[alsa-devel] [PATCH 1/2] ASoC: nau8825: Add FLL configuration
Ben Zhang
benzh at chromium.org
Fri Oct 9 23:49:00 CEST 2015
snd_soc_codec_driver.set_pll is implemented to configure the FLL.
The codec internal SYSCLK can be from either the MCLK pin directly,
or the FLL. This is configured by snd_soc_codec_driver.set_pll.
Signed-off-by: Ben Zhang <benzh at chromium.org>
---
sound/soc/codecs/nau8825.c | 162 +++++++++++++++++++++++++++++++++++++++++++++
sound/soc/codecs/nau8825.h | 28 ++++++--
2 files changed, 185 insertions(+), 5 deletions(-)
diff --git a/sound/soc/codecs/nau8825.c b/sound/soc/codecs/nau8825.c
index 5c1badf..010f50b 100644
--- a/sound/soc/codecs/nau8825.c
+++ b/sound/soc/codecs/nau8825.c
@@ -29,6 +29,58 @@
#include "nau8825.h"
+#define NAU_FREF_MAX 13500000
+#define NAU_FVCO_MAX 100000000
+#define NAU_FVCO_MIN 90000000
+
+struct nau88xx_fll {
+ int mclk_src;
+ int ratio;
+ int fll_frac;
+ int fll_int;
+ int clk_ref_div;
+};
+
+struct nau88xx_fll_attr {
+ unsigned int param;
+ unsigned int val;
+};
+
+/* scaling for mclk from sysclk_src output */
+static const struct nau88xx_fll_attr mclk_src_scaling[] = {
+ { 1, 0x0 },
+ { 2, 0x2 },
+ { 4, 0x3 },
+ { 8, 0x4 },
+ { 16, 0x5 },
+ { 32, 0x6 },
+ { 3, 0x7 },
+ { 6, 0xa },
+ { 12, 0xb },
+ { 24, 0xc },
+ { 48, 0xd },
+ { 96, 0xe },
+ { 5, 0xf },
+};
+
+/* ratio for input clk freq */
+static const struct nau88xx_fll_attr fll_ratio[] = {
+ { 512000, 0x01 },
+ { 256000, 0x02 },
+ { 128000, 0x04 },
+ { 64000, 0x08 },
+ { 32000, 0x10 },
+ { 8000, 0x20 },
+ { 4000, 0x40 },
+};
+
+static const struct nau88xx_fll_attr fll_pre_scalar[] = {
+ { 1, 0x0 },
+ { 2, 0x1 },
+ { 4, 0x2 },
+ { 8, 0x3 },
+};
+
static const struct reg_default nau8825_reg_defaults[] = {
{ NAU8825_REG_ENA_CTRL, 0x00ff },
{ NAU8825_REG_CLK_DIVIDER, 0x0050 },
@@ -808,6 +860,115 @@ static int nau8825_codec_probe(struct snd_soc_codec *codec)
return 0;
}
+/**
+ * nau88xx_calc_fll_param - Calculate FLL parameters.
+ * @fll_in: external clock provided to codec.
+ * @fs: sampling rate.
+ * @fll_param: Pointer to structure of FLL parameters.
+ *
+ * Calculate FLL parameters to configure codec.
+ *
+ * Returns 0 for success or negative error code.
+ */
+static int nau88xx_calc_fll_param(unsigned int fll_in, unsigned int fs,
+ struct nau88xx_fll *fll_param)
+{
+ u64 fref, fvco, fll_input;
+ int i;
+
+ /* Ensure the reference clock frequency (FREF) is <= 13.5MHz by dividing
+ * freq_in by 1, 2, 4, or 8 using FLL pre-scalar.
+ * FREF = freq_in / NAU8825_FLL_REF_DIV_MASK
+ */
+ for (i = 0; i < ARRAY_SIZE(fll_pre_scalar); i++) {
+ fref = fll_in / fll_pre_scalar[i].param;
+ if (fref <= NAU_FREF_MAX)
+ break;
+ }
+ if (i == ARRAY_SIZE(fll_pre_scalar))
+ return -EINVAL;
+ fll_param->clk_ref_div = fll_pre_scalar[i].val;
+
+ /* Choose the FLL ratio based on FREF */
+ for (i = 0; i < ARRAY_SIZE(fll_ratio); i++) {
+ if (fref >= fll_ratio[i].param)
+ break;
+ }
+ if (i == ARRAY_SIZE(fll_ratio))
+ return -EINVAL;
+ fll_param->ratio = fll_ratio[i].val;
+
+ /* Calculate the frequency of DCO (FDCO) given freq_out = 256 * Fs.
+ * FDCO must be within the 90MHz - 100MHz or the FFL cannot be
+ * guaranteed across the full range of operation.
+ * FDCO = freq_out * 2 * mclk_src_scaling
+ */
+ for (i = 0; i < ARRAY_SIZE(mclk_src_scaling); i++) {
+ fvco = 256 * fs * 2 * mclk_src_scaling[i].param;
+ if (NAU_FVCO_MIN < fvco && fvco < NAU_FVCO_MAX)
+ break;
+ }
+ if (i == ARRAY_SIZE(mclk_src_scaling))
+ return -EINVAL;
+ fll_param->mclk_src = mclk_src_scaling[i].val;
+
+ /* Calculate the FLL 10-bit integer input and the FLL 16-bit fractional
+ * input based on FDCO, FREF and FLL ratio.
