| Message ID | bca7fb9e406bbfa9ee7e8457cacd34418ef689be.1498636759.git.lukas@wunner.de (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
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. Acked-by: Mark Brown <broonie@kernel.org>
On Wed, Jun 28, 2017 at 8:20 PM, Lukas Wunner <lukas@wunner.de> 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. > spiSclkPeriod /* period in ns */ > +#include <linux/math64.h> > + if (!acpi_dev_get_property(dev, "spiSclkPeriod", ACPI_TYPE_BUFFER, &o)) > + spi->max_speed_hz = div64_u64(NSEC_PER_SEC, > + *(u64 *)o->buffer.pointer); Why do you need 64 bit division here? It's obviously 32. It makes nonsense to have variable more than NSEC_PER_SEC (if one paranoid enough it could be checked). > + 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) In such cases I would prefer the notation like ret = func(); if (!ret && ...) ... Also we usually name object variable as obj, though it's minor here. > + spi->mode |= SPI_LSB_FIRST;
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@kernel.org> > Cc: Federico Lorenzi <florenzi@gmail.com> > Reported-by: Leif Liddy <leif.liddy@gmail.com> > Tested-by: Ronald Tschalär <ronald@innovation.ch> > Signed-off-by: Lukas Wunner <lukas@wunner.de> Acked-by: Mika Westerberg <mika.westerberg@linux.intel.com> -- To unsubscribe from this list: send the line "unsubscribe linux-spi" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c index 89254a55eb2e..51b7bdf841e4 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 +1687,32 @@ 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 (!IS_ENABLED(CONFIG_X86) || !dmi_match(DMI_SYS_VENDOR, "Apple Inc.")) + return; + + 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 +1786,8 @@ static acpi_status acpi_register_spi_device(struct spi_master *master, 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;