V4L/DVB (11793): xc5000: Properly support power down for newer firmware

Xceive got rid of the XREG_POWER_DOWN register in later firmware revisions.
Their technical support informed me that the correct way to put the tuner
to sleep is to pull the reset pin (but don't reload the firmware).

Signed-off-by: Devin Heitmueller <dheitmueller@kernellabs.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

drivers/media/common/tuners/xc5000.c

@@ -83,7 +83,7 @@ struct xc5000_priv {
 #define XREG_D_CODE       0x04
 #define XREG_IF_OUT       0x05
 #define XREG_SEEK_MODE    0x07
-#define XREG_POWER_DOWN   0x0A
+#define XREG_POWER_DOWN   0x0A /* Obsolete */
 #define XREG_SIGNALSOURCE 0x0D /* 0=Air, 1=Cable */
 #define XREG_SMOOTHEDCVBS 0x0E
 #define XREG_XTALFREQ     0x0F
@@ -841,12 +841,14 @@ static int xc_load_fw_and_init_tuner(struct dvb_frontend *fe)
 
 static int xc5000_sleep(struct dvb_frontend *fe)
 {
-	struct xc5000_priv *priv = fe->tuner_priv;
 	int ret;
 
 	dprintk(1, "%s()\n", __func__);
 
-	ret = xc_write_reg(priv, XREG_POWER_DOWN, 0);
+	/* According to Xceive technical support, the "powerdown" register
+	   was removed in newer versions of the firmware.  The "supported"
+	   way to sleep the tuner is to pull the reset pin low for 10ms */
+	ret = xc5000_TunerReset(fe);
 	if (ret != XC_RESULT_SUCCESS) {
 		printk(KERN_ERR
 			"xc5000: %s() unable to shutdown tuner\n",