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authorTakashi Sakamoto <o-takashi@sakamocchi.jp>2014-11-28 18:59:13 +0300
committerTakashi Iwai <tiwai@suse.de>2014-11-29 22:04:15 +0300
commit7c2d4c0cf5bacb42bc3079e61d299dfaa3dbdde5 (patch)
tree6ff440320390f383d2af28128e409a56b4f5feb5 /sound/firewire/amdtp.c
parent14ff6a094815988b018ea4d698c2e2cc3ceee27c (diff)
downloadlinux-7c2d4c0cf5bacb42bc3079e61d299dfaa3dbdde5.tar.xz
ALSA: dice: Split transaction functionality into a file
This commit adds a file with some helper functions for transaction, and move some codes into the file with some arrangements. For Dice chipset, well-known FCP or AV/C commands are not used to control devices. It's achieved by read/write transactions into specific addresses. Dice's address area is split into 5 areas. Each area has its own role. The offset for each area can be got by reading head of the address area. By reading these areas, drivers can get to know device status. By writing these areas, drivers can change device status. Dice has a specific mechanism called as 'notification'. When device status is changed, Dice devices tells the event by sending transaction. This notification is sent to an address which drivers register in advance. But this causes an issue to drivers. To handle the notification, drivers need to allocate its own callback function to the address region in host controller. This region is exclusive. For the other applications, drivers must give a mechanism to read the received notification. For this purpose, Dice driver already implements hwdep interface. Dice chipset doesn't allow drivers to register several addresses. In this reason, when this driver is applied to a device, the other drivers should _not_ try to register its own address to the device. Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp> Signed-off-by: Takashi Iwai <tiwai@suse.de>
Diffstat (limited to 'sound/firewire/amdtp.c')
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