linux-kernel - [PATCH] drm/rockchip: vop: Correct enabled clocks during setup

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Message-Id: <1443518893-28142-1-git-send-email-sjoerd.simons@collabora.co.uk>
Date:	Tue, 29 Sep 2015 11:28:13 +0200
From:	Sjoerd Simons <sjoerd.simons@...labora.co.uk>
To:	Mark Yao <mark.yao@...k-chips.com>
Cc:	Heiko Stuebner <heiko@...ech.de>, linux-kernel@...r.kernel.org,
	dri-devel@...ts.freedesktop.org,
	linux-rockchip@...ts.infradead.org,
	David Airlie <airlied@...ux.ie>,
	linux-arm-kernel@...ts.infradead.org
Subject: [PATCH] drm/rockchip: vop: Correct enabled clocks during setup

When doing the initial setup both the hclk and the aclk need to be
enabled otherwise the board will simply hang. This only occurs when
building the vop driver as a module, when its built-in the initial setup
happens to run before the clock framework shuts of unused clocks
(including the aclk).

While there also switch to doing prepare and enable in one step rather
then separate steps to reduce the amount of code required.

Signed-off-by: Sjoerd Simons <sjoerd.simons@...labora.co.uk>

---

 drivers/gpu/drm/rockchip/rockchip_drm_vop.c | 36 +++++++++++------------------
 1 file changed, 14 insertions(+), 22 deletions(-)

diff --git a/drivers/gpu/drm/rockchip/rockchip_drm_vop.c b/drivers/gpu/drm/rockchip/rockchip_drm_vop.c
index 5d8ae5e..48719df 100644
--- a/drivers/gpu/drm/rockchip/rockchip_drm_vop.c
+++ b/drivers/gpu/drm/rockchip/rockchip_drm_vop.c
@@ -1575,32 +1575,25 @@ static int vop_initial(struct vop *vop)
 		return PTR_ERR(vop->dclk);
 	}
 
-	ret = clk_prepare(vop->hclk);
-	if (ret < 0) {
-		dev_err(vop->dev, "failed to prepare hclk\n");
-		return ret;
-	}
-
 	ret = clk_prepare(vop->dclk);
 	if (ret < 0) {
 		dev_err(vop->dev, "failed to prepare dclk\n");
-		goto err_unprepare_hclk;
+		return ret;
 	}
 
-	ret = clk_prepare(vop->aclk);
+	/* Enable both the hclk and aclk to setup the vop */
+	ret = clk_prepare_enable(vop->hclk);
 	if (ret < 0) {
-		dev_err(vop->dev, "failed to prepare aclk\n");
+		dev_err(vop->dev, "failed to prepare/enable hclk\n");
 		goto err_unprepare_dclk;
 	}
 
-	/*
-	 * enable hclk, so that we can config vop register.
-	 */
-	ret = clk_enable(vop->hclk);
+	ret = clk_prepare_enable(vop->aclk);
 	if (ret < 0) {
-		dev_err(vop->dev, "failed to prepare aclk\n");
-		goto err_unprepare_aclk;
+		dev_err(vop->dev, "failed to prepare/enable aclk\n");
+		goto err_disable_hclk;
 	}
+
 	/*
 	 * do hclk_reset, reset all vop registers.
 	 */
@@ -1608,7 +1601,7 @@ static int vop_initial(struct vop *vop)
 	if (IS_ERR(ahb_rst)) {
 		dev_err(vop->dev, "failed to get ahb reset\n");
 		ret = PTR_ERR(ahb_rst);
-		goto err_disable_hclk;
+		goto err_disable_aclk;
 	}
 	reset_control_assert(ahb_rst);
 	usleep_range(10, 20);
@@ -1634,26 +1627,25 @@ static int vop_initial(struct vop *vop)
 	if (IS_ERR(vop->dclk_rst)) {
 		dev_err(vop->dev, "failed to get dclk reset\n");
 		ret = PTR_ERR(vop->dclk_rst);
-		goto err_unprepare_aclk;
+		goto err_disable_aclk;
 	}
 	reset_control_assert(vop->dclk_rst);
 	usleep_range(10, 20);
 	reset_control_deassert(vop->dclk_rst);
 
 	clk_disable(vop->hclk);
+	clk_disable(vop->aclk);
 
 	vop->is_enabled = false;
 
 	return 0;
 
+err_disable_aclk:
+	clk_disable_unprepare(vop->aclk);
 err_disable_hclk:
-	clk_disable(vop->hclk);
-err_unprepare_aclk:
-	clk_unprepare(vop->aclk);
+	clk_disable_unprepare(vop->hclk);
 err_unprepare_dclk:
 	clk_unprepare(vop->dclk);
-err_unprepare_hclk:
-	clk_unprepare(vop->hclk);
 	return ret;
 }
 
-- 
2.5.3

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