The patch below does not apply to the 4.19-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 90b7c1c66132c20e8a550006011a3cbfb73dbfc1 Mon Sep 17 00:00:00 2001

From: Marijn Suijten marijn.suijten@somainline.org Date: Mon, 6 Sep 2021 22:25:51 +0200 Subject: [PATCH] drm/msm/dsi: dsi_phy_14nm: Take ready-bit into account in poll_for_ready

The downstream driver models this PLL lock check as an if-elseif-else. The only way to reach the else case where pll_locked=true [1] is by succeeding both readl_poll_timeout_atomic calls (which return zero on success) in the if _and_ elseif condition. Hence both the "lock" and "ready" bit need to be tested in the SM_READY_STATUS register before considering the PLL locked and ready to go.

Tested on the Sony Xperia XA2 Ultra (nile-discovery, sdm630).

[1]: https://source.codeaurora.org/quic/la/kernel/msm-4.19/tree/drivers/clk/qcom/...

Fixes: f079f6d999cb ("drm/msm/dsi: Add PHY/PLL for 8x96") Signed-off-by: Marijn Suijten marijn.suijten@somainline.org Reviewed-by: Dmitry Baryshkov dmitry.baryshkov@linaro.org Link: https://lore.kernel.org/r/20210906202552.824598-1-marijn.suijten@somainline.... Signed-off-by: Dmitry Baryshkov dmitry.baryshkov@linaro.org Signed-off-by: Rob Clark robdclark@chromium.org

diff --git a/drivers/gpu/drm/msm/dsi/phy/dsi_phy_14nm.c b/drivers/gpu/drm/msm/dsi/phy/dsi_phy_14nm.c index d13552b2213b..5b4e991f220d 100644 --- a/drivers/gpu/drm/msm/dsi/phy/dsi_phy_14nm.c +++ b/drivers/gpu/drm/msm/dsi/phy/dsi_phy_14nm.c @@ -110,14 +110,13 @@ static struct dsi_pll_14nm *pll_14nm_list[DSI_MAX]; static bool pll_14nm_poll_for_ready(struct dsi_pll_14nm *pll_14nm, u32 nb_tries, u32 timeout_us) { - bool pll_locked = false; + bool pll_locked = false, pll_ready = false; void __iomem *base = pll_14nm->phy->pll_base; u32 tries, val;

tries = nb_tries; while (tries--) { - val = dsi_phy_read(base + - REG_DSI_14nm_PHY_PLL_RESET_SM_READY_STATUS); + val = dsi_phy_read(base + REG_DSI_14nm_PHY_PLL_RESET_SM_READY_STATUS); pll_locked = !!(val & BIT(5));

if (pll_locked) @@ -126,23 +125,24 @@ static bool pll_14nm_poll_for_ready(struct dsi_pll_14nm *pll_14nm, udelay(timeout_us); }

- if (!pll_locked) { - tries = nb_tries; - while (tries--) { - val = dsi_phy_read(base + - REG_DSI_14nm_PHY_PLL_RESET_SM_READY_STATUS); - pll_locked = !!(val & BIT(0)); + if (!pll_locked) + goto out;

- if (pll_locked) - break; + tries = nb_tries; + while (tries--) { + val = dsi_phy_read(base + REG_DSI_14nm_PHY_PLL_RESET_SM_READY_STATUS); + pll_ready = !!(val & BIT(0));

- udelay(timeout_us); - } + if (pll_ready) + break; + + udelay(timeout_us); }

- DBG("DSI PLL is %slocked", pll_locked ? "" : "*not* "); +out: + DBG("DSI PLL is %slocked, %sready", pll_locked ? "" : "*not* ", pll_ready ? "" : "*not* ");

- return pll_locked; + return pll_locked && pll_ready; }

static void dsi_pll_14nm_config_init(struct dsi_pll_config *pconf)