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Subject[PATCH] v4l2: i2c: ov7670: Implement OF mbus configuration
Date
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+renesas@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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