linux-kernel - [PATCH v7 1/5] drm/msm/disp/dpu1: set mdp clk to the maximum frequency in opp table during probe

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Date:   Tue, 22 Mar 2022 08:57:07 +0530
From:   Vinod Polimera <quic_vpolimer@...cinc.com>
To:     dri-devel@...ts.freedesktop.org, linux-arm-msm@...r.kernel.org,
        freedreno@...ts.freedesktop.org, devicetree@...r.kernel.org
Cc:     Vinod Polimera <quic_vpolimer@...cinc.com>,
        linux-kernel@...r.kernel.org, robdclark@...il.com,
        dmitry.baryshkov@...aro.org, dianders@...omium.org,
        quic_kalyant@...cinc.com
Subject: [PATCH v7 1/5] drm/msm/disp/dpu1: set mdp clk to the maximum frequency in opp table during probe

Set mdp clock to max clock rate during probe/bind sequence from the
opp table so that rails are not at undetermined state. Since we do not
know what will be the rate set in boot loader, it would be ideal to
vote at max frequency. There could be a firmware display programmed
in bootloader and we want to transition it to kernel without underflowing.
The clock will be scaled down later when framework sends an update.

Fixes: 25fdd5933e4c ("drm/msm: Add SDM845 DPU support")
Signed-off-by: Vinod Polimera <quic_vpolimer@...cinc.com>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
Reviewed-by: Douglas Anderson <dianders@...omium.org>
---
 drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c
index e29796c..9c346ce 100644
--- a/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c
+++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c
@@ -1202,7 +1202,9 @@ static int dpu_bind(struct device *dev, struct device *master, void *data)
 	struct platform_device *pdev = to_platform_device(dev);
 	struct drm_device *ddev = priv->dev;
 	struct dpu_kms *dpu_kms;
+	struct dev_pm_opp *opp;
 	int ret = 0;
+	unsigned long max_freq = ULONG_MAX;
 
 	dpu_kms = devm_kzalloc(&pdev->dev, sizeof(*dpu_kms), GFP_KERNEL);
 	if (!dpu_kms)
@@ -1225,6 +1227,12 @@ static int dpu_bind(struct device *dev, struct device *master, void *data)
 	}
 	dpu_kms->num_clocks = ret;
 
+	opp = dev_pm_opp_find_freq_floor(dev, &max_freq);
+	if (!IS_ERR(opp))
+		dev_pm_opp_put(opp);
+
+	dev_pm_opp_set_rate(dev, max_freq);
+
 	platform_set_drvdata(pdev, dpu_kms);
 
 	ret = msm_kms_init(&dpu_kms->base, &kms_funcs);
-- 
2.7.4