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Message-ID: <CAE-0n52obotsMwXLHm8Fkd3+7QnXCEZgVhO_FNSY7RsbC+pbcA@mail.gmail.com>
Date: Wed, 25 Aug 2021 17:49:47 +0000
From: Stephen Boyd <swboyd@...omium.org>
To: Kuogee Hsieh <khsieh@...eaurora.org>, agross@...nel.org,
bjorn.andersson@...aro.org, devicetree@...r.kernel.org,
robdclark@...il.com, robh+dt@...nel.org, sean@...rly.run,
vkoul@...nel.org
Cc: abhinavk@...eaurora.org, aravindh@...eaurora.org,
freedreno@...ts.freedesktop.org, linux-arm-msm@...r.kernel.org,
linux-kernel@...r.kernel.org, kishon@...com, p.zabel@...gutronix.de
Subject: Re: [PATCH] phy: qcom-qmp: add support for voltage and pre emphesis swing
Quoting Kuogee Hsieh (2021-08-24 16:29:35)
> Add voltage and pre emphesis swing tables so that voltage and
Is it "pre-emphasis"?
> pre emphsis swing level can be configured base on link rate.
This one is also different.
>
> Signed-off-by: Kuogee Hsieh <khsieh@...eaurora.org>
Presumably
Fixes: aff188feb5e1 ("phy: qcom-qmp: add support for sm8250-usb3-dp phy")
> ---
> 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),
Is 0x22 the better "default"? Can that be described in the commit text?
> 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;
> }
Nitpick: Newline here please.
> +/*
> + * 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;
> +*/
> +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] = {
This looks the same as qmp_dp_v3_voltage_swing_hbr3_hbr2. Can that be
used?
> + /* 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 */
Do these comments add any value? Can we drop them?
> +};
> +
> +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;
> + 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]);
> + }
> +
> +
Nitpick: Drop extra newline.
> + 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)
> + 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 is copy/pasted from qcom_qmp_phy_configure_dp_swing() right? How
about making a function
static int
__qcom_qmp_phy_configure_dp_swing(struct qmp_phy *qphy,
unsigned int drv_lvl_reg,
unsigned int emp_post_reg,
const u8 **voltage_rbr_hbr,
const u8 **pre_emphasis_rbr_hbr,
const u8 **voltage_hbr3_hbr2,
const u8 **pre_emphasis_hbr3_hbr2)
that does the same stuff but allows the tables to be different.
> +
> + 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);
Is this mentioned in the commit text? Is this fixing the sequence?
It doesn't look like we're adding tables.
> +
> 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);
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