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 7285543..b6574e8 100644 --- a/drivers/phy/phy-miphy28lp.c +++ b/drivers/phy/phy-miphy28lp.c @@ -579,6 +579,35 @@ static void miphy_sata_tune_ssc(struct miphy28lp_phy *miphy_phy) } } +static void miphy_pcie_tune_ssc(struct miphy28lp_phy *miphy_phy) +{ + u8 val; + + /* Compensate Tx impedance to avoid out of range values */ + /* + * Enable the SSC on PLL for all banks + * SSC Modulation @ 31 KHz and 4000 ppm modulation amp + */ + val = readb_relaxed(miphy_phy->base + MIPHY_BOUNDARY_2); + val |= SSC_EN_SW; + writeb_relaxed(val, miphy_phy->base + MIPHY_BOUNDARY_2); + + val = readb_relaxed(miphy_phy->base + MIPHY_BOUNDARY_SEL); + val |= SSC_SEL; + writeb_relaxed(val, miphy_phy->base + MIPHY_BOUNDARY_SEL); + + for (val = 0; val < 2; val++) { + writeb_relaxed(val, miphy_phy->base + MIPHY_CONF); + writeb_relaxed(0x69, miphy_phy->base + MIPHY_PLL_SBR_3); + writeb_relaxed(0x21, miphy_phy->base + MIPHY_PLL_SBR_4); + writeb_relaxed(0x3c, miphy_phy->base + MIPHY_PLL_SBR_2); + writeb_relaxed(0x21, miphy_phy->base + MIPHY_PLL_SBR_4); + writeb_relaxed(0x00, miphy_phy->base + MIPHY_PLL_SBR_1); + writeb_relaxed(0x02, miphy_phy->base + MIPHY_PLL_SBR_1); + writeb_relaxed(0x00, miphy_phy->base + MIPHY_PLL_SBR_1); + } +} + static inline int miphy28lp_configure_sata(struct miphy28lp_phy *miphy_phy) { void __iomem *base = miphy_phy->base; @@ -647,6 +676,9 @@ static inline int miphy28lp_configure_pcie(struct miphy28lp_phy *miphy_phy) if (err) return err; + if (miphy_phy->ssc) + miphy_pcie_tune_ssc(miphy_phy); + return 0; } -- 1.9.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
