[PATCH v2 3/4] drm/panfrost: Add bus_ace optional clock support for RZ/G2L

[Biju <biju.das.au@gmail.com>]

From: Biju Das <biju.das.jz@bp.renesas.com>

On RZ/G2L SoCs, the GPU MMU requires a bus_ace clock to operate correctly.
Without it, unbind/bind cycles leave the GPU non-operational, manifesting
as an AS_ACTIVE bit stuck and a soft reset timeout falling back to hard
reset. Add bus_ace_clock as an optional clock, wiring it into init/fini,
and the runtime suspend/resume paths alongside the existing optional
bus_clock.

Reviewed-by: Steven Price <steven.price@arm.com>
Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
---
v1->v2:
 * Dropped duplicate err assignment
 * Changed the format string of dev_err to "%d" and simplify the dev_err()
   line by using err rather than the same PTR_ERR().
 * Collected tag
---
 drivers/gpu/drm/panfrost/panfrost_device.c | 22 ++++++++++++++++++++++
 drivers/gpu/drm/panfrost/panfrost_device.h |  1 +
 2 files changed, 23 insertions(+)

diff --git a/drivers/gpu/drm/panfrost/panfrost_device.c b/drivers/gpu/drm/panfrost/panfrost_device.c
index 01e702a0b2f0..7fed22d555a5 100644
--- a/drivers/gpu/drm/panfrost/panfrost_device.c
+++ b/drivers/gpu/drm/panfrost/panfrost_device.c
@@ -70,8 +70,21 @@ static int panfrost_clk_init(struct panfrost_device *pfdev)
 			goto disable_clock;
 	}
 
+	pfdev->bus_ace_clock = devm_clk_get_optional(pfdev->base.dev, "bus_ace");
+	if (IS_ERR(pfdev->bus_ace_clock)) {
+		err = PTR_ERR(pfdev->bus_ace_clock);
+		dev_err(pfdev->base.dev, "get bus_ace_clock failed %d\n", err);
+		goto disable_bus_clock;
+	}
+
+	err = clk_prepare_enable(pfdev->bus_ace_clock);
+	if (err)
+		goto disable_bus_clock;
+
 	return 0;
 
+disable_bus_clock:
+	clk_disable_unprepare(pfdev->bus_clock);
 disable_clock:
 	clk_disable_unprepare(pfdev->clock);
 
@@ -80,6 +93,7 @@ static int panfrost_clk_init(struct panfrost_device *pfdev)
 
 static void panfrost_clk_fini(struct panfrost_device *pfdev)
 {
+	clk_disable_unprepare(pfdev->bus_ace_clock);
 	clk_disable_unprepare(pfdev->bus_clock);
 	clk_disable_unprepare(pfdev->clock);
 }
@@ -432,6 +446,10 @@ static int panfrost_device_runtime_resume(struct device *dev)
 		ret = clk_enable(pfdev->bus_clock);
 		if (ret)
 			goto err_bus_clk;
+
+		ret = clk_enable(pfdev->bus_ace_clock);
+		if (ret)
+			goto err_bus_ace_clk;
 	}
 
 	panfrost_device_reset(pfdev, true);
@@ -439,6 +457,9 @@ static int panfrost_device_runtime_resume(struct device *dev)
 
 	return 0;
 
+err_bus_ace_clk:
+	if (pfdev->comp->pm_features & BIT(GPU_PM_RT))
+		clk_disable(pfdev->bus_clock);
 err_bus_clk:
 	if (pfdev->comp->pm_features & BIT(GPU_PM_RT))
 		clk_disable(pfdev->clock);
@@ -462,6 +483,7 @@ static int panfrost_device_runtime_suspend(struct device *dev)
 	panfrost_gpu_power_off(pfdev);
 
 	if (pfdev->comp->pm_features & BIT(GPU_PM_RT)) {
+		clk_disable(pfdev->bus_ace_clock);
 		clk_disable(pfdev->bus_clock);
 		clk_disable(pfdev->clock);
 		reset_control_assert(pfdev->rstc);
diff --git a/drivers/gpu/drm/panfrost/panfrost_device.h b/drivers/gpu/drm/panfrost/panfrost_device.h
index 0f3992412205..ec55c136b1b6 100644
--- a/drivers/gpu/drm/panfrost/panfrost_device.h
+++ b/drivers/gpu/drm/panfrost/panfrost_device.h
@@ -136,6 +136,7 @@ struct panfrost_device {
 	void __iomem *iomem;
 	struct clk *clock;
 	struct clk *bus_clock;
+	struct clk *bus_ace_clock;
 	struct regulator_bulk_data *regulators;
 	struct reset_control *rstc;
 	/* pm_domains for devices with more than one. */
-- 
2.43.0