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From:   Fabien Dessenne <fabien.dessenne@foss.st.com>
To:     Ohad Ben-Cohen <ohad@wizery.com>,
        Bjorn Andersson <bjorn.andersson@linaro.org>,
        Maxime Coquelin <mcoquelin.stm32@gmail.com>,
        Alexandre Torgue <alexandre.torgue@foss.st.com>,
        <linux-remoteproc@vger.kernel.org>,
        <linux-stm32@st-md-mailman.stormreply.com>,
        <linux-arm-kernel@lists.infradead.org>,
        <linux-kernel@vger.kernel.org>
CC:     Fabien Dessenne <fabien.dessenne@foss.st.com>
Subject: [PATCH] hwspinlock: stm32: enable clock at probe
Date:   Mon, 11 Oct 2021 11:33:26 +0200
Message-ID: <20211011093326.817797-1-fabien.dessenne@foss.st.com>
MIME-Version: 1.0
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Precedence: bulk

Set the clock during probe and keep its control during suspend / resume
operations.
This fixes an issue when CONFIG_PM is not set and where the clock is
never enabled.

Make use of devm_ functions to simplify the code.

Signed-off-by: Fabien Dessenne <fabien.dessenne@foss.st.com>
---
 drivers/hwspinlock/stm32_hwspinlock.c | 60 +++++++++++++++++----------
 1 file changed, 38 insertions(+), 22 deletions(-)

diff --git a/drivers/hwspinlock/stm32_hwspinlock.c b/drivers/hwspinlock/stm32_hwspinlock.c
index 3ad0ce0da4d9..6c3be33f3faf 100644
--- a/drivers/hwspinlock/stm32_hwspinlock.c
+++ b/drivers/hwspinlock/stm32_hwspinlock.c
@@ -54,8 +54,23 @@ static const struct hwspinlock_ops stm32_hwspinlock_ops = {
 	.relax		= stm32_hwspinlock_relax,
 };
 
+static void stm32_hwspinlock_disable_clk(void *data)
+{
+	struct platform_device *pdev = data;
+	struct stm32_hwspinlock *hw = platform_get_drvdata(pdev);
+	struct device *dev = &pdev->dev;
+
+	pm_runtime_get_sync(dev);
+	pm_runtime_disable(dev);
+	pm_runtime_set_suspended(dev);
+	pm_runtime_put_noidle(dev);
+
+	clk_disable_unprepare(hw->clk);
+}
+
 static int stm32_hwspinlock_probe(struct platform_device *pdev)
 {
+	struct device *dev = &pdev->dev;
 	struct stm32_hwspinlock *hw;
 	void __iomem *io_base;
 	size_t array_size;
@@ -66,41 +81,43 @@ static int stm32_hwspinlock_probe(struct platform_device *pdev)
 		return PTR_ERR(io_base);
 
 	array_size = STM32_MUTEX_NUM_LOCKS * sizeof(struct hwspinlock);
-	hw = devm_kzalloc(&pdev->dev, sizeof(*hw) + array_size, GFP_KERNEL);
+	hw = devm_kzalloc(dev, sizeof(*hw) + array_size, GFP_KERNEL);
 	if (!hw)
 		return -ENOMEM;
 
-	hw->clk = devm_clk_get(&pdev->dev, "hsem");
+	hw->clk = devm_clk_get(dev, "hsem");
 	if (IS_ERR(hw->clk))
 		return PTR_ERR(hw->clk);
 
-	for (i = 0; i < STM32_MUTEX_NUM_LOCKS; i++)
-		hw->bank.lock[i].priv = io_base + i * sizeof(u32);
+	ret = clk_prepare_enable(hw->clk);
+	if (ret) {
+		dev_err(dev, "Failed to prepare_enable clock\n");
+		return ret;
+	}
+
+	pm_runtime_get_noresume(dev);
+	pm_runtime_set_active(dev);
+	pm_runtime_enable(dev);
+	pm_runtime_put(dev);
 
 	platform_set_drvdata(pdev, hw);
-	pm_runtime_enable(&pdev->dev);
 
-	ret = hwspin_lock_register(&hw->bank, &pdev->dev, &stm32_hwspinlock_ops,
-				   0, STM32_MUTEX_NUM_LOCKS);
+	ret = devm_add_action_or_reset(dev, stm32_hwspinlock_disable_clk, pdev);
+	if (ret) {
+		dev_err(dev, "Failed to register action\n");
+		return ret;
+	}
 
-	if (ret)
-		pm_runtime_disable(&pdev->dev);
-
-	return ret;
-}
+	for (i = 0; i < STM32_MUTEX_NUM_LOCKS; i++)
+		hw->bank.lock[i].priv = io_base + i * sizeof(u32);
 
-static int stm32_hwspinlock_remove(struct platform_device *pdev)
-{
-	struct stm32_hwspinlock *hw = platform_get_drvdata(pdev);
-	int ret;
+	ret = devm_hwspin_lock_register(dev, &hw->bank, &stm32_hwspinlock_ops,
+					0, STM32_MUTEX_NUM_LOCKS);
 
-	ret = hwspin_lock_unregister(&hw->bank);
 	if (ret)
-		dev_err(&pdev->dev, "%s failed: %d\n", __func__, ret);
-
-	pm_runtime_disable(&pdev->dev);
+		dev_err(dev, "Failed to register hwspinlock\n");
 
-	return 0;
+	return ret;
 }
 
 static int __maybe_unused stm32_hwspinlock_runtime_suspend(struct device *dev)
@@ -135,7 +152,6 @@ MODULE_DEVICE_TABLE(of, stm32_hwpinlock_ids);
 
 static struct platform_driver stm32_hwspinlock_driver = {
 	.probe		= stm32_hwspinlock_probe,
-	.remove		= stm32_hwspinlock_remove,
 	.driver		= {
 		.name	= "stm32_hwspinlock",
 		.of_match_table = stm32_hwpinlock_ids,
-- 
2.25.1