| Message ID | c137d15be96c954f405bda5acaaf730cccc8e601.1499983092.git.lukas@wunner.de (mailing list archive) |
|---|---|
| State | Changes Requested, archived |
| Headers | show |
On Fri, 2017-07-14 at 00:36 +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? */ > Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> (obj is better than o) > Cc: Federico Lorenzi <florenzi@gmail.com> > Reported-by: Leif Liddy <leif.liddy@gmail.com> > Tested-by: Ronald Tschalär <ronald@innovation.ch> > Acked-by: Mark Brown <broonie@kernel.org> > Acked-by: Mika Westerberg <mika.westerberg@linux.intel.com> > Signed-off-by: Lukas Wunner <lukas@wunner.de> > --- > Changes v2 -> v3: > - Check buffer length for extra safety. Rename "o" to "obj", > use 32 bit division to calculate max_speed_hz. (Andy) > > drivers/spi/spi.c | 31 +++++++++++++++++++++++++++++++ > 1 file changed, 31 insertions(+) > > diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c > index 4fcbb0aa71d3..cce133057700 100644 > --- a/drivers/spi/spi.c > +++ b/drivers/spi/spi.c > @@ -1693,6 +1693,35 @@ static void of_register_spi_devices(struct > spi_controller *ctlr) { } > #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 *obj; > + > + if (!is_apple_system) > + return; > + > + if (!acpi_dev_get_property(dev, "spiSclkPeriod", > ACPI_TYPE_BUFFER, &obj) > + && obj->buffer.length >= 4) > + spi->max_speed_hz = NSEC_PER_SEC / *(u32 *)obj- > >buffer.pointer; > + > + if (!acpi_dev_get_property(dev, "spiWordSize", > ACPI_TYPE_BUFFER, &obj) > + && obj->buffer.length == 8) > + spi->bits_per_word = *(u64 *)obj->buffer.pointer; > + > + if (!acpi_dev_get_property(dev, "spiBitOrder", > ACPI_TYPE_BUFFER, &obj) > + && obj->buffer.length == 8 && !*(u64 *)obj- > >buffer.pointer) > + spi->mode |= SPI_LSB_FIRST; > + > + if (!acpi_dev_get_property(dev, "spiSPO", ACPI_TYPE_BUFFER, > &obj) > + && obj->buffer.length == 8 && *(u64 *)obj- > >buffer.pointer) > + spi->mode |= SPI_CPOL; > + > + if (!acpi_dev_get_property(dev, "spiSPH", ACPI_TYPE_BUFFER, > &obj) > + && obj->buffer.length == 8 && *(u64 *)obj- > >buffer.pointer) > + spi->mode |= SPI_CPHA; > +} > + > static int acpi_spi_add_resource(struct acpi_resource *ares, void > *data) > { > struct spi_device *spi = data; > @@ -1766,6 +1795,8 @@ static acpi_status > acpi_register_spi_device(struct spi_controller *ctlr, > acpi_spi_add_resource, spi); > acpi_dev_free_resource_list(&resource_list); > > + acpi_spi_parse_apple_properties(spi); > + > if (ret < 0 || !spi->max_speed_hz) { > spi_dev_put(spi); > return AE_OK;
diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c index 4fcbb0aa71d3..cce133057700 100644 --- a/drivers/spi/spi.c +++ b/drivers/spi/spi.c @@ -1693,6 +1693,35 @@ static void of_register_spi_devices(struct spi_controller *ctlr) { } #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 *obj; + + if (!is_apple_system) + return; + + if (!acpi_dev_get_property(dev, "spiSclkPeriod", ACPI_TYPE_BUFFER, &obj) + && obj->buffer.length >= 4) + spi->max_speed_hz = NSEC_PER_SEC / *(u32 *)obj->buffer.pointer; + + if (!acpi_dev_get_property(dev, "spiWordSize", ACPI_TYPE_BUFFER, &obj) + && obj->buffer.length == 8) + spi->bits_per_word = *(u64 *)obj->buffer.pointer; + + if (!acpi_dev_get_property(dev, "spiBitOrder", ACPI_TYPE_BUFFER, &obj) + && obj->buffer.length == 8 && !*(u64 *)obj->buffer.pointer) + spi->mode |= SPI_LSB_FIRST; + + if (!acpi_dev_get_property(dev, "spiSPO", ACPI_TYPE_BUFFER, &obj) + && obj->buffer.length == 8 && *(u64 *)obj->buffer.pointer) + spi->mode |= SPI_CPOL; + + if (!acpi_dev_get_property(dev, "spiSPH", ACPI_TYPE_BUFFER, &obj) + && obj->buffer.length == 8 && *(u64 *)obj->buffer.pointer) + spi->mode |= SPI_CPHA; +} + static int acpi_spi_add_resource(struct acpi_resource *ares, void *data) { struct spi_device *spi = data; @@ -1766,6 +1795,8 @@ static acpi_status acpi_register_spi_device(struct spi_controller *ctlr, acpi_spi_add_resource, spi); acpi_dev_free_resource_list(&resource_list); + acpi_spi_parse_apple_properties(spi); + if (ret < 0 || !spi->max_speed_hz) { spi_dev_put(spi); return AE_OK;