[media] snd_tea575x: Add write_/read_val operations

Some devices which use the tea575x tuner chip don't allow bit banging the
lines, instead they offer a method to directly set / get the contents of the
25 bit shift-register in the chip. Notably the Griffin radioSHARK USB radio
receiver does this.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
CC: Ondrej Zary <linux@rainbow-software.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

include/sound/tea575x-tuner.h

@@ -37,6 +37,10 @@
 struct snd_tea575x;
 
 struct snd_tea575x_ops {
+	/* Drivers using snd_tea575x must either define read_ and write_val */
+	void (*write_val)(struct snd_tea575x *tea, u32 val);
+	u32 (*read_val)(struct snd_tea575x *tea);
+	/* Or define the 3 pin functions */
 	void (*set_pins)(struct snd_tea575x *tea, u8 pins);
 	u8 (*get_pins)(struct snd_tea575x *tea);
 	void (*set_direction)(struct snd_tea575x *tea, bool output);

sound/i2c/other/tea575x-tuner.c

@@ -71,6 +71,9 @@ static void snd_tea575x_write(struct snd_tea575x *tea, unsigned int val)
 	u16 l;
 	u8 data;
 
+	if (tea->ops->write_val)
+		return tea->ops->write_val(tea, val);
+
 	tea->ops->set_direction(tea, 1);
 	udelay(16);
 
@@ -94,6 +97,9 @@ static u32 snd_tea575x_read(struct snd_tea575x *tea)
 	u16 l, rdata;
 	u32 data = 0;
 
+	if (tea->ops->read_val)
+		return tea->ops->read_val(tea);
+
 	tea->ops->set_direction(tea, 0);
 	tea->ops->set_pins(tea, 0);
 	udelay(16);