The Windows Baytrail SPI host controller driver uses 1 as the first (and only) value for ACPI DeviceSelection like can be seen in DSDT taken from Lenovo Thinkpad 10: Device (FPNT) { ... Method (_CRS, 0, NotSerialized) // _CRS: Current Resource Settings { Name (UBUF, ResourceTemplate () { SpiSerialBus (0x0001, // DeviceSelection PolarityLow, FourWireMode, 0x08, ControllerInitiated, 0x007A1200, ClockPolarityLow, ClockPhaseFirst, "\\_SB.SPI1", 0x00, ResourceConsumer,,) This will fail to enumerate in Linux with following error: [ 0.241296] pxa2xx-spi 80860F0E:00: cs1 >= max 1 [ 0.241312] spi_master spi32766: failed to add SPI device VFSI6101:00 from ACPI To make the Linux SPI core successfully enumerate the device we provide a custom version of ->fw_translate_cs() that translates DeviceSelection correctly. Signed-off-by: Mika Westerberg <mika.westerberg@xxxxxxxxxxxxxxx> Reviewed-by: Jarkko Nikula <jarkko.nikula@xxxxxxxxxxxxxxx> --- drivers/spi/spi-pxa2xx.c | 23 +++++++++++++++++++++++ 1 file changed, 23 insertions(+) diff --git a/drivers/spi/spi-pxa2xx.c b/drivers/spi/spi-pxa2xx.c index ab9914ad8365..7c795cfbbf9d 100644 --- a/drivers/spi/spi-pxa2xx.c +++ b/drivers/spi/spi-pxa2xx.c @@ -1438,6 +1438,28 @@ pxa2xx_spi_init_pdata(struct platform_device *pdev) } #endif +static int pxa2xx_spi_fw_translate_cs(struct spi_master *master, unsigned cs) +{ + struct driver_data *drv_data = spi_master_get_devdata(master); + + if (has_acpi_companion(&drv_data->pdev->dev)) { + switch (drv_data->ssp_type) { + /* + * For Atoms the ACPI DeviceSelection used by the Windows + * driver starts from 1 instead of 0 so translate it here + * to match what Linux expects. + */ + case LPSS_BYT_SSP: + return cs - 1; + + default: + break; + } + } + + return cs; +} + static int pxa2xx_spi_probe(struct platform_device *pdev) { struct device *dev = &pdev->dev; @@ -1490,6 +1512,7 @@ static int pxa2xx_spi_probe(struct platform_device *pdev) master->setup = setup; master->transfer_one_message = pxa2xx_spi_transfer_one_message; master->unprepare_transfer_hardware = pxa2xx_spi_unprepare_transfer; + master->fw_translate_cs = pxa2xx_spi_fw_translate_cs; master->auto_runtime_pm = true; drv_data->ssp_type = ssp->type; -- 2.7.0 -- To unsubscribe from this list: send the line "unsubscribe linux-spi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html