linux-kernel - [PATCH v2 3/6] media: ov5647: Add support for non-continuous clock mode

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Message-Id: <cd04fe908fc1a747949ee83044f4d2abc1885cee.1589850165.git.roman.kovalivskyi@globallogic.com>
Date:   Tue, 19 May 2020 04:16:18 +0300
From:   Roman Kovalivskyi <roman.kovalivskyi@...ballogic.com>
To:     linux-kernel@...r.kernel.org, linux-media@...r.kernel.org,
        linux-renesas-soc@...r.kernel.org
Cc:     Luis Oliveira <lolivei@...opsys.com>,
        Niklas Söderlund <niklas.soderlund@...natech.se>,
        Jacopo Mondi <jacopo@...ndi.org>,
        Michael Rodin <mrodin@...adit-jv.com>,
        Mauro Carvalho Chehab <mchehab@...nel.org>,
        Sakari Ailus <sakari.ailus@...ux.intel.com>,
        Hugues Fruchet <hugues.fruchet@...com>,
        Maxime Ripard <mripard@...nel.org>,
        Adam Ford <aford173@...il.com>,
        Todor Tomov <todor.tomov@...aro.org>,
        Suresh Udipi <sudipi@...adit-jv.com>,
        Andrew Gabbasov <andrew_gabbasov@...tor.com>,
        Eugeniu Rosca <erosca@...adit-jv.com>,
        Dave Stevenson <dave.stevenson@...pberrypi.org>,
        Roman Kovalivskyi <roman.kovalivskyi@...ballogic.com>
Subject: [PATCH v2 3/6] media: ov5647: Add support for non-continuous clock mode

From: Dave Stevenson <dave.stevenson@...pberrypi.org>

The driver was only supporting continuous clock mode
although this was not stated anywhere.
Non-continuous clock saves a small amount of power and
on some SoCs is easier to interface with.

Signed-off-by: Dave Stevenson <dave.stevenson@...pberrypi.org>
Signed-off-by: Roman Kovalivskyi <roman.kovalivskyi@...ballogic.com>
---
 drivers/media/i2c/ov5647.c | 25 ++++++++++++++++++++++---
 1 file changed, 22 insertions(+), 3 deletions(-)

diff --git a/drivers/media/i2c/ov5647.c b/drivers/media/i2c/ov5647.c
index 796cc80f8ee1..10f35c637f91 100644
--- a/drivers/media/i2c/ov5647.c
+++ b/drivers/media/i2c/ov5647.c
@@ -44,6 +44,7 @@
 #define PWDN_ACTIVE_DELAY_MS	20
 
 #define MIPI_CTRL00_CLOCK_LANE_GATE		BIT(5)
+#define MIPI_CTRL00_LINE_SYNC_ENABLE		BIT(4)
 #define MIPI_CTRL00_BUS_IDLE			BIT(2)
 #define MIPI_CTRL00_CLOCK_LANE_DISABLE		BIT(0)
 
@@ -95,6 +96,7 @@ struct ov5647 {
 	int				power_count;
 	struct clk			*xclk;
 	struct gpio_desc		*pwdn;
+	bool				is_clock_contiguous;
 };
 
 static inline struct ov5647 *to_state(struct v4l2_subdev *sd)
@@ -274,9 +276,15 @@ static int ov5647_set_virtual_channel(struct v4l2_subdev *sd, int channel)
 
 static int ov5647_stream_on(struct v4l2_subdev *sd)
 {
+	struct ov5647 *ov5647 = to_state(sd);
+	u8 val = MIPI_CTRL00_BUS_IDLE;
 	int ret;
 
-	ret = ov5647_write(sd, OV5647_REG_MIPI_CTRL00, MIPI_CTRL00_BUS_IDLE);
+	if (ov5647->is_clock_contiguous)
+		val |= MIPI_CTRL00_CLOCK_LANE_GATE |
+		       MIPI_CTRL00_LINE_SYNC_ENABLE;
+
+	ret = ov5647_write(sd, OV5647_REG_MIPI_CTRL00, val);
 	if (ret < 0)
 		return ret;
 
@@ -573,7 +581,7 @@ static const struct v4l2_subdev_internal_ops ov5647_subdev_internal_ops = {
 	.open = ov5647_open,
 };
 
-static int ov5647_parse_dt(struct device_node *np)
+static int ov5647_parse_dt(struct ov5647 *sensor, struct device_node *np)
 {
 	struct v4l2_fwnode_endpoint bus_cfg = { .bus_type = 0 };
 	struct device_node *ep;
@@ -586,6 +594,17 @@ static int ov5647_parse_dt(struct device_node *np)
 
 	ret = v4l2_fwnode_endpoint_parse(of_fwnode_handle(ep), &bus_cfg);
 
+	if (!ret) {
+		of_node_put(ep);
+		of_node_put(np);
+		return ret;
+	}
+
+	if (bus_cfg.bus_type == V4L2_MBUS_CSI2_DPHY
+		|| bus_cfg.bus_type == V4L2_MBUS_CSI2_CPHY)
+		sensor->is_clock_contiguous = bus_cfg.bus.mipi_csi2.flags
+			& V4L2_MBUS_CSI2_NONCONTINUOUS_CLOCK;
+
 	of_node_put(ep);
 	return ret;
 }
@@ -604,7 +623,7 @@ static int ov5647_probe(struct i2c_client *client)
 		return -ENOMEM;
 
 	if (IS_ENABLED(CONFIG_OF) && np) {
-		ret = ov5647_parse_dt(np);
+		ret = ov5647_parse_dt(sensor, np);
 		if (ret) {
 			dev_err(dev, "DT parsing error: %d\n", ret);
 			return ret;
-- 
2.17.1