[7/9] drm: bridge/dw_hdmi: remove ratio support from ACR code
diff mbox

Message ID E1ZO6hh-0003Nc-A7@rmk-PC.arm.linux.org.uk
State New
Headers show

Commit Message

Russell King Aug. 8, 2015, 4:10 p.m. UTC
We never set the ratio for CTS/N calculation for the audio clock
regenerator (ACR) to anything but 100, so this adds pointless
complexity.  Should we support pixel repetition, we should update the
CTS/N calculation code to use those parameters or the actual TMDS clock
rate instead of a ratio.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
---
 drivers/gpu/drm/bridge/dw_hdmi.c | 44 ++++++++++++++++------------------------
 1 file changed, 18 insertions(+), 26 deletions(-)

Comments

Doug Anderson Sept. 4, 2015, 6:24 p.m. UTC | #1
Russell,

On Sat, Aug 8, 2015 at 9:10 AM, Russell King
<rmk+kernel@arm.linux.org.uk> wrote:
> We never set the ratio for CTS/N calculation for the audio clock
> regenerator (ACR) to anything but 100, so this adds pointless
> complexity.  Should we support pixel repetition, we should update the
> CTS/N calculation code to use those parameters or the actual TMDS clock
> rate instead of a ratio.
>
> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
> ---
>  drivers/gpu/drm/bridge/dw_hdmi.c | 44 ++++++++++++++++------------------------
>  1 file changed, 18 insertions(+), 26 deletions(-)

It looks like I've got a slightly older version of the driver in my
tree (based on some earlier mailing list postings), but backporting
this was pretty trivial and I've tried it in my 3.14 kernel.  It
doesn't cause any problems for me to remove the "radio" and I agree
that we should add it if/when pixel repetition is added.

Reviewed-by: Douglas Anderson <dianders@chromium.org>
Tested-by: Douglas Anderson <dianders@chromium.org>

Patch
diff mbox

diff --git a/drivers/gpu/drm/bridge/dw_hdmi.c b/drivers/gpu/drm/bridge/dw_hdmi.c
index 5576cd7d7abb..60487bff48e3 100644
--- a/drivers/gpu/drm/bridge/dw_hdmi.c
+++ b/drivers/gpu/drm/bridge/dw_hdmi.c
@@ -140,7 +140,6 @@  struct dw_hdmi {
 	unsigned int audio_cts;
 	unsigned int audio_n;
 	bool audio_enable;
-	int ratio;
 
 	void (*write)(struct dw_hdmi *hdmi, u8 val, int offset);
 	u8 (*read)(struct dw_hdmi *hdmi, int offset);
@@ -217,8 +216,7 @@  static void hdmi_set_cts_n(struct dw_hdmi *hdmi, unsigned int cts,
 	hdmi_writeb(hdmi, n & 0xff, HDMI_AUD_N1);
 }
 
-static unsigned int hdmi_compute_n(unsigned int freq, unsigned long pixel_clk,
-				   unsigned int ratio)
+static unsigned int hdmi_compute_n(unsigned int freq, unsigned long pixel_clk)
 {
 	unsigned int n = (128 * freq) / 1000;
 	unsigned int mult = 1;
@@ -231,9 +229,9 @@  static unsigned int hdmi_compute_n(unsigned int freq, unsigned long pixel_clk,
 	switch (freq) {
 	case 32000:
 		if (pixel_clk == 25175000)
-			n = (ratio == 150) ? 9152 : 4576;
+			n = 4576;
 		else if (pixel_clk == 27027000)
-			n = (ratio == 150) ? 8192 : 4096;
+			n = 4096;
 		else if (pixel_clk == 74176000 || pixel_clk == 148352000)
 			n = 11648;
 		else
@@ -247,7 +245,7 @@  static unsigned int hdmi_compute_n(unsigned int freq, unsigned long pixel_clk,
 		else if (pixel_clk == 74176000)
 			n = 17836;
 		else if (pixel_clk == 148352000)
-			n = (ratio == 150) ? 17836 : 8918;
+			n = 8918;
 		else
 			n = 6272;
 		n *= mult;
@@ -255,13 +253,13 @@  static unsigned int hdmi_compute_n(unsigned int freq, unsigned long pixel_clk,
 
 	case 48000:
 		if (pixel_clk == 25175000)
-			n = (ratio == 150) ? 9152 : 6864;
+			n = 6864;
 		else if (pixel_clk == 27027000)
-			n = (ratio == 150) ? 8192 : 6144;
+			n = 6144;
 		else if (pixel_clk == 74176000)
 			n = 11648;
 		else if (pixel_clk == 148352000)
-			n = (ratio == 150) ? 11648 : 5824;
+			n = 5824;
 		else
 			n = 6144;
 		n *= mult;
@@ -274,13 +272,11 @@  static unsigned int hdmi_compute_n(unsigned int freq, unsigned long pixel_clk,
 	return n;
 }
 
