V4L/DVB (7160): em28xx: Allow register dump/setting for debug

Adds vidioc_[g|s]_register handlers. This allows getting/setting register
from em28xx.
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>

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

@@ -830,6 +830,64 @@ static int vidioc_s_frequency(struct file *file, void *priv,
 	return 0;
 }
 
+#ifdef CONFIG_VIDEO_ADV_DEBUG
+static int em28xx_reg_len(int reg)
+{
+	switch (reg) {
+	case AC97LSB_REG:
+	case HSCALELOW_REG:
+	case VSCALELOW_REG:
+
+		return 2;
+	default:
+		return 1;
+	}
+}
+
+static int vidioc_g_register(struct file *file, void *priv,
+			     struct v4l2_register *reg)
+{
+	struct em28xx_fh      *fh  = priv;
+	struct em28xx         *dev = fh->dev;
+	int ret;
+
+	if (!v4l2_chip_match_host(reg->match_type, reg->match_chip))
+		return -EINVAL;
+
+	if (em28xx_reg_len(reg->reg) == 1) {
+		ret = em28xx_read_reg(dev, reg->reg);
+		if (ret < 0)
+			return ret;
+
+		reg->val = ret;
+	} else {
+		u16 val;
+		ret = em28xx_read_reg_req_len(dev, USB_REQ_GET_STATUS,
+						   reg->reg, (char *)&val, 2);
+		if (ret < 0)
+			return ret;
+
+		reg->val = val;
+	}
+
+	return 0;
+}
+
+static int vidioc_s_register(struct file *file, void *priv,
+			     struct v4l2_register *reg)
+{
+	struct em28xx_fh      *fh  = priv;
+	struct em28xx         *dev = fh->dev;
+	u16 buf;
+
+	buf = be16_to_cpu((__u16)reg->val);
+
+	return em28xx_write_regs(dev, reg->reg, (char *)&buf,
+				 em28xx_reg_len(reg->reg));
+}
+#endif
+
+
 static int vidioc_cropcap(struct file *file, void *priv,
 					struct v4l2_cropcap *cc)
 {
@@ -1730,6 +1788,10 @@ static const struct video_device em28xx_video_template = {
 	.vidioc_s_tuner             = vidioc_s_tuner,
 	.vidioc_g_frequency         = vidioc_g_frequency,
 	.vidioc_s_frequency         = vidioc_s_frequency,
+#ifdef CONFIG_VIDEO_ADV_DEBUG
+	.vidioc_g_register          = vidioc_g_register,
+	.vidioc_s_register          = vidioc_s_register,
+#endif
 
 	.tvnorms                    = V4L2_STD_ALL,
 	.current_norm               = V4L2_STD_PAL,
@@ -1752,6 +1814,10 @@ static struct video_device em28xx_radio_template = {
 	.vidioc_s_ctrl        = vidioc_s_ctrl,
 	.vidioc_g_frequency   = vidioc_g_frequency,
 	.vidioc_s_frequency   = vidioc_s_frequency,
+#ifdef CONFIG_VIDEO_ADV_DEBUG
+	.vidioc_g_register    = vidioc_g_register,
+	.vidioc_s_register    = vidioc_s_register,
+#endif
 };
 
 /******************************** usb interface *****************************************/