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0ff2de8bb1
For some SPI devices that support speed_hz > 1MHz the default 10 us delay when cs_change = 1 is typically way to long and may result in poor spi bus utilization. This patch makes it possible to control the delay at micro or nano second resolution on a per spi_transfer basis. It even allows an "as fast as possible" mode with: xfer.cs_change_delay_unit = SPI_DELAY_UNIT_NSECS; xfer.cs_change_delay = 0; The delay code is shared between delay_usecs and cs_change_delay for consistency and reuse, so in the future this change_delay_unit could also apply to delay_usec as well. Note that on slower SOCs/CPU actually reaching ns deasserts on cs is not realistic as the gpio overhead alone (without any delays added ) may already leave cs deasserted for more than 1us - at least on a raspberry pi. But at the very least this way we can keep it as short as possible. Signed-off-by: Martin Sperl <kernel@martin.sperl.org> Signed-off-by: Mark Brown <broonie@kernel.org> |
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ad7877.h | ||
ads7846.h | ||
at73c213.h | ||
at86rf230.h | ||
cc2520.h | ||
corgi_lcd.h | ||
ds1305.h | ||
eeprom.h | ||
flash.h | ||
ifx_modem.h | ||
l4f00242t03.h | ||
libertas_spi.h | ||
lms283gf05.h | ||
max7301.h | ||
mc33880.h | ||
mcp23s08.h | ||
mmc_spi.h | ||
mxs-spi.h | ||
pxa2xx_spi.h | ||
rspi.h | ||
s3c24xx.h | ||
sh_hspi.h | ||
sh_msiof.h | ||
spi-fsl-dspi.h | ||
spi-mem.h | ||
spi.h | ||
spi_bitbang.h | ||
spi_gpio.h | ||
spi_oc_tiny.h | ||
tdo24m.h | ||
tle62x0.h | ||
xilinx_spi.h |