[media] radio: Add Sanyo LM7000 tuner driver

Add very simple driver for Sanyo LM7000 AM/FM tuner chip. Only FM is supported
as there is no known HW with AM implemented.

This will be used by radio-aimslab and radio-sf16fmi.
Signed-off-by: Ondrej Zary <linux@rainbow-software.org>
Acked-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

drivers/media/radio/lm7000.h

+#ifndef __LM7000_H
+#define __LM7000_H
+
+/* Sanyo LM7000 tuner chip control
+ *
+ * Copyright 2012 Ondrej Zary <linux@rainbow-software.org>
+ * based on radio-aimslab.c by M. Kirkwood
+ * and radio-sf16fmi.c by M. Kirkwood and Petr Vandrovec
+ */
+
+#define LM7000_DATA	(1 << 0)
+#define LM7000_CLK	(1 << 1)
+#define LM7000_CE	(1 << 2)
+
+#define LM7000_FM_100	(0 << 20)
+#define LM7000_FM_50	(1 << 20)
+#define LM7000_FM_25	(2 << 20)
+#define LM7000_BIT_FM	(1 << 23)
+
+static inline void lm7000_set_freq(u32 freq, void *handle,
+				void (*set_pins)(void *handle, u8 pins))
+{
+	int i;
+	u8 data;
+	u32 val;
+
+	freq += 171200;		/* Add 10.7 MHz IF */
+	freq /= 400;		/* Convert to 25 kHz units */
+	val = freq | LM7000_FM_25 | LM7000_BIT_FM;
+	/* write the 24-bit register, starting with LSB */
+	for (i = 0; i < 24; i++) {
+		data = val & (1 << i) ? LM7000_DATA : 0;
+		set_pins(handle, data | LM7000_CE);
+		udelay(2);
+		set_pins(handle, data | LM7000_CE | LM7000_CLK);
+		udelay(2);
+		set_pins(handle, data | LM7000_CE);
+		udelay(2);
+	}
+	set_pins(handle, 0);
+}
+
+#endif /* __LM7000_H */