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

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Message-ID: <fd47f637-6d1a-8fec-e275-5e7aa53671eb@arm.com>
Date:   Fri, 22 Sep 2023 09:40:14 +0530
From:   Anshuman Khandual <anshuman.khandual@....com>
To:     Suzuki K Poulose <suzuki.poulose@....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 9/21/23 16:40, Suzuki K Poulose wrote:
> 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

Agreed, IS_ERR_OR_NULL() should be used instead.

> 
> Same applies throughout the series.

Updated suspend/resume callbacks in each driver to use IS_ERR_OR_NULL().