soundforte radio driver, from Vladimir Popov <jumbo@narod.ru>

1 files changed, 93 insertions, 0 deletions

diff --git a/sys/dev/ic/pt2254a.c b/sys/dev/ic/pt2254a.c
new file mode 100644
index 00000000000..7428c43197d
--- /dev/null
+++ b/sys/dev/ic/pt2254a.c
@@ -0,0 +1,93 @@
+/*	$OpenBSD: pt2254a.c,v 1.1 2002/04/25 04:56:59 mickey Exp $	*/
+/*
+ * Copyright (c) 2002 Vladimir Popov <jumbo@narod.ru>.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
+ * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
+ * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
+ * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
+ * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+/*
+ * Princeton Technology Corp.'s Electronic Volume Controller IC PT2254A
+ *  http://www.princeton.com.tw
+ *
+ *  PT2254A is an electronic volume controller IC utilizing CMOS Technology
+ *  specially designed for use in audio equipment. It has two built-in
+ *  channels making it highly suitable for mono and stereo sound applications.
+ *  Through the specially designated signals that are applied externally to
+ *  the data, clock and strobe input pins, PT2254A can control attenuation
+ *  and channel balance.
+ */
+
+#include <sys/param.h>
+
+#include <dev/ic/pt2254a.h>
+
+u_int32_t
+pt2254a_encode_volume(u_int8_t *current, u_int8_t max) {
+	u_int32_t ret = 0ul;
+	u_int8_t vol, tens, ones;
+	int steps;
+
+	/*
+	 * Volume management is done nonlinear.
+	 *
+	 * Approximate the curve with three lines:
+	 * low volume:		y = - (48 /(max/3)) * x + 68
+	 * middle volume:	y = - (14 /(max/3)) * x + 34
+	 * high volume:		y = - (6 /(max/3)) * x + 18
+	 */
+	if (*current > 0 && *current <= max / 3) {
+		vol = PT2254A_MAX_ATTENUATION - (144 * (int)(*current) / max);
+	} else if (*current > max / 3 && *current <= 2 * max / 3) {
+		vol = 34 - (42 * (int)(*current) / max);
+	} else if (*current > 2 * max / 3) {
+		vol = 18 - (18 * (int)(*current) / max);
+	} else vol = PT2254A_MAX_ATTENUATION;
+
+	/* Report adjusted volume */
+	/* *current = max - (vol * max / PT2254A_MAX_ATTENUATION); */
+	steps = *current * PT2254A_MAX_ATTENUATION / max;
+	*current = steps * max / PT2254A_MAX_ATTENUATION;
+
+	tens = vol / 10;
+	ones = vol - tens * 10;
+
+	ret = PT2254A_ATTENUATION_MAJOR(tens) | PT2254A_ATTENUATION_MINOR(ones);
+
+	return ret;
+}
+
+u_int32_t
+pt2254a_compose_register(u_int32_t lvol, u_int32_t rvol, int left, int right) {
+	u_int32_t ret = 0ul;
+
+	if (left == USE_CHANNEL) {
+		ret |= PT2254A_LEFT_CHANNEL;
+		ret |= lvol;
+	}
+	if (right == USE_CHANNEL) {
+		ret |= PT2254A_RIGHT_CHANNEL;
+		ret |= rvol;
+	}
+
+	ret |= PT2254A_ZERO_PADDING;
+	ret |= PT2254A_EMPTY_BIT;
+
+	return ret;
+}