[PATCH v1 15/30] drm/tegra: hdmi: Support OPP and SoC core voltage scaling

Dmitry Osipenko
2020-11-04T23:48:16Z

Add OPP and SoC core voltage scaling support to the HDMI driver.
This is required for enabling system-wide DVFS on older Tegra SoCs.

Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
drivers/gpu/drm/tegra/hdmi.c | 63 +++++++++++++++++++++++++++++++++++-
1 file changed, 62 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/tegra/hdmi.c b/drivers/gpu/drm/tegra/hdmi.c
index d09a24931c87..92e96990854b 100644
--- a/drivers/gpu/drm/tegra/hdmi.c
+++ b/drivers/gpu/drm/tegra/hdmi.c
@@ -11,6 +11,7 @@
#include <linux/math64.h>
#include <linux/module.h>
#include <linux/of_device.h>
+#include <linux/pm_opp.h>
#include <linux/pm_runtime.h>
#include <linux/regulator/consumer.h>
#include <linux/reset.h>
@@ -1195,7 +1196,7 @@ static void tegra_hdmi_encoder_enable(struct drm_encoder *encoder)
h_back_porch = mode->htotal - mode->hsync_end;
h_front_porch = mode->hsync_start - mode->hdisplay;

- err = clk_set_rate(hdmi->clk, hdmi->pixel_clock);
+ err = dev_pm_opp_set_rate(hdmi->dev, hdmi->pixel_clock);
if (err < 0) {
dev_err(hdmi->dev, "failed to set HDMI clock frequency: %d\n",
err);
@@ -1499,6 +1500,7 @@ static int tegra_hdmi_runtime_suspend(struct host1x_client *client)
usleep_range(1000, 2000);

clk_disable_unprepare(hdmi->clk);
+ dev_pm_opp_set_rate(hdmi->dev, 0);
pm_runtime_put_sync(dev);

return 0;
@@ -1633,6 +1635,60 @@ static irqreturn_t tegra_hdmi_irq(int irq, void *data)
return IRQ_HANDLED;
}

+static void tegra_hdmi_deinit_opp_table(void *data)
+{
+ struct device *dev = data;
+ struct opp_table *opp_table;
+
+ opp_table = dev_pm_opp_get_opp_table(dev);
+ dev_pm_opp_of_remove_table(dev);
+ dev_pm_opp_put_regulators(opp_table);
+ dev_pm_opp_put_opp_table(opp_table);
+}
+
+static int devm_tegra_hdmi_init_opp_table(struct device *dev)
+{
+ struct opp_table *opp_table;
+ const char *rname = "core";
+ int err;
+
+ /* voltage scaling is optional */
+ if (device_property_present(dev, "core-supply"))
+ opp_table = dev_pm_opp_set_regulators(dev, &rname, 1);
+ else
+ opp_table = dev_pm_opp_get_opp_table(dev);
+
+ if (IS_ERR(opp_table))
+ return dev_err_probe(dev, PTR_ERR(opp_table),
+ "failed to prepare OPP table\n");
+
+ /*
+ * OPP table presence is optional and we want the set_rate() of OPP
+ * API to work similarly to clk_set_rate() if table is missing in a
+ * device-tree. The add_table() errors out if OPP is missing in DT.
+ */
+ if (device_property_present(dev, "operating-points-v2")) {
+ err = dev_pm_opp_of_add_table(dev);
+ if (err) {
+ dev_err(dev, "failed to add OPP table: %d\n", err);
+ goto put_table;
+ }
+ }
+
+ err = devm_add_action(dev, tegra_hdmi_deinit_opp_table, dev);
+ if (err)
+ goto remove_table;
+
+ return 0;
+
+remove_table:
+ dev_pm_opp_of_remove_table(dev);
+put_table:
+ dev_pm_opp_put_regulators(opp_table);
+
+ return err;
+}
+
static int tegra_hdmi_probe(struct platform_device *pdev)
{
const char *level = KERN_ERR;
@@ -1667,6 +1723,11 @@ static int tegra_hdmi_probe(struct platform_device *pdev)
if (IS_ERR(hdmi->clk_parent))
return PTR_ERR(hdmi->clk_parent);

+ err = devm_tegra_hdmi_init_opp_table(&pdev->dev);
+ if (err)
+ return dev_err_probe(&pdev->dev, err,
+ "failed to initialize OPP\n");
+
err = clk_set_parent(hdmi->clk, hdmi->clk_parent);
if (err < 0) {
dev_err(&pdev->dev, "failed to setup clocks: %d\n", err);
--
2.27.0