ide: add warm-plug support for IDE devices (take 2)

* Add 'struct class ide_port_class' ('ide_port' class) and a 'struct
  device *portdev' ('ide_port' class device) in ide_hwif_t.

* Register 'ide_port' class in ide_init() and unregister it in
  cleanup_module().

* Create ->portdev in ide_register_port () and unregister it in
  ide_unregister().

* Add "delete_devices" class device attribute for unregistering IDE devices
  on a port and "scan" one for probing+registering IDE devices on a port.

* Add ide_sysfs_register_port() helper for registering "delete_devices"
  and "scan" attributes with ->portdev.  Call it in ide_device_add_all().

* Document IDE warm-plug support in Documentation/ide/warm-plug-howto.txt.

v2:
* Convert patch from using 'struct class_device' to use 'struct device'.
  (thanks to Kay Sievers for doing it)

Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>

1 files changed, 4 insertions, 1 deletions

diff --git a/include/linux/ide.h b/include/linux/ide.h
index e43570a19200..9cebf3054080 100644
--- a/include/linux/ide.h
+++ b/include/linux/ide.h
@@ -579,7 +579,9 @@ typedef struct hwif_s {
         unsigned        mmio       : 1; /* host uses MMIO */
         unsigned        straight8  : 1; /* Alan's straight 8 check */
 
-        struct device   gendev;
+        struct device           gendev;
+        struct device           *portdev;
+
         struct completion gendev_rel_comp; /* To deal with device release() */
 
         void            *hwif_data;     /* extra hwif data */
@@ -1275,6 +1277,7 @@ extern struct mutex ide_cfg_mtx;
 #define local_irq_set(flags)    do { local_save_flags((flags)); local_irq_enable_in_hardirq(); } while (0)
 
 extern struct bus_type ide_bus_type;
+extern struct class *ide_port_class;
 
 /* check if CACHE FLUSH (EXT) command is supported (bits defined in ATA-6) */
 #define ide_id_has_flush_cache(id)      ((id)->cfs_enable_2 & 0x3000)