Diff: drivers/I2S.h

Revision:

4:21603d68bcf7

Parent:

1:f90318e0923b

Child:

9:c4c2240e06d6

--- a/drivers/I2S.h	Wed Dec 14 14:23:12 2016 +0100
+++ b/drivers/I2S.h	Wed Dec 21 20:24:16 2016 +0100
@@ -164,6 +164,17 @@
     */
     int set_dma_priority(i2s_dma_prio_t prio);
 
+    /** Harmonize the frequencies of the given I2S objects so that they are
+     *  exact multiple one of the other. It can be useful whenever two I2S
+     *  peripherals have to work together and no drift is allowed between them.
+     *
+     *  @param dev_i2s_1 reference to the first I2S object.
+     *  @param dev_i2s_2 reference to the second I2S object.
+     *  @return Zero if the frequencies have been harmonized correctly, -1
+     *          otherwise.
+     */
+    static int harmonize(I2S *dev_i2s_1, I2S *dev_i2s_2);
+
 protected:
     /** I2S TX DMA IRQ handler
      *
@@ -229,6 +240,31 @@
     /* betzw - WAS : static */ CircularBuffer<Transaction<I2S>, TRANSACTION_QUEUE_SIZE_I2S> _transaction_buffer;
 #endif // TRANSACTION_QUEUE_SIZE_I2S
 
+    /** Compute the real frequency of a given I2S objects.
+     *
+     *  @param dev_i2s reference to the I2S object.
+     *  @return the computed real frequency.
+     */
+    static float compute_real_frequency(I2S *dev_i2s);
+
+    /** Computes the two-div-plus-odd factor of a given I2S objects
+     *  on a desired frequency.
+     *
+     *  @param dev_i2s reference to the I2S object.
+     *  @frequency the desired frequency.
+     *  @return the computed two-div-plus-odd factor.
+     */
+    static float compute_magic_factor(I2S *dev_i2s, float f);
+
+    /** Compute the desired frequency of a given I2S objects, given the magic
+     *  factor.
+     *
+     *  @param dev_i2s reference to the I2S object.
+     *  @param mf the two-div-plus-odd factor.
+     *  @return the computed desired frequency.
+     */
+    static float compute_desired_frequency(I2S *dev_i2s, float mf);
+
 public:
     virtual ~I2S() {
     	/* betzw - TODO: cleanup has still to be revised completely! */