Re: [PATCHv5 3/9] devfreq: event: Add exynos-ppmu devfreq-event driver

[Varka Bhadram]

On Tue, Dec 23, 2014 at 8:48 AM, Chanwoo Choi <cw00.choi@xxxxxxxxxxx> wrote:
> This patch adds exynos-ppmu devfreq-event driver to get performance data
> of each IP for Samsung Exynos SoC. These event from Exynos PPMU provide
> useful information about the behavior of the SoC that you can use when
> analyzing system performance, and made visible and can be counted using
> logic in each IP.
>
> This patch is based on existing drivers/devfreq/exynos/exynos-ppmu.c
>
> Cc: MyungJoo Ham <myungjoo.ham@xxxxxxxxxxx>
> Cc: Kyungmin Park <kyungmin.park@xxxxxxxxxxx>
> Signed-off-by: Chanwoo Choi <cw00.choi@xxxxxxxxxxx>

(...)
> +static int exynos_ppmu_parse_dt(struct exynos_ppmu_data *data)
> +{
> +       struct device *dev = data->dev;
> +       struct device_node *np = dev->of_node;
> +       int ret = 0;
> +
> +       if (!np) {
> +               dev_err(dev, "failed to find devicetree node\n");
> +               return -EINVAL;
> +       }
> +
> +       /* Maps the memory mapped IO to control PPMU register */
> +       data->ppmu.base = of_iomap(np, 0);
> +       if (IS_ERR_OR_NULL(data->ppmu.base)) {
> +               dev_err(dev, "failed to map memory region\n");
> +               return -EINVAL;
-ENOMEM or -ENXIO is the proper error return value..?

> +       }
> +
> +       data->clk_ppmu = devm_clk_get(dev, "ppmu");
> +       if (IS_ERR(data->clk_ppmu)) {
> +               data->clk_ppmu = NULL;
> +               dev_warn(dev, "failed to get PPMU clock\n");
> +       }
If PPMU clk get fails..?  return PTR_ERR(data->clk_ppmu)
> +
> +       ret = of_get_devfreq_events(np, data);
> +       if (ret < 0) {
> +               dev_err(dev, "failed to parse exynos ppmu dt node\n");
> +               goto err;
> +       }
> +
> +       return 0;
> +
> +err:
> +       iounmap(data->ppmu.base);
> +
> +       return ret;
> +}
> +
> +static int exynos_ppmu_probe(struct platform_device *pdev)
> +{
> +       struct exynos_ppmu_data *data;
> +       struct devfreq_event_dev **edev;
> +       struct devfreq_event_desc *desc;
> +       int i, ret = 0, size;
> +
> +       data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
> +       if (!data)
> +               return -ENOMEM;
> +
> +       mutex_init(&data->lock);
> +       data->dev = &pdev->dev;
> +
> +       /* Parse dt data to get resource */
> +       ret = exynos_ppmu_parse_dt(data);
> +       if (ret < 0) {
> +               dev_err(&pdev->dev,
> +                       "failed to parse devicetree for resource\n");
> +               return ret;
> +       }
> +       desc = data->desc;
> +
> +       size = sizeof(struct devfreq_event_dev *) * data->num_events;
> +       data->edev = devm_kzalloc(&pdev->dev, size, GFP_KERNEL);
> +       if (!data->edev) {
> +               dev_err(&pdev->dev,
> +                       "failed to allocate memory devfreq-event devices\n");
> +               return -ENOMEM;
> +       }
> +       edev = data->edev;
> +       platform_set_drvdata(pdev, data);
> +
> +       for (i = 0; i < data->num_events; i++) {
> +               edev[i] = devfreq_event_add_edev(&pdev->dev, &desc[i]);
> +               if (IS_ERR(edev)) {
> +                       ret = PTR_ERR(edev);
> +                       dev_err(&pdev->dev,
> +                               "failed to add devfreq-event device\n");
> +                       goto err;
> +               }
> +       }
> +
> +       clk_prepare_enable(data->clk_ppmu);
> +
> +       return 0;
> +err:
> +       iounmap(data->ppmu.base);
> +
> +       return ret;
> +}
> +
> +static int exynos_ppmu_remove(struct platform_device *pdev)
> +{
> +       struct exynos_ppmu_data *data = platform_get_drvdata(pdev);
> +       int i, ret = 0;
> +
> +       for (i = 0; i < data->num_events; i++) {
> +               ret = devfreq_event_remove_edev(data->edev[i]);
> +               if (ret < 0) {
> +                       dev_err(&pdev->dev,
> +                               "failed to remove devfreq-event device\n");
> +                       goto err;
> +               }
> +       }
> +
> +err:
> +       clk_disable_unprepare(data->clk_ppmu);
> +       iounmap(data->ppmu.base);
> +
> +       return ret;
> +}
> +
> +static struct of_device_id exynos_ppmu_id_match[] = {
> +       { .compatible = "samsung,exynos-ppmu", },
> +       { /* sentinel */ },
> +};
> +
> +static struct platform_driver exynos_ppmu_driver = {
> +       .probe  = exynos_ppmu_probe,
> +       .remove = exynos_ppmu_remove,
> +       .driver = {
> +               .name   = "exynos-ppmu",
> +               .owner  = THIS_MODULE,
remove owner field. It will be populate by driver core.
> +               .of_match_table = exynos_ppmu_id_match,
> +       },
> +};
> +module_platform_driver(exynos_ppmu_driver);
> +
> +MODULE_DESCRIPTION("Exynos PPMU(Platform Performance Monitoring Unit) driver");
> +MODULE_AUTHOR("Chanwoo Choi <cw00.choi@xxxxxxxxxxx>");
> +MODULE_LICENSE("GPL");
> +MODULE_ALIAS("platform:exynos-ppmu");
> --
> 1.8.5.5
>
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-- 
Thanks and Regards,
Varka Bhadram.
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