Re: [PATCH v2 4/9] coresight: Disable programming clock properly

On Fri, May 02, 2025 at 11:40:31AM +0530, Anshuman Khandual wrote:

Even though this might seem to be being bike shedding, the subject line above could be re-organized something like the following for better clarity.

coresight: Properly/Appropriately disable programming clocks

Sure. I will change the subject to this.

[...]

...

@@ -725,8 +723,6 @@ static void debug_platform_remove(struct platform_device *pdev) __debug_remove(&pdev->dev); pm_runtime_disable(&pdev->dev);

• if (!IS_ERR_OR_NULL(drvdata->pclk))

• clk_put(drvdata->pclk);
  

}

Should not these IS_ERR_OR_NULL() here be changed to IS_ERR() ?

For the case above, after changed to devm_clk_get_enabled() for the enabling programming clocks, we don't need any special handling and leave the clock disabling and releasing to the device model layer.

Because now there could not be a NULL return value.

drvdata->pclk = coresight_get_enable_apb_pclk(&pdev->dev)

#ifdef CONFIG_PM static int debug_runtime_suspend(struct device *dev) { struct debug_drvdata *drvdata = dev_get_drvdata(dev);

    if (drvdata && !IS_ERR_OR_NULL(drvdata->pclk))
            clk_disable_unprepare(drvdata->pclk);
    return 0;

}

static int debug_runtime_resume(struct device *dev) { struct debug_drvdata *drvdata = dev_get_drvdata(dev);

    if (drvdata && !IS_ERR_OR_NULL(drvdata->pclk))
            clk_prepare_enable(drvdata->pclk);
    return 0;

} #endif

There might more instances like these as well. git grep IS_ERR_OR_NULL drivers/hwtracing/coresight/ | grep "drvdata->pclk" drivers/hwtracing/coresight/coresight-cpu-debug.c: if (drvdata && !IS_ERR_OR_NULL(drvdata->pclk)) drivers/hwtracing/coresight/coresight-cpu-debug.c: if (drvdata && !IS_ERR_OR_NULL(drvdata->pclk)) drivers/hwtracing/coresight/coresight-funnel.c: if (drvdata && !IS_ERR_OR_NULL(drvdata->pclk)) drivers/hwtracing/coresight/coresight-funnel.c: if (drvdata && !IS_ERR_OR_NULL(drvdata->pclk)) drivers/hwtracing/coresight/coresight-replicator.c: if (drvdata && !IS_ERR_OR_NULL(drvdata->pclk)) drivers/hwtracing/coresight/coresight-replicator.c: if (drvdata && !IS_ERR_OR_NULL(drvdata->pclk)) drivers/hwtracing/coresight/coresight-stm.c: if (drvdata && !IS_ERR_OR_NULL(drvdata->pclk)) drivers/hwtracing/coresight/coresight-stm.c: if (drvdata && !IS_ERR_OR_NULL(drvdata->pclk)) drivers/hwtracing/coresight/coresight-tpiu.c: if (drvdata && !IS_ERR_OR_NULL(drvdata->pclk)) drivers/hwtracing/coresight/coresight-tpiu.c: if (drvdata && !IS_ERR_OR_NULL(drvdata->pclk))

I would like the current patch to focus on the issue of disabling / releasing the programming clocks.

Though the IS_ERR_OR_NULL() check is redundant, it does not cause issue or regression. The refactoring is left in patch 09 for removing IS_ERR_OR_NULL() checks.

Does this make sense?

Thanks Leo