/spi/spidev.c | 8 +-------
1 file changed, 1 insertion(+), 7 deletions(-)
diff --git a/drivers/spi/spidev.c b/drivers/spi/spidev.c
index dda7632..6e37c59 100644
--- a/drivers/spi/spidev.c
+++ b/drivers/spi/spidev.c
@@ -120,15 +120,9 @@ spidev_sync(struct spidev_data *spidev, struct spi_message *message)
if (spidev->spi == NULL)
status = -ESHUTDOWN;
else
- status = spi_async(spidev->spi, message);
+ status = spi_sync(spidev->spi, message);
spin_unlock_irq(&spidev->spi_lock);
- if (status == 0) {
- wait_for_completion(&done);
- status = message->status;
- if (status == 0)
- status = message->actual_length;
- }
return status;
}
--
2.0.1
next prev parent reply other threads:[~2014-09-01 15:00 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-09-01 14:30 [RFC 0/4] Improving SPI driver latency (vs v3.8.13.14-rt31) Jeff Epler
2014-09-01 14:30 ` [PATCH 1/4] spi: reenable sync SPI transfers Jeff Epler
2014-09-01 14:30 ` [PATCH 2/4] spidev: Avoid runtime memory allocations Jeff Epler
2014-09-01 14:30 ` Jeff Epler [this message]
2014-09-01 14:30 ` [PATCH 4/4] spidev-s3c64xx: allocate dma channel at startup Jeff Epler
2014-09-01 15:41 ` [RFC 0/4] Improving SPI driver latency (vs v3.8.13.14-rt31) Philipp Lutz
2014-09-01 18:13 ` Jeff Epler
2014-09-01 22:30 ` Harry van Haaren
2014-09-09 20:01 ` Uwe Kleine-König
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