diff mbox series

[v2,3/3] media: exynos4-is: fimc-is: replace duplicate pmu node with phandle

Message ID 20230807131256.254243-3-krzysztof.kozlowski@linaro.org
State Superseded
Headers show
Series [v2,1/3] media: dt-bindings: samsung,exynos4212-fimc-is: replace duplicate pmu node with phandle | expand

Commit Message

Krzysztof Kozlowski Aug. 7, 2023, 1:12 p.m. UTC
Devicetree for the FIMC IS camera included duplicated PMU node as its
child like:

  soc@0 {
    system-controller@10020000 { ... }; // Real PMU

    camera@11800000 {
      fimc-is@12000000 {
        // FIMC IS camera node
        pmu@10020000 {
          reg = <0x10020000 0x3000>; // Fake PMU node
        };
      };
    };
  };

This is not a correct representation of the hardware.  Mapping the PMU
(Power Management Unit) IO memory should be via syscon-like phandle
(samsung,pmu-syscon, already used for other drivers), not by duplicating
"pmu" Devicetree node inside the FIMC IS.  Backward compatibility is
preserved.

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>

---

Changes in v2:
1. Use IOMEM_ERR_PTR (Hans)
---
 .../platform/samsung/exynos4-is/fimc-is.c     | 33 ++++++++++++++-----
 1 file changed, 24 insertions(+), 9 deletions(-)

Comments

Andi Shyti Aug. 7, 2023, 11:13 p.m. UTC | #1
Hi Krzysztof,

[...]

> +static void __iomem *fimc_is_get_pmu_regs(struct device *dev)
> +{
> +	struct device_node *node;
> +	void __iomem *regs;
> +
> +	node = of_parse_phandle(dev->of_node, "samsung,pmu-syscon", 0);
> +	if (!node) {
> +		dev_warn(dev, "Finding PMU node via deprecated method, update your DTB\n");
> +		node = of_get_child_by_name(dev->of_node, "pmu");
> +		if (!node)
> +			return IOMEM_ERR_PTR(-ENODEV);

in my opinion this should be:

		...
		if (!node)
			return IOMEM_ERR_PTR(-ENODEV);

		dev_warn(dev, "Finding PMU node via deprecated method, update your DTB\n");

Because if you don't have both "samsung,pmu-syscon and "pmu" then
the warning should not be printed and you need to return -ENODEV.

... and... "*please* update your DTB", the user might get upset
and out of sheer spite, decides not to do it – just because! :)

Andi

> +	}
Krzysztof Kozlowski Aug. 8, 2023, 6:22 a.m. UTC | #2
On 08/08/2023 01:13, Andi Shyti wrote:
> Hi Krzysztof,
> 
> [...]
> 
>> +static void __iomem *fimc_is_get_pmu_regs(struct device *dev)
>> +{
>> +	struct device_node *node;
>> +	void __iomem *regs;
>> +
>> +	node = of_parse_phandle(dev->of_node, "samsung,pmu-syscon", 0);
>> +	if (!node) {
>> +		dev_warn(dev, "Finding PMU node via deprecated method, update your DTB\n");
>> +		node = of_get_child_by_name(dev->of_node, "pmu");
>> +		if (!node)
>> +			return IOMEM_ERR_PTR(-ENODEV);
> 
> in my opinion this should be:
> 
> 		...
> 		if (!node)
> 			return IOMEM_ERR_PTR(-ENODEV);
> 
> 		dev_warn(dev, "Finding PMU node via deprecated method, update your DTB\n");
> 
> Because if you don't have both "samsung,pmu-syscon and "pmu" then
> the warning should not be printed and you need to return -ENODEV.

Why not? Warning is correct - the driver is trying to find, thus
continuous tense "Finding", PMU node via old method.

> 
> ... and... "*please* update your DTB", the user might get upset
> and out of sheer spite, decides not to do it – just because! :)

The message is already long enough, why making it longer? Anyone who
ships DTS outside of Linux kernel is doomed anyway...

Best regards,
Krzysztof
Hans Verkuil Aug. 11, 2023, 9:49 a.m. UTC | #3
Hi Krzysztof,

On 08/08/2023 01:13, Andi Shyti wrote:
> Hi Krzysztof,
> 
> [...]
> 
>> +static void __iomem *fimc_is_get_pmu_regs(struct device *dev)
>> +{
>> +	struct device_node *node;
>> +	void __iomem *regs;
>> +
>> +	node = of_parse_phandle(dev->of_node, "samsung,pmu-syscon", 0);
>> +	if (!node) {
>> +		dev_warn(dev, "Finding PMU node via deprecated method, update your DTB\n");
>> +		node = of_get_child_by_name(dev->of_node, "pmu");
>> +		if (!node)
>> +			return IOMEM_ERR_PTR(-ENODEV);
> 
> in my opinion this should be:
> 
> 		...
> 		if (!node)
> 			return IOMEM_ERR_PTR(-ENODEV);
> 
> 		dev_warn(dev, "Finding PMU node via deprecated method, update your DTB\n");
> 
> Because if you don't have both "samsung,pmu-syscon and "pmu" then
> the warning should not be printed and you need to return -ENODEV.

