[PATCH v2 1/2] v4l2: i2c: ov7670: Implement OF mbus configuration

[Jacopo Mondi]

ov7670 driver supports two optional properties supplied through platform
data, but currently does not support any standard video interface
property.

Add support through OF parsing for 2 generic properties (vsync and hsync
polarities) and for two custom properties already supported by platform
data.

While at there, check return value of register writes in set_fmt
function and rationalize spacings.

Signal polarities and pixel clock blanking verified through scope and
image capture.

Signed-off-by: Jacopo Mondi <jacopo+renesas@xxxxxxxxxx>
---
 drivers/media/i2c/ov7670.c | 124 ++++++++++++++++++++++++++++++++++++++++-----
 1 file changed, 110 insertions(+), 14 deletions(-)

diff --git a/drivers/media/i2c/ov7670.c b/drivers/media/i2c/ov7670.c
index 950a0ac..d40a601 100644
--- a/drivers/media/i2c/ov7670.c
+++ b/drivers/media/i2c/ov7670.c
@@ -21,6 +21,7 @@
 #include <linux/gpio/consumer.h>
 #include <media/v4l2-device.h>
 #include <media/v4l2-ctrls.h>
+#include <media/v4l2-fwnode.h>
 #include <media/v4l2-mediabus.h>
 #include <media/v4l2-image-sizes.h>
 #include <media/i2c/ov7670.h>
@@ -237,6 +238,7 @@ struct ov7670_info {
 	struct clk *clk;
 	struct gpio_desc *resetb_gpio;
 	struct gpio_desc *pwdn_gpio;
+	unsigned int mbus_config;	/* Media bus configuration flags */
 	int min_width;			/* Filter out smaller sizes */
 	int min_height;			/* Filter out smaller sizes */
 	int clock_speed;		/* External clock speed (MHz) */
@@ -995,7 +997,7 @@ static int ov7670_set_fmt(struct v4l2_subdev *sd,
 #ifdef CONFIG_VIDEO_V4L2_SUBDEV_API
 	struct v4l2_mbus_framefmt *mbus_fmt;
 #endif
-	unsigned char com7;
+	unsigned char com7, com10 = 0;
 	int ret;
 
 	if (format->pad)
@@ -1015,7 +1017,6 @@ static int ov7670_set_fmt(struct v4l2_subdev *sd,
 	}
 
 	ret = ov7670_try_fmt_internal(sd, &format->format, &ovfmt, &wsize);
-
 	if (ret)
 		return ret;
 	/*
@@ -1026,16 +1027,41 @@ static int ov7670_set_fmt(struct v4l2_subdev *sd,
 	 */
 	com7 = ovfmt->regs[0].value;
 	com7 |= wsize->com7_bit;
-	ov7670_write(sd, REG_COM7, com7);
+	ret = ov7670_write(sd, REG_COM7, com7);
+	if (ret)
+		return ret;
+
+	/*
+	 * Configure the media bus through COM10 register
+	 */
+	if (info->mbus_config & V4L2_MBUS_VSYNC_ACTIVE_LOW)
+		com10 |= COM10_VS_NEG;
+	if (info->mbus_config & V4L2_MBUS_HSYNC_ACTIVE_LOW)
+		com10 |= COM10_HREF_REV;
+	if (info->pclk_hb_disable)
+		com10 |= COM10_PCLK_HB;
+	ret = ov7670_write(sd, REG_COM10, com10);
+	if (ret)
+		return ret;
+
 	/*
 	 * Now write the rest of the array.  Also store start/stops
 	 */
-	ov7670_write_array(sd, ovfmt->regs + 1);
-	ov7670_set_hw(sd, wsize->hstart, wsize->hstop, wsize->vstart,
-			wsize->vstop);
-	ret = 0;
-	if (wsize->regs)
+	ret = ov7670_write_array(sd, ovfmt->regs + 1);
+	if (ret)
+		return ret;
+
+	ret = ov7670_set_hw(sd, wsize->hstart, wsize->hstop, wsize->vstart,
+			    wsize->vstop);
+	if (ret)
+		return ret;
+
+	if (wsize->regs) {
 		ret = ov7670_write_array(sd, wsize->regs);
+		if (ret)
+			return ret;
+	}
+
 	info->fmt = ovfmt;
 
