1 files changed, 132 insertions, 0 deletions
diff --git a/sound/soc/codecs/l3.c b/sound/soc/codecs/l3.c
new file mode 100644
index 000000000000..b84f6f1f6800
--- /dev/null
+++ b/sound/soc/codecs/l3.c
@@ -0,0 +1,132 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * L3 code
+ *
+ *  Copyright (C) 2008, Christian Pellegrin <chripell@evolware.org>
+ *
+ * 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 <linux/device.h>
+#include <linux/gpio.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(adap, 0);
+		udelay(adap->data_hold);
+		adap->setdat(adap, byte & 1);
+		udelay(adap->data_setup);
+		adap->setclk(adap, 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(adap, 0);
+			udelay(adap->mode);
+		}
+		adap->setmode(adap, 1);
+		udelay(adap->mode_setup);
+		sendbyte(adap, buf[i]);
+	}
+}
+
+int l3_write(struct l3_pins *adap, u8 addr, u8 *data, int len)
+{
+	adap->setclk(adap, 1);
+	adap->setdat(adap, 1);
+	adap->setmode(adap, 1);
+	udelay(adap->mode);
+
+	adap->setmode(adap, 0);
+	udelay(adap->mode_setup);
+	sendbyte(adap, addr);
+	udelay(adap->mode_hold);
+
+	sendbytes(adap, data, len);
+
+	adap->setclk(adap, 1);
+	adap->setdat(adap, 1);
+	adap->setmode(adap, 0);
+
+	return len;
+}
+EXPORT_SYMBOL_GPL(l3_write);
+
+
+static void l3_set_clk(struct l3_pins *adap, int val)
+{
+	gpio_set_value(adap->gpio_clk, val);
+}
+
+static void l3_set_data(struct l3_pins *adap, int val)
+{
+	gpio_set_value(adap->gpio_data, val);
+}
+
+static void l3_set_mode(struct l3_pins *adap, int val)
+{
+	gpio_set_value(adap->gpio_mode, val);
+}
+
+int l3_set_gpio_ops(struct device *dev, struct l3_pins *adap)
+{
+	int ret;
+
+	if (!adap->use_gpios)
+		return -EINVAL;
+
+	ret = devm_gpio_request_one(dev, adap->gpio_data,
+				GPIOF_OUT_INIT_LOW, "l3_data");
+	if (ret < 0)
+		return ret;
+	adap->setdat = l3_set_data;
+
+	ret = devm_gpio_request_one(dev, adap->gpio_clk,
+				GPIOF_OUT_INIT_LOW, "l3_clk");
+	if (ret < 0)
+		return ret;
+	adap->setclk = l3_set_clk;
+
+	ret = devm_gpio_request_one(dev, adap->gpio_mode,
+				GPIOF_OUT_INIT_LOW, "l3_mode");
+	if (ret < 0)
+		return ret;
+	adap->setmode = l3_set_mode;
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(l3_set_gpio_ops);
+
+MODULE_DESCRIPTION("L3 bit-banging driver");
+MODULE_AUTHOR("Christian Pellegrin <chripell@evolware.org>");
+MODULE_LICENSE("GPL");