drm: i2c: adv7511: Use internal timing generator

ADV7533 provides an internal timing generator for certain modes that it
can't use the DSI clock directly.

We've observed that hdmi is more stable with the internal timing
generator. Especially if there is instabilities in the dsi clock source.

The data spec recommends usage of the timing generator too. Use it all
the time.

Signed-off-by: Archit Taneja <architt@codeaurora.org>

2 files changed, 49 insertions, 2 deletions

diff --git a/drivers/gpu/drm/i2c/adv7511.c b/drivers/gpu/drm/i2c/adv7511.c
index 62db6430f24b4..8e5e5d41dc029 100644
--- a/drivers/gpu/drm/i2c/adv7511.c
+++ b/drivers/gpu/drm/i2c/adv7511.c
@@ -367,22 +367,66 @@ static void adv7511_set_link_config(struct adv7511 *adv7511,
 	adv7511->vsync_polarity = config->vsync_polarity;
 }
 
+static void adv7511_dsi_config_tgen(struct adv7511 *adv7511)
+{
+	struct drm_display_mode *mode = adv7511->curr_mode;
+	unsigned int hsw, hfp, hbp, vsw, vfp, vbp;
+
+	hsw = mode->hsync_end - mode->hsync_start;
+	hfp = mode->hsync_start - mode->hdisplay;
+	hbp = mode->htotal - mode->hsync_end;
+	vsw = mode->vsync_end - mode->vsync_start;
+	vfp = mode->vsync_start - mode->vdisplay;
+	vbp = mode->vtotal - mode->vsync_end;
+
+	/* set pixel clock divider mode to auto */
+	regmap_write(adv7511->regmap_cec, 0x16, 0x00);
+
+	/* horizontal porch params */
+	regmap_write(adv7511->regmap_cec, 0x28, mode->htotal >> 4);
+	regmap_write(adv7511->regmap_cec, 0x29, (mode->htotal << 4) & 0xff);
+	regmap_write(adv7511->regmap_cec, 0x2a, hsw >> 4);
+	regmap_write(adv7511->regmap_cec, 0x2b, (hsw << 4) & 0xff);
+	regmap_write(adv7511->regmap_cec, 0x2c, hfp >> 4);
+	regmap_write(adv7511->regmap_cec, 0x2d, (hfp << 4) & 0xff);
+	regmap_write(adv7511->regmap_cec, 0x2e, hbp >> 4);
+	regmap_write(adv7511->regmap_cec, 0x2f, (hbp << 4) & 0xff);
+
+	/* vertical porch params */
+	regmap_write(adv7511->regmap_cec, 0x30, mode->vtotal >> 4);
+	regmap_write(adv7511->regmap_cec, 0x31, (mode->vtotal << 4) & 0xff);
+	regmap_write(adv7511->regmap_cec, 0x32, vsw >> 4);
+	regmap_write(adv7511->regmap_cec, 0x33, (vsw << 4) & 0xff);
+	regmap_write(adv7511->regmap_cec, 0x34, vfp >> 4);
+	regmap_write(adv7511->regmap_cec, 0x35, (vfp << 4) & 0xff);
+	regmap_write(adv7511->regmap_cec, 0x36, vbp >> 4);
+	regmap_write(adv7511->regmap_cec, 0x37, (vbp << 4) & 0xff);
+}
+
 static void adv7511_dsi_receiver_dpms(struct adv7511 *adv7511)
 {
 	if (adv7511->type != ADV7533)
 		return;
 
 	if (adv7511->powered) {
+		adv7511_dsi_config_tgen(adv7511);
+
 		/* set number of dsi lanes */
 		regmap_write(adv7511->regmap_cec, 0x1c, adv7511->num_dsi_lanes << 4);
-		/* disable internal timing generator */
-		regmap_write(adv7511->regmap_cec, 0x27, 0x0b);
+
+		/* reset internal timing generator */
+		regmap_write(adv7511->regmap_cec, 0x27, 0xcb);
+		regmap_write(adv7511->regmap_cec, 0x27, 0x8b);
+		regmap_write(adv7511->regmap_cec, 0x27, 0xcb);
+
 		/* enable hdmi */
 		regmap_write(adv7511->regmap_cec, 0x03, 0x89);
+
 		/* explicitly disable test mode */
 		regmap_write(adv7511->regmap_cec, 0x55, 0x00);
 	} else {
 		regmap_write(adv7511->regmap_cec, 0x03, 0x0b);
+		regmap_write(adv7511->regmap_cec, 0x27, 0x0b);
 	}
 }
 
@@ -769,6 +813,7 @@ static void adv7511_mode_set(struct adv7511 *adv7511,
 	regmap_update_bits(adv7511->regmap, 0x17,
 		0x60, (vsync_polarity << 6) | (hsync_polarity << 5));
 
+	adv7511->curr_mode = adj_mode;
 	/*
 	 * TODO Test first order 4:2:2 to 4:4:4 up conversion method, which is
 	 * supposed to give better results.
diff --git a/drivers/gpu/drm/i2c/adv7511.h b/drivers/gpu/drm/i2c/adv7511.h
index a31c673a1552f..26c9045f6b465 100644
--- a/drivers/gpu/drm/i2c/adv7511.h
+++ b/drivers/gpu/drm/i2c/adv7511.h
@@ -256,6 +256,8 @@ struct adv7511 {
 	enum drm_connector_status status;
 	bool powered;
 
+	struct drm_display_mode *curr_mode;
+
 	unsigned int f_tmds;
 	unsigned int f_audio;
 	unsigned int audio_source;