From: Trent Piepho <tpiepho-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
To: spi-devel-general-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org,
Mark Brown <broonie-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>,
yuhang wang
<wangyuhang2014-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
Cc: Sourav Poddar <sourav.poddar-l0cyMroinI0@public.gmane.org>
Subject: [PATCH 2/4] spi: Order fields in spi_device for better packing
Date: Wed, 25 Sep 2013 16:52:14 -0700 [thread overview]
Message-ID: <20130925235214.22061.8047.stgit@Graphine> (raw)
In-Reply-To: <CA+7tXigzKW8sydfnktr4F5uY-SKk0JAMjaxFn74XLbw_NTYVXg-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
Now that spi_device->mode is a u16, the chip_select, bits_per_mode,
and mode fields pack poorly, taking 8 bytes: four data and four
padding. By moving (u8)bits_per_word up one position, to after
(u8)chip_select, they pack better and only use 4 bytes.
Signed-off-by: Trent Piepho <tpiepho-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
---
include/linux/spi/spi.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/include/linux/spi/spi.h b/include/linux/spi/spi.h
index 887116d..beaffe8 100644
--- a/include/linux/spi/spi.h
+++ b/include/linux/spi/spi.h
@@ -74,6 +74,7 @@ struct spi_device {
struct spi_master *master;
u32 max_speed_hz;
u8 chip_select;
+ u8 bits_per_word;
u16 mode;
#define SPI_CPHA 0x01 /* clock phase */
#define SPI_CPOL 0x02 /* clock polarity */
@@ -91,7 +92,6 @@ struct spi_device {
#define SPI_TX_QUAD 0x200 /* transmit with 4 wires */
#define SPI_RX_DUAL 0x400 /* receive with 2 wires */
#define SPI_RX_QUAD 0x800 /* receive with 4 wires */
- u8 bits_per_word;
int irq;
void *controller_state;
void *controller_data;
------------------------------------------------------------------------------
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next prev parent reply other threads:[~2013-09-25 23:52 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-08-11 10:15 [PATCH v3 1/2]spi: DUAL and QUAD support wangyuhang
2013-08-22 12:30 ` Mark Brown
2013-08-22 12:35 ` Sourav Poddar
2013-08-22 13:21 ` Mark Brown
[not found] ` <20130822132122.GK26118-GFdadSzt00ze9xe1eoZjHA@public.gmane.org>
2013-08-22 14:23 ` Sourav Poddar
2013-08-22 12:37 ` Mark Brown
[not found] ` <1376216117-5864-1-git-send-email-wangyuhang2014-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
2013-09-04 3:24 ` Trent Piepho
[not found] ` <CA+7tXih4XkhZ8xGcaUdGU6O4ZN1ZLfqyjb2UEKsRxsZBA+=DZw-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2013-09-04 7:07 ` yuhang wang
[not found] ` <CAHSAbzOCRhpxMzQRtD2po3LrmNExscoYESPPi_-jnZQaEBuFTg-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2013-09-25 23:33 ` Trent Piepho
[not found] ` <CA+7tXigzKW8sydfnktr4F5uY-SKk0JAMjaxFn74XLbw_NTYVXg-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2013-09-25 23:52 ` [PATCH 1/4] spi: Use of_property_read_u32 Trent Piepho
2013-09-26 6:12 ` Sourav Poddar
2013-09-25 23:52 ` Trent Piepho [this message]
2013-09-26 6:14 ` [PATCH 2/4] spi: Order fields in spi_device for better packing Sourav Poddar
2013-09-25 23:52 ` [PATCH 3/4] spi: Encode data width more efficiently Trent Piepho
2013-09-26 6:14 ` Sourav Poddar
2013-09-25 23:52 ` [PATCH 4/4] spi: Simplify bit width checking code Trent Piepho
2013-09-26 6:14 ` Sourav Poddar
2013-09-04 9:45 ` [PATCH v3 1/2]spi: DUAL and QUAD support Mark Brown
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