Hi Ramiro,

On Mon, Feb 06, 2017 at 11:38:28AM +0000, Ramiro Oliveira wrote:
...

quoted

quoted

+	ret = ov5647_write_array(sd, ov5647_640x480,
+					ARRAY_SIZE(ov5647_640x480));
+	if (ret < 0) {
+		dev_err(&client->dev, "write sensor_default_regs error\n");
+		return ret;
+	}
+
+	ov5647_set_virtual_channel(sd, 0);
+
+	ov5647_read(sd, 0x0100, &resetval);
+	if (!(resetval & 0x01)) {

Can this ever happen? Streaming start is at the end of the register list.

I'm not sure it can happen. It was just a safeguard, but I can remove it if you
think it's not necessary

You're not reading back the other registers either, albeit I'd check that
the I2C accesses actually succeed. Generally the return values are ignored.

quoted

quoted

+		dev_err(&client->dev, "Device was in SW standby");
+		ov5647_write(sd, 0x0100, 0x01);
+	}
+
+	ov5647_write(sd, 0x4800, 0x04);
+	ov5647_stream_on(sd);
+
+	return 0;
+}
+
+/**
+ * @short Control sensor power state
+ * @param[in] sd v4l2 subdev
+ * @param[in] on Sensor power
+ * @return Error code
+ */
+static int sensor_power(struct v4l2_subdev *sd, int on)
+{
+	int ret;
+	struct ov5647 *ov5647 = to_state(sd);
+	struct i2c_client *client = v4l2_get_subdevdata(sd);
+
+	ret = 0;
+	mutex_lock(&ov5647->lock);
+
+	if (on && !ov5647->power_count)	{
+		dev_dbg(&client->dev, "OV5647 power on\n");
+
+		clk_set_rate(ov5647->xclk, ov5647->xclk_freq);
+
+		ret = clk_prepare_enable(ov5647->xclk);
+		if (ret < 0) {
+			dev_err(ov5647->dev, "clk prepare enable failed\n");
+			goto out;
+		}
+
+		ret = ov5647_write_array(sd, sensor_oe_enable_regs,
+				ARRAY_SIZE(sensor_oe_enable_regs));
+		if (ret < 0) {
+			clk_disable_unprepare(ov5647->xclk);
+			dev_err(&client->dev,
+				"write sensor_oe_enable_regs error\n");
+			goto out;
+		}
+
+		ret = __sensor_init(sd);
+		if (ret < 0) {
+			clk_disable_unprepare(ov5647->xclk);
+			dev_err(&client->dev,
+				"Camera not available, check Power\n");
+			goto out;
+		}
+	} else if (!on && ov5647->power_count == 1) {
+		dev_dbg(&client->dev, "OV5647 power off\n");
+
+		dev_dbg(&client->dev, "disable oe\n");
+		ret = ov5647_write_array(sd, sensor_oe_disable_regs,
+				ARRAY_SIZE(sensor_oe_disable_regs));
+
+		if (ret < 0)
+			dev_dbg(&client->dev, "disable oe failed\n");
+
+		ret = set_sw_standby(sd, true);
+
+		if (ret < 0)
+			dev_dbg(&client->dev, "soft stby failed\n");
+
+		clk_disable_unprepare(ov5647->xclk);
+	}
+
+	/* Update the power count. */
+	ov5647->power_count += on ? 1 : -1;
+	WARN_ON(ov5647->power_count < 0);
+
+out:
+	mutex_unlock(&ov5647->lock);
+
+	return ret;
+}
+
+#ifdef CONFIG_VIDEO_ADV_DEBUG
+/**
+ * @short Get register value
+ * @param[in] sd v4l2 subdev
+ * @param[in] reg register struct
+ * @return Error code
+ */
+static int sensor_get_register(struct v4l2_subdev *sd,
+				struct v4l2_dbg_register *reg)
+{
+	unsigned char val = 0;
+	int ret;
+
+	ret = ov5647_read(sd, reg->reg & 0xff, &val);
+	if (ret != 0)
+		return ret;
+
+	reg->val = val;
+	reg->size = 1;
+
+	return ret;
+}
+
+/**
+ * @short Set register value
+ * @param[in] sd v4l2 subdev
+ * @param[in] reg register struct
+ * @return Error code
+ */
+static int sensor_set_register(struct v4l2_subdev *sd,
+				const struct v4l2_dbg_register *reg)
+{
+	return ov5647_write(sd, reg->reg & 0xff, reg->val & 0xff);
+}
+#endif
+
+/**
+ * @short Subdev core operations registration
+ */
+static const struct v4l2_subdev_core_ops sensor_core_ops = {
+	.s_power		= sensor_power,
+#ifdef CONFIG_VIDEO_ADV_DEBUG
+	.g_register		= sensor_get_register,
+	.s_register		= sensor_set_register,
+#endif
+};
+
+static int enum_mbus_code(struct v4l2_subdev *sd,
+				struct v4l2_subdev_pad_config *cfg,
+				struct v4l2_subdev_mbus_code_enum *code)
+{
+	if (code->index > 0)
+		return -EINVAL;
+
+	code->code = MEDIA_BUS_FMT_SBGGR8_1X8;
+
+	return 0;
+}
+
+static const struct v4l2_subdev_pad_ops subdev_pad_ops = {
+	.enum_mbus_code = enum_mbus_code,
+};
+
+
+/**
+ * @short Subdev operations registration
+ *
+ */
+static const struct v4l2_subdev_ops subdev_ops = {
+	.core		= &sensor_core_ops,
+	.pad		= &subdev_pad_ops,

You should implement s_stream() in video ops to control the streaming state.

I don't know about this particular sensor, but on SMIA compliant sensors
the SW standby means streaming is disabled. There seem to be additional
registers as well; my educated guess is that writing all those to control
streaming would be the right thing to do.

The CSI-2 bus initialisation could fail if you start streaming right away
when the sensor is powered on.

I haven't had any error yet, but I'll add set_stream() and start streaming video
there, just to be sure.

It depends on the receiver. Some might work whereas some definitely don't.

Please see Documentation/media/kapi/csi2.rst .

-- 
Kind regards,

Sakari Ailus
e-mail: sakari.ailus-X3B1VOXEql0@public.gmane.org	XMPP: sailus-PCDdDYkjdNMDXYZnReoRVg@public.gmane.org
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