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Diffstat (limited to 'include/linux/spi/spi.h')
-rw-r--r--include/linux/spi/spi.h13
1 files changed, 12 insertions, 1 deletions
diff --git a/include/linux/spi/spi.h b/include/linux/spi/spi.h
index 68bb1c501d0..a0faa18f7b1 100644
--- a/include/linux/spi/spi.h
+++ b/include/linux/spi/spi.h
@@ -204,6 +204,7 @@ static inline void spi_unregister_driver(struct spi_driver *sdrv)
* SPI slaves, and are numbered from zero to num_chipselects.
* each slave has a chipselect signal, but it's common that not
* every chipselect is connected to a slave.
+ * @dma_alignment: SPI controller constraint on DMA buffers alignment.
* @setup: updates the device mode and clocking records used by a
* device's SPI controller; protocol code may call this. This
* must fail if an unrecognized or unsupported mode is requested.
@@ -239,7 +240,17 @@ struct spi_master {
*/
u16 num_chipselect;
- /* setup mode and clock, etc (spi driver may call many times) */
+ /* some SPI controllers pose alignment requirements on DMAable
+ * buffers; let protocol drivers know about these requirements.
+ */
+ u16 dma_alignment;
+
+ /* Setup mode and clock, etc (spi driver may call many times).
+ *
+ * IMPORTANT: this may be called when transfers to another
+ * device are active. DO NOT UPDATE SHARED REGISTERS in ways
+ * which could break those transfers.
+ */
int (*setup)(struct spi_device *spi);
/* bidirectional bulk transfers