On Thu, Jun 22, 2017 at 11:10:48AM +0300, Mika Westerberg wrote: > On Wed, Jun 21, 2017 at 08:05:53PM +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> > > Cc: Ronald Tschalär <ronald@xxxxxxxxxxxxx> > > Signed-off-by: Lukas Wunner <lukas@xxxxxxxxx> > > --- > > drivers/spi/spi.c | 30 ++++++++++++++++++++++++++++++ > > 1 file changed, 30 insertions(+) > > > > diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c > > index 89254a55eb2e..a4066b75d02b 100644 > > --- a/drivers/spi/spi.c > > +++ b/drivers/spi/spi.c > > @@ -21,6 +21,8 @@ > > #include <linux/cache.h> > > #include <linux/dma-mapping.h> > > #include <linux/dmaengine.h> > > +#include <linux/dmi.h> > > +#include <linux/math64.h> > > #include <linux/mutex.h> > > #include <linux/of_device.h> > > #include <linux/of_irq.h> > > @@ -1685,6 +1687,29 @@ static void of_register_spi_devices(struct spi_master *master) { } > > #endif > > > > #ifdef CONFIG_ACPI > > +static void acpi_spi_parse_apple_properties(struct spi_device *spi) > > +{ > > + struct acpi_device *dev = ACPI_COMPANION(&spi->dev); > > + const union acpi_object *o; > > + > > + if (!acpi_dev_get_property(dev, "spiSclkPeriod", ACPI_TYPE_BUFFER, &o)) > > + spi->max_speed_hz = div64_u64(NSEC_PER_SEC, > > + *(u64 *)o->buffer.pointer); > > + > > + if (!acpi_dev_get_property(dev, "spiWordSize", ACPI_TYPE_BUFFER, &o)) > > + spi->bits_per_word = *(u64 *)o->buffer.pointer; > > + > > + if (!acpi_dev_get_property(dev, "spiBitOrder", ACPI_TYPE_BUFFER, &o) && > > + !*(u64 *)o->buffer.pointer) > > + spi->mode |= SPI_LSB_FIRST; > > + if (!acpi_dev_get_property(dev, "spiSPO", ACPI_TYPE_BUFFER, &o) && > > + *(u64 *)o->buffer.pointer) > > + spi->mode |= SPI_CPOL; > > + if (!acpi_dev_get_property(dev, "spiSPH", ACPI_TYPE_BUFFER, &o) && > > + *(u64 *)o->buffer.pointer) > > + spi->mode |= SPI_CPHA; > > +} > > + > > static int acpi_spi_add_resource(struct acpi_resource *ares, void *data) > > { > > struct spi_device *spi = data; > > @@ -1758,6 +1783,11 @@ static acpi_status acpi_register_spi_device(struct spi_master *master, > > acpi_spi_add_resource, spi); > > acpi_dev_free_resource_list(&resource_list); > > > > + /* Zero ACPI resources? Try Apple device properties instead. */ > > + if (!ret && IS_ENABLED(CONFIG_X86) && > > + dmi_match(DMI_SYS_VENDOR, "Apple Inc.")) > > + acpi_spi_parse_apple_properties(spi); > > Same comment here, move the conditionals to > acpi_spi_parse_apple_properties() and then do > > if (!ret) > acpi_spi_parse_apple_properties(spi); Good idea. Actually, I think I'll just call the function unconditionally to let it augment or take precedence over _CRS data. Thanks! Lukas -- 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
