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spi: Clean up SPI driver interface

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1. Add new structure spi_ctrlr_buses that allows platform to define a
mapping from SPI controller to buses managed by the controller.
2. Provide weak implementations of spi_init and spi_setup_slave that
will be used by platforms using the new interface.

BUG=chrome-os-partner:59832
BRANCH=None
TEST=Compiles successfully

Change-Id: Ia6f47941b786299f4d823895898ffb1b36e02f73
Signed-off-by: Furquan Shaikh <furquan@chromium.org>
Reviewed-on: https://review.coreboot.org/17561
Tested-by: build bot (Jenkins)
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
This commit is contained in:
Furquan Shaikh
2016-12-01 07:25:31 -08:00
committed by Martin Roth
parent 2dc8b77d0e
commit b5d41cb063
2 changed files with 54 additions and 0 deletions
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35
src/drivers/spi/spi-generic.c
View File

@ -41,3 +41,38 @@ int spi_xfer(const struct spi_slave *slave, const void *dout, size_t bytesout,
return -1;
}
void __attribute__((weak)) spi_init(void)
{
/* Default weak implementation - do nothing. */
}
const struct spi_ctrlr_buses spi_ctrlr_bus_map[0] __attribute__((weak));
const size_t spi_ctrlr_bus_map_count __attribute__((weak));
int __attribute__((weak)) spi_setup_slave(unsigned int bus, unsigned int cs,
struct spi_slave *slave)
{
size_t i;
memset(slave, 0, sizeof(*slave));
for (i = 0; i < spi_ctrlr_bus_map_count; i++) {
if ((spi_ctrlr_bus_map[i].bus_start <= bus) &&
(spi_ctrlr_bus_map[i].bus_end >= bus)) {
slave->ctrlr = spi_ctrlr_bus_map[i].ctrlr;
break;
}
}
if (slave->ctrlr == NULL)
return -1;
slave->bus = bus;
slave->cs = cs;
if (slave->ctrlr->setup)
return slave->ctrlr->setup(slave);
return 0;
}

19
src/include/spi-generic.h
View File

@ -42,14 +42,33 @@ struct spi_slave {
* claim_bus: Claim SPI bus and prepare for communication.
* release_bus: Release SPI bus.
* xfer: SPI transfer
* setup: Setup given SPI device bus.
*/
struct spi_ctrlr {
int (*claim_bus)(const struct spi_slave *slave);
void (*release_bus)(const struct spi_slave *slave);
int (*xfer)(const struct spi_slave *slave, const void *dout,
size_t bytesout, void *din, size_t bytesin);
int (*setup)(const struct spi_slave *slave);
};
/*-----------------------------------------------------------------------
* Structure defining mapping of SPI buses to controller.
*
* ctrlr: Pointer to controller structure managing the given SPI buses.
* bus_start: Start bus number managed by the controller.
* bus_end: End bus number manager by the controller.
*/
struct spi_ctrlr_buses {
const struct spi_ctrlr *ctrlr;
unsigned int bus_start;
unsigned int bus_end;
};
/* Mapping of SPI buses to controllers - should be defined by platform. */
extern const struct spi_ctrlr_buses spi_ctrlr_bus_map[];
extern const size_t spi_ctrlr_bus_map_count;
/*-----------------------------------------------------------------------
* Initialization, must be called once on start up.
*