From: Jeff Epler <jepler-ixP+gI44yfQ4d9/VWYMlNA@public.gmane.org>
To: linux-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
linux-spi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
Subject: [RFC 3/4] spidev: actually use synchronous transfers
Date: Sun, 14 Sep 2014 09:45:07 -0500 [thread overview]
Message-ID: <1410705908-20847-4-git-send-email-jepler@unpythonic.net> (raw)
In-Reply-To: <1410705908-20847-1-git-send-email-jepler-ixP+gI44yfQ4d9/VWYMlNA@public.gmane.org>
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;
}
--
2.1.0
--
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next prev parent reply other threads:[~2014-09-14 14:45 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-09-14 14:45 [RFC 0/4] Improving SPI driver latency (vs v3.8.13.14-rt31) Jeff Epler
[not found] ` <1410705908-20847-1-git-send-email-jepler-ixP+gI44yfQ4d9/VWYMlNA@public.gmane.org>
2014-09-14 14:45 ` [RFC 1/4] spi: reenable sync SPI transfers Jeff Epler
[not found] ` <1410705908-20847-2-git-send-email-jepler-ixP+gI44yfQ4d9/VWYMlNA@public.gmane.org>
2014-09-28 12:24 ` Mark Brown
2014-09-14 14:45 ` [RFC 2/4] spidev: Avoid runtime memory allocations Jeff Epler
2014-09-14 14:45 ` Jeff Epler [this message]
2014-09-14 14:45 ` [RFC 4/4] spidev-s3c64xx: allocate dma channel at startup Jeff Epler
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