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| author | Alexandru Ardelean <alexandru.ardelean@analog.com> | 2019-09-26 13:51:43 +0300 |
|---|---|---|
| committer | Mark Brown <broonie@kernel.org> | 2019-10-15 13:46:12 +0300 |
| commit | 25093bdeb6bcae728e12e3795261dbd3677060a9 (patch) | |
| tree | 919f7a6c5ac4f3bea9bf63ed8259ef0703940cb2 /include/linux/spi | |
| parent | 8105936684681195d9073880b06a123b2e316811 (diff) | |
| download | linux-25093bdeb6bcae728e12e3795261dbd3677060a9.tar.xz | |
spi: implement SW control for CS times
This change implements CS control for setup, hold & inactive delays.
The `cs_setup` delay is completely new, and can help with cases where
asserting the CS, also brings the device out of power-sleep, where there
needs to be a longer (than usual), before transferring data.
The `cs_hold` time can overlap with the `delay` (or `delay_usecs`) from an
SPI transfer. The main difference is that `cs_hold` implies that CS will be
de-asserted.
The `cs_inactive` delay does not have a clear use-case yet. It has been
implemented mostly because the `spi_set_cs_timing()` function implements
it. To some degree, this could overlap or replace `cs_change_delay`, but
this will require more consideration/investigation in the future.
All these delays have been added to the `spi_controller` struct, as they
would typically be configured by calling `spi_set_cs_timing()` after an
`spi_setup()` call.
Software-mode for CS control, implies that the `set_cs_timing()` hook has
not been provided for the `spi_controller` object.
Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
Link: https://lore.kernel.org/r/20190926105147.7839-16-alexandru.ardelean@analog.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Diffstat (limited to 'include/linux/spi')
| -rw-r--r-- | include/linux/spi/spi.h | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/include/linux/spi/spi.h b/include/linux/spi/spi.h index f9b4ba2db08d..cfd87b18f077 100644 --- a/include/linux/spi/spi.h +++ b/include/linux/spi/spi.h @@ -609,6 +609,11 @@ struct spi_controller { /* Optimized handlers for SPI memory-like operations. */ const struct spi_controller_mem_ops *mem_ops; + /* CS delays */ + struct spi_delay cs_setup; + struct spi_delay cs_hold; + struct spi_delay cs_inactive; + /* gpio chip select */ int *cs_gpios; struct gpio_desc **cs_gpiods; |