From 0dc34e19f66eb84744af2fea4235302da39fd7e7 Mon Sep 17 00:00:00 2001 From: Thierry Reding Date: Fri, 23 Nov 2018 13:06:37 +0100 Subject: drm/tegra: vic: Implement explicit reset support 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. Reviewed-by: Jon Hunter Signed-off-by: Thierry Reding --- drivers/gpu/drm/tegra/vic.c | 35 ++++++++++++++++++++++++++++++++++- 1 file changed, 34 insertions(+), 1 deletion(-) (limited to 'drivers/gpu/drm/tegra') diff --git a/drivers/gpu/drm/tegra/vic.c b/drivers/gpu/drm/tegra/vic.c index 9f657a63b0bb..396f29f289f5 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(10, 20); + + err = reset_control_deassert(vic->rst); + if (err < 0) + goto disable; + + usleep_range(10, 20); + + 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); @@ -323,6 +348,14 @@ 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; -- cgit v1.2.3-59-g8ed1b