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From:   Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
To:     Sylwester Nawrocki <s.nawrocki@samsung.com>,
        Mauro Carvalho Chehab <mchehab@kernel.org>,
        Rob Herring <robh+dt@kernel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
        Conor Dooley <conor+dt@kernel.org>,
        Alim Akhtar <alim.akhtar@samsung.com>,
        linux-media@vger.kernel.org, devicetree@vger.kernel.org,
        linux-arm-kernel@lists.infradead.org,
        linux-samsung-soc@vger.kernel.org, linux-kernel@vger.kernel.org
Cc:     Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Subject: [PATCH v2 3/3] media: exynos4-is: fimc-is: replace duplicate pmu node with phandle
Date:   Mon,  7 Aug 2023 15:12:56 +0200
Message-Id: <20230807131256.254243-3-krzysztof.kozlowski@linaro.org>
In-Reply-To: <20230807131256.254243-1-krzysztof.kozlowski@linaro.org>
References: <20230807131256.254243-1-krzysztof.kozlowski@linaro.org>
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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(-)

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) {
-- 
2.34.1