[PATCH v2 0/4] drm/etnaviv: Tidy up clocks handling

[PATCH v2 0/4] drm/etnaviv: Tidy up clocks handling

[Lubomir Rintel]

Hi,

please consider applying patches that are chained to this message.

They make getting/enabling the clocks in the etnaviv driver slightly nicer,
first two also fix potential problems.

Compared to v1, patch 2/4 was fixed and patch 3/4 was added.

As it was pointed out in response to v1, the clocks documented as
mandatory by the binding document are different from what the driver
enforces. Moreover, there is no agreement on which clocks must be
present in the device tree, so I'm leaving the binding document until
it's cleared up.

In any case, the "core" clock is always present so it's safe to make it
mandatory and regardless of what ends up happening to the binding
documentation, the other clocks can't be enforced without regressions.
At most a comment or a warning could be added. I'm leaving it as it is.

Thank you
Lubo



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[PATCH v2 1/4] drm/etnaviv: Fix error path on failure to enable bus clk

[Lubomir Rintel]

Since commit 65f037e8e908 ("drm/etnaviv: add support for slave interface
clock") the reg clock is enabled before the bus clock and we need to undo
its enablement on error.

Fixes: 65f037e8e908 ("drm/etnaviv: add support for slave interface clock")
Signed-off-by: Lubomir Rintel <lkundrak@v3.sk>
---
 drivers/gpu/drm/etnaviv/etnaviv_gpu.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/etnaviv/etnaviv_gpu.c b/drivers/gpu/drm/etnaviv/etnaviv_gpu.c
index a31eeff2b297..c6dacfe3d321 100644
--- a/drivers/gpu/drm/etnaviv/etnaviv_gpu.c
+++ b/drivers/gpu/drm/etnaviv/etnaviv_gpu.c
@@ -1496,7 +1496,7 @@ static int etnaviv_gpu_clk_enable(struct etnaviv_gpu *gpu)
 	if (gpu->clk_bus) {
 		ret = clk_prepare_enable(gpu->clk_bus);
 		if (ret)
-			return ret;
+			goto disable_clk_reg;
 	}
 
 	if (gpu->clk_core) {
@@ -1519,6 +1519,9 @@ static int etnaviv_gpu_clk_enable(struct etnaviv_gpu *gpu)
 disable_clk_bus:
 	if (gpu->clk_bus)
 		clk_disable_unprepare(gpu->clk_bus);
+disable_clk_reg:
+	if (gpu->clk_reg)
+		clk_disable_unprepare(gpu->clk_reg);
 
 	return ret;
 }
-- 
2.26.2

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[PATCH v2 2/4] drm/etnaviv: Don't ignore errors on getting clocks

[Lubomir Rintel]

There might be good reasons why the getting a clock failed. To treat the
clocks as optional we're specifically only interested in ignoring -ENOENT,
and devm_clk_get_optional() does just that.

Note that this preserves the original behavior of all clocks being
optional. The binding document mandates the "bus" clock while the dove
machine only specifies "core".

Signed-off-by: Lubomir Rintel <lkundrak@v3.sk>

---
Changes since v1:
- Fix the actual return value
---
 drivers/gpu/drm/etnaviv/etnaviv_gpu.c | 16 ++++++++--------
 1 file changed, 8 insertions(+), 8 deletions(-)

diff --git a/drivers/gpu/drm/etnaviv/etnaviv_gpu.c b/drivers/gpu/drm/etnaviv/etnaviv_gpu.c
index c6dacfe3d321..f303172c091d 100644
--- a/drivers/gpu/drm/etnaviv/etnaviv_gpu.c
+++ b/drivers/gpu/drm/etnaviv/etnaviv_gpu.c
@@ -1786,26 +1786,26 @@ static int etnaviv_gpu_platform_probe(struct platform_device *pdev)
 	}
 
 	/* Get Clocks: */
-	gpu->clk_reg = devm_clk_get(&pdev->dev, "reg");
+	gpu->clk_reg = devm_clk_get_optional(&pdev->dev, "reg");
 	DBG("clk_reg: %p", gpu->clk_reg);
 	if (IS_ERR(gpu->clk_reg))
-		gpu->clk_reg = NULL;
+		return PTR_ERR(gpu->clk_reg);
 
-	gpu->clk_bus = devm_clk_get(&pdev->dev, "bus");
+	gpu->clk_bus = devm_clk_get_optional(&pdev->dev, "bus");
 	DBG("clk_bus: %p", gpu->clk_bus);
 	if (IS_ERR(gpu->clk_bus))
-		gpu->clk_bus = NULL;
+		return PTR_ERR(gpu->clk_bus);
 
-	gpu->clk_core = devm_clk_get(&pdev->dev, "core");
+	gpu->clk_core = devm_clk_get_optional(&pdev->dev, "core");
 	DBG("clk_core: %p", gpu->clk_core);
 	if (IS_ERR(gpu->clk_core))
-		gpu->clk_core = NULL;
+		return PTR_ERR(gpu->clk_core);
 	gpu->base_rate_core = clk_get_rate(gpu->clk_core);
 
-	gpu->clk_shader = devm_clk_get(&pdev->dev, "shader");
+	gpu->clk_shader = devm_clk_get_optional(&pdev->dev, "shader");
 	DBG("clk_shader: %p", gpu->clk_shader);
 	if (IS_ERR(gpu->clk_shader))
-		gpu->clk_shader = NULL;
+		return PTR_ERR(gpu->clk_shader);
 	gpu->base_rate_shader = clk_get_rate(gpu->clk_shader);
 
 	/* TODO: figure out max mapped size */
-- 
2.26.2

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[PATCH v2 3/4] drm/etnaviv: Make the "core" clock mandatory

[Lubomir Rintel]

It is always present. It was documented as mandatory prior to
commit 90aeca875f8a ("dt-bindings: display: Convert etnaviv to
json-schema").

