V4L/DVB (9657): em28xx: add a functio to write on a single register

Introduce a new function that writes to a single register.  This is
useful because the vast majority of register writes are a single
register, and this format permits or'ing register value bits together.
Signed-off-by: Devin Heitmueller <devin.heitmueller@gmail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

drivers/media/video/em28xx/em28xx-core.c

@@ -196,6 +196,12 @@ int em28xx_write_regs(struct em28xx *dev, u16 reg, char *buf, int len)
 	return rc;
 }
 
+/* Write a single register */
+int em28xx_write_reg(struct em28xx *dev, u16 reg, u8 val)
+{
+	return em28xx_write_regs(dev, reg, &val, 1);
+}
+
 /*
  * em28xx_write_reg_bits()
  * sets only some bits (specified by bitmask) of a register, by first reading

drivers/media/video/em28xx/em28xx.h

@@ -555,6 +555,8 @@ int em28xx_read_reg(struct em28xx *dev, u16 reg);
 int em28xx_write_regs_req(struct em28xx *dev, u8 req, u16 reg, char *buf,
 			  int len);
 int em28xx_write_regs(struct em28xx *dev, u16 reg, char *buf, int len);
+int em28xx_write_reg(struct em28xx *dev, u16 reg, u8 val);
+
 int em28xx_audio_analog_set(struct em28xx *dev);
 int em28xx_audio_setup(struct em28xx *dev);