drm/msm/dpu: Use OPP API to set clk/perf state

On some qualcomm platforms DPU needs to express a performance state
requirement on a power domain depending on the clock rates.
Use OPP table from DT to register with OPP framework and use
dev_pm_opp_set_rate() to set the clk/perf state.
Signed-off-by: Rajendra Nayak <rnayak@codeaurora.org>
Reviewed-by: Rob Clark <robdclark@chromium.org>
Reviewed-by: Matthias Kaehlcke <mka@chromium.org>
Signed-off-by: Rob Clark <robdclark@chromium.org>

drivers/gpu/drm/msm/disp/dpu1/dpu_core_perf.c

@@ -7,6 +7,7 @@
 #include <linux/debugfs.h>
 #include <linux/errno.h>
 #include <linux/mutex.h>
+#include <linux/pm_opp.h>
 #include <linux/sort.h>
 #include <linux/clk.h>
 #include <linux/bitmap.h>
@@ -218,7 +219,7 @@ static int _dpu_core_perf_set_core_clk_rate(struct dpu_kms *kms, u64 rate)
 		rate = core_clk->max_rate;
 
 	core_clk->rate = rate;
-	return msm_dss_clk_set_rate(core_clk, 1);
+	return dev_pm_opp_set_rate(&kms->pdev->dev, core_clk->rate);
 }
 
 static u64 _dpu_core_perf_get_core_clk_rate(struct dpu_kms *kms)

drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c

@@ -10,6 +10,7 @@
 #include <linux/debugfs.h>
 #include <linux/dma-buf.h>
 #include <linux/of_irq.h>
+#include <linux/pm_opp.h>
 
 #include <drm/drm_crtc.h>
 #include <drm/drm_file.h>
@@ -1025,11 +1026,24 @@ static int dpu_bind(struct device *dev, struct device *master, void *data)
 	if (!dpu_kms)
 		return -ENOMEM;
 
+	dpu_kms->opp_table = dev_pm_opp_set_clkname(dev, "core");
+	if (IS_ERR(dpu_kms->opp_table))
+		return PTR_ERR(dpu_kms->opp_table);
+	/* OPP table is optional */
+	ret = dev_pm_opp_of_add_table(dev);
+	if (!ret) {
+		dpu_kms->has_opp_table = true;
+	} else if (ret != -ENODEV) {
+		dev_err(dev, "invalid OPP table in device tree\n");
+		dev_pm_opp_put_clkname(dpu_kms->opp_table);
+		return ret;
+	}
+
 	mp = &dpu_kms->mp;
 	ret = msm_dss_parse_clock(pdev, mp);
 	if (ret) {
 		DPU_ERROR("failed to parse clocks, ret=%d\n", ret);
-		return ret;
+		goto err;
 	}
 
 	platform_set_drvdata(pdev, dpu_kms);
@@ -1043,6 +1057,11 @@ static int dpu_bind(struct device *dev, struct device *master, void *data)
 
 	priv->kms = &dpu_kms->base;
 	return ret;
+err:
+	if (dpu_kms->has_opp_table)
+		dev_pm_opp_of_remove_table(dev);
+	dev_pm_opp_put_clkname(dpu_kms->opp_table);
+	return ret;
 }
 
 static void dpu_unbind(struct device *dev, struct device *master, void *data)
@@ -1057,6 +1076,10 @@ static void dpu_unbind(struct device *dev, struct device *master, void *data)
 
 	if (dpu_kms->rpm_enabled)
 		pm_runtime_disable(&pdev->dev);
+
+	if (dpu_kms->has_opp_table)
+		dev_pm_opp_of_remove_table(dev);
+	dev_pm_opp_put_clkname(dpu_kms->opp_table);
 }
 
 static const struct component_ops dpu_ops = {
@@ -1082,6 +1105,8 @@ static int __maybe_unused dpu_runtime_suspend(struct device *dev)
 	struct dpu_kms *dpu_kms = platform_get_drvdata(pdev);
 	struct dss_module_power *mp = &dpu_kms->mp;
 
+	/* Drop the performance state vote */
+	dev_pm_opp_set_rate(dev, 0);
 	rc = msm_dss_enable_clk(mp->clk_config, mp->num_clk, false);
 	if (rc)
 		DPU_ERROR("clock disable failed rc:%d\n", rc);

drivers/gpu/drm/msm/disp/dpu1/dpu_kms.h

@@ -128,6 +128,10 @@ struct dpu_kms {
 
 	struct platform_device *pdev;
 	bool rpm_enabled;
+
+	struct opp_table *opp_table;
+	bool has_opp_table;
+
 	struct dss_module_power mp;
 
 	/* reference count bandwidth requests, so we know when we can