Re: [PATCH 3/4] mfd: dln2: add support for ACPI
On Friday, January 23, 2015 08:47:58 AM Octavian Purdila wrote: On Fri, Jan 23, 2015 at 12:09 AM, Rafael J. Wysocki r...@rjwysocki.net wrote: On Thursday, January 22, 2015 12:13:13 PM Octavian Purdila wrote: On Thu, Jan 22, 2015 at 4:00 AM, Rafael J. Wysocki r...@rjwysocki.net wrote: snip The idea here is to set the companion for the MFD sub-devices. Mika's commit mfd: Add ACPI support propagates the parent's companion to the MFD sub-devices, so it is sufficient to set the ACPI companion to the USB device. For the USB device itself you'll then end up with an incomplete binding (you can't get back to the USB device from the ACPI object), so no, it isn't sufficient. Then, the companion will be propagated to the sub-devices after which acpi_bind_one() will be called for the sub-devices from mfd_add_devices (via platform_device_add - device_add - platform_notify). In fact, your use case doesn't seem to cover any of the use cases that the Mika's commit addressed. Namely, your parent device doesn't have an ACPI companion to start with and you want your MFD cells to be bound to the DLN2000 thing. That's why you're setting the ACPI companion for the USB device, isn't it? It is true that the USB dev will have its ACPI companion set without having acpi_bind_one called but I do not see any harm in that. Even though acpi_unbind_one() is called it will not find the USB dev on the physical node list so no put_device() imbalance is caused. Well, there are places where it matters. Some links in sysfs will be missing for one example. Also please see the changelog of commit 52870786ff5d (ACPI: Use ACPI companion to match only the first physical device). Bottom line: You really should be using acpi_bind_one() here and acpi_unbind_one() on disconnect if you have to. OK, I understand now. And no, Let's come up with a patch that sort of works, throw it at the maintainers and see what happens is not an acceptable approach, sorry. This patch is based on your feedback of the previous RFC patch set: Oh, is it? I can't recall advising you to use request_firmware() for uploading ACPI tables or some other questionable things that the patch is doing. And if it still was an RFC, that wouldn't be a problem, but if you just send non-RFC patches out, that means you want people to merge them. This is bad if the patches in question are not in a good enough shape and this one isn't. Yes, this should have been tagged with RFC, sorry about that. Now, why is this a bad idea to load ACPI tables from a driver using request_firmware()? Because those tables are not device firmare. They are not firmware that you load into a device to make it work (which then works with all instances of the given hardware), they are part of system configuration information and have to match what's there in the system. For instance, if you ship your example SSDT with a general-purpose distro, it may just not match the hardware configuration of systems that people will try to use it with. So, while it is sort of OK to look up DLN2000 and bind the USB device to that by hand (although this looks ugly to me), it is not OK to load a random custom SSDT if it is missing. We need to add a generic mechanism for loading custom SSDTs not present in the firmware image and maybe even to load them on demand, but that cannot happen in an ad-hoc way. So the entire table loading-unloading code in your patch can go away for now and you need to fail probing if the DLN2000 ACPI object is not present. That sounds interesting, I like the idea of a generic mechanism for loading custom SSDTs. Do you have any initial thoughts/pointers for starting that? Thoughts - yes, pointers - not so much. I'll get back to you when I'm done with the e-mail backlog from the last few weeks. Thanks for the review and feedback. No problem. -- I speak only for myself. Rafael J. Wysocki, Intel Open Source Technology Center. -- To unsubscribe from this list: send the line unsubscribe linux-usb in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCH 3/4] mfd: dln2: add support for ACPI
