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Date: Tue, 25 Jan 2022 04:56:18 +0300
From: Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
To: Rajeev Nandan <quic_rajeevny@...cinc.com>,
dri-devel@...ts.freedesktop.org, linux-arm-msm@...r.kernel.org,
freedreno@...ts.freedesktop.org, devicetree@...r.kernel.org
Cc: linux-kernel@...r.kernel.org, sean@...rly.run, robdclark@...il.com,
robh+dt@...nel.org, robh@...nel.org, quic_abhinavk@...cinc.com,
quic_kalyant@...cinc.com, quic_mkrishn@...cinc.com,
jonathan@...ek.ca, airlied@...ux.ie, daniel@...ll.ch,
swboyd@...omium.org
Subject: Re: [v3 3/3] drm/msm/dsi: Add 10nm dsi phy tuning configuration
support
On 18/01/2022 23:38, Rajeev Nandan wrote:
> The clock and data lanes of the DSI PHY have a calibration circuitry
> feature. As per the MSM DSI PHY tuning guidelines, the drive strength
> tuning can be done by adjusting rescode offset for hstop/hsbot, and
> the drive level tuning can be done by adjusting the LDO output level
> for the HSTX drive.
>
> Signed-off-by: Rajeev Nandan <quic_rajeevny@...cinc.com>
> ---
>
> Changes in v2:
> - Split into generic code and 10nm-specific part (Dmitry Baryshkov)
> - Fix the backward compatibility (Dmitry Baryshkov)
>
> Changes in v3:
> - Address comments for phy tuning data structure (Dmitry Baryshkov)
> - Make changes as per updated dt-bindings
>
>
> drivers/gpu/drm/msm/dsi/phy/dsi_phy_10nm.c | 97 ++++++++++++++++++++++++++++--
> 1 file changed, 91 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/gpu/drm/msm/dsi/phy/dsi_phy_10nm.c b/drivers/gpu/drm/msm/dsi/phy/dsi_phy_10nm.c
> index d8128f5..2d225fb 100644
> --- a/drivers/gpu/drm/msm/dsi/phy/dsi_phy_10nm.c
> +++ b/drivers/gpu/drm/msm/dsi/phy/dsi_phy_10nm.c
> @@ -83,6 +83,18 @@ struct dsi_pll_10nm {
>
> #define to_pll_10nm(x) container_of(x, struct dsi_pll_10nm, clk_hw)
>
> +/**
> + * struct dsi_phy_10nm_tuning_cfg - Holds 10nm PHY tuning config parameters.
> + * @rescode_offset_top: Offset for pull-up legs rescode.
> + * @rescode_offset_bot: Offset for pull-down legs rescode.
> + * @vreg_ctrl: vreg ctrl to drive LDO level
> + */
> +struct dsi_phy_10nm_tuning_cfg {
> + u8 rescode_offset_top[DSI_LANE_MAX];
> + u8 rescode_offset_bot[DSI_LANE_MAX];
> + u8 vreg_ctrl;
> +};
> +
> /*
> * Global list of private DSI PLL struct pointers. We need this for bonded DSI
> * mode, where the master PLL's clk_ops needs access the slave's private data
> @@ -747,6 +759,7 @@ static void dsi_phy_hw_v3_0_lane_settings(struct msm_dsi_phy *phy)
> int i;
> u8 tx_dctrl[] = { 0x00, 0x00, 0x00, 0x04, 0x01 };
> void __iomem *lane_base = phy->lane_base;
> + struct dsi_phy_10nm_tuning_cfg *tuning_cfg = phy->tuning_cfg;
>
> if (phy->cfg->quirks & DSI_PHY_10NM_QUIRK_OLD_TIMINGS)
> tx_dctrl[3] = 0x02;
> @@ -775,10 +788,13 @@ static void dsi_phy_hw_v3_0_lane_settings(struct msm_dsi_phy *phy)
> dsi_phy_write(lane_base + REG_DSI_10nm_PHY_LN_CFG2(i), 0x0);
> dsi_phy_write(lane_base + REG_DSI_10nm_PHY_LN_CFG3(i),
> i == 4 ? 0x80 : 0x0);
> - dsi_phy_write(lane_base +
> - REG_DSI_10nm_PHY_LN_OFFSET_TOP_CTRL(i), 0x0);
> - dsi_phy_write(lane_base +
> - REG_DSI_10nm_PHY_LN_OFFSET_BOT_CTRL(i), 0x0);
> +
> + /* platform specific dsi phy drive strength adjustment */
> + dsi_phy_write(lane_base + REG_DSI_10nm_PHY_LN_OFFSET_TOP_CTRL(i),
> + tuning_cfg->rescode_offset_top[i]);
> + dsi_phy_write(lane_base + REG_DSI_10nm_PHY_LN_OFFSET_BOT_CTRL(i),
> + tuning_cfg->rescode_offset_bot[i]);
> +
> dsi_phy_write(lane_base + REG_DSI_10nm_PHY_LN_TX_DCTRL(i),
> tx_dctrl[i]);
> }
> @@ -799,6 +815,7 @@ static int dsi_10nm_phy_enable(struct msm_dsi_phy *phy,
> u32 const timeout_us = 1000;
