[PATCH] v4l2: i2c: ov7670: Implement OF mbus configuration

Jacopo Mondi
2018-01-02T15:05:02Z

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