On Thu, Jan 22, 2015 at 4:00 AM, Rafael J. Wysocki r...@rjwysocki.net wrote: Hi Rafael, Thanks for reviewing the patch. On Tuesday, December 16, 2014 06:12:32 PM Octavian Purdila wrote: This patch adds support to load a custom ACPI table that describes devices connected via the DLN2 USB to I2C/SPI/GPIO bridge. The ACPI table can be loaded either externally (from QEMU or with CONFIG_ACPI_CUSTOM_DSDT) or it can be loaded as firmware file with the name dln2.aml. The driver looks for an ACPI device entry with _HID set to DLN2 and makes it the ACPI companion for DLN2 USB sub-drivers. Signed-off-by: Octavian Purdila octavian.purd...@intel.com --- Documentation/acpi/dln2-acpi.txt | 62 ++ drivers/mfd/dln2.c | 134 +++ 2 files changed, 196 insertions(+) create mode 100644 Documentation/acpi/dln2-acpi.txt diff --git a/Documentation/acpi/dln2-acpi.txt b/Documentation/acpi/dln2-acpi.txt new file mode 100644 index 000..d76605f --- /dev/null +++ b/Documentation/acpi/dln2-acpi.txt @@ -0,0 +1,62 @@ +Diolan DLN2 custom APCI table + +The Diolan DLN2 is an USB to I2C/SPI/GPIO bridge and as such it can be used to +connect to various I2C or SPI devices. Because these busses lack an enumeration +protocol, the driver obtains various information about the device (such as I2C +address and GPIO pins) from either ACPI or device tree. + +To allow enumerating devices and their properties via ACPI, the Diolan +driver looks for an ACPI tree with the root _HID set to DLN2. If +it finds such an ACPI object it will set the ACPI companion to the +DLN2 MFD driver and from their it will be propagated to all its +sub-devices (I2C, GPIO, SPI). + +The user can either load the custom DSDT table with three methods: s/DSDT/ACPI/ OK. + +1. Via QEMU (see -acpitable) + +2. Via the CONFIG_ACPI_CUSTOM_DSDT kernel config option (see +Documentation/acpi/dsdt-override.txt) + +3. By placing the custom DSDT in the firmware paths in a file name +dln2.aml. Surely SSDT? Correct. snip diff --git a/drivers/mfd/dln2.c b/drivers/mfd/dln2.c index f9c4a0b..93f6d1d 100644 --- a/drivers/mfd/dln2.c +++ b/drivers/mfd/dln2.c @@ -23,6 +23,8 @@ #include linux/mfd/core.h #include linux/mfd/dln2.h #include linux/rculist.h +#include linux/acpi.h +#include linux/firmware.h OK, so correct me if I'm wrong. When the (USB) dnl2 device is probed, it is supposed to find an ACPI companion for itself and if it's not there, the driver will try to load a custom SSDT from a firmware blob in the hope that the companion will be there? So if I'm not wrong, why is this not broken? It is not sufficient to call ACPI_COMPANION_SET(dev, ai-dev) to set the device's companion. acpi_bind_one() needs to be run in addition to that, but acpi_bind_one() is not to be called from drivers. It is called by the core automatically during device registration and ACPI_COMPANION_SET() is to be used *before* that, not after. So if I'm not missing anything, the design here is entirely backwards and we need to talk about how to implement it correctly at the design level in the first place. The idea here is to set the companion for the MFD sub-devices. Mika's commit mfd: Add ACPI support propagates the parent's companion to the MFD sub-devices, so it is sufficient to set the ACPI companion to the USB device. Then, the companion will be propagated to the sub-devices after which acpi_bind_one() will be called for the sub-devices from mfd_add_devices (via platform_device_add - device_add - platform_notify). It is true that the USB dev will have its ACPI companion set without having acpi_bind_one called but I do not see any harm in that. Even though acpi_unbind_one() is called it will not find the USB dev on the physical node list so no put_device() imbalance is caused. And no, Let's come up with a patch that sort of works, throw it at the maintainers and see what happens is not an acceptable approach, sorry. This patch is based on your feedback of the previous RFC patch set: On Thu, Dec 11, 2014 at 11:44 PM, Rafael J. Wysocki r...@rjwysocki.net wrote: it seems to me that it would be much more straightforward to check for the existence of the DLN2 device when you are about to register DLN2 USB sub-devices and set it directly as an ACPI companion for them if present. -- To unsubscribe from this list: send the line unsubscribe linux-usb in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCH 3/4] mfd: dln2: add support for ACPI
