Add the rt linux 4.1.3-rt3 as base

[kvmfornfv.git] / kernel / sound / soc / codecs / l3.c

diff --git a/kernel/sound/soc/codecs/l3.c b/kernel/sound/soc/codecs/l3.c
new file mode 100644 (file)
index 0000000..5353af5
--- /dev/null
+++ b/kernel/sound/soc/codecs/l3.c
@@ -0,0 +1,91 @@
+/*
+ * L3 code
+ *
+ *  Copyright (C) 2008, Christian Pellegrin <chripell@evolware.org>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ *
+ * based on:
+ *
+ * L3 bus algorithm module.
+ *
+ *  Copyright (C) 2001 Russell King, All Rights Reserved.
+ *
+ *
+ */
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/delay.h>
+
+#include <sound/l3.h>
+
+/*
+ * Send one byte of data to the chip.  Data is latched into the chip on
+ * the rising edge of the clock.
+ */
+static void sendbyte(struct l3_pins *adap, unsigned int byte)
+{
+       int i;
+
+       for (i = 0; i < 8; i++) {
+               adap->setclk(0);
+               udelay(adap->data_hold);
+               adap->setdat(byte & 1);
+               udelay(adap->data_setup);
+               adap->setclk(1);
+               udelay(adap->clock_high);
+               byte >>= 1;
+       }
+}
+
+/*
+ * Send a set of bytes to the chip.  We need to pulse the MODE line
+ * between each byte, but never at the start nor at the end of the
+ * transfer.
+ */
+static void sendbytes(struct l3_pins *adap, const u8 *buf,
+                     int len)
+{
+       int i;
+
+       for (i = 0; i < len; i++) {
+               if (i) {
+                       udelay(adap->mode_hold);
+                       adap->setmode(0);
+                       udelay(adap->mode);
+               }
+               adap->setmode(1);
+               udelay(adap->mode_setup);
+               sendbyte(adap, buf[i]);
+       }
+}
+
+int l3_write(struct l3_pins *adap, u8 addr, u8 *data, int len)
+{
+       adap->setclk(1);
+       adap->setdat(1);
+       adap->setmode(1);
+       udelay(adap->mode);
+
+       adap->setmode(0);
+       udelay(adap->mode_setup);
+       sendbyte(adap, addr);
+       udelay(adap->mode_hold);
+
+       sendbytes(adap, data, len);
+
+       adap->setclk(1);
+       adap->setdat(1);
+       adap->setmode(0);
+
+       return len;
+}
+EXPORT_SYMBOL_GPL(l3_write);
+
+MODULE_DESCRIPTION("L3 bit-banging driver");
+MODULE_AUTHOR("Christian Pellegrin <chripell@evolware.org>");
+MODULE_LICENSE("GPL");