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.

Signed-off-by: Jacopo Mondi <jacopo+rene...@jmondi.org>
---

I have made sure signal polarities gets properly changed using a scope and
capturing images with negative polarities using CEU capture interface.
Also verified with a scope that pixel clock gets suppressed on horizontal
blankings as well when "ov7670,pclk-hb-disable" property is specified.

Thanks
   j
---

 .../devicetree/bindings/media/i2c/ov7670.txt       |  12 +++
 drivers/media/i2c/ov7670.c                         | 101 +++++++++++++++++++--
 2 files changed, 106 insertions(+), 7 deletions(-)

diff --git a/Documentation/devicetree/bindings/media/i2c/ov7670.txt 
b/Documentation/devicetree/bindings/media/i2c/ov7670.txt
index 826b656..c005453 100644
--- a/Documentation/devicetree/bindings/media/i2c/ov7670.txt
+++ b/Documentation/devicetree/bindings/media/i2c/ov7670.txt
@@ -9,11 +9,20 @@ Required Properties:
 - clocks: reference to the xclk input clock.
 - clock-names: should be "xclk".

+The following properties, as defined by "video-interfaces.txt", are supported:
+- hsync-active: active state of the HSYNC signal, 0/1 for LOW/HIGH 
respectively.
+- vsync-active: active state of the VSYNC signal, 0/1 for LOW/HIGH 
respectively.
+
+Default is high active state for both vsync and hsync signals.
+
 Optional Properties:
 - reset-gpios: reference to the GPIO connected to the resetb pin, if any.
   Active is low.
 - powerdown-gpios: reference to the GPIO connected to the pwdn pin, if any.
   Active is high.
+- ov7670,pll-bypass: set to 1 to bypass PLL for pixel clock generation.
+- ov7670,pclk-hb-disable: set to 1 to suppress pixel clock output signal during
+  horizontal blankings.

 The device node must contain one 'port' child node for its digital output
 video port, in accordance with the video interface bindings defined in
@@ -34,6 +43,9 @@ Example:
                        assigned-clocks = <&pck0>;
                        assigned-clock-rates = <25000000>;

+                       vsync-active = <0>;
+                       pclk-sample = <1>;
+
                        port {
                                ov7670_0: endpoint {
                                        remote-endpoint = <&isi_0>;
diff --git a/drivers/media/i2c/ov7670.c b/drivers/media/i2c/ov7670.c
index 950a0ac..a42bee7 100644
--- a/drivers/media/i2c/ov7670.c
+++ b/drivers/media/i2c/ov7670.c
@@ -11,6 +11,7 @@
  * Public License, version 2.
  */
 #include <linux/clk.h>
+#include <linux/fwnode.h>
 #include <linux/init.h>
 #include <linux/module.h>
 #include <linux/slab.h>
@@ -21,6 +22,7 @@
 #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 +239,7 @@ 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 +998,7 @@ 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)
@@ -1027,6 +1030,18 @@ static int ov7670_set_fmt(struct v4l2_subdev *sd,
        com7 = ovfmt->regs[0].value;
        com7 |= wsize->com7_bit;
        ov7670_write(sd, REG_COM7, com7);
+
+       /*
+        * 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;
+       ov7670_write(sd, REG_COM10, com10);
+
        /*
         * Now write the rest of the array.  Also store start/stops
         */
@@ -1036,6 +1051,9 @@ static int ov7670_set_fmt(struct v4l2_subdev *sd,
        ret = 0;
        if (wsize->regs)
                ret = ov7670_write_array(sd, wsize->regs);
+       if (ret)
+               return ret;
+
        info->fmt = ovfmt;

        /*
@@ -1048,8 +1066,10 @@ 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 +1678,71 @@ 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;
+       struct device_node *dep;
+       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. */
+       dep = to_of_node(ep);
+       ret = of_property_read_u32(dep, "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;
+       }
+       if (ret == 0 && propval)
+               info->pclk_hb_disable = true;
+       else
+               info->pclk_hb_disable = false;
+
+       ret = of_property_read_u32(dep, "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;
+       }
+       if (ret == 0 && propval)
+               info->pll_bypass = true;
+       else
+               info->pll_bypass = false;
+
+       fwnode_handle_put(ep);
+       return 0;
+}
+
 static int ov7670_probe(struct i2c_client *client,
                        const struct i2c_device_id *id)
 {
@@ -1678,7 +1763,12 @@ static int ov7670_probe(struct i2c_client *client,
 #endif

        info->clock_speed = 30; /* default: a guess */
-       if (client->dev.platform_data) {
+
+       if (IS_ENABLED(CONFIG_OF) && client->dev.of_node) {
+               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 +1835,6 @@ 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

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