[PATCH 3/4] ASoC: da7213: Refactor sysclk(), pll() functions to improve handling

From: Adam Thomson
Date: Thu Aug 04 2016 - 10:43:48 EST


Currently the handling of the PLL in the driver is a little clunky,
and not ideal for all modes. This patch updates the code to make it
cleaner and more sensible for the various PLL states.

Key items of note are:
- MCLK squaring is now handled directly as part of the sysclk()
function, removing the need for a private flag to set this feature.
- All PLL modes are defined as an enum, and are handled as a case
statement in pll() function to clean up configuration. This also
removes any need for a private flag for SRM.
- For 32KHz mode, checks are made on codec master mode and correct
MCLK rates, to avoid incorrect usage of PLL for this operation.
- For 32KHz mode, SRM flag now correctly enabled and fout set to
sensible value to achieve appropriate PLL dividers.

Signed-off-by: Adam Thomson <Adam.Thomson.Opensource@xxxxxxxxxxx>
---
sound/soc/codecs/da7213.c | 85 +++++++++++++++++++++++++++--------------------
sound/soc/codecs/da7213.h | 12 ++++---
2 files changed, 57 insertions(+), 40 deletions(-)

diff --git a/sound/soc/codecs/da7213.c b/sound/soc/codecs/da7213.c
index 7701f4e..79b8324 100644
--- a/sound/soc/codecs/da7213.c
+++ b/sound/soc/codecs/da7213.c
@@ -1297,10 +1297,13 @@ static int da7213_set_dai_sysclk(struct snd_soc_dai *codec_dai,

switch (clk_id) {
case DA7213_CLKSRC_MCLK:
- da7213->mclk_squarer_en = false;
+ snd_soc_update_bits(codec, DA7213_PLL_CTRL,
+ DA7213_PLL_MCLK_SQR_EN, 0);
break;
case DA7213_CLKSRC_MCLK_SQR:
- da7213->mclk_squarer_en = true;
+ snd_soc_update_bits(codec, DA7213_PLL_CTRL,
+ DA7213_PLL_MCLK_SQR_EN,
+ DA7213_PLL_MCLK_SQR_EN);
break;
default:
dev_err(codec_dai->dev, "Unknown clock source %d\n", clk_id);
@@ -1324,7 +1327,7 @@ static int da7213_set_dai_sysclk(struct snd_soc_dai *codec_dai,
return 0;
}

-/* Supported PLL input frequencies are 5MHz - 54MHz. */
+/* Supported PLL input frequencies are 32KHz, 5MHz - 54MHz. */
static int da7213_set_dai_pll(struct snd_soc_dai *codec_dai, int pll_id,
int source, unsigned int fref, unsigned int fout)
{
@@ -1336,22 +1339,26 @@ static int da7213_set_dai_pll(struct snd_soc_dai *codec_dai, int pll_id,
u32 freq_ref;
u64 frac_div;

- /* Reset PLL configuration */
- snd_soc_write(codec, DA7213_PLL_CTRL, 0);
-
- pll_ctrl = 0;
-
/* Workout input divider based on MCLK rate */
if (da7213->mclk_rate == 32768) {
+ if (!da7213->master) {
+ dev_err(codec->dev,
+ "32KHz only valid if codec is clock master\n");
+ return -EINVAL;
+ }
+
/* 32KHz PLL Mode */
indiv_bits = DA7213_PLL_INDIV_9_TO_18_MHZ;
indiv = DA7213_PLL_INDIV_9_TO_18_MHZ_VAL;
+ source = DA7213_SYSCLK_PLL_32KHZ;
freq_ref = 3750000;
- pll_ctrl |= DA7213_PLL_32K_MODE;
+
} else {
- /* 5 - 54MHz MCLK */
if (da7213->mclk_rate < 5000000) {
- goto pll_err;
+ dev_err(codec->dev,
+ "PLL input clock %d below valid range\n",
+ da7213->mclk_rate);
+ return -EINVAL;
} else if (da7213->mclk_rate <= 9000000) {
indiv_bits = DA7213_PLL_INDIV_5_TO_9_MHZ;
indiv = DA7213_PLL_INDIV_5_TO_9_MHZ_VAL;
@@ -1365,32 +1372,44 @@ static int da7213_set_dai_pll(struct snd_soc_dai *codec_dai, int pll_id,
indiv_bits = DA7213_PLL_INDIV_36_TO_54_MHZ;
indiv = DA7213_PLL_INDIV_36_TO_54_MHZ_VAL;
} else {
- goto pll_err;
+ dev_err(codec->dev,
+ "PLL input clock %d above valid range\n",
+ da7213->mclk_rate);
+ return -EINVAL;
}
freq_ref = (da7213->mclk_rate / indiv);
}

- pll_ctrl |= indiv_bits;
+ pll_ctrl = indiv_bits;

