From 3cf956eebe54cdb7cf1701642085507f0354e56a Mon Sep 17 00:00:00 2001 From: Mark Brown Date: Wed, 20 Mar 2013 10:12:10 +0100 Subject: [PATCH] ASoC: wm8994: Support constraining the maximum number of channels clocked Some systems use the audio CODEC to clock a DAI with multiple data lines in parallel, meaning that bit clocks are only required for a smaller number of channels than data is sent for. In some cases providing the extra bit clocks can take the other devices on the audio bus out of spec. Support such systems by allowing a maximum number of channels to be specified. Signed-off-by: Mark Brown --- include/linux/mfd/wm8994/pdata.h | 8 ++++++++ sound/soc/codecs/wm8994.c | 13 +++++++++++-- 2 files changed, 19 insertions(+), 2 deletions(-) diff --git a/include/linux/mfd/wm8994/pdata.h b/include/linux/mfd/wm8994/pdata.h index 8e21a094836d..68e776594889 100644 --- a/include/linux/mfd/wm8994/pdata.h +++ b/include/linux/mfd/wm8994/pdata.h @@ -17,6 +17,7 @@ #define WM8994_NUM_LDO 2 #define WM8994_NUM_GPIO 11 +#define WM8994_NUM_AIF 3 struct wm8994_ldo_pdata { /** GPIOs to enable regulator, 0 or less if not available */ @@ -215,6 +216,13 @@ struct wm8994_pdata { * system. */ bool spkmode_pu; + + /** + * Maximum number of channels clocks will be generated for, + * useful for systems where and I2S bus with multiple data + * lines is mastered. + */ + int max_channels_clocked[WM8994_NUM_AIF]; }; #endif diff --git a/sound/soc/codecs/wm8994.c b/sound/soc/codecs/wm8994.c index c9bd445c4976..318ea64b9800 100644 --- a/sound/soc/codecs/wm8994.c +++ b/sound/soc/codecs/wm8994.c @@ -2656,6 +2656,8 @@ static int wm8994_hw_params(struct snd_pcm_substream *substream, { struct snd_soc_codec *codec = dai->codec; struct wm8994_priv *wm8994 = snd_soc_codec_get_drvdata(codec); + struct wm8994 *control = wm8994->wm8994; + struct wm8994_pdata *pdata = &control->pdata; int aif1_reg; int aif2_reg; int bclk_reg; @@ -2723,7 +2725,14 @@ static int wm8994_hw_params(struct snd_pcm_substream *substream, } wm8994->channels[id] = params_channels(params); - switch (params_channels(params)) { + if (pdata->max_channels_clocked[id] && + wm8994->channels[id] > pdata->max_channels_clocked[id]) { + dev_dbg(dai->dev, "Constraining channels to %d from %d\n", + pdata->max_channels_clocked[id], wm8994->channels[id]); + wm8994->channels[id] = pdata->max_channels_clocked[id]; + } + + switch (wm8994->channels[id]) { case 1: case 2: bclk_rate *= 2; @@ -2745,7 +2754,7 @@ static int wm8994_hw_params(struct snd_pcm_substream *substream, dev_dbg(dai->dev, "AIF%dCLK is %dHz, target BCLK %dHz\n", dai->id, wm8994->aifclk[id], bclk_rate); - if (params_channels(params) == 1 && + if (wm8994->channels[id] == 1 && (snd_soc_read(codec, aif1_reg) & 0x18) == 0x18) aif2 |= WM8994_AIF1_MONO; -- 2.39.5