Re: [PATCH v13 17/35] bus: tegra-gmi: Add runtime PM and OPP support

Ulf Hansson
2021-10-01T14:19:42Z

On Mon, 27 Sept 2021 at 00:42, Dmitry Osipenko <digetx@gmail.com> wrote:
>
> The GMI bus on Tegra belongs to the core power domain and we're going to
> enable GENPD support for the core domain. Now GMI must be resumed using
> runtime PM API in order to initialize the GMI power state. Add runtime PM
> and OPP support to the GMI driver.
>
> Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
> ---
> drivers/bus/tegra-gmi.c | 52 ++++++++++++++++++++++++++++++++++++-----
> 1 file changed, 46 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/bus/tegra-gmi.c b/drivers/bus/tegra-gmi.c
> index a6570789f7af..72ef8a8c236b 100644
> --- a/drivers/bus/tegra-gmi.c
> +++ b/drivers/bus/tegra-gmi.c
> @@ -13,8 +13,11 @@
> #include <linux/io.h>
> #include <linux/module.h>
> #include <linux/of_device.h>
> +#include <linux/pm_runtime.h>
> #include <linux/reset.h>
>
> +#include <soc/tegra/common.h>
> +
> #define TEGRA_GMI_CONFIG 0x00
> #define TEGRA_GMI_CONFIG_GO BIT(31)
> #define TEGRA_GMI_BUS_WIDTH_32BIT BIT(30)
> @@ -54,9 +57,9 @@ static int tegra_gmi_enable(struct tegra_gmi *gmi)
> {
> int err;
>
> - err = clk_prepare_enable(gmi->clk);
> - if (err < 0) {
> - dev_err(gmi->dev, "failed to enable clock: %d\n", err);
> + err = pm_runtime_resume_and_get(gmi->dev);
> + if (err) {
> + pm_runtime_disable(gmi->dev);
> return err;
> }
>
> @@ -83,7 +86,8 @@ static void tegra_gmi_disable(struct tegra_gmi *gmi)
> writel(config, gmi->base + TEGRA_GMI_CONFIG);
>
> reset_control_assert(gmi->rst);
> - clk_disable_unprepare(gmi->clk);
> +
> + pm_runtime_put(gmi->dev);
> }
>
> static int tegra_gmi_parse_dt(struct tegra_gmi *gmi)
> @@ -213,6 +217,7 @@ static int tegra_gmi_probe(struct platform_device *pdev)
> if (!gmi)
> return -ENOMEM;
>
> + platform_set_drvdata(pdev, gmi);
> gmi->dev = dev;
>
> res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> @@ -232,6 +237,14 @@ static int tegra_gmi_probe(struct platform_device *pdev)
> return PTR_ERR(gmi->rst);
> }
>
> + err = devm_pm_runtime_enable(gmi->dev);
> + if (err)
> + return err;
> +
> + err = devm_tegra_core_dev_init_opp_table_common(&pdev->dev);
> + if (err)
> + return err;
> +
> err = tegra_gmi_parse_dt(gmi);
> if (err)
> return err;
> @@ -247,8 +260,6 @@ static int tegra_gmi_probe(struct platform_device *pdev)
> return err;
> }
>
> - platform_set_drvdata(pdev, gmi);
> -
> return 0;
> }
>
> @@ -262,6 +273,34 @@ static int tegra_gmi_remove(struct platform_device *pdev)

Similar comment as for patch13, for the ->remove() callback.

This problem, which sometimes also exists in the error path in
->probe() (according to my comments in patch13), seems to be a common
issue in the series. I will therefore not continue to repeat my
comment on this for the remaining patches in the series, I think I
have made my point. :-)

Kind regards
Uffe