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author | Kim Phillips <kim.phillips@freescale.com> | 2014-06-02 19:42:58 -0500 |
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committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2014-07-08 15:31:26 -0700 |
commit | 3d713e0e382e6fcfb4bba1501645b66c129ad60b (patch) | |
tree | 9b47c38f09df44537b163ca18eabc8c979aa1f04 /drivers/base/platform.c | |
parent | 1cec24c59b4a133fc9c83912996168f511075485 (diff) | |
download | op-kernel-dev-3d713e0e382e6fcfb4bba1501645b66c129ad60b.zip op-kernel-dev-3d713e0e382e6fcfb4bba1501645b66c129ad60b.tar.gz |
driver core: platform: add device binding path 'driver_override'
Needed by platform device drivers, such as the upcoming
vfio-platform driver, in order to bypass the existing OF, ACPI,
id_table and name string matches, and successfully be able to be
bound to any device, like so:
echo vfio-platform > /sys/bus/platform/devices/fff51000.ethernet/driver_override
echo fff51000.ethernet > /sys/bus/platform/devices/fff51000.ethernet/driver/unbind
echo fff51000.ethernet > /sys/bus/platform/drivers_probe
This mimics "PCI: Introduce new device binding path using
pci_dev.driver_override", which is an interface enhancement
for more deterministic PCI device binding, e.g., when in the
presence of hotplug.
Reviewed-by: Alex Williamson <alex.williamson@redhat.com>
Reviewed-by: Alexander Graf <agraf@suse.de>
Reviewed-by: Stuart Yoder <stuart.yoder@freescale.com>
Signed-off-by: Kim Phillips <kim.phillips@freescale.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/base/platform.c')
-rw-r--r-- | drivers/base/platform.c | 47 |
1 files changed, 47 insertions, 0 deletions
diff --git a/drivers/base/platform.c b/drivers/base/platform.c index c48c4ac..148f66a 100644 --- a/drivers/base/platform.c +++ b/drivers/base/platform.c @@ -23,6 +23,7 @@ #include <linux/pm_runtime.h> #include <linux/idr.h> #include <linux/acpi.h> +#include <linux/limits.h> #include "base.h" #include "power/power.h" @@ -191,6 +192,7 @@ static void platform_device_release(struct device *dev) kfree(pa->pdev.dev.platform_data); kfree(pa->pdev.mfd_cell); kfree(pa->pdev.resource); + kfree(pa->pdev.driver_override); kfree(pa); } @@ -698,8 +700,49 @@ static ssize_t modalias_show(struct device *dev, struct device_attribute *a, } static DEVICE_ATTR_RO(modalias); +static ssize_t driver_override_store(struct device *dev, + struct device_attribute *attr, + const char *buf, size_t count) +{ + struct platform_device *pdev = to_platform_device(dev); + char *driver_override, *old = pdev->driver_override, *cp; + + if (count > PATH_MAX) + return -EINVAL; + + driver_override = kstrndup(buf, count, GFP_KERNEL); + if (!driver_override) + return -ENOMEM; + + cp = strchr(driver_override, '\n'); + if (cp) + *cp = '\0'; + + if (strlen(driver_override)) { + pdev->driver_override = driver_override; + } else { + kfree(driver_override); + pdev->driver_override = NULL; + } + + kfree(old); + + return count; +} + +static ssize_t driver_override_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct platform_device *pdev = to_platform_device(dev); + + return sprintf(buf, "%s\n", pdev->driver_override); +} +static DEVICE_ATTR_RW(driver_override); + + static struct attribute *platform_dev_attrs[] = { &dev_attr_modalias.attr, + &dev_attr_driver_override.attr, NULL, }; ATTRIBUTE_GROUPS(platform_dev); @@ -755,6 +798,10 @@ static int platform_match(struct device *dev, struct device_driver *drv) struct platform_device *pdev = to_platform_device(dev); struct platform_driver *pdrv = to_platform_driver(drv); + /* When driver_override is set, only bind to the matching driver */ + if (pdev->driver_override) + return !strcmp(pdev->driver_override, drv->name); + /* Attempt an OF style match first */ if (of_driver_match_device(dev, drv)) return 1; |