linux-kernel - [PATCH 4.19 031/113] drm/rockchip: Properly adjust to a true clock in adjusted

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Date:   Mon, 29 Jul 2019 21:21:58 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Douglas Anderson <dianders@...omium.org>,
        Sean Paul <seanpaul@...omium.org>,
        Yakir Yang <ykk@...k-chips.com>,
        Heiko Stuebner <heiko@...ech.de>,
        Sasha Levin <sashal@...nel.org>
Subject: [PATCH 4.19 031/113] drm/rockchip: Properly adjust to a true clock in adjusted_mode

[ Upstream commit 99b9683f2142b20bad78e61f7f829e8714e45685 ]

When fixing up the clock in vop_crtc_mode_fixup() we're not doing it
quite correctly.  Specifically if we've got the true clock 266666667 Hz,
we'll perform this calculation:
   266666667 / 1000 => 266666

Later when we try to set the clock we'll do clk_set_rate(266666 *
1000).  The common clock framework won't actually pick the proper clock
in this case since it always wants clocks <= the specified one.

Let's solve this by using DIV_ROUND_UP.

Fixes: b59b8de31497 ("drm/rockchip: return a true clock rate to adjusted_mode")
Signed-off-by: Douglas Anderson <dianders@...omium.org>
Signed-off-by: Sean Paul <seanpaul@...omium.org>
Reviewed-by: Yakir Yang <ykk@...k-chips.com>
Signed-off-by: Heiko Stuebner <heiko@...ech.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20190614224730.98622-1-dianders@chromium.org
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 drivers/gpu/drm/rockchip/rockchip_drm_vop.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/rockchip/rockchip_drm_vop.c b/drivers/gpu/drm/rockchip/rockchip_drm_vop.c
index f8f9ae6622eb..873624a11ce8 100644
--- a/drivers/gpu/drm/rockchip/rockchip_drm_vop.c
+++ b/drivers/gpu/drm/rockchip/rockchip_drm_vop.c
@@ -880,7 +880,8 @@ static bool vop_crtc_mode_fixup(struct drm_crtc *crtc,
 	struct vop *vop = to_vop(crtc);
 
 	adjusted_mode->clock =
-		clk_round_rate(vop->dclk, mode->clock * 1000) / 1000;
+		DIV_ROUND_UP(clk_round_rate(vop->dclk, mode->clock * 1000),
+			     1000);
 
 	return true;
 }
-- 
2.20.1