On Thursday, January 22, 2015 12:13:13 PM Octavian Purdila wrote: On Thu, Jan 22, 2015 at 4:00 AM, Rafael J. Wysocki r...@rjwysocki.net wrote: Hi Rafael, Thanks for reviewing the patch. On Tuesday, December 16, 2014 06:12:32 PM Octavian Purdila wrote: This patch adds support to load a custom ACPI table that describes devices connected via the DLN2 USB to I2C/SPI/GPIO bridge. The ACPI table can be loaded either externally (from QEMU or with CONFIG_ACPI_CUSTOM_DSDT) or it can be loaded as firmware file with the name dln2.aml. The driver looks for an ACPI device entry with _HID set to DLN2 and makes it the ACPI companion for DLN2 USB sub-drivers. Signed-off-by: Octavian Purdila octavian.purd...@intel.com --- Documentation/acpi/dln2-acpi.txt | 62 ++ drivers/mfd/dln2.c | 134 +++ 2 files changed, 196 insertions(+) create mode 100644 Documentation/acpi/dln2-acpi.txt diff --git a/Documentation/acpi/dln2-acpi.txt b/Documentation/acpi/dln2-acpi.txt new file mode 100644 index 000..d76605f --- /dev/null +++ b/Documentation/acpi/dln2-acpi.txt @@ -0,0 +1,62 @@ +Diolan DLN2 custom APCI table + +The Diolan DLN2 is an USB to I2C/SPI/GPIO bridge and as such it can be used to +connect to various I2C or SPI devices. Because these busses lack an enumeration +protocol, the driver obtains various information about the device (such as I2C +address and GPIO pins) from either ACPI or device tree. + +To allow enumerating devices and their properties via ACPI, the Diolan +driver looks for an ACPI tree with the root _HID set to DLN2. If +it finds such an ACPI object it will set the ACPI companion to the +DLN2 MFD driver and from their it will be propagated to all its +sub-devices (I2C, GPIO, SPI). + +The user can either load the custom DSDT table with three methods: s/DSDT/ACPI/ OK. + +1. Via QEMU (see -acpitable) + +2. Via the CONFIG_ACPI_CUSTOM_DSDT kernel config option (see +Documentation/acpi/dsdt-override.txt) + +3. By placing the custom DSDT in the firmware paths in a file name +dln2.aml. Surely SSDT? Correct. snip diff --git a/drivers/mfd/dln2.c b/drivers/mfd/dln2.c index f9c4a0b..93f6d1d 100644 --- a/drivers/mfd/dln2.c +++ b/drivers/mfd/dln2.c @@ -23,6 +23,8 @@ #include linux/mfd/core.h #include linux/mfd/dln2.h #include linux/rculist.h +#include linux/acpi.h +#include linux/firmware.h OK, so correct me if I'm wrong. When the (USB) dnl2 device is probed, it is supposed to find an ACPI companion for itself and if it's not there, the driver will try to load a custom SSDT from a firmware blob in the hope that the companion will be there? So if I'm not wrong, why is this not broken? It is not sufficient to call ACPI_COMPANION_SET(dev, ai-dev) to set the device's companion. acpi_bind_one() needs to be run in addition to that, but acpi_bind_one() is not to be called from drivers. It is called by the core automatically during device registration and ACPI_COMPANION_SET() is to be used *before* that, not after. So if I'm not missing anything, the design here is entirely backwards and we need to talk about how to implement it correctly at the design level in the first place. The idea here is to set the companion for the MFD sub-devices. Mika's commit mfd: Add ACPI support propagates the parent's companion to the MFD sub-devices, so it is sufficient to set the ACPI companion to the USB device. For the USB device itself you'll then end up with an incomplete binding (you can't get back to the USB device from the ACPI object), so no, it isn't sufficient. Then, the companion will be propagated to the sub-devices after which acpi_bind_one() will be called for the sub-devices from mfd_add_devices (via platform_device_add - device_add - platform_notify). In fact, your use case doesn't seem to cover any of the use cases that the Mika's commit addressed. Namely, your parent device doesn't have an ACPI companion to start with and you want your MFD cells to be bound to the DLN2000 thing. That's why you're setting the ACPI companion for the USB device, isn't it? It is true that the USB dev will have its ACPI companion set without having acpi_bind_one called but I do not see any harm in that. Even though acpi_unbind_one() is called it will not find the USB dev on the physical node list so no put_device() imbalance is caused. Well, there are places where it matters. Some links in sysfs will be missing for one example. Also please see the changelog of commit 52870786ff5d (ACPI: Use ACPI companion to match only the first physical device). Bottom line: You really should be using acpi_bind_one() here and acpi_unbind_one() on disconnect if you have to. And no, Let's come
