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From: Dario Binacchi <dariobin@libero.it>
To: linux-kernel@vger.kernel.org
Cc: Dario Binacchi <dariobin@libero.it>,
	Daniel Vetter <daniel@ffwll.ch>, David Airlie <airlied@linux.ie>,
	Jyri Sarha <jyri.sarha@iki.fi>, Tomi Valkeinen <tomba@kernel.org>,
	dri-devel@lists.freedesktop.org
Subject: [PATCH v3 2/3] drm/tilcdc: fix LCD pixel clock setting
Date: Mon, 22 Mar 2021 22:33:36 +0100	[thread overview]
Message-ID: <20210322213337.26667-3-dariobin@libero.it> (raw)
In-Reply-To: <20210322213337.26667-1-dariobin@libero.it>

The tilcdc_pclk_diff() compares the requested pixel clock rate to the
real one, so passing it clk_rate instead of clk_rate / clkdiv caused
it to fail even if the clk_rate was properly set. Adding the
real_pclk_rate variable makes the code more readable.

Signed-off-by: Dario Binacchi <dariobin@libero.it>

---

(no changes since v2)

Changes in v2:
- Rename clk_div_rate to real_pclk_rate.
- Provide pixel clock rate to tilcdc_pclk_diff().

 drivers/gpu/drm/tilcdc/tilcdc_crtc.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/tilcdc/tilcdc_crtc.c b/drivers/gpu/drm/tilcdc/tilcdc_crtc.c
index aeec5786617d..ac6228cb04d9 100644
--- a/drivers/gpu/drm/tilcdc/tilcdc_crtc.c
+++ b/drivers/gpu/drm/tilcdc/tilcdc_crtc.c
@@ -203,7 +203,7 @@ static void tilcdc_crtc_set_clk(struct drm_crtc *crtc)
 	struct drm_device *dev = crtc->dev;
 	struct tilcdc_drm_private *priv = dev->dev_private;
 	struct tilcdc_crtc *tilcdc_crtc = to_tilcdc_crtc(crtc);
-	unsigned long clk_rate, real_rate, pclk_rate;
+	unsigned long clk_rate, real_rate, real_pclk_rate, pclk_rate;
 	unsigned int clkdiv;
 	int ret;
 
@@ -214,7 +214,8 @@ static void tilcdc_crtc_set_clk(struct drm_crtc *crtc)
 
 	ret = clk_set_rate(priv->clk, pclk_rate * clkdiv);
 	clk_rate = clk_get_rate(priv->clk);
-	if (ret < 0 || tilcdc_pclk_diff(pclk_rate, clk_rate) > 5) {
+	real_pclk_rate = clk_rate / clkdiv;
+	if (ret < 0 || tilcdc_pclk_diff(pclk_rate, real_pclk_rate) > 5) {
 		/*
 		 * If we fail to set the clock rate (some architectures don't
 		 * use the common clock framework yet and may not implement
-- 
2.17.1


  parent reply	other threads:[~2021-03-22 21:35 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-03-22 21:33 [PATCH v3 0/3] drm/tilcdc: fix LCD pixel clock setting Dario Binacchi
2021-03-22 21:33 ` [PATCH v3 1/3] drm/tilcdc: rename req_rate to pclk_rate Dario Binacchi
2021-03-22 21:33 ` Dario Binacchi [this message]
2021-03-22 21:33 ` [PATCH v3 3/3] drm/tilcdc: fix pixel clock setting warning message Dario Binacchi
2021-03-23 12:05 ` [PATCH v3 0/3] drm/tilcdc: fix LCD pixel clock setting Jyri Sarha

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