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 some SoCs) by using sigma-delta modulation to generate a fractional-N factor. As the PLL hardware is identical in most chips, we can port the settings for H3 onto the A64.
Signed-off-by: Chen-Yu Tsai wens@csie.org --- drivers/clk/sunxi-ng/ccu-sun50i-a64.c | 37 +++++++++++++++++---------- 1 file changed, 24 insertions(+), 13 deletions(-)
diff --git a/drivers/clk/sunxi-ng/ccu-sun50i-a64.c b/drivers/clk/sunxi-ng/ccu-sun50i-a64.c index 1f45b20ad752..181b599dc163 100644 --- a/drivers/clk/sunxi-ng/ccu-sun50i-a64.c +++ b/drivers/clk/sunxi-ng/ccu-sun50i-a64.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 SUN50I_A64_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_MIN_MAX(pll_video0_clk, "pll-video0", "osc24M", 0x010, @@ -594,9 +605,9 @@ static SUNXI_CCU_M_WITH_GATE(gpu_clk, "gpu", "pll-gpu", /* Fixed Factor clocks */ static CLK_FIXED_FACTOR(osc12M_clk, "osc12M", "osc24M", 2, 1, 0);
-/* 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", @@ -916,10 +927,10 @@ static int sun50i_a64_ccu_probe(struct platform_device *pdev) if (IS_ERR(reg)) return PTR_ERR(reg);
- /* Force the PLL-Audio-1x divider to 4 */ + /* Force the PLL-Audio-1x divider to 1 */ val = readl(reg + SUN50I_A64_PLL_AUDIO_REG); val &= ~GENMASK(19, 16); - writel(val | (3 << 16), reg + SUN50I_A64_PLL_AUDIO_REG); + writel(val | (0 << 16), reg + SUN50I_A64_PLL_AUDIO_REG);
writel(0x515, reg + SUN50I_A64_PLL_MIPI_REG);