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 <[email protected]> Signed-off-by: Gabriel Fernandez <[email protected]> --- 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 -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
