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. This patch copies the
parameters for the A83T.
Signed-off-by: Chen-Yu Tsai <w...@csie.org>
---
drivers/clk/sunxi-ng/ccu-sun8i-a83t.c | 11 ++++++++++-
1 file changed, 10 insertions(+), 1 deletion(-)
diff --git a/drivers/clk/sunxi-ng/ccu-sun8i-a83t.c
b/drivers/clk/sunxi-ng/ccu-sun8i-a83t.c
index 06b69e433d0f..04a9c33f53f0 100644
--- a/drivers/clk/sunxi-ng/ccu-sun8i-a83t.c
+++ b/drivers/clk/sunxi-ng/ccu-sun8i-a83t.c
@@ -76,17 +76,26 @@ static struct ccu_mult pll_c1cpux_clk = {
*/
#define SUN8I_A83T_PLL_AUDIO_REG 0x008
+/* clock rates doubled for post divider */
+static struct ccu_sdm_setting pll_audio_sdm_table[] = {
+ { .rate = 45158400, .pattern = 0xc00121ff, .m = 29, .n = 54 },
+ { .rate = 49152000, .pattern = 0xc000e147, .m = 30, .n = 61 },
+};
+
static struct ccu_nm pll_audio_clk = {
.enable = BIT(31),
.lock = BIT(2),
.n = _SUNXI_CCU_MULT_OFFSET_MIN_MAX(8, 8, 0, 12, 0),
.m = _SUNXI_CCU_DIV(0, 6),
.fixed_post_div = 2,
+ .sdm = _SUNXI_CCU_SDM(pll_audio_sdm_table, BIT(24),
+ 0x284, BIT(31)),
.common = {
.reg = SUN8I_A83T_PLL_AUDIO_REG,
.lock_reg = CCU_SUN8I_A83T_LOCK_REG,
.features = CCU_FEATURE_LOCK_REG |
- CCU_FEATURE_FIXED_POSTDIV,
+ CCU_FEATURE_FIXED_POSTDIV |
+ CCU_FEATURE_SIGMA_DELTA_MOD,
.hw.init = CLK_HW_INIT("pll-audio", "osc24M",
&ccu_nm_ops, CLK_SET_RATE_UNGATE),
},
--
2.15.0
