The Asynchronous Sample Rate Converter (ASRC) converts the sampling rate of a(...)
signal associated with an input clock into a signal associated with a different
output clock. The driver currently works as a Front End of DPCM with other Back
Ends DAI links such as ESAI<->CS42888 and SSI<->WM8962 and SAI. It converts the
original sample rate to a common rate supported by Back Ends for playback while
converts the common rate of Back Ends to a desired rate for capture. It has 3
pairs to support three different substreams within totally 10 channels.
+Required properties:
+
+ - compatible : Compatible list, must contain "fsl,imx35-asrc" or
+ "fsl,imx53-asrc".
+
+ - reg : Offset and length of the register set for the device.
+
+ - interrupts : Contains the spdif interrupt.
+
+ - dmas : Generic dma devicetree binding as described in
+ Documentation/devicetree/bindings/dma/dma.txt.
+
+ - dma-names : Six dmas have to be defined: "rxa", "rxb", "rxc", "txa", "txb",
+ and "txc".
+
+ - clocks : Contains an entry for each entry in clock-names.
+
+ - clock-names : Includes the following entries:
+ "mem" Peripheral access clock to access registers.
+ "ipg" Peripheral clock to driver module.
+ "asrck_<0-f>" Clock sources for input and output clock.
+
+ - big-endian : If this property is absent, the native endian mode will
+ be in use as default, or the big endian mode will be in use
+ for all the device registers.
+
+ - fsl,asrc-rate : Defines a mutual sample rate used by Back End DAI link.
+
+ - fsl,asrc-width : Defines a mutual sample width used by Back End DAI link.
+
+
+static const struct platform_device_id fsl_asrc_devtype[] = {
+ {
+ .name = "imx35-asrc",
+ .driver_data = IMX35_ASRC,
+ }, {
+ .name = "imx53-asrc",
+ .driver_data = IMX53_ASRC,
+ }, {
+ /* sentinel */
+ }
+};
+MODULE_DEVICE_TABLE(platform, fsl_asrc_devtype);
+
+static const struct of_device_id fsl_asrc_ids[] = {
+ {
+ .compatible = "fsl,imx35-asrc",
+ .data = &fsl_asrc_devtype[IMX35_ASRC],
+ }, {
+ .compatible = "fsl,imx53-asrc",
+ .data = &fsl_asrc_devtype[IMX53_ASRC],
+ }, {
+ /* sentinel */
+ }
+};
+MODULE_DEVICE_TABLE(of, fsl_asrc_ids);
+
+static irqreturn_t fsl_asrc_isr(int irq, void *dev_id)
+{
+ struct fsl_asrc *asrc_priv = (struct fsl_asrc *)dev_id;
+ struct device *dev = &asrc_priv->pdev->dev;
+ enum asrc_pair_index index;
+ u32 status;
+
+ regmap_read(asrc_priv->regmap, REG_ASRSTR, &status);
+
+ /* Clean overload error */
+ regmap_write(asrc_priv->regmap, REG_ASRSTR, ASRSTR_AOLE);
+
+ /*
+ * We here use dev_dbg() for all exceptions because ASRC itself does
+ * not care if FIFO overflowed or underrun while a warning in the
+ * interrupt would result a ridged conversion.
+ */
+ for (index = ASRC_PAIR_A; index < ASRC_PAIR_MAX_NUM; index++) {
+ if (!asrc_priv->pair[index])
+ continue;
+
+ if (status & ASRSTR_ATQOL) {
+ asrc_priv->pair[index]->error |= ASRC_TASK_Q_OVERLOAD;
+ dev_dbg(dev, "ASRC Task Queue FIFO overload");
+ }
+
+ if (status & ASRSTR_AOOL(index)) {
+ asrc_priv->pair[index]->error |= ASRC_OUTPUT_TASK_OVERLOAD;
+ pair_dbg("Output Task Overload");
+ }
+
+ if (status & ASRSTR_AIOL(index)) {
+ asrc_priv->pair[index]->error |= ASRC_INPUT_TASK_OVERLOAD;
+ pair_dbg("Input Task Overload");
+ }
+
+ if (status & ASRSTR_AODO(index)) {
+ asrc_priv->pair[index]->error |= ASRC_OUTPUT_BUFFER_OVERFLOW;
+ pair_dbg("Output Data Buffer has overflowed");
+ }
+
+ if (status & ASRSTR_AIDU(index)) {
+ asrc_priv->pair[index]->error |= ASRC_INPUT_BUFFER_UNDERRUN;
+ pair_dbg("Input Data Buffer has underflowed");
+ }
+ }
+
+ return IRQ_HANDLED;
+}
+
+/**
+ * Configure input and output thresholds
+ */
+static int fsl_asrc_set_watermarks(struct fsl_asrc_pair *pair, u32 in, u32 out)
+{
+ struct fsl_asrc *asrc_priv = pair->asrc_priv;
+ enum asrc_pair_index index = pair->index;
+
+ regmap_update_bits(asrc_priv->regmap, REG_ASRMCR(index),
+ ASRMCRi_EXTTHRSHi_MASK |
+ ASRMCRi_INFIFO_THRESHOLD_MASK |
+ ASRMCRi_OUTFIFO_THRESHOLD_MASK,
+ ASRMCRi_EXTTHRSHi |
+ ASRMCRi_INFIFO_THRESHOLD(in) |
+ ASRMCRi_OUTFIFO_THRESHOLD(out));
+
+ return 0;
+}
+static const struct dev_pm_ops fsl_asrc_pm = {
+ SET_RUNTIME_PM_OPS(fsl_asrc_runtime_suspend, fsl_asrc_runtime_resume, NULL)
+ SET_SYSTEM_SLEEP_PM_OPS(fsl_asrc_suspend, fsl_asrc_resume)
+};
+
+static struct platform_driver fsl_asrc_driver = {
+ .probe = fsl_asrc_probe,
+ .driver = {
+ .name = "fsl-asrc",
+ .of_match_table = fsl_asrc_ids,
+ .pm = &fsl_asrc_pm,
+ },
+};
+module_platform_driver(fsl_asrc_driver);