> struct msm_dsi_dphy_timing *timing = &phy->timing;
> void __iomem *base = phy->base;
> + struct dsi_phy_10nm_tuning_cfg *tuning_cfg = phy->tuning_cfg;
> u32 data;
>
> DBG("");
> @@ -834,8 +851,9 @@ static int dsi_10nm_phy_enable(struct msm_dsi_phy *phy,
> /* Select MS1 byte-clk */
> dsi_phy_write(base + REG_DSI_10nm_PHY_CMN_GLBL_CTRL, 0x10);
>
> - /* Enable LDO */
> - dsi_phy_write(base + REG_DSI_10nm_PHY_CMN_VREG_CTRL, 0x59);
> + /* Enable LDO with platform specific drive level/amplitude adjustment */
> + dsi_phy_write(base + REG_DSI_10nm_PHY_CMN_VREG_CTRL,
> + tuning_cfg->vreg_ctrl);
>
> /* Configure PHY lane swap (TODO: we need to calculate this) */
> dsi_phy_write(base + REG_DSI_10nm_PHY_CMN_LANE_CFG0, 0x21);
> @@ -922,6 +940,71 @@ static void dsi_10nm_phy_disable(struct msm_dsi_phy *phy)
> DBG("DSI%d PHY disabled", phy->id);
> }
>
> +static int dsi_10nm_phy_parse_dt(struct msm_dsi_phy *phy)
> +{
> + struct device *dev = &phy->pdev->dev;
> + struct dsi_phy_10nm_tuning_cfg *tuning_cfg;
> + u8 offset_top[DSI_LANE_MAX] = { 0 }; /* No offset */
> + u8 offset_bot[DSI_LANE_MAX] = { 0 }; /* No offset */
> + u32 ldo_level = 400; /* 400mV */
> + u8 level;
> + int ret, i;
> +
> + tuning_cfg = devm_kzalloc(dev, sizeof(*tuning_cfg), GFP_KERNEL);
> + if (!tuning_cfg)
> + return -ENOMEM;
> +
> + /* Drive strength adjustment parameters */
> + ret = of_property_read_u8_array(dev->of_node, "qcom,phy-rescode-offset-top",
> + offset_top, DSI_LANE_MAX);
> + if (ret && ret != -EINVAL)
> + DRM_DEV_ERROR(dev, "failed to parse qcom,phy-rescode-offset-top, %d\n", ret);
> +
> + for (i = 0; i < DSI_LANE_MAX; i++)
> + tuning_cfg->rescode_offset_top[i] = 0x3f & offset_top[i];
You should validate offset_top and offset_bot to be withing expected
ranges and return an error otherwise.
> +
> + ret = of_property_read_u8_array(dev->of_node, "qcom,phy-rescode-offset-bot",
> + offset_bot, DSI_LANE_MAX);
> + if (ret && ret != -EINVAL)
> + DRM_DEV_ERROR(dev, "failed to parse qcom,phy-rescode-offset-bot, %d\n", ret);
> +
> + for (i = 0; i < DSI_LANE_MAX; i++)
> + tuning_cfg->rescode_offset_bot[i] = 0x3f & offset_bot[i];
> +
> + /* Drive level/amplitude adjustment parameters */
> + ret = of_property_read_u32(dev->of_node, "qcom,phy-drive-ldo-level", &ldo_level);
> + if (ret && ret != -EINVAL)
> + DRM_DEV_ERROR(dev, "failed to parse qcom,phy-drive-ldo-level, %d\n", ret);
> +
> + switch (ldo_level) {
> + case 375:
> + level = 0;
> + break;
> + case 400:
> + level = 1;
> + break;
> + case 425:
> + level = 2;
> + break;
> + case 450:
> + level = 3;
> + break;
> + case 475:
> + level = 4;
> + break;
> + case 500:
> + level = 5;
> + break;
> + default:
> + level = 1; /* 400mV */
Please change to:
dev_err(....);
return -EINVAL;
> + }
> + tuning_cfg->vreg_ctrl = 0x58 | (0x7 & level);
> +
> + phy->tuning_cfg = tuning_cfg;
> +
> + return 0;
> +}
> +
> const struct msm_dsi_phy_cfg dsi_phy_10nm_cfgs = {
> .has_phy_lane = true,
> .reg_cfg = {
> @@ -936,6 +1019,7 @@ const struct msm_dsi_phy_cfg dsi_phy_10nm_cfgs = {
> .pll_init = dsi_pll_10nm_init,
> .save_pll_state = dsi_10nm_pll_save_state,
> .restore_pll_state = dsi_10nm_pll_restore_state,
> + .parse_dt_properties = dsi_10nm_phy_parse_dt,
> },
> .min_pll_rate = 1000000000UL,
> .max_pll_rate = 3500000000UL,
> @@ -957,6 +1041,7 @@ const struct msm_dsi_phy_cfg dsi_phy_10nm_8998_cfgs = {
> .pll_init = dsi_pll_10nm_init,
> .save_pll_state = dsi_10nm_pll_save_state,
> .restore_pll_state = dsi_10nm_pll_restore_state,
> + .parse_dt_properties = dsi_10nm_phy_parse_dt,
> },
> .min_pll_rate = 1000000000UL,
> .max_pll_rate = 3500000000UL,
--
With best wishes
Dmitry
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