Re: [PATCH 3/4] mfd: dln2: add support for ACPI
On Fri, Jan 23, 2015 at 12:09 AM, Rafael J. Wysocki r...@rjwysocki.net wrote: On Thursday, January 22, 2015 12:13:13 PM Octavian Purdila wrote: On Thu, Jan 22, 2015 at 4:00 AM, Rafael J. Wysocki r...@rjwysocki.net wrote: snip The idea here is to set the companion for the MFD sub-devices. Mika's commit mfd: Add ACPI support propagates the parent's companion to the MFD sub-devices, so it is sufficient to set the ACPI companion to the USB device. For the USB device itself you'll then end up with an incomplete binding (you can't get back to the USB device from the ACPI object), so no, it isn't sufficient. Then, the companion will be propagated to the sub-devices after which acpi_bind_one() will be called for the sub-devices from mfd_add_devices (via platform_device_add - device_add - platform_notify). In fact, your use case doesn't seem to cover any of the use cases that the Mika's commit addressed. Namely, your parent device doesn't have an ACPI companion to start with and you want your MFD cells to be bound to the DLN2000 thing. That's why you're setting the ACPI companion for the USB device, isn't it? It is true that the USB dev will have its ACPI companion set without having acpi_bind_one called but I do not see any harm in that. Even though acpi_unbind_one() is called it will not find the USB dev on the physical node list so no put_device() imbalance is caused. Well, there are places where it matters. Some links in sysfs will be missing for one example. Also please see the changelog of commit 52870786ff5d (ACPI: Use ACPI companion to match only the first physical device). Bottom line: You really should be using acpi_bind_one() here and acpi_unbind_one() on disconnect if you have to. OK, I understand now. And no, Let's come up with a patch that sort of works, throw it at the maintainers and see what happens is not an acceptable approach, sorry. This patch is based on your feedback of the previous RFC patch set: Oh, is it? I can't recall advising you to use request_firmware() for uploading ACPI tables or some other questionable things that the patch is doing. And if it still was an RFC, that wouldn't be a problem, but if you just send non-RFC patches out, that means you want people to merge them. This is bad if the patches in question are not in a good enough shape and this one isn't. Yes, this should have been tagged with RFC, sorry about that. Now, why is this a bad idea to load ACPI tables from a driver using request_firmware()? Because those tables are not device firmare. They are not firmware that you load into a device to make it work (which then works with all instances of the given hardware), they are part of system configuration information and have to match what's there in the system. For instance, if you ship your example SSDT with a general-purpose distro, it may just not match the hardware configuration of systems that people will try to use it with. So, while it is sort of OK to look up DLN2000 and bind the USB device to that by hand (although this looks ugly to me), it is not OK to load a random custom SSDT if it is missing. We need to add a generic mechanism for loading custom SSDTs not present in the firmware image and maybe even to load them on demand, but that cannot happen in an ad-hoc way. So the entire table loading-unloading code in your patch can go away for now and you need to fail probing if the DLN2000 ACPI object is not present. That sounds interesting, I like the idea of a generic mechanism for loading custom SSDTs. Do you have any initial thoughts/pointers for starting that? Thanks for the review and feedback. -- To unsubscribe from this list: send the line unsubscribe linux-usb in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCH 3/4] mfd: dln2: add support for ACPI
On Tuesday, December 16, 2014 06:12:32 PM Octavian Purdila wrote:
This patch adds support to load a custom ACPI table that describes
devices connected via the DLN2 USB to I2C/SPI/GPIO bridge.
