drm: bridge/dw_hdmi: avoid being recursive in N calculation

There's no need to be recursive when computing the N value for the ACR
packet - we can instead calculate the multiplier prior to our switch()
based lookup, and multiply the N value appropriately afterwards.

Tested-by: Fabio Estevam <fabio.estevam@freescale.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

diff --git a/drivers/gpu/drm/bridge/dw_hdmi.c b/drivers/gpu/drm/bridge/dw_hdmi.c
index 70e7a938a37b7388a92a6bc51f79576371952a68..e5ee92370f49e73d73c414359d1eb2b76e499a43 100644 (file)
--- a/drivers/gpu/drm/bridge/dw_hdmi.c
+++ b/drivers/gpu/drm/bridge/dw_hdmi.c
@@ -221,6 +221,12 @@ static unsigned int hdmi_compute_n(unsigned int freq, unsigned long pixel_clk,
                                   unsigned int ratio)
 {
        unsigned int n = (128 * freq) / 1000;
+       unsigned int mult = 1;
+
+       while (freq > 48000) {
+               mult *= 2;
+               freq /= 2;
+       }
 
        switch (freq) {
        case 32000:
@@ -232,6 +238,7 @@ static unsigned int hdmi_compute_n(unsigned int freq, unsigned long pixel_clk,
                        n = 11648;
                else
                        n = 4096;
+               n *= mult;
                break;
 
        case 44100:
@@ -243,6 +250,7 @@ static unsigned int hdmi_compute_n(unsigned int freq, unsigned long pixel_clk,
                        n = (ratio == 150) ? 17836 : 8918;
                else
                        n = 6272;
+               n *= mult;
                break;
 
        case 48000:
@@ -256,22 +264,7 @@ static unsigned int hdmi_compute_n(unsigned int freq, unsigned long pixel_clk,
                        n = (ratio == 150) ? 11648 : 5824;
                else
                        n = 6144;
-               break;
-
-       case 88200:
-               n = hdmi_compute_n(44100, pixel_clk, ratio) * 2;
-               break;
-
-       case 96000:
-               n = hdmi_compute_n(48000, pixel_clk, ratio) * 2;
-               break;
-
-       case 176400:
-               n = hdmi_compute_n(44100, pixel_clk, ratio) * 4;
-               break;
-
-       case 192000:
-               n = hdmi_compute_n(48000, pixel_clk, ratio) * 4;
+               n *= mult;
                break;
 
        default: