ASoC: davinci-mcasp: Get rid of bclk_lrclk_ratio in private data

The slot_width is for essentially same thing. Instead of storing
bclk_lrclk_ratio, just store the slot_width. Comments has been updated
accordingly and some variable names changed to more descriptive.

Signed-off-by: Jyri Sarha <jsarha@ti.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

1 files changed, 31 insertions, 25 deletions

diff --git a/sound/soc/davinci/davinci-mcasp.c b/sound/soc/davinci/davinci-mcasp.c
index fa47a39fac86..452f2a36e51c 100644
--- a/sound/soc/davinci/davinci-mcasp.c
+++ b/sound/soc/davinci/davinci-mcasp.c
@@ -87,7 +87,6 @@ struct davinci_mcasp {
         u8      *serial_dir;
         u8      version;
         u8      bclk_div;
-        u16     bclk_lrclk_ratio;
         int     streams;
         u32     irq_request[2];
         int     dma_request[2];
@@ -558,8 +557,21 @@ static int __davinci_mcasp_set_clkdiv(struct snd_soc_dai *dai, int div_id,
                         mcasp->bclk_div = div;
                 break;
 
-        case 2:         /* BCLK/LRCLK ratio */
-                mcasp->bclk_lrclk_ratio = div;
+        case 2: /*
+                 * BCLK/LRCLK ratio descries how many bit-clock cycles
+                 * fit into one frame. The clock ratio is given for a
+                 * full period of data (for I2S format both left and
+                 * right channels), so it has to be divided by number
+                 * of tdm-slots (for I2S - divided by 2).
+                 * Instead of storing this ratio, we calculate a new
+                 * tdm_slot width by dividing the the ratio by the
+                 * number of configured tdm slots.
+                 */
+                mcasp->slot_width = div / mcasp->tdm_slots;
+                if (div % mcasp->tdm_slots)
+                        dev_warn(mcasp->dev,
+                                 "%s(): BCLK/LRCLK %d is not divisible by %d tdm slots",
+                                 __func__, div, mcasp->tdm_slots);
                 break;
 
         default:
@@ -677,11 +689,13 @@ static int davinci_mcasp_set_tdm_slot(struct snd_soc_dai *dai,
 }
 
 static int davinci_config_channel_size(struct davinci_mcasp *mcasp,
-                                       int word_length)
+                                       int sample_width)
 {
         u32 fmt;
-        u32 tx_rotate = (word_length / 4) & 0x7;
-        u32 mask = (1ULL << word_length) - 1;
+        u32 tx_rotate = (sample_width / 4) & 0x7;
+        u32 mask = (1ULL << sample_width) - 1;
+        u32 slot_width = sample_width;
+
         /*
          * For captured data we should not rotate, inversion and masking is
          * enoguh to get the data to the right position:
@@ -694,31 +708,23 @@ static int davinci_config_channel_size(struct davinci_mcasp *mcasp,
         u32 rx_rotate = 0;
 
         /*
-         * if s BCLK-to-LRCLK ratio has been configured via the set_clkdiv()
-         * callback, take it into account here. That allows us to for example
-         * send 32 bits per channel to the codec, while only 16 of them carry
-         * audio payload.
-         * The clock ratio is given for a full period of data (for I2S format
-         * both left and right channels), so it has to be divided by number of
-         * tdm-slots (for I2S - divided by 2).
+         * Setting the tdm slot width either with set_clkdiv() or
+         * set_tdm_slot() allows us to for example send 32 bits per
+         * channel to the codec, while only 16 of them carry audio
+         * payload.
          */
-        if (mcasp->bclk_lrclk_ratio) {
-                u32 slot_length = mcasp->bclk_lrclk_ratio / mcasp->tdm_slots;
-
+        if (mcasp->slot_width) {
                 /*
-                 * When we have more bclk then it is needed for the data, we
-                 * need to use the rotation to move the received samples to have
-                 * correct alignment.
+                 * When we have more bclk then it is needed for the
+                 * data, we need to use the rotation to move the
+                 * received samples to have correct alignment.
                  */
-                rx_rotate = (slot_length - word_length) / 4;
-                word_length = slot_length;
-        } else if (mcasp->slot_width) {
-                rx_rotate = (mcasp->slot_width - word_length) / 4;
-                word_length = mcasp->slot_width;
+                slot_width = mcasp->slot_width;
+                rx_rotate = (slot_width - sample_width) / 4;
         }
 
         /* mapping of the XSSZ bit-field as described in the datasheet */
-        fmt = (word_length >> 1) - 1;
+        fmt = (slot_width >> 1) - 1;
 
         if (mcasp->op_mode != DAVINCI_MCASP_DIT_MODE) {
                 mcasp_mod_bits(mcasp, DAVINCI_MCASP_RXFMT_REG, RXSSZ(fmt),