linux-kernel - [PATCH 4/6] media: ov6650: Don't reapply pixel clock divisor on format change

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Date:   Sun, 13 Oct 2019 14:50:48 +0200
From:   Janusz Krzysztofik <jmkrzyszt@...il.com>
To:     Sakari Ailus <sakari.ailus@...ux.intel.com>
Cc:     Mauro Carvalho Chehab <mchehab+samsung@...nel.org>,
        Hans Verkuil <hverkuil-cisco@...all.nl>,
        linux-media@...r.kernel.org, linux-kernel@...r.kernel.org,
        Janusz Krzysztofik <jmkrzyszt@...il.com>
Subject: [PATCH 4/6] media: ov6650: Don't reapply pixel clock divisor on format change

As calculation of pixel clock hardware divisor no longer depends on
mbus format specific maximum pixel clock, there is no need to reapply
the divisor on format change.  Drop related code from ov6650_s_fmt()
helper.

Since a master clock hardware divisor, so far applied only together
with the pixel clock divisor in a single operation, will no longer be
applied from ov6650_s_fmt(), apply it, still using a hardcoded value
for now, from  ov6650_prog_dflt() helper so hardware is still
initialised correctly on device probe.

Signed-off-by: Janusz Krzysztofik <jmkrzyszt@...il.com>
---
 drivers/media/i2c/ov6650.c | 17 +++--------------
 1 file changed, 3 insertions(+), 14 deletions(-)

diff --git a/drivers/media/i2c/ov6650.c b/drivers/media/i2c/ov6650.c
index 61ddd4ea4c26..e95ea132ef06 100644
--- a/drivers/media/i2c/ov6650.c
+++ b/drivers/media/i2c/ov6650.c
@@ -564,8 +564,7 @@ static int ov6650_s_fmt(struct v4l2_subdev *sd, struct v4l2_mbus_framefmt *mf)
 		.r.height = mf->height << half_scale,
 	};
 	u32 code = mf->code;
-	unsigned long mclk, pclk;
-	u8 coma_set = 0, coma_mask = 0, coml_set, coml_mask, clkrc;
+	u8 coma_set = 0, coma_mask = 0, coml_set, coml_mask;
 	int ret;
 
 	/* select color matrix configuration for given color encoding */
@@ -635,21 +634,9 @@ static int ov6650_s_fmt(struct v4l2_subdev *sd, struct v4l2_mbus_framefmt *mf)
 		coma_mask |= COMA_QCIF;
 	}
 
-	clkrc = CLKRC_12MHz;
-	mclk = 12000000;
-	dev_dbg(&client->dev, "using 12MHz input clock\n");
-
-	clkrc |= to_clkrc(priv->tpf.numerator);
-
-	pclk = priv->pclk_max / GET_CLKRC_DIV(clkrc);
-	dev_dbg(&client->dev, "pixel clock divider: %ld.%ld\n",
-			mclk / pclk, 10 * mclk % pclk / pclk);
-
 	ret = ov6650_set_selection(sd, NULL, &sel);
 	if (!ret)
 		ret = ov6650_reg_rmw(client, REG_COMA, coma_set, coma_mask);
-	if (!ret)
-		ret = ov6650_reg_write(client, REG_CLKRC, clkrc);
 	if (!ret) {
 		priv->half_scale = half_scale;
 
@@ -798,6 +785,8 @@ static int ov6650_prog_dflt(struct i2c_client *client)
 	dev_dbg(&client->dev, "initializing\n");
 
 	ret = ov6650_reg_write(client, REG_COMA, 0);	/* ~COMA_RESET */
+	if (!ret)
+		ret = ov6650_reg_write(client, REG_CLKRC, CLKRC_12MHz);
 	if (!ret)
 		ret = ov6650_reg_rmw(client, REG_COMB, 0, COMB_BAND_FILTER);
 
-- 
2.21.0