ASoC: arizona: Optimise FLL loop gains

For optimal performance the FLL loop gain should be adjusted depending on
the frequency of the input clock for the loop.

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

diff --git a/sound/soc/codecs/arizona.c b/sound/soc/codecs/arizona.c
index e3aee14..8b7855d 100644 (file)
--- a/sound/soc/codecs/arizona.c
+++ b/sound/soc/codecs/arizona.c
@@ -990,6 +990,16 @@ static struct {
        { 1000000, 13500000, 0,  1 },
 };
 
+static struct {
+       unsigned int min;
+       unsigned int max;
+       u16 gain;
+} fll_gains[] = {
+       {       0,   256000, 0 },
+       {  256000,  1000000, 2 },
+       { 1000000, 13500000, 4 },
+};
+
 struct arizona_fll_cfg {
        int n;
        int theta;
@@ -997,6 +1007,7 @@ struct arizona_fll_cfg {
        int refdiv;
        int outdiv;
        int fratio;
+       int gain;
 };
 
 static int arizona_calc_fll(struct arizona_fll *fll,
@@ -1056,6 +1067,18 @@ static int arizona_calc_fll(struct arizona_fll *fll,
                return -EINVAL;
        }
 
+       for (i = 0; i < ARRAY_SIZE(fll_gains); i++) {
+               if (fll_gains[i].min <= Fref && Fref <= fll_gains[i].max) {
+                       cfg->gain = fll_gains[i].gain;
+                       break;
+               }
+       }
+       if (i == ARRAY_SIZE(fll_gains)) {
+               arizona_fll_err(fll, "Unable to find gain for Fref=%uHz\n",
+                               Fref);
+               return -EINVAL;
+       }
+
        cfg->n = target / (ratio * Fref);
 
        if (target % (ratio * Fref)) {
@@ -1083,13 +1106,15 @@ static int arizona_calc_fll(struct arizona_fll *fll,
                        cfg->n, cfg->theta, cfg->lambda);
        arizona_fll_dbg(fll, "FRATIO=%x(%d) OUTDIV=%x REFCLK_DIV=%x\n",
                        cfg->fratio, cfg->fratio, cfg->outdiv, cfg->refdiv);
+       arizona_fll_dbg(fll, "GAIN=%d\n", cfg->gain);
 
        return 0;
 
 }
 
 static void arizona_apply_fll(struct arizona *arizona, unsigned int base,
-                             struct arizona_fll_cfg *cfg, int source)
+                             struct arizona_fll_cfg *cfg, int source,
+                             bool sync)
 {
        regmap_update_bits(arizona->regmap, base + 3,
                           ARIZONA_FLL1_THETA_MASK, cfg->theta);
@@ -1104,6 +1129,15 @@ static void arizona_apply_fll(struct arizona *arizona, unsigned int base,
                           cfg->refdiv << ARIZONA_FLL1_CLK_REF_DIV_SHIFT |
                           source << ARIZONA_FLL1_CLK_REF_SRC_SHIFT);
 
+       if (sync)
+               regmap_update_bits(arizona->regmap, base + 0x7,
+                                  ARIZONA_FLL1_GAIN_MASK,
+                                  cfg->gain << ARIZONA_FLL1_GAIN_SHIFT);
+       else
+               regmap_update_bits(arizona->regmap, base + 0x9,
+                                  ARIZONA_FLL1_GAIN_MASK,
+                                  cfg->gain << ARIZONA_FLL1_GAIN_SHIFT);
+
        regmap_update_bits(arizona->regmap, base + 2,
                           ARIZONA_FLL1_CTRL_UPD | ARIZONA_FLL1_N_MASK,
                           ARIZONA_FLL1_CTRL_UPD | cfg->n);
@@ -1141,17 +1175,18 @@ static void arizona_enable_fll(struct arizona_fll *fll,
                                   ARIZONA_FLL1_OUTDIV_MASK,
                                   ref->outdiv << ARIZONA_FLL1_OUTDIV_SHIFT);
 
-               arizona_apply_fll(arizona, fll->base, ref, fll->ref_src);
+               arizona_apply_fll(arizona, fll->base, ref, fll->ref_src,
+                                 false);
                if (fll->sync_src >= 0)
                        arizona_apply_fll(arizona, fll->base + 0x10, sync,
-                                         fll->sync_src);
+                                         fll->sync_src, true);
        } else if (fll->sync_src >= 0) {
                regmap_update_bits(arizona->regmap, fll->base + 5,
                                   ARIZONA_FLL1_OUTDIV_MASK,
                                   sync->outdiv << ARIZONA_FLL1_OUTDIV_SHIFT);
 
                arizona_apply_fll(arizona, fll->base, sync,
-                                 fll->sync_src);
+                                 fll->sync_src, false);
        } else {
                arizona_fll_err(fll, "No clocks provided\n");
                return;