From d0c96d168021a60555c692d860334814cc694d8b Mon Sep 17 00:00:00 2001 From: Russell King Date: Wed, 22 Jul 2015 10:35:41 +0100 Subject: [PATCH] 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 Signed-off-by: Russell King --- drivers/gpu/drm/bridge/dw_hdmi.c | 25 +++++++++---------------- 1 file changed, 9 insertions(+), 16 deletions(-) diff --git a/drivers/gpu/drm/bridge/dw_hdmi.c b/drivers/gpu/drm/bridge/dw_hdmi.c index 70e7a938a37b..e5ee92370f49 100644 --- 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: -- 2.34.1