Hi Phil,
On 8/12/25 11:04, Philippe Mathieu-Daudé wrote:
> A SPI transaction consists of shifting bit in sync with the CLK
> line, writing on the MOSI (output) line / and reading MISO (input)
> line.
>
> Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
> ---
> include/hw/ssi/ssi.h | 14 ++++++++++++++
> 1 file changed, 14 insertions(+)
>
> diff --git a/include/hw/ssi/ssi.h b/include/hw/ssi/ssi.h
> index 3cdcbd53904..2ad8033d8f5 100644
> --- a/include/hw/ssi/ssi.h
> +++ b/include/hw/ssi/ssi.h
> @@ -38,6 +38,7 @@ struct SSIPeripheralClass {
>
> /* if you have standard or no CS behaviour, just override transfer.
> * This is called when the device cs is active (true by default).
> + * See ssi_transfer().
> */
> uint32_t (*transfer)(SSIPeripheral *dev, uint32_t val);
> /* called when the CS line changes. Optional, devices only need to implement
> @@ -52,6 +53,7 @@ struct SSIPeripheralClass {
> * of the CS behaviour at the device level. transfer, set_cs, and
> * cs_polarity are unused if this is overwritten. Transfer_raw will
> * always be called for the device for every txrx access to the parent bus
> + * See ssi_transfer().
> */
> uint32_t (*transfer_raw)(SSIPeripheral *dev, uint32_t val);
> };
> @@ -110,6 +112,18 @@ bool ssi_realize_and_unref(DeviceState *dev, SSIBus *bus, Error **errp);
> /* Master interface. */
> SSIBus *ssi_create_bus(DeviceState *parent, const char *name);
>
> +/**
> + * Transfer a word on a SSI bus
> + * @bus: SSI bus
> + * @val: word to transmit
> + *
> + * At the same time, read a word and write the @val one on the SSI bus.
> + *
> + * SSI words might vary between 8 and 32 bits. The same number of bits
> + * written is received.
> + *
> + * Return: word value received
> + */
> uint32_t ssi_transfer(SSIBus *bus, uint32_t val);
>
> DeviceState *ssi_get_cs(SSIBus *bus, uint8_t cs_index);
Reviewed-by: Gustavo Romero <gustavo.romero@linaro.org>
Cheers,
Gustavo