- /* PLL Bypass mode */
- if (source == DA7213_SYSCLK_MCLK) {
- snd_soc_write(codec, DA7213_PLL_CTRL, pll_ctrl);
+ /* Configure PLL */
+ switch (source) {
+ case DA7213_SYSCLK_MCLK:
+ snd_soc_update_bits(codec, DA7213_PLL_CTRL,
+ DA7213_PLL_INDIV_MASK |
+ DA7213_PLL_MODE_MASK, pll_ctrl);
return 0;
- }
+ case DA7213_SYSCLK_PLL:
+ break;
+ case DA7213_SYSCLK_PLL_SRM:
+ pll_ctrl |= DA7213_PLL_SRM_EN;
+ fout = DA7213_PLL_FREQ_OUT_94310400;
+ break;
+ case DA7213_SYSCLK_PLL_32KHZ:
+ if (da7213->mclk_rate != 32768) {
+ dev_err(codec->dev,
+ "32KHz mode only valid with 32KHz MCLK\n");
+ return -EINVAL;
+ }

- /*
- * If Codec is slave and SRM enabled,
- * freq_out is (98304000 + 90316800)/2 = 94310400
- */
- if (!da7213->master && da7213->srm_en) {
+ pll_ctrl |= DA7213_PLL_32K_MODE | DA7213_PLL_SRM_EN;
fout = DA7213_PLL_FREQ_OUT_94310400;
- pll_ctrl |= DA7213_PLL_SRM_EN;
+ break;
+ default:
+ dev_err(codec->dev, "Invalid PLL config\n");
+ return -EINVAL;
}

- /* Enable MCLK squarer if required */
- if (da7213->mclk_squarer_en)
- pll_ctrl |= DA7213_PLL_MCLK_SQR_EN;
-
/* Calculate dividers for PLL */
pll_integer = fout / freq_ref;
frac_div = (u64)(fout % freq_ref) * 8192ULL;
@@ -1405,14 +1424,11 @@ static int da7213_set_dai_pll(struct snd_soc_dai *codec_dai, int pll_id,

/* Enable PLL */
pll_ctrl |= DA7213_PLL_EN;
- snd_soc_write(codec, DA7213_PLL_CTRL, pll_ctrl);
+ snd_soc_update_bits(codec, DA7213_PLL_CTRL,
+ DA7213_PLL_INDIV_MASK | DA7213_PLL_MODE_MASK,
+ pll_ctrl);

return 0;
-
-pll_err:
- dev_err(codec_dai->dev, "Unsupported PLL input frequency %d\n",
- da7213->mclk_rate);
- return -EINVAL;
}

/* DAI operations */
@@ -1607,9 +1623,6 @@ static int da7213_probe(struct snd_soc_codec *codec)
DA7213_ALC_CALIB_MODE_MAN, 0);
da7213->alc_calib_auto = true;

- /* Default to using SRM for slave mode */
- da7213->srm_en = true;
-
/* Default PC counter to free-running */
snd_soc_update_bits(codec, DA7213_PC_COUNT, DA7213_PC_FREERUN_MASK,
DA7213_PC_FREERUN_MASK);
diff --git a/sound/soc/codecs/da7213.h b/sound/soc/codecs/da7213.h
index fbb7a35..16ef56f 100644
--- a/sound/soc/codecs/da7213.h
+++ b/sound/soc/codecs/da7213.h
@@ -172,6 +172,7 @@
#define DA7213_PLL_32K_MODE (0x1 << 5)
#define DA7213_PLL_SRM_EN (0x1 << 6)
#define DA7213_PLL_EN (0x1 << 7)
+#define DA7213_PLL_MODE_MASK (0x7 << 5)

/* DA7213_DAI_CLK_MODE = 0x28 */
#define DA7213_DAI_BCLKS_PER_WCLK_32 (0x0 << 0)
@@ -499,8 +500,6 @@
#define DA7213_ALC_AVG_ITERATIONS 5

/* PLL related */
-#define DA7213_SYSCLK_MCLK 0
-#define DA7213_SYSCLK_PLL 1
#define DA7213_PLL_FREQ_OUT_90316800 90316800
#define DA7213_PLL_FREQ_OUT_98304000 98304000
#define DA7213_PLL_FREQ_OUT_94310400 94310400
@@ -515,6 +514,13 @@ enum da7213_clk_src {
DA7213_CLKSRC_MCLK_SQR,
};

+enum da7213_sys_clk {
+ DA7213_SYSCLK_MCLK = 0,
+ DA7213_SYSCLK_PLL,
+ DA7213_SYSCLK_PLL_SRM,
+ DA7213_SYSCLK_PLL_32KHZ
+};
+
/* Codec private data */
struct da7213_priv {
struct regmap *regmap;
@@ -522,8 +528,6 @@ struct da7213_priv {
unsigned int mclk_rate;
int clk_src;
bool master;
- bool mclk_squarer_en;
- bool srm_en;
bool alc_calib_auto;
bool alc_en;
struct da7213_platform_data *pdata;
--
1.9.3