The ACPI table can be loaded either externally (from QEMU or with
CONFIG_ACPI_CUSTOM_DSDT) or it can be loaded as firmware file with the
name dln2.aml. The driver looks for an ACPI device entry with _HID set
to DLN2 and makes it the ACPI companion for DLN2 USB
sub-drivers.
Signed-off-by: Octavian Purdila octavian.purd...@intel.com
---
Documentation/acpi/dln2-acpi.txt | 62 ++
drivers/mfd/dln2.c | 134
+++
2 files changed, 196 insertions(+)
create mode 100644 Documentation/acpi/dln2-acpi.txt
diff --git a/Documentation/acpi/dln2-acpi.txt
b/Documentation/acpi/dln2-acpi.txt
new file mode 100644
index 000..d76605f
--- /dev/null
+++ b/Documentation/acpi/dln2-acpi.txt
@@ -0,0 +1,62 @@
+Diolan DLN2 custom APCI table
+
+The Diolan DLN2 is an USB to I2C/SPI/GPIO bridge and as such it can be used
to
+connect to various I2C or SPI devices. Because these busses lack an
enumeration
+protocol, the driver obtains various information about the device (such as
I2C
+address and GPIO pins) from either ACPI or device tree.
+
+To allow enumerating devices and their properties via ACPI, the Diolan
+driver looks for an ACPI tree with the root _HID set to DLN2. If
+it finds such an ACPI object it will set the ACPI companion to the
+DLN2 MFD driver and from their it will be propagated to all its
+sub-devices (I2C, GPIO, SPI).
+
+The user can either load the custom DSDT table with three methods:
s/DSDT/ACPI/
+
+1. Via QEMU (see -acpitable)
+
+2. Via the CONFIG_ACPI_CUSTOM_DSDT kernel config option (see
+Documentation/acpi/dsdt-override.txt)
+
+3. By placing the custom DSDT in the firmware paths in a file name
+dln2.aml.
Surely SSDT?
+
+Here is an example ACPI table that enumerates a BMC150 accelerometer
+and defines its I2C address and GPIO pin used as an interrupt source:
+
+DefinitionBlock (ssdt.aml, SSDT, 1, INTEL , CpuDptf, 0x0003)
+{
+ Device (DLN0)
+ {
+ Name (_ADR, Zero)
+ Name (_HID, DLN2000)
+
+ Device (STAC)
+ {
+ Name (_ADR, Zero)
+ Name (_HID, BMC150A)
+ Name (_CID, INTACCL)
+ Name (_UID, One)
+
+ Method (_CRS, 0, Serialized)
+ {
+ Name (RBUF, ResourceTemplate ()
+ {
+ I2cSerialBus (0x0010,
ControllerInitiated, 0x00061A80,
+ AddressingMode7Bit,
\\DLN0,
+ 0x00, ResourceConsumer, ,)
+
+ GpioInt (Level, ActiveHigh, Exclusive,
PullDown, 0x,
+ \\DLN0, 0x00,
ResourceConsumer, , )
+ { // Pin list
+ 0
+ }
+ })
+ Return (RBUF)
+}
+ }
+ }
+}
+
+The resources defined in the devices under the DLN0 are those
+supported by the I2C, GPIO and SPI sub-systems.
diff --git a/drivers/mfd/dln2.c b/drivers/mfd/dln2.c
index f9c4a0b..93f6d1d 100644
--- a/drivers/mfd/dln2.c
+++ b/drivers/mfd/dln2.c
@@ -23,6 +23,8 @@
#include linux/mfd/core.h
#include linux/mfd/dln2.h
#include linux/rculist.h
+#include linux/acpi.h
+#include linux/firmware.h
OK, so correct me if I'm wrong.
