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>
---
drivers/spi/spi-pxa2xx.c | 20 ++++++++++++++++++++
1 file changed, 20 insertions(+)
diff --git a/drivers/spi/spi-pxa2xx.c b/drivers/spi/spi-pxa2xx.c
index ab9914ad8365..baa98365a490 100644
--- a/drivers/spi/spi-pxa2xx.c
+++ b/drivers/spi/spi-pxa2xx.c
@@ -1328,11 +1328,30 @@ static int pxa2xx_spi_get_port_id(struct acpi_device *adev)
port_id = devid;
return port_id;
}
+
+static int pxa2xx_spi_fw_translate_cs(struct spi_master *master, unsigned cs)
+{
+ struct driver_data *drv_data = spi_master_get_devdata(master);
+
+ switch (drv_data->ssp_type) {
+ /*
+ * For Atoms the Windows driver starts enumerating chip selects
+ * from 1 instead of 0 so translate it here to match what Linux
+ * expects.
+ */
+ case LPSS_BYT_SSP:
+ return cs - 1;
+
+ default:
+ return cs;
+ }
+}
#else /* !CONFIG_ACPI */
static int pxa2xx_spi_get_port_id(struct acpi_device *adev)
{
return -1;
}
+#define pxa2xx_spi_fw_translate_cs NULL
#endif
/*
@@ -1490,6 +1509,7 @@ 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.rc3
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