On 23/11/2018 12:06, Thierry Reding wrote:
> From: Thierry Reding <treding@xxxxxxxxxx>
>
> Tegra supports generic PM domains on 64-bit ARM, and if that is enabled,
> the power domain code will make sure that resets are asserted and
> deasserted at appropriate points in time.
>
> If generic PM domains are not implemented, such as on 32-bit Tegra, the
> resets need to be asserted and deasserted explicitly by the driver.
>
> Signed-off-by: Thierry Reding <treding@xxxxxxxxxx>
> ---
> drivers/gpu/drm/tegra/vic.c | 35 ++++++++++++++++++++++++++++++++++-
> 1 file changed, 34 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/tegra/vic.c b/drivers/gpu/drm/tegra/vic.c
> index 9fa77405db01..23f530db45ad 100644
> --- a/drivers/gpu/drm/tegra/vic.c
> +++ b/drivers/gpu/drm/tegra/vic.c
> @@ -38,6 +38,7 @@ struct vic {
> struct iommu_domain *domain;
> struct device *dev;
> struct clk *clk;
> + struct reset_control *rst;
>
> /* Platform configuration */
> const struct vic_config *config;
> @@ -56,13 +57,37 @@ static void vic_writel(struct vic *vic, u32 value, unsigned int offset)
> static int vic_runtime_resume(struct device *dev)
> {
> struct vic *vic = dev_get_drvdata(dev);
> + int err;
> +
> + err = clk_prepare_enable(vic->clk);
> + if (err < 0)
> + return err;
> +
> + usleep_range(2000, 4000);
The Tegra genpd code has a usleep_range(10, 20), is that not sufficient
here? If it is, it would be good to be consistent.
> +
> + err = reset_control_deassert(vic->rst);
> + if (err < 0)
> + goto disable;
> +
> + usleep_range(2000, 4000);
> +
> + return 0;
>
> - return clk_prepare_enable(vic->clk);
> +disable:
> + clk_disable_unprepare(vic->clk);
> + return err;
> }
>
> static int vic_runtime_suspend(struct device *dev)
> {
> struct vic *vic = dev_get_drvdata(dev);
> + int err;
> +
> + err = reset_control_assert(vic->rst);
> + if (err < 0)
> + return err;
> +
> + usleep_range(2000, 4000);
>
> clk_disable_unprepare(vic->clk);
>
> @@ -324,6 +349,14 @@ static int vic_probe(struct platform_device *pdev)
> return PTR_ERR(vic->clk);
> }
>
> + if (!dev->pm_domain) {
> + vic->rst = devm_reset_control_get(dev, "vic");
> + if (IS_ERR(vic->rst)) {
> + dev_err(&pdev->dev, "failed to get reset\n");
> + return PTR_ERR(vic->rst);
> + }
> + }
> +
> vic->falcon.dev = dev;
> vic->falcon.regs = vic->regs;
> vic->falcon.ops = &vic_falcon_ops;
>
Cheers
Jon
--
nvpublic
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