Add mISDN DSP

Enable support for digital audio processing capability.
This module may be used for special applications that require
cross connecting of bchannels, conferencing, dtmf decoding
echo cancelation, tone generation, and Blowfish encryption and
decryption.
It may use hardware features if available.

Signed-off-by: Karsten Keil <kkeil@suse.de>
diff --git a/drivers/isdn/mISDN/dsp_hwec.h b/drivers/isdn/mISDN/dsp_hwec.h
new file mode 100644
index 0000000..eebe80c
--- /dev/null
+++ b/drivers/isdn/mISDN/dsp_hwec.h
@@ -0,0 +1,10 @@
+/*
+ * dsp_hwec.h
+ */
+
+extern struct mISDN_dsp_element *dsp_hwec;
+extern void dsp_hwec_enable(struct dsp *dsp, const char *arg);
+extern void dsp_hwec_disable(struct dsp *dsp);
+extern int  dsp_hwec_init(void);
+extern void dsp_hwec_exit(void);
+