diff mbox

[3/3] spi: Use Apple device properties in absence of ACPI resources

Message ID 19c49c0351e452bff28199abcc6b3a11ec6949b2.1498044532.git.lukas@wunner.de (mailing list archive)
State Changes Requested, archived
Headers show

Commit Message

Lukas Wunner June 21, 2017, 6:05 p.m. UTC
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>
Cc: Ronald Tschalär <ronald@innovation.ch>
Signed-off-by: Lukas Wunner <lukas@wunner.de>
---
 drivers/spi/spi.c | 30 ++++++++++++++++++++++++++++++
 1 file changed, 30 insertions(+)

Comments

Mika Westerberg June 22, 2017, 8:10 a.m. UTC | #1
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@kernel.org>
> Cc: Federico Lorenzi <florenzi@gmail.com>
> Cc: Ronald Tschalär <ronald@innovation.ch>
> Signed-off-by: Lukas Wunner <lukas@wunner.de>
> ---
>  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);
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Lukas Wunner June 22, 2017, 8:44 a.m. UTC | #2
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@kernel.org>
> > Cc: Federico Lorenzi <florenzi@gmail.com>
> > Cc: Ronald Tschalär <ronald@innovation.ch>
> > Signed-off-by: Lukas Wunner <lukas@wunner.de>
> > ---
> >  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
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Mark Brown June 22, 2017, 9:28 a.m. UTC | #3
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

Please delete unneeded context from mails when replying.  Doing this
makes it much easier to find your reply in the message, helping ensure
it won't be missed by people scrolling through the irrelevant quoted
material.
diff mbox

Patch

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);
+
 	if (ret < 0 || !spi->max_speed_hz) {
 		spi_dev_put(spi);
 		return AE_OK;