When the (USB) dnl2 device is probed, it is supposed to find an ACPI companion
for itself and if it's not there, the driver will try to load a custom SSDT from
a firmware blob in the hope that the companion will be there?
So if I'm not wrong, why is this not broken?
It is not sufficient to call ACPI_COMPANION_SET(dev, ai-dev) to set the
device's
companion. acpi_bind_one() needs to be run in addition to that, but
acpi_bind_one()
is not to be called from drivers. It is called by the core automatically during
device registration and ACPI_COMPANION_SET() is to be used *before* that, not
after.
So if I'm not missing anything, the design here is entirely backwards and we
need to talk about how to implement it correctly at the design level in the
first place.
And no, Let's come up with a patch that sort of works, throw it at the
maintainers
and see what happens is not an acceptable approach, sorry.
--
I speak only for myself.
Rafael J. Wysocki, Intel Open Source Technology Center.
--
To unsubscribe from this list: send the line unsubscribe linux-usb in
the body of a message to majord...@vger.kernel.org
More majordomo info at
Re: [PATCH 3/4] mfd: dln2: add support for ACPI
I need an ACPI Ack on this.
This patch adds support to load a custom ACPI table that describes
devices connected via the DLN2 USB to I2C/SPI/GPIO bridge.
The ACPI table can be loaded either externally (from QEMU or with
CONFIG_ACPI_CUSTOM_DSDT) or it can be loaded as firmware file with the
name dln2.aml. The driver looks for an ACPI device entry with _HID set
to DLN2 and makes it the ACPI companion for DLN2 USB
sub-drivers.
Signed-off-by: Octavian Purdila octavian.purd...@intel.com
---
Documentation/acpi/dln2-acpi.txt | 62 ++
drivers/mfd/dln2.c | 134
+++
2 files changed, 196 insertions(+)
create mode 100644 Documentation/acpi/dln2-acpi.txt
diff --git a/Documentation/acpi/dln2-acpi.txt
b/Documentation/acpi/dln2-acpi.txt
new file mode 100644
index 000..d76605f
--- /dev/null
+++ b/Documentation/acpi/dln2-acpi.txt
@@ -0,0 +1,62 @@
+Diolan DLN2 custom APCI table
+
+The Diolan DLN2 is an USB to I2C/SPI/GPIO bridge and as such it can be used
to
+connect to various I2C or SPI devices. Because these busses lack an
enumeration
+protocol, the driver obtains various information about the device (such as
I2C
+address and GPIO pins) from either ACPI or device tree.
+
+To allow enumerating devices and their properties via ACPI, the Diolan
+driver looks for an ACPI tree with the root _HID set to DLN2. If
+it finds such an ACPI object it will set the ACPI companion to the
+DLN2 MFD driver and from their it will be propagated to all its
+sub-devices (I2C, GPIO, SPI).
+
+The user can either load the custom DSDT table with three methods:
+
+1. Via QEMU (see -acpitable)
+
+2. Via the CONFIG_ACPI_CUSTOM_DSDT kernel config option (see
+Documentation/acpi/dsdt-override.txt)
+
+3. By placing the custom DSDT in the firmware paths in a file name
+dln2.aml.
+
+Here is an example ACPI table that enumerates a BMC150 accelerometer
+and defines its I2C address and GPIO pin used as an interrupt source:
+
+DefinitionBlock (ssdt.aml, SSDT, 1, INTEL , CpuDptf, 0x0003)
+{
+ Device (DLN0)
+ {
+ Name (_ADR, Zero)
+ Name (_HID, DLN2000)
+
+ Device (STAC)
+ {
+ Name (_ADR, Zero)
+ Name (_HID, BMC150A)
+ Name (_CID, INTACCL)
+ Name (_UID, One)
+
+ Method (_CRS, 0, Serialized)
+ {
+ Name (RBUF, ResourceTemplate ()
+ {
+ I2cSerialBus (0x0010,
ControllerInitiated, 0x00061A80,
+ AddressingMode7Bit,
\\DLN0,
+ 0x00, ResourceConsumer, ,)
+
+ GpioInt (Level, ActiveHigh, Exclusive,
PullDown, 0x,
+ \\DLN0, 0x00,
ResourceConsumer, , )
+ { // Pin list
+ 0
+ }
+ })
+ Return (RBUF)
+}
+ }
+ }
+}
+
+The resources defined in the devices under the DLN0 are those
+supported by the I2C, GPIO and SPI sub-systems.
