On Wed, Jun 28, 2017 at 07:20:19PM +0200, Lukas Wunner wrote: > MacBooks and MacBook Pros introduced since 2015 return empty _CRS data > for SPI slaves, causing device initialization to fail. Most of the > information that would normally be conveyed via _CRS is available > through ACPI device properties instead, so take advantage of them. > > The meaning and appropriate usage of the device properties was reverse > engineered by Ronald Tschalär and carried over from these commits > authored by him: > > https://github.com/cb22/macbook12-spi-driver/commit/9a416d699ef4 > https://github.com/cb22/macbook12-spi-driver/commit/0c34936ed9a1 > > According to Ronald, the device properties have the following meaning: > > spiSclkPeriod /* period in ns */ > spiWordSize /* in number of bits */ > spiBitOrder /* 1 = MSB_FIRST, 0 = LSB_FIRST */ > spiSPO /* clock polarity: 0 = low, 1 = high */ > spiSPH /* clock phase: 0 = first, 1 = second */ > spiCSDelay /* delay between cs and receive on reads in 10 us */ > resetA2RUsec /* active-to-receive delay? */ > resetRecUsec /* receive delay? */ > > Cc: Mark Brown <broonie@xxxxxxxxxx> > Cc: Federico Lorenzi <florenzi@xxxxxxxxx> > Reported-by: Leif Liddy <leif.liddy@xxxxxxxxx> > Tested-by: Ronald Tschalär <ronald@xxxxxxxxxxxxx> > Signed-off-by: Lukas Wunner <lukas@xxxxxxxxx> Acked-by: Mika Westerberg <mika.westerberg@xxxxxxxxxxxxxxx> -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
