spi: Order fields in spi_device for better packing
authorTrent Piepho <tpiepho@gmail.com>
Sat, 14 Dec 2013 02:27:44 +0000 (18:27 -0800)
committerMark Brown <broonie@linaro.org>
Mon, 16 Dec 2013 21:03:42 +0000 (21:03 +0000)
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>g
Signed-off-by: Mark Brown <broonie@linaro.org>
include/linux/spi/spi.h

index 8c62ba74dd91d9800439038d86298f2e2477f1fe..27a882978c15a4dd7fa4d24efc50299a3e87544d 100644 (file)
@@ -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;