ASoC: omap-mcbsp - add support for upto 16 channels.

This patch increases the number of supported audio channels from 4
to 16 and has been sponsored by Shotspotter Inc. It also fixes a
FSYNC rate calculation bug when McBSP is FSYNC master.

Signed-off-by: Graeme Gregory <gg@slimlogic.co.uk>
Signed-off-by: Liam Girdwood <lrg@slimlogic.co.uk>
Acked-by: Peter Ujfalusi <peter.ujfalusi@nokia.com>
Tested-by: Peter Ujfalusi <peter.ujfalusi@nokia.com>
Acked-by: Jarkko Nikula <jhnikula@gmail.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

1 files changed, 37 insertions, 26 deletions

diff --git a/sound/soc/omap/omap-mcbsp.c b/sound/soc/omap/omap-mcbsp.c
index 3341f49402ca..45be94201c89 100644
--- a/sound/soc/omap/omap-mcbsp.c
+++ b/sound/soc/omap/omap-mcbsp.c
@@ -49,6 +49,8 @@ struct omap_mcbsp_data {
          */
         int                             active;
         int                             configured;
+        unsigned int                    in_freq;
+        int                             clk_div;
 };
 
 #define to_mcbsp(priv)  container_of((priv), struct omap_mcbsp_data, bus_id)
@@ -257,7 +259,7 @@ static int omap_mcbsp_dai_hw_params(struct snd_pcm_substream *substream,
         int dma, bus_id = mcbsp_data->bus_id, id = cpu_dai->id;
         int wlen, channels, wpf, sync_mode = OMAP_DMA_SYNC_ELEMENT;
         unsigned long port;
-        unsigned int format;
+        unsigned int format, div, framesize, master;
 
         if (cpu_class_is_omap1()) {
                 dma = omap1_dma_reqs[bus_id][substream->stream];
@@ -294,28 +296,19 @@ static int omap_mcbsp_dai_hw_params(struct snd_pcm_substream *substream,
 
         format = mcbsp_data->fmt & SND_SOC_DAIFMT_FORMAT_MASK;
         wpf = channels = params_channels(params);
-        switch (channels) {
-        case 2:
-                if (format == SND_SOC_DAIFMT_I2S) {
-                        /* Use dual-phase frames */
-                        regs->rcr2      |= RPHASE;
-                        regs->xcr2      |= XPHASE;
-                        /* Set 1 word per (McBSP) frame for phase1 and phase2 */
-                        wpf--;
-                        regs->rcr2      |= RFRLEN2(wpf - 1);
-                        regs->xcr2      |= XFRLEN2(wpf - 1);
-                }
-        case 1:
-        case 4:
-                /* Set word per (McBSP) frame for phase1 */
-                regs->rcr1      |= RFRLEN1(wpf - 1);
-                regs->xcr1      |= XFRLEN1(wpf - 1);
-                break;
-        default:
-                /* Unsupported number of channels */
-                return -EINVAL;
+        if (channels == 2 && format == SND_SOC_DAIFMT_I2S) {
+                /* Use dual-phase frames */
+                regs->rcr2      |= RPHASE;
+                regs->xcr2      |= XPHASE;
+                /* Set 1 word per (McBSP) frame for phase1 and phase2 */
+                wpf--;
+                regs->rcr2      |= RFRLEN2(wpf - 1);
+                regs->xcr2      |= XFRLEN2(wpf - 1);
         }
 
+        regs->rcr1      |= RFRLEN1(wpf - 1);
+        regs->xcr1      |= XFRLEN1(wpf - 1);
+
         switch (params_format(params)) {
         case SNDRV_PCM_FORMAT_S16_LE:
                 /* Set word lengths */
@@ -330,15 +323,30 @@ static int omap_mcbsp_dai_hw_params(struct snd_pcm_substream *substream,
                 return -EINVAL;
         }
 
+        /* In McBSP master modes, FRAME (i.e. sample rate) is generated
+         * by _counting_ BCLKs. Calculate frame size in BCLKs */
+        master = mcbsp_data->fmt & SND_SOC_DAIFMT_MASTER_MASK;
+        if (master ==   SND_SOC_DAIFMT_CBS_CFS) {
+                div = mcbsp_data->clk_div ? mcbsp_data->clk_div : 1;
+                framesize = (mcbsp_data->in_freq / div) / params_rate(params);
+
+                if (framesize < wlen * channels) {
+                        printk(KERN_ERR "%s: not enough bandwidth for desired rate and "
+                                        "channels\n", __func__);
+                        return -EINVAL;
+                }
+        } else
+                framesize = wlen * channels;
+
         /* Set FS period and length in terms of bit clock periods */
         switch (format) {
         case SND_SOC_DAIFMT_I2S:
-                regs->srgr2     |= FPER(wlen * channels - 1);
-                regs->srgr1     |= FWID(wlen - 1);
+                regs->srgr2     |= FPER(framesize - 1);
+                regs->srgr1     |= FWID((framesize >> 1) - 1);
                 break;
         case SND_SOC_DAIFMT_DSP_A:
         case SND_SOC_DAIFMT_DSP_B:
-                regs->srgr2     |= FPER(wlen * channels - 1);
+                regs->srgr2     |= FPER(framesize - 1);
                 regs->srgr1     |= FWID(0);
                 break;
         }
@@ -454,6 +462,7 @@ static int omap_mcbsp_dai_set_clkdiv(struct snd_soc_dai *cpu_dai,
         if (div_id != OMAP_MCBSP_CLKGDV)
                 return -ENODEV;
 
+        mcbsp_data->clk_div = div;
         regs->srgr1     |= CLKGDV(div - 1);
 
         return 0;
@@ -554,6 +563,8 @@ static int omap_mcbsp_dai_set_dai_sysclk(struct snd_soc_dai *cpu_dai,
         struct omap_mcbsp_reg_cfg *regs = &mcbsp_data->regs;
         int err = 0;
 
+        mcbsp_data->in_freq = freq;
+
         switch (clk_id) {
         case OMAP_MCBSP_SYSCLK_CLK:
                 regs->srgr2     |= CLKSM;
@@ -598,13 +609,13 @@ static struct snd_soc_dai_ops omap_mcbsp_dai_ops = {
         .id = (link_id),                                        \
         .playback = {                                           \
                 .channels_min = 1,                              \
-                .channels_max = 4,                              \
+                .channels_max = 16,                             \
                 .rates = OMAP_MCBSP_RATES,                      \
                 .formats = SNDRV_PCM_FMTBIT_S16_LE,             \
         },                                                      \
         .capture = {                                            \
                 .channels_min = 1,                              \
-                .channels_max = 4,                              \
+                .channels_max = 16,                             \
                 .rates = OMAP_MCBSP_RATES,                      \
                 .formats = SNDRV_PCM_FMTBIT_S16_LE,             \
         },                                                      \