 	/*
@@ -1048,8 +1074,10 @@ static int ov7670_set_fmt(struct v4l2_subdev *sd,
 	 * to write it unconditionally, and that will make the frame
 	 * rate persistent too.
 	 */
-	if (ret == 0)
-		ret = ov7670_write(sd, REG_CLKRC, info->clkrc);
+	ret = ov7670_write(sd, REG_CLKRC, info->clkrc);
+	if (ret)
+		return ret;
+
 	return 0;
 }
 
@@ -1658,6 +1686,71 @@ static int ov7670_init_gpio(struct i2c_client *client, struct ov7670_info *info)
 	return 0;
 }
 
+/*
+ * ov7670_parse_dt() - Parse device tree to collect mbus configuration
+ *			properties
+ */
+static int ov7670_parse_dt(struct device *dev,
+			   struct ov7670_info *info)
+{
+	struct fwnode_handle *fwnode = dev_fwnode(dev);
+	struct v4l2_fwnode_endpoint bus_cfg;
+	struct fwnode_handle *ep;
+	u32 propval;
+	int ret;
+
+	if (!fwnode)
+		return -EINVAL;
+
+	ep = fwnode_graph_get_next_endpoint(fwnode, NULL);
+	if (!ep)
+		return -EINVAL;
+
+	ret = v4l2_fwnode_endpoint_parse(ep, &bus_cfg);
+	if (ret) {
+		fwnode_handle_put(fwnode);
+		return ret;
+	}
+
+	/* Any CSI-2 property set? */
+	if (bus_cfg.bus_type != V4L2_MBUS_PARALLEL) {
+		fwnode_handle_put(fwnode);
+		return -EINVAL;
+	}
+	info->mbus_config = bus_cfg.bus.parallel.flags;
+	fwnode_handle_put(fwnode);
+
+	/* Parse custom OF properties. */
+	info->pclk_hb_disable = false;
+	info->pll_bypass = false;
+
+	ret = fwnode_property_read_u32(ep, "ov7670,pclk-hb-disable", &propval);
+	if (ret < 0 && ret != -EINVAL) {
+		dev_err(dev,
+			"Unable to parse property \"ov7670,pclk-hb-disable\"\n");
+		fwnode_handle_put(ep);
+		return ret;
+
+	} else if (ret == 0 && propval) {
+		info->pclk_hb_disable = true;
+	}
+
+	ret = fwnode_property_read_u32(ep, "ov7670,pll-bypass", &propval);
+	if (ret < 0 && ret != -EINVAL) {
+		dev_err(dev,
+			"Unable to parse property \"ov7670,pll-bypass\"\n");
+		fwnode_handle_put(ep);
+		return ret;
+
+	} else if (ret == 0 && propval) {
+		info->pll_bypass = true;
+	}
+
+	fwnode_handle_put(ep);
+
+	return 0;
+}
+
 static int ov7670_probe(struct i2c_client *client,
 			const struct i2c_device_id *id)
 {
@@ -1678,7 +1771,13 @@ static int ov7670_probe(struct i2c_client *client,
 #endif
 
 	info->clock_speed = 30; /* default: a guess */
-	if (client->dev.platform_data) {
+
+	if (dev_fwnode(&client->dev)) {
+		ret = ov7670_parse_dt(&client->dev, info);
+		if (ret)
+			return ret;
+
+	} else if (client->dev.platform_data) {
 		struct ov7670_config *config = client->dev.platform_data;
 
 		/*
@@ -1745,9 +1844,6 @@ static int ov7670_probe(struct i2c_client *client,
 	tpf.denominator = 30;
 	info->devtype->set_framerate(sd, &tpf);
 
-	if (info->pclk_hb_disable)
-		ov7670_write(sd, REG_COM10, COM10_PCLK_HB);
-
 	v4l2_ctrl_handler_init(&info->hdl, 10);
 	v4l2_ctrl_new_std(&info->hdl, &ov7670_ctrl_ops,
 			V4L2_CID_BRIGHTNESS, 0, 255, 1, 128);
-- 
2.7.4