On Mon, Feb 8, 2016 at 5:14 PM, Mika Westerberg <mika.westerberg@xxxxxxxxxxxxxxx> wrote: > It turns out that in Windows SPI drivers are responsible for handling ACPI > DeviceSelection field themselves. Furthermore there has been separate > drivers for big core and atom SPI host controllers. For atom (including > Baytrail and Braswell) the driver starts DeviceSelection from 1 instead of 0 > as expected by the Linux SPI core. > > As an example Microsoft Surface 3 has touch screen connected to SPI bus > described in ACPI DSDT like this: > > Scope (_SB.PCI0.SPI1) > { > Device (NTRG) > { > Name (_HID, "MSHW0037") // _HID: Hardware ID > ... > Name (CRS1, ResourceTemplate () > { > SpiSerialBus (0x0001, // SPI DeviceSelection > PolarityLow, FourWireMode, 0x10, > ControllerInitiated, 0x007A1200, ClockPolarityLow, > ClockPhaseFirst, "\\_SB.PCI0.SPI1", > 0x00, ResourceConsumer, , > ) > > This fails to enumerate because ACPI DeviceSelection of 1 is greater than > number of chip selects the driver supports [1]. > > This series adds a new hook to struct spi_master ->fw_translate_cs() that > allows a driver to translate the chip select number from firmware to the > numbering scheme expected by the Linux SPI core and implement that for both > Baytrail and Braswell. > > In addition to that we add support for the second chip select found on > Braswell. > Reviewed-by: Andy Shevchenko <andy.shevchenko@xxxxxxxxx> > This is a second revision of the series. Changes to the v1: > > - Added Jarkko's Reviewed-by > - Use runtime ACPI check in pxa2xx_spi_fw_translate_cs() to prevent build > breakage found by kbuild test robot. > > [1] https://bugzilla.kernel.org/show_bug.cgi?id=104291 > > Mika Westerberg (4): > spi: Let drivers translate ACPI DeviceSelection to suitable Linux chip select > spi: pxa2xx: Translate ACPI DeviceSelection to Linux chip select on Baytrail > spi: pxa2xx: Move chip select control bits into lpss_config structure > spi: pxa2xx: Add support for both chip selects on Intel Braswell > > drivers/spi/spi-pxa2xx.c | 108 ++++++++++++++++++++++++++++++++++----------- > drivers/spi/spi.c | 19 +++++++- > include/linux/pxa2xx_ssp.h | 1 + > include/linux/spi/spi.h | 5 +++ > 4 files changed, 107 insertions(+), 26 deletions(-) > > -- > 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 -- With Best Regards, Andy Shevchenko -- 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