linux-kernel - Re: [RFC RESEND 1/7] coresight: replicator: Move ACPI support from AMBA driver to platform driver

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Message-ID: <6a72387f-2749-0e27-000f-aeec265cb789@arm.com>
Date:   Thu, 21 Sep 2023 12:10:51 +0100
From:   Suzuki K Poulose <suzuki.poulose@....com>
To:     Anshuman Khandual <anshuman.khandual@....com>,
        linux-arm-kernel@...ts.infradead.org
Cc:     James Clark <james.clark@....com>,
        Mike Leach <mike.leach@...aro.org>, coresight@...ts.linaro.org,
        linux-kernel@...r.kernel.org
Subject: Re: [RFC RESEND 1/7] coresight: replicator: Move ACPI support from
 AMBA driver to platform driver

On 21/09/2023 05:20, Anshuman Khandual wrote:
> Add support for the dynamic replicator device in the platform driver, which
> can then be used on ACPI based platforms. This change would now allow
> runtime power management for repliacator devices on ACPI based systems.
> 
> The driver would try to enable the APB clock if available. Also, rename the
> code to reflect the fact that it now handles both static and dynamic
> replicators.
> 
> Signed-off-by: Anshuman Khandual <anshuman.khandual@....com>
> ---
>   drivers/acpi/arm64/amba.c                     |  1 -
>   .../coresight/coresight-replicator.c          | 44 ++++++++++++-------
>   2 files changed, 27 insertions(+), 18 deletions(-)
> 
> diff --git a/drivers/acpi/arm64/amba.c b/drivers/acpi/arm64/amba.c
> index 60be8ee1dbdc..ac59ce50de07 100644
> --- a/drivers/acpi/arm64/amba.c
> +++ b/drivers/acpi/arm64/amba.c
> @@ -27,7 +27,6 @@ static const struct acpi_device_id amba_id_list[] = {
>   	{"ARMHC503", 0}, /* ARM CoreSight Debug */
>   	{"ARMHC979", 0}, /* ARM CoreSight TPIU */
>   	{"ARMHC97C", 0}, /* ARM CoreSight SoC-400 TMC, SoC-600 ETF/ETB */
> -	{"ARMHC98D", 0}, /* ARM CoreSight Dynamic Replicator */
>   	{"ARMHC9CA", 0}, /* ARM CoreSight CATU */
>   	{"ARMHC9FF", 0}, /* ARM CoreSight Dynamic Funnel */
>   	{"", 0},
> diff --git a/drivers/hwtracing/coresight/coresight-replicator.c b/drivers/hwtracing/coresight/coresight-replicator.c
> index b6be73034996..a18d5e8fcba1 100644
> --- a/drivers/hwtracing/coresight/coresight-replicator.c
> +++ b/drivers/hwtracing/coresight/coresight-replicator.c
> @@ -38,6 +38,7 @@ DEFINE_CORESIGHT_DEVLIST(replicator_devs, "replicator");
>   struct replicator_drvdata {
>   	void __iomem		*base;
>   	struct clk		*atclk;
> +	struct clk		*pclk;
>   	struct coresight_device	*csdev;
>   	spinlock_t		spinlock;
>   	bool			check_idfilter_val;
> @@ -243,6 +244,10 @@ static int replicator_probe(struct device *dev, struct resource *res)
>   			return ret;
>   	}
>   
> +	drvdata->pclk = coresight_get_enable_apb_pclk(dev);
> +	if (IS_ERR(drvdata->pclk))
> +		return -ENODEV;
> +
>   	/*
>   	 * Map the device base for dynamic-replicator, which has been
>   	 * validated by AMBA core
> @@ -301,16 +306,16 @@ static int replicator_remove(struct device *dev)
>   	return 0;
>   }
>   
> -static int static_replicator_probe(struct platform_device *pdev)
> +static int replicator_platform_probe(struct platform_device *pdev)
>   {
> +	struct resource *res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
>   	int ret;
>   
>   	pm_runtime_get_noresume(&pdev->dev);
>   	pm_runtime_set_active(&pdev->dev);
>   	pm_runtime_enable(&pdev->dev);
>   
> -	/* Static replicators do not have programming base */
> -	ret = replicator_probe(&pdev->dev, NULL);
> +	ret = replicator_probe(&pdev->dev, res);
>   
>   	if (ret) {
>   		pm_runtime_put_noidle(&pdev->dev);
> @@ -320,7 +325,7 @@ static int static_replicator_probe(struct platform_device *pdev)
>   	return ret;
>   }
>   
> -static int static_replicator_remove(struct platform_device *pdev)
> +static int replicator_platform_remove(struct platform_device *pdev)
>   {
>   	replicator_remove(&pdev->dev);
>   	pm_runtime_disable(&pdev->dev);
> @@ -335,6 +340,8 @@ static int replicator_runtime_suspend(struct device *dev)
>   	if (drvdata && !IS_ERR(drvdata->atclk))
>   		clk_disable_unprepare(drvdata->atclk);
>   
> +	if (drvdata && !IS_ERR(drvdata->pclk))

!IS_ERR_OR_NULL() ? If we don't have pclk, drvdata->pclk is always NULL

Same applies throughout the series.

Suzuki