Add support for 44.1Khz frequency by dynamically calculating the slimbus
parameters instead of statically defining them.
Co-developed-by: Prudhvi Yarlagadda <pyarlaga@xxxxxxxxxxxxxx>
Signed-off-by: Prudhvi Yarlagadda <pyarlaga@xxxxxxxxxxxxxx>
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@xxxxxxxxxx>
---
Changes since v1:
1. Rebase (drop development pieces in the context).
---
drivers/slimbus/qcom-ngd-ctrl.c | 64 ++++++++++++++++++++++++++++++---
1 file changed, 59 insertions(+), 5 deletions(-)
diff --git a/drivers/slimbus/qcom-ngd-ctrl.c b/drivers/slimbus/qcom-ngd-ctrl.c
index ac84fdc2822f..051ac5cba207 100644
--- a/drivers/slimbus/qcom-ngd-ctrl.c
+++ b/drivers/slimbus/qcom-ngd-ctrl.c
@@ -944,6 +944,54 @@ static int qcom_slim_ngd_xfer_msg_sync(struct slim_controller *ctrl,
return ret;
}
+static int qcom_slim_calc_coef(struct slim_stream_runtime *rt, int *exp)
+{
+ struct slim_controller *ctrl = rt->dev->ctrl;
+ int coef;
+
+ if (rt->ratem * ctrl->a_framer->superfreq < rt->rate)
+ rt->ratem++;
+
+ coef = rt->ratem;
+ *exp = 0;
+
+ /*
+ * CRM = Cx(2^E) is the formula we are using.
+ * Here C is the coffecient and E is the exponent.
+ * CRM is the Channel Rate Multiplier.
+ * Coefficeint should be either 1 or 3 and exponenet
+ * should be an integer between 0 to 9, inclusive.
+ */
+ while (1) {
+ while ((coef & 0x1) != 0x1) {
+ coef >>= 1;
+ *exp = *exp + 1;
+ }
+
+ if (coef <= 3)
+ break;
+
+ coef++;
+ }
+
+ /*
+ * we rely on the coef value (1 or 3) to set a bit
+ * in the slimbus message packet. This bit is
+ * BIT(5) which is the segment rate coefficient.
+ */
+ if (coef == 1) {
+ if (*exp > 9)
+ return -EIO;
+ coef = 0;
+ } else {
+ if (*exp > 8)
+ return -EIO;
+ coef = 1;
+ }
+
+ return coef;
+}
+
static int qcom_slim_ngd_enable_stream(struct slim_stream_runtime *rt)
{
struct slim_device *sdev = rt->dev;
@@ -967,16 +1015,22 @@ static int qcom_slim_ngd_enable_stream(struct slim_stream_runtime *rt)
struct slim_port *port = &rt->ports[i];
if (txn.msg->num_bytes == 0) {
- int seg_interval = SLIM_SLOTS_PER_SUPERFRAME/rt->ratem;
- int exp;
+ int exp = 0, coef = 0;
wbuf[txn.msg->num_bytes++] = sdev->laddr;
wbuf[txn.msg->num_bytes] = rt->bps >> 2 |
(port->ch.aux_fmt << 6);
- /* Data channel segment interval not multiple of 3 */
- exp = seg_interval % 3;
- if (exp)
+ /* calculate coef dynamically */
+ coef = qcom_slim_calc_coef(rt, &exp);
+ if (coef < 0) {
+ dev_err(&sdev->dev,
+ "%s: error calculating coef %d\n", __func__,
+ coef);
+ return -EIO;
+ }
+
+ if (coef)
wbuf[txn.msg->num_bytes] |= BIT(5);
txn.msg->num_bytes++;
--
2.34.1