diff --git a/drivers/mfd/dln2.c b/drivers/mfd/dln2.c
index f9c4a0b..93f6d1d 100644
--- a/drivers/mfd/dln2.c
+++ b/drivers/mfd/dln2.c
@@ -23,6 +23,8 @@
#include linux/mfd/core.h
#include linux/mfd/dln2.h
#include linux/rculist.h
+#include linux/acpi.h
+#include linux/firmware.h
struct dln2_header {
__le16 size;
@@ -714,6 +716,134 @@ static void dln2_stop(struct dln2_dev *dln2)
dln2_stop_rx_urbs(dln2);
}
+
+#if IS_ENABLED(CONFIG_ACPI)
+
+static struct dln2_acpi_info {
+ const struct firmware *fw;
+ acpi_owner_id table_id;
+ struct acpi_device *dev;
+ int users;
+} dln2_acpi_info;
+
+static DEFINE_MUTEX(dln2_acpi_lock);
+
+static acpi_status dln2_find_acpi_handle(acpi_handle handle, u32 level,
+ void *ctxt, void **retv)
+{
+ acpi_handle *dln2_handle = (acpi_handle *)retv;
+
+ *dln2_handle = handle;
+
+ return AE_CTRL_TERMINATE;
+}
+
+static void dln2_probe_acpi(struct dln2_dev *dln2)
+{
+ struct device *dev = dln2-interface-dev;
+ struct dln2_acpi_info *ai = dln2_acpi_info;
+ acpi_handle h = NULL;
+ int ret;
+ bool fw_loaded = false;
+
+ mutex_lock(dln2_acpi_lock);
+
+ if (ai-dev)
+ goto out_success;
+
+ /*
+ * Look for the DLN2000 HID in case the ACPI table was loaded
+ * externally (e.g. from qemu).
+ */
+ acpi_get_devices(DLN2, dln2_find_acpi_handle, NULL, h);
+ if (!h) {
+ /* Try to load the
[PATCH 3/4] mfd: dln2: add support for ACPI
This patch adds support to load a custom ACPI table that describes
devices connected via the DLN2 USB to I2C/SPI/GPIO bridge.
The ACPI table can be loaded either externally (from QEMU or with
CONFIG_ACPI_CUSTOM_DSDT) or it can be loaded as firmware file with the
name dln2.aml. The driver looks for an ACPI device entry with _HID set
to DLN2 and makes it the ACPI companion for DLN2 USB
sub-drivers.
Signed-off-by: Octavian Purdila octavian.purd...@intel.com
---
Documentation/acpi/dln2-acpi.txt | 62 ++
drivers/mfd/dln2.c | 134 +++
2 files changed, 196 insertions(+)
create mode 100644 Documentation/acpi/dln2-acpi.txt
diff --git a/Documentation/acpi/dln2-acpi.txt b/Documentation/acpi/dln2-acpi.txt
new file mode 100644
index 000..d76605f
--- /dev/null
+++ b/Documentation/acpi/dln2-acpi.txt
@@ -0,0 +1,62 @@
+Diolan DLN2 custom APCI table
+
+The Diolan DLN2 is an USB to I2C/SPI/GPIO bridge and as such it can be used to
+connect to various I2C or SPI devices. Because these busses lack an enumeration
+protocol, the driver obtains various information about the device (such as I2C
+address and GPIO pins) from either ACPI or device tree.
