From 37bb18398aa190c281228e8ac76d892744dc1677 Mon Sep 17 00:00:00 2001 From: Chen-Yu Tsai Date: Wed, 5 Dec 2018 18:11:50 +0800 Subject: clk: sunxi-ng: a33: Use sigma-delta modulation for audio PLL The audio blocks require specific clock rates. Until now we were using the closest clock rate possible with integer N-M factors. This resulted in audio playback being slightly slower than it should be. The vendor kernel gets around this (for newer SoCs) by using sigma-delta modulation to generate a fractional-N factor. As the PLL hardware is identical in most chips, we can back port the settings from the newer SoC, in this case the H3, onto the A33. Signed-off-by: Chen-Yu Tsai Signed-off-by: Maxime Ripard --- drivers/clk/sunxi-ng/ccu-sun8i-a33.c | 37 +++++++++++++++++++++++------------- 1 file changed, 24 insertions(+), 13 deletions(-) (limited to 'drivers/clk/sunxi-ng/ccu-sun8i-a33.c') diff --git a/drivers/clk/sunxi-ng/ccu-sun8i-a33.c b/drivers/clk/sunxi-ng/ccu-sun8i-a33.c index 13eb5b23c5e7..f763648a5f20 100644 --- a/drivers/clk/sunxi-ng/ccu-sun8i-a33.c +++ b/drivers/clk/sunxi-ng/ccu-sun8i-a33.c @@ -51,18 +51,29 @@ static struct ccu_nkmp pll_cpux_clk = { * the base (2x, 4x and 8x), and one variable divider (the one true * pll audio). * - * We don't have any need for the variable divider for now, so we just - * hardcode it to match with the clock names + * With sigma-delta modulation for fractional-N on the audio PLL, + * we have to use specific dividers. This means the variable divider + * can no longer be used, as the audio codec requests the exact clock + * rates we support through this mechanism. So we now hard code the + * variable divider to 1. This means the clock rates will no longer + * match the clock names. */ #define SUN8I_A33_PLL_AUDIO_REG 0x008 -static SUNXI_CCU_NM_WITH_GATE_LOCK(pll_audio_base_clk, "pll-audio-base", - "osc24M", 0x008, - 8, 7, /* N */ - 0, 5, /* M */ - BIT(31), /* gate */ - BIT(28), /* lock */ - CLK_SET_RATE_UNGATE); +static struct ccu_sdm_setting pll_audio_sdm_table[] = { + { .rate = 22579200, .pattern = 0xc0010d84, .m = 8, .n = 7 }, + { .rate = 24576000, .pattern = 0xc000ac02, .m = 14, .n = 14 }, +}; + +static SUNXI_CCU_NM_WITH_SDM_GATE_LOCK(pll_audio_base_clk, "pll-audio-base", + "osc24M", 0x008, + 8, 7, /* N */ + 0, 5, /* M */ + pll_audio_sdm_table, BIT(24), + 0x284, BIT(31), + BIT(31), /* gate */ + BIT(28), /* lock */ + CLK_SET_RATE_UNGATE); static SUNXI_CCU_NM_WITH_FRAC_GATE_LOCK(pll_video_clk, "pll-video", "osc24M", 0x010, @@ -576,9 +587,9 @@ static struct ccu_common *sun8i_a33_ccu_clks[] = { &ats_clk.common, }; -/* We hardcode the divider to 4 for now */ +/* We hardcode the divider to 1 for now */ static CLK_FIXED_FACTOR(pll_audio_clk, "pll-audio", - "pll-audio-base", 4, 1, CLK_SET_RATE_PARENT); + "pll-audio-base", 1, 1, CLK_SET_RATE_PARENT); static CLK_FIXED_FACTOR(pll_audio_2x_clk, "pll-audio-2x", "pll-audio-base", 2, 1, CLK_SET_RATE_PARENT); static CLK_FIXED_FACTOR(pll_audio_4x_clk, "pll-audio-4x", @@ -781,10 +792,10 @@ static void __init sun8i_a33_ccu_setup(struct device_node *node) return; } - /* Force the PLL-Audio-1x divider to 4 */ + /* Force the PLL-Audio-1x divider to 1 */ val = readl(reg + SUN8I_A33_PLL_AUDIO_REG); val &= ~GENMASK(19, 16); - writel(val | (3 << 16), reg + SUN8I_A33_PLL_AUDIO_REG); + writel(val | (0 << 16), reg + SUN8I_A33_PLL_AUDIO_REG); /* Force PLL-MIPI to MIPI mode */ val = readl(reg + SUN8I_A33_PLL_MIPI_REG); -- cgit v1.2.3