diff options
| author | Sowjanya Komatineni <skomatineni@nvidia.com> | 2019-04-05 02:14:16 +0200 |
|---|---|---|
| committer | Mark Brown <broonie@kernel.org> | 2019-04-08 09:14:10 +0200 |
| commit | f1ca9992ced71029735784de138f53446363087f (patch) | |
| tree | e0dc359aa07e160039ce89071bd7d73c461ec200 /include | |
| parent | spi-summary: document set_cs_timing (diff) | |
| download | linux-f1ca9992ced71029735784de138f53446363087f.tar.xz linux-f1ca9992ced71029735784de138f53446363087f.zip | |
spi: add a method for configuring CS timing
This patch creates set_cs_timing SPI master optional method for
SPI masters to implement configuring CS timing if applicable.
This patch also creates spi_cs_timing accessory for SPI clients to
use for requesting SPI master controllers to configure device requested
CS setup time, hold time and inactive delay.
Signed-off-by: Sowjanya Komatineni <skomatineni@nvidia.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/spi/spi.h | 15 |
1 files changed, 15 insertions, 0 deletions
diff --git a/include/linux/spi/spi.h b/include/linux/spi/spi.h index a0975cf76cf6..589f9dc9ac2b 100644 --- a/include/linux/spi/spi.h +++ b/include/linux/spi/spi.h @@ -330,6 +330,9 @@ static inline void spi_unregister_driver(struct spi_driver *sdrv) * must fail if an unrecognized or unsupported mode is requested. * It's always safe to call this unless transfers are pending on * the device whose settings are being modified. + * @set_cs_timing: optional hook for SPI devices to request SPI master + * controller for configuring specific CS setup time, hold time and inactive + * delay interms of clock counts * @transfer: adds a message to the controller's transfer queue. * @cleanup: frees controller-specific state * @can_dma: determine whether this controller supports DMA @@ -363,6 +366,7 @@ static inline void spi_unregister_driver(struct spi_driver *sdrv) * @unprepare_transfer_hardware: there are currently no more messages on the * queue so the subsystem notifies the driver that it may relax the * hardware by issuing this call + * * @set_cs: set the logic level of the chip select line. May be called * from interrupt context. * @prepare_message: set up the controller to transfer a single message, @@ -488,6 +492,17 @@ struct spi_controller { */ int (*setup)(struct spi_device *spi); + /* + * set_cs_timing() method is for SPI controllers that supports + * configuring CS timing. + * + * This hook allows SPI client drivers to request SPI controllers + * to configure specific CS timing through spi_set_cs_timing() after + * spi_setup(). + */ + void (*set_cs_timing)(struct spi_device *spi, u8 setup_clk_cycles, + u8 hold_clk_cycles, u8 inactive_clk_cycles); + /* bidirectional bulk transfers * * + The transfer() method may not sleep; its main role is |