I agree with Andi for this part.

The only time you want to see this message is if samsung,pmu-syscon is
missing AND pmu is present. If both are missing, then just return ENODEV as
it was before.

> 
> ... and... "*please* update your DTB", the user might get upset
> and out of sheer spite, decides not to do it – just because! :)

I don't care about this bit. I guess it doesn't hurt to add 'please', but
I accept it either way.

Regards,

	Hans

> 
> Andi
> 
>> +	}
Krzysztof Kozlowski Aug. 15, 2023, 6:02 a.m. UTC | #4
On 11/08/2023 11:49, Hans Verkuil wrote:
> Hi Krzysztof,
> 
> On 08/08/2023 01:13, Andi Shyti wrote:
>> Hi Krzysztof,
>>
>> [...]
>>
>>> +static void __iomem *fimc_is_get_pmu_regs(struct device *dev)
>>> +{
>>> +	struct device_node *node;
>>> +	void __iomem *regs;
>>> +
>>> +	node = of_parse_phandle(dev->of_node, "samsung,pmu-syscon", 0);
>>> +	if (!node) {
>>> +		dev_warn(dev, "Finding PMU node via deprecated method, update your DTB\n");
>>> +		node = of_get_child_by_name(dev->of_node, "pmu");
>>> +		if (!node)
>>> +			return IOMEM_ERR_PTR(-ENODEV);
>>
>> in my opinion this should be:
>>
>> 		...
>> 		if (!node)
>> 			return IOMEM_ERR_PTR(-ENODEV);
>>
>> 		dev_warn(dev, "Finding PMU node via deprecated method, update your DTB\n");
>>
>> Because if you don't have both "samsung,pmu-syscon and "pmu" then
>> the warning should not be printed and you need to return -ENODEV.
> 
> I agree with Andi for this part.
> 
> The only time you want to see this message is if samsung,pmu-syscon is
> missing AND pmu is present. If both are missing, then just return ENODEV as
> it was before.

OK, understood. I will send a v3.

Best regards,
Krzysztof
diff mbox series

Patch

diff --git a/drivers/media/platform/samsung/exynos4-is/fimc-is.c b/drivers/media/platform/samsung/exynos4-is/fimc-is.c
index 530a148fe4d3..c995b1226ca3 100644
--- a/drivers/media/platform/samsung/exynos4-is/fimc-is.c
+++ b/drivers/media/platform/samsung/exynos4-is/fimc-is.c
@@ -767,12 +767,32 @@  static void fimc_is_debugfs_create(struct fimc_is *is)
 static int fimc_is_runtime_resume(struct device *dev);
 static int fimc_is_runtime_suspend(struct device *dev);
 
+static void __iomem *fimc_is_get_pmu_regs(struct device *dev)
+{
+	struct device_node *node;
+	void __iomem *regs;
+
+	node = of_parse_phandle(dev->of_node, "samsung,pmu-syscon", 0);
+	if (!node) {
+		dev_warn(dev, "Finding PMU node via deprecated method, update your DTB\n");
+		node = of_get_child_by_name(dev->of_node, "pmu");
+		if (!node)
+			return IOMEM_ERR_PTR(-ENODEV);
+	}
+
+	regs = of_iomap(node, 0);
+	of_node_put(node);
+	if (!regs)
+		return IOMEM_ERR_PTR(-ENOMEM);
+
+	return regs;
+}
+
 static int fimc_is_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
 	struct fimc_is *is;
 	struct resource res;
-	struct device_node *node;
 	int ret;
 
 	is = devm_kzalloc(&pdev->dev, sizeof(*is), GFP_KERNEL);
@@ -794,14 +814,9 @@  static int fimc_is_probe(struct platform_device *pdev)
 	if (IS_ERR(is->regs))
 		return PTR_ERR(is->regs);
 
-	node = of_get_child_by_name(dev->of_node, "pmu");
-	if (!node)
-		return -ENODEV;
-
-	is->pmu_regs = of_iomap(node, 0);
-	of_node_put(node);
-	if (!is->pmu_regs)
-		return -ENOMEM;
+	is->pmu_regs = fimc_is_get_pmu_regs(dev);
+	if (IS_ERR(is->pmu_regs))
+		return PTR_ERR(is->pmu_regs);
 
 	is->irq = irq_of_parse_and_map(dev->of_node, 0);
 	if (!is->irq) {