-static unsigned int hdmi_compute_cts(unsigned int freq, unsigned long pixel_clk,
-				     unsigned int ratio)
+static unsigned int hdmi_compute_cts(unsigned int freq, unsigned long pixel_clk)
 {
 	unsigned int cts = 0;
 
-	pr_debug("%s: freq: %d pixel_clk: %ld ratio: %d\n", __func__, freq,
-		 pixel_clk, ratio);
+	pr_debug("%s: freq: %d pixel_clk: %ld\n", __func__, freq, pixel_clk);
 
 	switch (freq) {
 	case 32000:
@@ -341,26 +337,24 @@  static unsigned int hdmi_compute_cts(unsigned int freq, unsigned long pixel_clk,
 	default:
 		break;
 	}
-	if (ratio == 100)
-		return cts;
-	return (cts * ratio) / 100;
+	return cts;
 }
 
 static void hdmi_set_clk_regenerator(struct dw_hdmi *hdmi,
-	unsigned long pixel_clk, unsigned int sample_rate, unsigned int ratio)
+	unsigned long pixel_clk, unsigned int sample_rate)
 {
 	unsigned int n, cts;
 
-	n = hdmi_compute_n(sample_rate, pixel_clk, ratio);
-	cts = hdmi_compute_cts(sample_rate, pixel_clk, ratio);
+	n = hdmi_compute_n(sample_rate, pixel_clk);
+	cts = hdmi_compute_cts(sample_rate, pixel_clk);
 	if (!cts) {
 		dev_err(hdmi->dev,
 			"%s: pixel clock/sample rate not supported: %luMHz / %ukHz\n",
 			__func__, pixel_clk, sample_rate);
 	}
 
-	dev_dbg(hdmi->dev, "%s: samplerate=%ukHz ratio=%d pixelclk=%luMHz N=%d cts=%d\n",
-		__func__, sample_rate, ratio, pixel_clk, n, cts);
+	dev_dbg(hdmi->dev, "%s: samplerate=%ukHz pixelclk=%luMHz N=%d cts=%d\n",
+		__func__, sample_rate, pixel_clk, n, cts);
 
 	spin_lock_irq(&hdmi->audio_lock);
 	hdmi->audio_n = n;
@@ -372,8 +366,7 @@  static void hdmi_set_clk_regenerator(struct dw_hdmi *hdmi,
 static void hdmi_init_clk_regenerator(struct dw_hdmi *hdmi)
 {
 	mutex_lock(&hdmi->audio_mutex);
-	hdmi_set_clk_regenerator(hdmi, 74250000, hdmi->sample_rate,
-				 hdmi->ratio);
+	hdmi_set_clk_regenerator(hdmi, 74250000, hdmi->sample_rate);
 	mutex_unlock(&hdmi->audio_mutex);
 }
 
@@ -381,7 +374,7 @@  static void hdmi_clk_regenerator_update_pixel_clock(struct dw_hdmi *hdmi)
 {
 	mutex_lock(&hdmi->audio_mutex);
 	hdmi_set_clk_regenerator(hdmi, hdmi->hdmi_data.video_mode.mpixelclock,
-				 hdmi->sample_rate, hdmi->ratio);
+				 hdmi->sample_rate);
 	mutex_unlock(&hdmi->audio_mutex);
 }
 
@@ -390,7 +383,7 @@  void dw_hdmi_set_sample_rate(struct dw_hdmi *hdmi, unsigned int rate)
 	mutex_lock(&hdmi->audio_mutex);
 	hdmi->sample_rate = rate;
 	hdmi_set_clk_regenerator(hdmi, hdmi->hdmi_data.video_mode.mpixelclock,
-				 hdmi->sample_rate, hdmi->ratio);
+				 hdmi->sample_rate);
 	mutex_unlock(&hdmi->audio_mutex);
 }
 EXPORT_SYMBOL_GPL(dw_hdmi_set_sample_rate);
@@ -1746,7 +1739,6 @@  int dw_hdmi_bind(struct device *dev, struct device *master,
 	hdmi->dev = dev;
 	hdmi->dev_type = plat_data->dev_type;
 	hdmi->sample_rate = 48000;
-	hdmi->ratio = 100;
 	hdmi->encoder = encoder;
 	hdmi->disabled = true;
 	hdmi->rxsense = true;