From 87904c3e82319cf2bad8d656d79c5030dab9490e Mon Sep 17 00:00:00 2001 From: Thierry Reding Date: Fri, 12 Aug 2016 16:00:53 +0200 Subject: drm/tegra: dsi: Enhance runtime power management The MIPI DSI output on Tegra SoCs requires some external logic to calibrate the MIPI pads before a video signal can be transmitted. This MIPI calibration logic requires to be powered on while the MIPI pads are being used, which is currently done as part of the DSI driver's probe implementation. This is suboptimal because it will leave the MIPI calibration logic powered up even if the DSI output is never used. On Tegra114 and earlier this behaviour also causes the driver to hang while trying to power up the MIPI calibration logic because the power partition that contains the MIPI calibration logic will be powered on by the display controller at output pipeline configuration time. Thus the power up sequence for the MIPI calibration logic happens before it's power partition is guaranteed to be enabled. Fix this by splitting up the API into a request/free pair of functions that manage the runtime dependency between the DSI and the calibration modules (no registers are accessed) and a set of enable, calibrate and disable functions that program the MIPI calibration logic at points in time where the power partition is really enabled. While at it, make sure that the runtime power management also works in ganged mode, which is currently also broken. Reported-by: Jonathan Hunter Tested-by: Jonathan Hunter Signed-off-by: Thierry Reding --- include/linux/host1x.h | 2 ++ 1 file changed, 2 insertions(+) (limited to 'include/linux') diff --git a/include/linux/host1x.h b/include/linux/host1x.h index d2ba7d334039..1ffbf2a8cb99 100644 --- a/include/linux/host1x.h +++ b/include/linux/host1x.h @@ -304,6 +304,8 @@ struct tegra_mipi_device; struct tegra_mipi_device *tegra_mipi_request(struct device *device); void tegra_mipi_free(struct tegra_mipi_device *device); +int tegra_mipi_enable(struct tegra_mipi_device *device); +int tegra_mipi_disable(struct tegra_mipi_device *device); int tegra_mipi_calibrate(struct tegra_mipi_device *device); #endif -- cgit v1.2.3