linux-kernel - Re: [PATCH v2] hwspinlock: stm32: enable clock at probe

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Message-ID: <aa3e90a8-4b48-c2ea-2b8b-88e6c30204d2@foss.st.com>
Date:   Wed, 17 Nov 2021 11:31:34 +0100
From:   Fabien DESSENNE <fabien.dessenne@...s.st.com>
To:     Ohad Ben-Cohen <ohad@...ery.com>,
        Bjorn Andersson <bjorn.andersson@...aro.org>,
        Maxime Coquelin <mcoquelin.stm32@...il.com>,
        Alexandre Torgue <alexandre.torgue@...s.st.com>,
        <linux-remoteproc@...r.kernel.org>,
        <linux-stm32@...md-mailman.stormreply.com>,
        <linux-arm-kernel@...ts.infradead.org>,
        <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v2] hwspinlock: stm32: enable clock at probe

Hi

Any comments on this patch?

BR

Fabien

On 11/10/2021 15:58, Fabien Dessenne wrote:
> 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@...s.st.com>
> ---
> Changes since v1:
> - Call platform_set_drvdata() before pm_runtime_...() calls
> ---
>   drivers/hwspinlock/stm32_hwspinlock.c | 58 +++++++++++++++++----------
>   1 file changed, 37 insertions(+), 21 deletions(-)
> 
> diff --git a/drivers/hwspinlock/stm32_hwspinlock.c b/drivers/hwspinlock/stm32_hwspinlock.c
> index 3ad0ce0da4d9..5bd11a7fab65 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;
> +	}
>   
>   	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);
> +	pm_runtime_get_noresume(dev);
> +	pm_runtime_set_active(dev);
> +	pm_runtime_enable(dev);
> +	pm_runtime_put(dev);
>   
> -	if (ret)
> -		pm_runtime_disable(&pdev->dev);
> +	ret = devm_add_action_or_reset(dev, stm32_hwspinlock_disable_clk, pdev);
> +	if (ret) {
> +		dev_err(dev, "Failed to register action\n");
> +		return ret;
> +	}
>   
> -	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,
>