Messages in this thread Patch in this message | | | From | Amit Kucheria <> | Subject | [PATCH 2/2] als: add unique device-ids to the als device class | Date | Mon, 30 Nov 2009 13:46:38 +0200 |
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Other devices classes such as hwmon and input class handle assignment of unique device-ids inside the core functions instead of pushing it out to individual drivers. This reduces code duplication and resulting bugs.
V2 - Updated the header to reflect the change is signature of als_device_register(). Thanks to Jean for the review.
V1 - Add capability to als core to create unique ids
Signed-off-by: Amit Kucheria <amit.kucheria@verdurent.com> Acked-by: Jean Delvare <khali@linux-fr.org> Acked-by: Jonathan Cameron <jic23@cam.ac.uk> --- drivers/als/als_sys.c | 48 ++++++++++++++++++++++++++++++++++++++++++++-- include/linux/als_sys.h | 2 +- 2 files changed, 46 insertions(+), 4 deletions(-)
diff --git a/drivers/als/als_sys.c b/drivers/als/als_sys.c index e1d6395..aa15ad8 100644 --- a/drivers/als/als_sys.c +++ b/drivers/als/als_sys.c @@ -26,22 +26,55 @@ #include <linux/device.h> #include <linux/err.h> #include <linux/kdev_t.h> +#include <linux/idr.h> MODULE_AUTHOR("Zhang Rui <rui.zhang@intel.com>"); MODULE_DESCRIPTION("Ambient Light Sensor sysfs/class support"); MODULE_LICENSE("GPL"); +#define ALS_ID_PREFIX "als" +#define ALS_ID_FORMAT ALS_ID_PREFIX "%d" + static struct class *als_class; +static DEFINE_IDR(als_idr); +static DEFINE_SPINLOCK(idr_lock); + /** * als_device_register - register a new Ambient Light Sensor class device * @parent: the device to register. * * Returns the pointer to the new device */ -struct device *als_device_register(struct device *dev, char *name) +struct device *als_device_register(struct device *dev) { - return device_create(als_class, dev, MKDEV(0, 0), NULL, name); + int id, err; + struct device *alsdev; + +again: + if (unlikely(idr_pre_get(&als_idr, GFP_KERNEL) == 0)) + return ERR_PTR(-ENOMEM); + + spin_lock(&idr_lock); + err = idr_get_new(&als_idr, NULL, &id); + spin_unlock(&idr_lock); + + if (unlikely(err == -EAGAIN)) + goto again; + else if (unlikely(err)) + return ERR_PTR(err); + + id = id & MAX_ID_MASK; + alsdev = device_create(als_class, dev, MKDEV(0, 0), NULL, + ALS_ID_FORMAT, id); + + if (IS_ERR(alsdev)) { + spin_lock(&idr_lock); + idr_remove(&als_idr, id); + spin_unlock(&idr_lock); + } + + return alsdev; } EXPORT_SYMBOL(als_device_register); @@ -51,7 +84,16 @@ EXPORT_SYMBOL(als_device_register); */ void als_device_unregister(struct device *dev) { - device_unregister(dev); + int id; + + if (likely(sscanf(dev_name(dev), ALS_ID_FORMAT, &id) == 1)) { + device_unregister(dev); + spin_lock(&idr_lock); + idr_remove(&als_idr, id); + spin_unlock(&idr_lock); + } else + dev_dbg(dev->parent, + "als_device_unregister() failed: bad class ID!\n"); } EXPORT_SYMBOL(als_device_unregister); diff --git a/include/linux/als_sys.h b/include/linux/als_sys.h index 500f300..41793f7 100644 --- a/include/linux/als_sys.h +++ b/include/linux/als_sys.h @@ -29,7 +29,7 @@ #define ALS_ILLUMINANCE_MIN 0 #define ALS_ILLUMINANCE_MAX -1 -struct device *als_device_register(struct device *dev, char *name); +struct device *als_device_register(struct device *dev); void als_device_unregister(struct device *dev); #endif /* __ALS_SYS_H__ */ -- 1.6.3.3
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