SSC is the technique of modulating the operating frequency of a signal
slightly to spread its radiated emissions over a range of frequencies.
This reduction in the maximum emission for a given frequency helps meet
radiated emission requirements.
These settings are applicable for PCIE with Internal clock.
Signed-off-by: Harsh Gupta <harsh.gupta@xxxxxx>
Signed-off-by: Gabriel Fernandez <gabriel.fernandez@xxxxxxxxxxx>
---
drivers/phy/phy-miphy28lp.c | 32 ++++++++++++++++++++++++++++++++
1 file changed, 32 insertions(+)
diff --git a/drivers/phy/phy-miphy28lp.c b/drivers/phy/phy-miphy28lp.c
index b36e737..976fdda 100644
--- a/drivers/phy/phy-miphy28lp.c
+++ b/drivers/phy/phy-miphy28lp.c
@@ -679,6 +679,36 @@ static int miphy28lp_init_sata(struct miphy28lp_phy *miphy_phy)
return miphy_is_ready(miphy_phy);
}
+static void miphy_pcie_tune_ssc(struct miphy28lp_phy *miphy_phy)
+{
+ u8 val;
+
+ /* Compensate Tx impedance to avoid out of range values */
+ if (miphy_phy->ssc) {
+ /*
+ * Enable the SSC on PLL for all banks
+ * SSC Modulation @ 31 KHz and 4000 ppm modulation amp
+ */
+ val = readb_relaxed(miphy_phy->base + 0x0c);
+ val |= 0x04;
+ writeb_relaxed(val, miphy_phy->base + 0x0c);
+ val = readb_relaxed(miphy_phy->base + 0x0a);
+ val |= 0x10;
+ writeb_relaxed(val, miphy_phy->base + 0x0a);
+
+ for (val = 0; val < 2; val++) {
+ writeb_relaxed(val, miphy_phy->base + 0x0f);
+ writeb_relaxed(0x69, miphy_phy->base + 0xe5);
+ writeb_relaxed(0x21, miphy_phy->base + 0xe6);
+ writeb_relaxed(0x3c, miphy_phy->base + 0xe4);
+ writeb_relaxed(0x21, miphy_phy->base + 0xe6);
+ writeb_relaxed(0x00, miphy_phy->base + 0xe3);
+ writeb_relaxed(0x02, miphy_phy->base + 0xe3);
+ writeb_relaxed(0x00, miphy_phy->base + 0xe3);
+ }
+ }
+}
+
static int miphy28lp_init_pcie(struct miphy28lp_phy *miphy_phy)
{
struct miphy28lp_dev *miphy_dev = miphy_phy->phydev;
@@ -710,6 +740,8 @@ static int miphy28lp_init_pcie(struct miphy28lp_phy *miphy_phy)
/* initialize miphy */
miphy28lp_configure_pcie(miphy_phy);
+ miphy_pcie_tune_ssc(miphy_phy);
+
/* Waiting for Compensation to complete */
do {
val = readb_relaxed(miphy_phy->base + MIPHY_COMP_FSM_6);
--
1.9.1
--
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