diff options
| -rw-r--r-- | drivers/spi/spi.c | 19 | ||||
| -rw-r--r-- | include/linux/spi/spi.h | 5 |
2 files changed, 23 insertions, 1 deletions
diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c index 47eff8012a77..2c0c26a57f03 100644 --- a/drivers/spi/spi.c +++ b/drivers/spi/spi.c @@ -1581,13 +1581,30 @@ static void of_register_spi_devices(struct spi_master *master) { } static int acpi_spi_add_resource(struct acpi_resource *ares, void *data) { struct spi_device *spi = data; + struct spi_master *master = spi->master; if (ares->type == ACPI_RESOURCE_TYPE_SERIAL_BUS) { struct acpi_resource_spi_serialbus *sb; sb = &ares->data.spi_serial_bus; if (sb->type == ACPI_RESOURCE_SERIAL_TYPE_SPI) { - spi->chip_select = sb->device_selection; + /* + * ACPI DeviceSelection numbering is handled by the + * host controller driver in Windows and can vary + * from driver to driver. In Linux we always expect + * 0 .. max - 1 so we need to ask the driver to + * translate between the two schemes. + */ + if (master->fw_translate_cs) { + int cs = master->fw_translate_cs(master, + sb->device_selection); + if (cs < 0) + return cs; + spi->chip_select = cs; + } else { + spi->chip_select = sb->device_selection; + } + spi->max_speed_hz = sb->connection_speed; if (sb->clock_phase == ACPI_SPI_SECOND_PHASE) diff --git a/include/linux/spi/spi.h b/include/linux/spi/spi.h index 53be3a4c60cb..8a25e6c2fb56 100644 --- a/include/linux/spi/spi.h +++ b/include/linux/spi/spi.h @@ -369,6 +369,9 @@ static inline void spi_unregister_driver(struct spi_driver *sdrv) * @dma_rx: DMA receive channel * @dummy_rx: dummy receive buffer for full-duplex devices * @dummy_tx: dummy transmit buffer for full-duplex devices + * @fw_translate_cs: If the boot firmware uses different numbering scheme + * what Linux expects, this optional hook can be used to translate + * between the two. * * Each SPI master controller can communicate with one or more @spi_device * children. These make a small bus, sharing MOSI, MISO and SCK signals @@ -537,6 +540,8 @@ struct spi_master { /* dummy data for full duplex devices */ void *dummy_rx; void *dummy_tx; + + int (*fw_translate_cs)(struct spi_master *master, unsigned cs); }; static inline void *spi_master_get_devdata(struct spi_master *master) |