[PATCH 5.14 133/151] drm/msm/dsi: dsi_phy_14nm: Take ready-bit into account in poll_for_ready

Greg Kroah-Hartman
2021-10-18T14:03:01Z

From: Marijn Suijten <marijn.suijten@somainline.org>

commit 90b7c1c66132c20e8a550006011a3cbfb73dbfc1 upstream.

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/mdss/mdss-dsi-pll-14nm-util.c?h=LA.UM.9.2.1.r1-08000-sdm660.0#n302

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.org
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Signed-off-by: Rob Clark <robdclark@chromium.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/gpu/drm/msm/dsi/phy/dsi_phy_14nm.c | 30 ++++++++++++++---------------
1 file changed, 15 insertions(+), 15 deletions(-)

--- 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_lis
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(stru
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)