drm/bridge: dw-hdmi-i2s: enable only the required i2s lanes

Enable the i2s lanes depending on the number of channel in the stream
Reviewed-by: NJonas Karlman <jonas@kwiboo.se>
Signed-off-by: NJerome Brunet <jbrunet@baylibre.com>
Reviewed-by: NNeil Armstrong <narmstrong@baylibre.com>
Signed-off-by: NNeil Armstrong <narmstrong@baylibre.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190812120726.1528-8-jbrunet@baylibre.com

drivers/gpu/drm/bridge/synopsys/dw-hdmi-i2s-audio.c

@@ -54,7 +54,20 @@ static int dw_hdmi_i2s_hw_params(struct device *dev, void *data,
 	hdmi_write(audio, (u8)~HDMI_MC_SWRSTZ_I2SSWRST_REQ, HDMI_MC_SWRSTZ);
 
 	inputclkfs	= HDMI_AUD_INPUTCLKFS_64FS;
-	conf0		= HDMI_AUD_CONF0_I2S_ALL_ENABLE;
+	conf0		= (HDMI_AUD_CONF0_I2S_SELECT | HDMI_AUD_CONF0_I2S_EN0);
+
+	/* Enable the required i2s lanes */
+	switch (hparms->channels) {
+	case 7 ... 8:
+		conf0 |= HDMI_AUD_CONF0_I2S_EN3;
+		/* Fall-thru */
+	case 5 ... 6:
+		conf0 |= HDMI_AUD_CONF0_I2S_EN2;
+		/* Fall-thru */
+	case 3 ... 4:
+		conf0 |= HDMI_AUD_CONF0_I2S_EN1;
+		/* Fall-thru */
+	}
 
 	switch (hparms->sample_width) {
 	case 16:

drivers/gpu/drm/bridge/synopsys/dw-hdmi.h

@@ -865,7 +865,11 @@ enum {
 
 /* AUD_CONF0 field values */
 	HDMI_AUD_CONF0_SW_RESET = 0x80,
-	HDMI_AUD_CONF0_I2S_ALL_ENABLE = 0x2F,
+	HDMI_AUD_CONF0_I2S_SELECT = 0x20,
+	HDMI_AUD_CONF0_I2S_EN3 = 0x08,
+	HDMI_AUD_CONF0_I2S_EN2 = 0x04,
+	HDMI_AUD_CONF0_I2S_EN1 = 0x02,
+	HDMI_AUD_CONF0_I2S_EN0 = 0x01,
 
 /* AUD_CONF1 field values */
 	HDMI_AUD_CONF1_MODE_I2S = 0x00,