This patch to tune on/off the ssc on miphy sata setup. User can now enable ssc via dt blob, it is useful to reduce effects of EMI. Signed-off-by: Giuseppe Condorelli <giuseppe.condorelli@xxxxxx> Signed-off-by: Gabriel Fernandez <gabriel.fernandez@xxxxxxxxxx> --- .../devicetree/bindings/phy/phy-miphy28lp.txt | 1 + drivers/phy/phy-miphy28lp.c | 46 ++++++++++++++++++++++ 2 files changed, 47 insertions(+) diff --git a/Documentation/devicetree/bindings/phy/phy-miphy28lp.txt b/Documentation/devicetree/bindings/phy/phy-miphy28lp.txt index b7c13ad..4a3b4af 100644 --- a/Documentation/devicetree/bindings/phy/phy-miphy28lp.txt +++ b/Documentation/devicetree/bindings/phy/phy-miphy28lp.txt @@ -39,6 +39,7 @@ Optional properties (port (child) node): register. - st,px_rx_pol_inv : to invert polarity of RXn/RXp (respectively negative line and positive line). +- st,scc-on : enable ssc to reduce effects of EMI (only for sata or PCIe). example: diff --git a/drivers/phy/phy-miphy28lp.c b/drivers/phy/phy-miphy28lp.c index 7d592e6..d2f797c 100644 --- a/drivers/phy/phy-miphy28lp.c +++ b/drivers/phy/phy-miphy28lp.c @@ -191,6 +191,8 @@ #define SYSCFG_PCIE_PCIE_VAL 0x80 #define SATA_SPDMODE 1 +#define MIPHY_SATA_BANK_NB 3 + struct miphy28lp_phy { struct phy *phy; struct miphy28lp_dev *phydev; @@ -200,6 +202,7 @@ struct miphy28lp_phy { bool osc_force_ext; bool osc_rdy; bool px_rx_pol_inv; + bool ssc; struct reset_control *miphy_rst; @@ -550,6 +553,44 @@ static inline void miphy28_usb3_miphy_reset(struct miphy28lp_phy *miphy_phy) writeb_relaxed(0x00, base + MIPHY_CONF); } +static void miphy_sata_tune_ssc(struct miphy28lp_phy *miphy_phy) +{ + void __iomem *base = miphy_phy->base; + 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(base + MIPHY_BOUNDARY_2); + val |= SSC_EN_SW; + writeb_relaxed(val, base + MIPHY_BOUNDARY_2); + + val = readb_relaxed(base + MIPHY_BOUNDARY_SEL); + val |= SSC_SEL; + writeb_relaxed(val, base + MIPHY_BOUNDARY_SEL); + + for (val = 0; val < MIPHY_SATA_BANK_NB; val++) { + writeb_relaxed(val, base + MIPHY_CONF); + + /* Add value to each reference clock cycle */ + /* and define the period length of the SSC */ + writeb_relaxed(0x3c, base + MIPHY_PLL_SBR_2); + writeb_relaxed(0x6c, base + MIPHY_PLL_SBR_3); + writeb_relaxed(0x81, base + MIPHY_PLL_SBR_4); + + /* Clear any previous request */ + writeb_relaxed(0x00, base + MIPHY_PLL_SBR_1); + + /* requests the PLL to take in account new parameters */ + writeb_relaxed(SET_NEW_CHANGE, base + MIPHY_PLL_SBR_1); + + /* To be sure there is no other pending requests */ + writeb_relaxed(0x00, base + MIPHY_PLL_SBR_1); + } +} + static inline int miphy28lp_configure_sata(struct miphy28lp_phy *miphy_phy) { void __iomem *base = miphy_phy->base; @@ -585,6 +626,9 @@ static inline int miphy28lp_configure_sata(struct miphy28lp_phy *miphy_phy) writeb_relaxed(val, miphy_phy->base + MIPHY_CONTROL); } + if (miphy_phy->ssc) + miphy_sata_tune_ssc(miphy_phy); + return 0; } @@ -1064,6 +1108,8 @@ static int miphy28lp_of_probe(struct device_node *np, miphy_phy->px_rx_pol_inv = of_property_read_bool(np, "st,px_rx_pol_inv"); + miphy_phy->ssc = of_property_read_bool(np, "st,ssc-on"); + of_property_read_u32(np, "st,sata-gen", &miphy_phy->sata_gen); if (!miphy_phy->sata_gen) miphy_phy->sata_gen = SATA_GEN1; -- 1.9.1 -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html