From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Brownell Subject: [patch 2.6.25-rc2-git] crosslink ACPI and "real" device nodes Date: Fri, 22 Feb 2008 21:54:24 -0800 Message-ID: <200802222154.25204.david-b@pacbell.net> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: linux-pm-bounces@lists.linux-foundation.org Errors-To: linux-pm-bounces@lists.linux-foundation.org To: linux-acpi@vger.kernel.org Cc: linux-pm@lists.linux-foundation.org List-Id: linux-acpi@vger.kernel.org Add cross-links between ACPI device and "real" devices in sysfs, exposing otherwise-hidden interrelationships between the various device nodes for ACPI stuff. As a representative example, one hardware device is exposed as two logical devices (PNP and ACPI): .../pnp0/00:06/ .../LNXSYSTM:00/device:00/PNP0A03:00/device:15/PNP0B00:00/ The PNP device gets a "firmware_node" link pointing to the ACPI device, and is what a Linux device driver binds to. The ACPI device has instead a "physical_node" link pointing back to the PNP device. Other firmware frameworks, like OpenFirmware, could do the same thing to couple their firmware tables to the rest of the system. (Based on a patch from Zhang Rui. This version is modified to not depend on the patch makig ACPI initialize driver model wakeup flags.) Signed-off-by: David Brownell Cc: Zhang Rui --- Another extract from the "teach ACPI how to use driver model wakeup flags" patch series. The linkage helps sort out confusion about which devices are wakeup-capable, among other things, and can help when interpreting /proc/acpi/wakeup contents. drivers/acpi/glue.c | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+) --- g26.orig/drivers/acpi/glue.c 2008-02-22 20:39:19.000000000 -0800 +++ g26/drivers/acpi/glue.c 2008-02-22 20:46:40.000000000 -0800 @@ -142,6 +142,7 @@ EXPORT_SYMBOL(acpi_get_physical_device); static int acpi_bind_one(struct device *dev, acpi_handle handle) { + struct acpi_device *acpi_dev; acpi_status status; if (dev->archdata.acpi_handle) { @@ -157,6 +158,16 @@ static int acpi_bind_one(struct device * } dev->archdata.acpi_handle = handle; + status = acpi_bus_get_device(handle, &acpi_dev); + if (!ACPI_FAILURE(status)) { + int ret; + + ret = sysfs_create_link(&dev->kobj, &acpi_dev->dev.kobj, + "firmware_node"); + ret = sysfs_create_link(&acpi_dev->dev.kobj, &dev->kobj, + "physical_node"); + } + return 0; } @@ -165,8 +176,17 @@ static int acpi_unbind_one(struct device if (!dev->archdata.acpi_handle) return 0; if (dev == acpi_get_physical_device(dev->archdata.acpi_handle)) { + struct acpi_device *acpi_dev; + /* acpi_get_physical_device increase refcnt by one */ put_device(dev); + + if (!acpi_bus_get_device(dev->archdata.acpi_handle, + &acpi_dev)) { + sysfs_remove_link(&dev->kobj, "firmware_node"); + sysfs_remove_link(&acpi_dev->dev.kobj, "physical_node"); + } + acpi_detach_data(dev->archdata.acpi_handle, acpi_glue_data_handler); dev->archdata.acpi_handle = NULL;