+ */
+ fll_input = (fvco << 16) / (fref * fll_param->ratio);
+ fll_param->fll_int = fll_input >> 16;
+ fll_param->fll_frac = fll_input & 0xFFFF;
+ return 0;
+}
+
+static void nau88xx_fll_apply(struct nau8825 *nau8825,
+ struct nau88xx_fll *fll_param)
+{
+ regmap_update_bits(nau8825->regmap, NAU8825_REG_CLK_DIVIDER,
+ NAU8825_CLK_MCLK_SRC_MASK, fll_param->mclk_src);
+ regmap_update_bits(nau8825->regmap, NAU8825_REG_FLL1,
+ NAU8825_FLL_RATIO_MASK, fll_param->ratio);
+ /* FLL 16-bit fractional input */
+ regmap_write(nau8825->regmap, NAU8825_REG_FLL2, fll_param->fll_frac);
+ /* FLL 10-bit integer input */
+ regmap_update_bits(nau8825->regmap, NAU8825_REG_FLL3,
+ NAU8825_FLL_INTEGER_MASK, fll_param->fll_int);
+ /* FLL pre-scaler */
+ regmap_update_bits(nau8825->regmap, NAU8825_REG_FLL4,
+ NAU8825_FLL_REF_DIV_MASK, fll_param->clk_ref_div);
+ /* select divided VCO input */
+ regmap_update_bits(nau8825->regmap, NAU8825_REG_FLL5,
+ NAU8825_FLL_FILTER_SW_MASK, 0x0000);
+ /* FLL sigma delta modulator enable */
+ regmap_update_bits(nau8825->regmap, NAU8825_REG_FLL6,
+ NAU8825_SDM_EN_MASK, NAU8825_SDM_EN);
+}
+
+/* freq_out must be 256*Fs in order to achieve the best performance */
+static int nau8825_set_pll(struct snd_soc_codec *codec, int pll_id, int source,
+ unsigned int freq_in, unsigned int freq_out)
+{
+ struct nau8825 *nau8825 = snd_soc_codec_get_drvdata(codec);
+ struct nau88xx_fll fll_param;
+ int ret, fs;
+
+ fs = freq_out / 256;
+ ret = nau88xx_calc_fll_param(freq_in, fs, &fll_param);
+ if (ret < 0) {
+ dev_err(codec->dev, "Unsupported input clock %d\n", freq_in);
+ return ret;
+ }
+ dev_dbg(codec->dev, "mclk_src=%x ratio=%x fll_frac=%x fll_int=%x clk_ref_div=%x\n",
+ fll_param.mclk_src, fll_param.ratio, fll_param.fll_frac,
+ fll_param.fll_int, fll_param.clk_ref_div);
+
+ nau88xx_fll_apply(nau8825, &fll_param);
+ mdelay(2);
+ regmap_update_bits(nau8825->regmap, NAU8825_REG_CLK_DIVIDER,
+ NAU8825_CLK_SRC_MASK, NAU8825_CLK_SRC_VCO);
+ return 0;
+}
+
static int nau8825_configure_sysclk(struct nau8825 *nau8825, int clk_id,
unsigned int freq)
{
@@ -920,6 +1081,7 @@ static int nau8825_set_bias_level(struct snd_soc_codec *codec,
static struct snd_soc_codec_driver nau8825_codec_driver = {
.probe = nau8825_codec_probe,
.set_sysclk = nau8825_set_sysclk,
+ .set_pll = nau8825_set_pll,
.set_bias_level = nau8825_set_bias_level,
.suspend_bias_off = true,
diff --git a/sound/soc/codecs/nau8825.h b/sound/soc/codecs/nau8825.h
index 8774923..dff8edb 100644
--- a/sound/soc/codecs/nau8825.h
+++ b/sound/soc/codecs/nau8825.h
@@ -101,13 +101,31 @@
#define NAU8825_ENABLE_SAR_SFT 1
/* CLK_DIVIDER (0x3) */
-#define NAU8825_CLK_SRC_SFT 15
-#define NAU8825_CLK_SRC_MASK (1 << NAU8825_CLK_SRC_SFT)
-#define NAU8825_CLK_SRC_VCO (1 << NAU8825_CLK_SRC_SFT)
-#define NAU8825_CLK_SRC_MCLK (0 << NAU8825_CLK_SRC_SFT)
+#define NAU8825_CLK_SRC_SFT 15
+#define NAU8825_CLK_SRC_MASK (1 << NAU8825_CLK_SRC_SFT)
+#define NAU8825_CLK_SRC_VCO (1 << NAU8825_CLK_SRC_SFT)
+#define NAU8825_CLK_SRC_MCLK (0 << NAU8825_CLK_SRC_SFT)
+#define NAU8825_CLK_MCLK_SRC_MASK (0xf << 0)
+
+/* FLL1 (0x04) */
+#define NAU8825_FLL_RATIO_MASK (0x7f << 0)
+
+/* FLL3 (0x06) */
+#define NAU8825_FLL_INTEGER_MASK (0x3ff << 0)
+
+/* FLL4 (0x07) */
+#define NAU8825_FLL_REF_DIV_MASK (0x3 << 10)
+
+/* FLL5 (0x08) */
+#define NAU8825_FLL_FILTER_SW_MASK (0x1 << 14)
/* FLL6 (0x9) */
-#define NAU8825_DCO_EN (1 << 15)
+#define NAU8825_DCO_EN_MASK (0x1 << 15)
+#define NAU8825_DCO_EN (0x1 << 15)
+#define NAU8825_DCO_DIS (0x0 << 15)
+#define NAU8825_SDM_EN_MASK (0x1 << 14)
+#define NAU8825_SDM_EN (0x1 << 14)
+#define NAU8825_SDM_DIS (0x0 << 14)
/* HSD_CTRL (0xc) */
#define NAU8825_HSD_AUTO_MODE (1 << 6)
--
2.6.0.rc2.230.g3dd15c0
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