drm/panfrost: Implement ability to turn on/off regulators in suspend

Some platforms/SoCs can power off the GPU entirely by completely cutting
off power, greatly enhancing battery time during system suspend: add a
new pm_feature GPU_PM_VREG_OFF to allow turning off the GPU regulators
during full suspend only on selected platforms.

Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Reviewed-by: Steven Price <steven.price@arm.com>
Signed-off-by: Steven Price <steven.price@arm.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20231109102543.42971-6-angelogioacchino.delregno@collabora.com

diff --git a/drivers/gpu/drm/panfrost/panfrost_device.c b/drivers/gpu/drm/panfrost/panfrost_device.c
index b4ddbc3b80698b6f31470cb82f448606a6cf9f5c..c90ad5ee34e7aebdbf7a112460f9238e35bd4dca 100644 (file)
--- a/drivers/gpu/drm/panfrost/panfrost_device.c
+++ b/drivers/gpu/drm/panfrost/panfrost_device.c
@@ -431,10 +431,21 @@ static int panfrost_device_resume(struct device *dev)
        struct panfrost_device *pfdev = dev_get_drvdata(dev);
        int ret;
 
+       if (pfdev->comp->pm_features & BIT(GPU_PM_VREG_OFF)) {
+               unsigned long freq = pfdev->pfdevfreq.fast_rate;
+               struct dev_pm_opp *opp;
+
+               opp = dev_pm_opp_find_freq_ceil(dev, &freq);
+               if (IS_ERR(opp))
+                       return PTR_ERR(opp);
+               dev_pm_opp_set_opp(dev, opp);
+               dev_pm_opp_put(opp);
+       }
+
        if (pfdev->comp->pm_features & BIT(GPU_PM_CLK_DIS)) {
                ret = clk_enable(pfdev->clock);
                if (ret)
-                       return ret;
+                       goto err_clk;
 
                if (pfdev->bus_clock) {
                        ret = clk_enable(pfdev->bus_clock);
@@ -455,6 +466,9 @@ err_resume:
 err_bus_clk:
        if (pfdev->comp->pm_features & BIT(GPU_PM_CLK_DIS))
                clk_disable(pfdev->clock);
+err_clk:
+       if (pfdev->comp->pm_features & BIT(GPU_PM_VREG_OFF))
+               dev_pm_opp_set_opp(dev, NULL);
        return ret;
 }
 
@@ -474,6 +488,9 @@ static int panfrost_device_suspend(struct device *dev)
                clk_disable(pfdev->clock);
        }
 
+       if (pfdev->comp->pm_features & BIT(GPU_PM_VREG_OFF))
+               dev_pm_opp_set_opp(dev, NULL);
+
        return 0;
 }
 

diff --git a/drivers/gpu/drm/panfrost/panfrost_device.h b/drivers/gpu/drm/panfrost/panfrost_device.h
index 32453b97c39cb2a6879c7dc8204b04ad474beb73..7de77990a22173198155b7df9de1ad47006e1b88 100644 (file)
--- a/drivers/gpu/drm/panfrost/panfrost_device.h
+++ b/drivers/gpu/drm/panfrost/panfrost_device.h
@@ -28,9 +28,11 @@ struct panfrost_perfcnt;
 /**
  * enum panfrost_gpu_pm - Supported kernel power management features
  * @GPU_PM_CLK_DIS:  Allow disabling clocks during system suspend
+ * @GPU_PM_VREG_OFF: Allow turning off regulators during system suspend
  */
 enum panfrost_gpu_pm {
        GPU_PM_CLK_DIS,
+       GPU_PM_VREG_OFF,
 };
 
 struct panfrost_features {