driver core: platform: add device binding path 'driver_override'

[cascardo/linux.git] / drivers / base / platform.c

diff --git a/drivers/base/platform.c b/drivers/base/platform.c
index 9e9227e..148f66a 100644 (file)
--- 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"
@@ -165,7 +166,7 @@ EXPORT_SYMBOL_GPL(platform_add_devices);
 
 struct platform_object {
        struct platform_device pdev;
-       char name[1];
+       char name[];
 };
 
 /**
@@ -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);
 }
 
@@ -206,7 +208,7 @@ struct platform_device *platform_device_alloc(const char *name, int id)
 {
        struct platform_object *pa;
 
-       pa = kzalloc(sizeof(struct platform_object) + strlen(name), GFP_KERNEL);
+       pa = kzalloc(sizeof(*pa) + strlen(name) + 1, GFP_KERNEL);
        if (pa) {
                strcpy(pa->name, name);
                pa->pdev.name = pa->name;
@@ -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;