Signed-off-by: Lubomir Rintel <lkundrak@v3.sk>

---
Changes since v1:
- Add this patch
---
 drivers/gpu/drm/etnaviv/etnaviv_gpu.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/etnaviv/etnaviv_gpu.c b/drivers/gpu/drm/etnaviv/etnaviv_gpu.c
index f303172c091d..798fdbc8ecdb 100644
--- a/drivers/gpu/drm/etnaviv/etnaviv_gpu.c
+++ b/drivers/gpu/drm/etnaviv/etnaviv_gpu.c
@@ -1796,7 +1796,7 @@ static int etnaviv_gpu_platform_probe(struct platform_device *pdev)
 	if (IS_ERR(gpu->clk_bus))
 		return PTR_ERR(gpu->clk_bus);
 
-	gpu->clk_core = devm_clk_get_optional(&pdev->dev, "core");
+	gpu->clk_core = devm_clk_get(&pdev->dev, "core");
 	DBG("clk_core: %p", gpu->clk_core);
 	if (IS_ERR(gpu->clk_core))
 		return PTR_ERR(gpu->clk_core);
-- 
2.26.2

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[PATCH v2 4/4] drm/etnaviv: Simplify clock enable/disable

[Lubomir Rintel]

All the NULL checks are pointless, clk_*() routines already deal with NULL
just fine.

Signed-off-by: Lubomir Rintel <lkundrak@v3.sk>
---
 drivers/gpu/drm/etnaviv/etnaviv_gpu.c | 53 ++++++++++-----------------
 1 file changed, 19 insertions(+), 34 deletions(-)

diff --git a/drivers/gpu/drm/etnaviv/etnaviv_gpu.c b/drivers/gpu/drm/etnaviv/etnaviv_gpu.c
index 798fdbc8ecdb..fb37787449bb 100644
--- a/drivers/gpu/drm/etnaviv/etnaviv_gpu.c
+++ b/drivers/gpu/drm/etnaviv/etnaviv_gpu.c
@@ -1487,55 +1487,40 @@ static int etnaviv_gpu_clk_enable(struct etnaviv_gpu *gpu)
 {
 	int ret;
 
-	if (gpu->clk_reg) {
-		ret = clk_prepare_enable(gpu->clk_reg);
-		if (ret)
-			return ret;
-	}
+	ret = clk_prepare_enable(gpu->clk_reg);
+	if (ret)
+		return ret;
 
-	if (gpu->clk_bus) {
-		ret = clk_prepare_enable(gpu->clk_bus);
-		if (ret)
-			goto disable_clk_reg;
-	}
+	ret = clk_prepare_enable(gpu->clk_bus);
+	if (ret)
+		goto disable_clk_reg;
 
-	if (gpu->clk_core) {
-		ret = clk_prepare_enable(gpu->clk_core);
-		if (ret)
-			goto disable_clk_bus;
-	}
+	ret = clk_prepare_enable(gpu->clk_core);
+	if (ret)
+		goto disable_clk_bus;
 
-	if (gpu->clk_shader) {
-		ret = clk_prepare_enable(gpu->clk_shader);
-		if (ret)
-			goto disable_clk_core;
-	}
+	ret = clk_prepare_enable(gpu->clk_shader);
+	if (ret)
+		goto disable_clk_core;
 
 	return 0;
 
 disable_clk_core:
-	if (gpu->clk_core)
-		clk_disable_unprepare(gpu->clk_core);
+	clk_disable_unprepare(gpu->clk_core);
 disable_clk_bus:
-	if (gpu->clk_bus)
-		clk_disable_unprepare(gpu->clk_bus);
+	clk_disable_unprepare(gpu->clk_bus);
 disable_clk_reg:
-	if (gpu->clk_reg)
-		clk_disable_unprepare(gpu->clk_reg);
+	clk_disable_unprepare(gpu->clk_reg);
 
 	return ret;
 }
 
 static int etnaviv_gpu_clk_disable(struct etnaviv_gpu *gpu)
 {
-	if (gpu->clk_shader)
-		clk_disable_unprepare(gpu->clk_shader);
-	if (gpu->clk_core)
-		clk_disable_unprepare(gpu->clk_core);
-	if (gpu->clk_bus)
-		clk_disable_unprepare(gpu->clk_bus);
-	if (gpu->clk_reg)
-		clk_disable_unprepare(gpu->clk_reg);
+	clk_disable_unprepare(gpu->clk_shader);
+	clk_disable_unprepare(gpu->clk_core);
+	clk_disable_unprepare(gpu->clk_bus);
+	clk_disable_unprepare(gpu->clk_reg);
 
 	return 0;
 }
-- 
2.26.2

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