linux-kernel - [PATCH 06/39] drm: renesas: shmobile: Add support for Runtime PM

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Date:   Thu, 22 Jun 2023 11:21:18 +0200
From:   Geert Uytterhoeven <geert+renesas@...der.be>
To:     Laurent Pinchart <laurent.pinchart@...asonboard.com>,
        Kieran Bingham <kieran.bingham+renesas@...asonboard.com>,
        David Airlie <airlied@...il.com>,
        Daniel Vetter <daniel@...ll.ch>,
        Thomas Zimmermann <tzimmermann@...e.de>,
        Magnus Damm <magnus.damm@...il.com>
Cc:     dri-devel@...ts.freedesktop.org, linux-renesas-soc@...r.kernel.org,
        linux-kernel@...r.kernel.org,
        Geert Uytterhoeven <geert+renesas@...der.be>
Subject: [PATCH 06/39] drm: renesas: shmobile: Add support for Runtime PM

The SH-Mobile LCD Controller is part of a PM Domain on all relevant SoCs
(clock domain on all, power domain on some).  Hence it may not be
sufficient to manage the LCDC module clock explicitly (e.g. if the
selected clock source differs from SHMOB_DRM_CLK_BUS).

Fix this by using Runtime PM instead.

Signed-off-by: Geert Uytterhoeven <geert+renesas@...der.be>
---
 drivers/gpu/drm/renesas/shmobile/shmob_drm_crtc.c | 11 ++++++++++-
 drivers/gpu/drm/renesas/shmobile/shmob_drm_drv.c  |  5 +++++
 2 files changed, 15 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/renesas/shmobile/shmob_drm_crtc.c b/drivers/gpu/drm/renesas/shmobile/shmob_drm_crtc.c
index fbfd906844da490c..84dbf35025d7be63 100644
--- a/drivers/gpu/drm/renesas/shmobile/shmob_drm_crtc.c
+++ b/drivers/gpu/drm/renesas/shmobile/shmob_drm_crtc.c
@@ -9,6 +9,7 @@
 
 #include <linux/backlight.h>
 #include <linux/clk.h>
+#include <linux/pm_runtime.h>
 
 #include <drm/drm_crtc.h>
 #include <drm/drm_crtc_helper.h>
@@ -170,10 +171,16 @@ static void shmob_drm_crtc_start(struct shmob_drm_crtc *scrtc)
 	if (WARN_ON(format == NULL))
 		return;
 
+	ret = pm_runtime_resume_and_get(sdev->dev);
+	if (ret)
+		return;
+
 	/* Enable clocks before accessing the hardware. */
 	ret = shmob_drm_clk_on(sdev);
-	if (ret < 0)
+	if (ret < 0) {
+		pm_runtime_put(sdev->dev);
 		return;
+	}
 
 	/* Reset and enable the LCDC. */
 	lcdc_write(sdev, LDCNT2R, lcdc_read(sdev, LDCNT2R) | LDCNT2R_BR);
@@ -271,6 +278,8 @@ static void shmob_drm_crtc_stop(struct shmob_drm_crtc *scrtc)
 	/* Stop clocks. */
 	shmob_drm_clk_off(sdev);
 
+	pm_runtime_put(sdev->dev);
+
 	scrtc->started = false;
 }
 
diff --git a/drivers/gpu/drm/renesas/shmobile/shmob_drm_drv.c b/drivers/gpu/drm/renesas/shmobile/shmob_drm_drv.c
index 30493ce874192e3e..4f01caa119637032 100644
--- a/drivers/gpu/drm/renesas/shmobile/shmob_drm_drv.c
+++ b/drivers/gpu/drm/renesas/shmobile/shmob_drm_drv.c
@@ -13,6 +13,7 @@
 #include <linux/module.h>
 #include <linux/platform_device.h>
 #include <linux/pm.h>
+#include <linux/pm_runtime.h>
 #include <linux/slab.h>
 
 #include <drm/drm_drv.h>
@@ -216,6 +217,10 @@ static int shmob_drm_probe(struct platform_device *pdev)
 	if (IS_ERR(sdev->mmio))
 		return PTR_ERR(sdev->mmio);
 
+	ret = devm_pm_runtime_enable(&pdev->dev);
+	if (ret)
+		return ret;
+
 	ret = shmob_drm_setup_clocks(sdev, pdata->clk_source);
 	if (ret < 0)
 		return ret;
-- 
2.34.1