linux-kernel - [PATCH v1 4/4] media: staging: tegra-vde: Power-cycle hardware on probe

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Message-Id: <20200514210847.9269-5-digetx@gmail.com>
Date:   Fri, 15 May 2020 00:08:47 +0300
From:   Dmitry Osipenko <digetx@...il.com>
To:     Thierry Reding <thierry.reding@...il.com>,
        Jonathan Hunter <jonathanh@...dia.com>,
        Mauro Carvalho Chehab <mchehab@...nel.org>,
        Hans Verkuil <hverkuil@...all.nl>,
        Dan Carpenter <dan.carpenter@...cle.com>
Cc:     linux-media@...r.kernel.org, linux-tegra@...r.kernel.org,
        devel@...verdev.osuosl.org, linux-kernel@...r.kernel.org
Subject: [PATCH v1 4/4] media: staging: tegra-vde: Power-cycle hardware on probe

VDE partition is left turned ON after bootloader on most devices, hence
let's ensure that it's turned OFF in order to lower power leakage while
hardware is idling by turning it ON and OFF during of the driver's probe.

Signed-off-by: Dmitry Osipenko <digetx@...il.com>
---
 drivers/staging/media/tegra-vde/vde.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/drivers/staging/media/tegra-vde/vde.c b/drivers/staging/media/tegra-vde/vde.c
index b64e35b86fb4..3be96c36bf43 100644
--- a/drivers/staging/media/tegra-vde/vde.c
+++ b/drivers/staging/media/tegra-vde/vde.c
@@ -1068,6 +1068,14 @@ static int tegra_vde_probe(struct platform_device *pdev)
 	pm_runtime_use_autosuspend(dev);
 	pm_runtime_set_autosuspend_delay(dev, 300);
 
+	/*
+	 * VDE partition may be left ON after bootloader, hence let's
+	 * power-cycle it in order to put hardware into a predictable lower
+	 * power state.
+	 */
+	pm_runtime_get_sync(dev);
+	pm_runtime_put(dev);
+
 	return 0;
 
 err_deinit_iommu:
-- 
2.26.0