On Tue 24 Aug 16:29 PDT 2021, Kuogee Hsieh wrote: > Add voltage and pre emphesis swing tables so that voltage and > pre emphsis swing level can be configured base on link rate. >
I think it would be nice if $subject, or at least the commit message mentioned that this relates to the DisplayPort part of the QMP driver. Also the commit message states that this allows someone/something to configure the properties based on link rate. But it doesn't state why this is needed. > Signed-off-by: Kuogee Hsieh <[email protected]> > --- > drivers/phy/qualcomm/phy-qcom-qmp.c | 95 > ++++++++++++++++++++++++++++++++----- > 1 file changed, 82 insertions(+), 13 deletions(-) > > diff --git a/drivers/phy/qualcomm/phy-qcom-qmp.c > b/drivers/phy/qualcomm/phy-qcom-qmp.c > index 31036aa..52bab6e 100644 > --- a/drivers/phy/qualcomm/phy-qcom-qmp.c > +++ b/drivers/phy/qualcomm/phy-qcom-qmp.c > @@ -1916,7 +1916,7 @@ static const struct qmp_phy_init_tbl qmp_v4_dp_tx_tbl[] > = { > QMP_PHY_INIT_CFG(QSERDES_V4_TX_RES_CODE_LANE_OFFSET_RX, 0x11), > QMP_PHY_INIT_CFG(QSERDES_V4_TX_TX_BAND, 0x4), > QMP_PHY_INIT_CFG(QSERDES_V4_TX_TX_POL_INV, 0x0a), > - QMP_PHY_INIT_CFG(QSERDES_V4_TX_TX_DRV_LVL, 0x2a), > + QMP_PHY_INIT_CFG(QSERDES_V4_TX_TX_DRV_LVL, 0x22), Why is this initial value changed in order to make the swing and emphasis configurable? > QMP_PHY_INIT_CFG(QSERDES_V4_TX_TX_EMP_POST1_LVL, 0x20), > }; > > @@ -3727,6 +3727,81 @@ static int qcom_qmp_v3_dp_phy_calibrate(struct qmp_phy > *qphy) > > return 0; > } > +/* > + * 0x20 deducted from tables > + * > + * swing_value |= DP_PHY_TXn_TX_DRV_LVL_MUX_EN; > + * pre_emphasis_value |= DP_PHY_TXn_TX_EMP_POST1_LVL_MUX_EN; How about rewriting this as something like "The values in these tables are given without MUX_EN (0x20) bit set" ? > +*/ > +static const u8 qmp_dp_v4_pre_emphasis_hbr3_hbr2[4][4] = { > + /* p0 p1 p2 p3 */ > + { 0x00, 0x0c, 0x15, 0x1b }, /* s0 */ > + { 0x02, 0x0e, 0x16, 0xff }, /* s1 */ > + { 0x02, 0x11, 0xff, 0xff }, /* s2 */ > + { 0x04, 0xff, 0xff, 0xff } /* s3 */ > +}; > + > +static const u8 qmp_dp_v4_voltage_swing_hbr3_hbr2[4][4] = { > + /* p0 p1 p2 p3 */ > + { 0x02, 0x12, 0x16, 0x1a }, /* s0 */ > + { 0x09, 0x19, 0x1f, 0xff }, /* s1 */ > + { 0x10, 0x1f, 0xff, 0xff }, /* s2 */ > + { 0x1f, 0xff, 0xff, 0xff } /* s3 */ > +}; > + > +static const u8 qmp_dp_v4_pre_emphasis_hbr_rbr[4][4] = { > + /* p0 p1 p2 p3 */ > + { 0x00, 0x0e, 0x15, 0x1b }, /* s0 */ > + { 0x00, 0x0e, 0x15, 0xff }, /* s1 */ > + { 0x00, 0x0e, 0xff, 0xff }, /* s2 */ > + { 0x04, 0xff, 0xff, 0xff } /* s3 */ > +}; > + > +static const u8 qmp_dp_v4_voltage_swing_hbr_rbr[4][4] = { > + /* p0 p1 p2 p3 */ > + { 0x08, 0x0f, 0x16, 0x1f }, /* s0 */ > + { 0x11, 0x1e, 0x1f, 0xff }, /* s1 */ > + { 0x16, 0x1f, 0xff, 0xff }, /* s2 */ > + { 0x1f, 0xff, 0xff, 0xff } /* s3 */ > +}; > + > +static int qcom_qmp_v4_phy_configure_dp_swing(struct qmp_phy *qphy, > + unsigned int drv_lvl_reg, unsigned int emp_post_reg) > +{ > + const struct phy_configure_opts_dp *dp_opts = &qphy->dp_opts; > + unsigned int v_level = 0, p_level = 0; > + u8 voltage_swing_cfg, pre_emphasis_cfg; The "_cfg" suffix on these variables doesn't really add any value. Frankly, calling them "voltage" (or "swing") and "emphasis" seems just as expressive, but easier to read. > + int i; > + > + for (i = 0; i < dp_opts->lanes; i++) { > + v_level = max(v_level, dp_opts->voltage[i]); > + p_level = max(p_level, dp_opts->pre[i]); > + } > + > + > + if (dp_opts->link_rate <= 2700) { > + voltage_swing_cfg = > qmp_dp_v4_voltage_swing_hbr_rbr[v_level][p_level]; > + pre_emphasis_cfg = > qmp_dp_v4_pre_emphasis_hbr_rbr[v_level][p_level]; > + } else { > + voltage_swing_cfg = > qmp_dp_v4_voltage_swing_hbr3_hbr2[v_level][p_level]; > + pre_emphasis_cfg = > qmp_dp_v4_pre_emphasis_hbr3_hbr2[v_level][p_level]; > + } > + > + /* TODO: Move check to config check */ > + if (voltage_swing_cfg == 0xFF && pre_emphasis_cfg == 0xFF) Why is this && and not || ? > + return -EINVAL; > + > + /* Enable MUX to use Cursor values from these registers */ > + voltage_swing_cfg |= DP_PHY_TXn_TX_DRV_LVL_MUX_EN; > + pre_emphasis_cfg |= DP_PHY_TXn_TX_EMP_POST1_LVL_MUX_EN; > + > + writel(voltage_swing_cfg, qphy->tx + drv_lvl_reg); > + writel(pre_emphasis_cfg, qphy->tx + emp_post_reg); > + writel(voltage_swing_cfg, qphy->tx2 + drv_lvl_reg); > + writel(pre_emphasis_cfg, qphy->tx2 + emp_post_reg); > + This function is called once, so why is drv_lvl_reg and emp_post_reg variables passed to the function, rather than just using the defines directly? Regards, Bjorn > + return 0; > +} > > static void qcom_qmp_v4_phy_dp_aux_init(struct qmp_phy *qphy) > { > @@ -3757,14 +3832,7 @@ static void qcom_qmp_v4_phy_dp_aux_init(struct qmp_phy > *qphy) > > static void qcom_qmp_v4_phy_configure_dp_tx(struct qmp_phy *qphy) > { > - /* Program default values before writing proper values */ > - writel(0x27, qphy->tx + QSERDES_V4_TX_TX_DRV_LVL); > - writel(0x27, qphy->tx2 + QSERDES_V4_TX_TX_DRV_LVL); > - > - writel(0x20, qphy->tx + QSERDES_V4_TX_TX_EMP_POST1_LVL); > - writel(0x20, qphy->tx2 + QSERDES_V4_TX_TX_EMP_POST1_LVL); > - > - qcom_qmp_phy_configure_dp_swing(qphy, > + qcom_qmp_v4_phy_configure_dp_swing(qphy, > QSERDES_V4_TX_TX_DRV_LVL, > QSERDES_V4_TX_TX_EMP_POST1_LVL); > } > @@ -3885,6 +3953,9 @@ static int qcom_qmp_v4_phy_configure_dp_phy(struct > qmp_phy *qphy) > writel(drvr1_en, qphy->tx2 + QSERDES_V4_TX_HIGHZ_DRVR_EN); > writel(bias1_en, qphy->tx2 + QSERDES_V4_TX_TRANSCEIVER_BIAS_EN); > > + writel(0x0a, qphy->tx + QSERDES_V4_TX_TX_POL_INV); > + writel(0x0a, qphy->tx2 + QSERDES_V4_TX_TX_POL_INV); > + > writel(0x18, qphy->pcs + QSERDES_DP_PHY_CFG); > udelay(2000); > writel(0x19, qphy->pcs + QSERDES_DP_PHY_CFG); > @@ -3896,11 +3967,9 @@ static int qcom_qmp_v4_phy_configure_dp_phy(struct > qmp_phy *qphy) > 10000)) > return -ETIMEDOUT; > > - writel(0x0a, qphy->tx + QSERDES_V4_TX_TX_POL_INV); > - writel(0x0a, qphy->tx2 + QSERDES_V4_TX_TX_POL_INV); > > - writel(0x27, qphy->tx + QSERDES_V4_TX_TX_DRV_LVL); > - writel(0x27, qphy->tx2 + QSERDES_V4_TX_TX_DRV_LVL); > + writel(0x22, qphy->tx + QSERDES_V4_TX_TX_DRV_LVL); > + writel(0x22, qphy->tx2 + QSERDES_V4_TX_TX_DRV_LVL); > > writel(0x20, qphy->tx + QSERDES_V4_TX_TX_EMP_POST1_LVL); > writel(0x20, qphy->tx2 + QSERDES_V4_TX_TX_EMP_POST1_LVL); > -- > The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, > a Linux Foundation Collaborative Project >