+
+To allow enumerating devices and their properties via ACPI, the Diolan
+driver looks for an ACPI tree with the root _HID set to DLN2. If
+it finds such an ACPI object it will set the ACPI companion to the
+DLN2 MFD driver and from their it will be propagated to all its
+sub-devices (I2C, GPIO, SPI).
+
+The user can either load the custom DSDT table with three methods:
+
+1. Via QEMU (see -acpitable)
+
+2. Via the CONFIG_ACPI_CUSTOM_DSDT kernel config option (see
+Documentation/acpi/dsdt-override.txt)
+
+3. By placing the custom DSDT in the firmware paths in a file name
+dln2.aml.
+
+Here is an example ACPI table that enumerates a BMC150 accelerometer
+and defines its I2C address and GPIO pin used as an interrupt source:
+
+DefinitionBlock (ssdt.aml, SSDT, 1, INTEL , CpuDptf, 0x0003)
+{
+ Device (DLN0)
+ {
+ Name (_ADR, Zero)
+ Name (_HID, DLN2000)
+
+ Device (STAC)
+ {
+ Name (_ADR, Zero)
+ Name (_HID, BMC150A)
+ Name (_CID, INTACCL)
+ Name (_UID, One)
+
+ Method (_CRS, 0, Serialized)
+ {
+ Name (RBUF, ResourceTemplate ()
+ {
+ I2cSerialBus (0x0010,
ControllerInitiated, 0x00061A80,
+ AddressingMode7Bit,
\\DLN0,
+ 0x00, ResourceConsumer, ,)
+
+ GpioInt (Level, ActiveHigh, Exclusive,
PullDown, 0x,
+\\DLN0, 0x00,
ResourceConsumer, , )
+ { // Pin list
+ 0
+ }
+ })
+ Return (RBUF)
+ }
+ }
+ }
+}
+
+The resources defined in the devices under the DLN0 are those
+supported by the I2C, GPIO and SPI sub-systems.
diff --git a/drivers/mfd/dln2.c b/drivers/mfd/dln2.c
index f9c4a0b..93f6d1d 100644
--- a/drivers/mfd/dln2.c
+++ b/drivers/mfd/dln2.c
@@ -23,6 +23,8 @@
#include linux/mfd/core.h
#include linux/mfd/dln2.h
#include linux/rculist.h
+#include linux/acpi.h
+#include linux/firmware.h
struct dln2_header {
__le16 size;
@@ -714,6 +716,134 @@ static void dln2_stop(struct dln2_dev *dln2)
dln2_stop_rx_urbs(dln2);
}
+
+#if IS_ENABLED(CONFIG_ACPI)
+
+static struct dln2_acpi_info {
+ const struct firmware *fw;
+ acpi_owner_id table_id;
+ struct acpi_device *dev;
+ int users;
+} dln2_acpi_info;
+
+static DEFINE_MUTEX(dln2_acpi_lock);
+
+static acpi_status dln2_find_acpi_handle(acpi_handle handle, u32 level,
+void *ctxt, void **retv)
+{
+ acpi_handle *dln2_handle = (acpi_handle *)retv;
+
+ *dln2_handle = handle;
+
+ return AE_CTRL_TERMINATE;
+}
+
+static void dln2_probe_acpi(struct dln2_dev *dln2)
+{
+ struct device *dev = dln2-interface-dev;
+ struct dln2_acpi_info *ai = dln2_acpi_info;
+ acpi_handle h = NULL;
+ int ret;
+ bool fw_loaded = false;
+
+ mutex_lock(dln2_acpi_lock);
+
+ if (ai-dev)
+ goto out_success;
+
+ /*
+* Look for the DLN2000 HID in case the ACPI table was loaded
+* externally (e.g. from qemu).
+*/
+ acpi_get_devices(DLN2, dln2_find_acpi_handle, NULL, h);
+ if (!h) {
+ /* Try to load the ACPI table via a firmware file */
+ ret = request_firmware(ai-fw,
