Commit 89c1f607 authored Dec 13, 2013 by Trent Piepho Committed by Mark Brown Dec 16, 2013

spi: Order fields in spi_device for better packing



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@gmail.com>
Reviewed-by: Sourav Poddar <sourav.poddar@ti.com>
Tested-by: Sourav Poddar <sourav.poddar@ti.com&gt;g>
Signed-off-by: Mark Brown <broonie@linaro.org>

parent 0c64bc1b

include/linux/spi/spi.h

+1 −1

Original line number	Diff line number	Diff line
		@@ -75,6 +75,7 @@ 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 */
		@@ -92,7 +93,6 @@ 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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