ov7670 currently supports configuration of a few parameters only through
platform data. Implement media bus configuration by parsing DT properties
at probe() time and opportunely configure REG_COM10 during s_format().
Signed-off-by: Jacopo Mondi <jacopo+renesas@xxxxxxxxxx>
---
Hi linux-media,
I'm using this sensor to test the CEU driver I have submitted some time ago
and I would like to change synchronization signal polarities to test them in
combination with that driver.
So I added support for retrieving some properties listed in the device tree
bindings documentation from sensor's DT node and made a patch, BUT I'm
slightly confused about this (and that's why this is an RFC).
I did a grep for "sync-active" in drivers/media/i2c/ and no sensor driver
implements any property parsing, so I guess I'm doing something wrong here.
I thought that maybe sensor media bus configuration should come from the
platform driver, through the s_mbus_config() operation in v4l2_subdev_video_ops,
but that's said to be deprecated. So maybe is the framework providing support
for parsing those properties? Another grep there and I found only v4l2-fwnode.c
has support for parsing serial/parallel bus properties, but my understanding is
that those functions are meant to be used by the platform driver when
parsing the remote fw node.
So please help me out here: where should I implement media bus configuration
for sensor drivers?
Thanks
j
PS: being this just an RFC I have not updated dt bindings, and only
compile-tested the patch
---
drivers/media/i2c/ov7670.c | 108 ++++++++++++++++++++++++++++++++++++++++++---
1 file changed, 101 insertions(+), 7 deletions(-)
diff --git a/drivers/media/i2c/ov7670.c b/drivers/media/i2c/ov7670.c
index e88549f..7e2de7e 100644
--- a/drivers/media/i2c/ov7670.c
+++ b/drivers/media/i2c/ov7670.c
@@ -88,6 +88,7 @@ MODULE_PARM_DESC(debug, "Debug level (0-1)");
#define REG_COM10 0x15 /* Control 10 */
#define COM10_HSYNC 0x40 /* HSYNC instead of HREF */
#define COM10_PCLK_HB 0x20 /* Suppress PCLK on horiz blank */
+#define COM10_PCLK_REV 0x10 /* Latch data on PCLK rising edge */
#define COM10_HREF_REV 0x08 /* Reverse HREF */
#define COM10_VS_LEAD 0x04 /* VSYNC on clock leading edge */
#define COM10_VS_NEG 0x02 /* VSYNC negative */
@@ -233,6 +234,7 @@ 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) */
@@ -985,7 +987,7 @@ static int ov7670_set_fmt(struct v4l2_subdev *sd,
struct ov7670_format_struct *ovfmt;
struct ov7670_win_size *wsize;
struct ov7670_info *info = to_state(sd);
- unsigned char com7;
+ unsigned char com7, com10;
int ret;
if (format->pad)
@@ -1021,6 +1023,9 @@ 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;
/*
@@ -1033,8 +1038,26 @@ 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;
+
+ /* Configure the media bus after the image format */
+ com10 = 0;
+ if (info->mbus_config & V4L2_MBUS_VSYNC_ACTIVE_LOW)
+ com10 |= COM10_VS_NEG;
+ if (info->mbus_config & V4L2_MBUS_HSYNC_ACTIVE_LOW)
+ com10 |= COM10_HS_NEG;
+ if (info->mbus_config & V4L2_MBUS_PCLK_SAMPLE_RISING)
+ com10 |= COM10_PCLK_REV;
+ if (info->pclk_hb_disable)
+ com10 |= COM10_PCLK_HB;
+
+ if (com10)
+ ret = ov7670_write(sd, REG_COM10, com10);
+ if (ret)
+ return ret;
+
return 0;
}
@@ -1572,6 +1595,29 @@ static int ov7670_init_gpio(struct i2c_client *client, struct ov7670_info *info)
return 0;
}
+/**
+ * ov7670_parse_dt_prop() - parse property "prop_name" in OF node
+ *
+ * @return The property value or < 0 if property not present
+ * or wrongly specified.
+ */
+static int ov7670_parse_dt_prop(struct device *dev, char *prop_name)
+{
+ struct device_node *np = dev->of_node;
+ u32 prop_val;
+ int ret;
+
+ ret = of_property_read_u32(np, prop_name, &prop_val);
+ if (ret) {
+ if (ret != -EINVAL)
+ dev_err(dev, "Unable to parse property %s: %d\n",
+ prop_name, ret);
+ return ret;
+ }
+
+ return prop_val;
+}
+
static int ov7670_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
@@ -1587,7 +1633,58 @@ static int ov7670_probe(struct i2c_client *client,
v4l2_i2c_subdev_init(sd, client, &ov7670_ops);
info->clock_speed = 30; /* default: a guess */
- if (client->dev.platform_data) {
+
+ if (IS_ENABLED(CONFIG_OF) && client->dev.of_node) {
+ /*
+ * Parse OF properties to initialize media bus configuration.
+ *
+ * Use sensor's default configuration if a property is not
+ * specified (ret == -EINVAL):
+ */
+ info->mbus_config = 0;
+
+ ret = ov7670_parse_dt_prop(&client->dev, "hsync-active");
+ if (ret < 0 && ret != -EINVAL)
+ return ret;
+ else if (ret == 0)
+ info->mbus_config |= V4L2_MBUS_HSYNC_ACTIVE_LOW;
+ else
+ info->mbus_config |= V4L2_MBUS_HSYNC_ACTIVE_HIGH;
+
+ ret = ov7670_parse_dt_prop(&client->dev, "vsync-active");
+ if (ret < 0 && ret != -EINVAL)
+ return ret;
+ else if (ret == 0)
+ info->mbus_config |= V4L2_MBUS_VSYNC_ACTIVE_LOW;
+ else
+ info->mbus_config |= V4L2_MBUS_VSYNC_ACTIVE_HIGH;
+
+ ret = ov7670_parse_dt_prop(&client->dev, "pclk-sample");
+ if (ret < 0 && ret != -EINVAL)
+ return ret;
+ else if (ret > 0)
+ info->mbus_config |= V4L2_MBUS_PCLK_SAMPLE_RISING;
+ else
+ info->mbus_config |= V4L2_MBUS_PCLK_SAMPLE_FALLING;
+
+ ret = ov7670_parse_dt_prop(&client->dev,
+ "ov7670,pclk-hb-disable");
+ if (ret < 0 && ret != -EINVAL)
+ return ret;
+ else if (ret > 0)
+ info->pclk_hb_disable = true;
+ else
+ info->pclk_hb_disable = false;
+
+ ret = ov7670_parse_dt_prop(&client->dev, "ov7670,pll-bypass");
+ if (ret < 0 && ret != -EINVAL)
+ return ret;
+ else if (ret > 0)
+ info->pll_bypass = true;
+ else
+ info->pll_bypass = false;
+
+ } else if (client->dev.platform_data) {
struct ov7670_config *config = client->dev.platform_data;
/*
@@ -1649,9 +1746,6 @@ 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
