Re: [PATCH] media: i2c: ov5640: Re-work MIPI startup sequence

[jacopo mondi <jacopo@jmondi.org>]

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Hi Steve,
   thanks for testing!

On Mon, Jul 09, 2018 at 02:52:09PM -0700, Steve Longerbeam wrote:
> Hi Jacopo,
>
> I tested this patch on the i.MX6Q SabreSD with the OV5640 module.
> It fixes the LP-11 timeout at stream on, but the captured images
> are completely blank/black.

Intersting that the module was not starting up properly on other
(all?) i.MX6Q platforms, not only on Engicam's one. I didn't get this
initially.

Ok, so that's a step forward, but not enough probably. I'll keep
looking into this and get back!

Thanks
   j

>
> Steve
>
>
> On 07/06/2018 04:00 AM, Jacopo Mondi wrote:
> >From: Jacopo Mondi <jacopo@jmondi.org>
> >
> >Rework the MIPI interface startup sequence with the following changes:
> >
> >- Remove MIPI bus initialization from the initial settings blob
> >- At set_power(1) time power up MIPI Tx/Rx and set data and clock lanes in
> >   LP11 during 'sleep' and 'idle' with MIPI clock in non-continuous mode.
> >- At s_stream time enable/disable the MIPI interface output.
> >- Restore default settings at set_power(0) time.
> >
> >Before this commit the sensor MIPI interface was initialized with settings
> >that require a start/stop sequence at power-up time in order to force lanes
> >into LP11 state, as they were initialized in LP00 when in 'sleep mode',
> >which is assumed to be the sensor manual definition for the D-PHY defined
> >stop mode.
> >
> >The stream start/stop was performed by enabling disabling clock gating,
> >and had the side effect to change the lanes sleep mode configuration when
> >stream was stopped.
> >
> >Clock gating/ungating:
> >-       ret = ov5640_mod_reg(sensor, OV5640_REG_MIPI_CTRL00, BIT(5),
> >-                            on ? 0 : BIT(5));
> >-       if (ret)
> >
> >Set lanes in LP11 when in 'sleep mode':
> >-       ret = ov5640_write_reg(sensor, OV5640_REG_PAD_OUTPUT00,
> >-                              on ? 0x00 : 0x70);
> >
> >This commit fixes an issue reported by Jagan Teki on i.MX6 platforms that
> >prevents the host interface from powering up correctly:
> >https://lkml.org/lkml/2018/6/1/38
> >
> >It also improves MIPI capture operations stability on my testing platform
> >where MIPI capture often (silently) failed and returned all-purple frames.
> >
> >fixes: f22996db44e2 ("media: ov5640: add support of DVP parallel interface")
> >Reported-by: Jagan Teki <jagan@amarulasolutions.com>
> >Signed-off-by: Jacopo Mondi <jacopo@jmondi.org>
> >
> >---
> >
> >Hello,
> >   I'm sending this one as new patch instead of a v2 of the previously sent
> >series "media: i2c: ov5640: Re-work MIPI interface configuration" as the
> >previous one was not working on the Engicam i.Mx6 platform where Jagan
> >initially reported issues on.
> >
> >I've been able to test that capture now starts on said platform, but I've not
> >been able to visually verify any of the image content as I have no way yet to
> >transfer the raw images to my development host and verify their content (network
> >still not working for me on that platform :/ )
> >
> >On my other testing platform images are correct, but they already were with the
> >previous version of this patches too, so I assume the CSI-2 receiver is far more
> >tolerant there.
> >
> >Jagan, is there any way you could verify images? I would appreciate your
> >Tested-by tag in case they're correct.
> >
> >Also, as there seems to be a lot of people interested in ov5640 these days, I
> >have expanded the receivers list. Anyone that could give these patches a spin?
> >(ie. Sam reported issues too with the current MIPI startup sequence in a patch
> >series he shared on dropbox iirc...)
> >
> >Thanks
> >    j
> >---
> >  drivers/media/i2c/ov5640.c | 91 ++++++++++++++++++++++++++++++++++++----------
> >  1 file changed, 71 insertions(+), 20 deletions(-)
> >
> >diff --git a/drivers/media/i2c/ov5640.c b/drivers/media/i2c/ov5640.c
> >index 1ecbb7a..7bbd1d7 100644
> >--- a/drivers/media/i2c/ov5640.c
> >+++ b/drivers/media/i2c/ov5640.c
> >@@ -286,10 +286,10 @@ static const struct reg_value ov5640_init_setting_30fps_VGA[] = {
> >  	{0x3a0d, 0x04, 0, 0}, {0x3a14, 0x03, 0, 0}, {0x3a15, 0xd8, 0, 0},
> >  	{0x4001, 0x02, 0, 0}, {0x4004, 0x02, 0, 0}, {0x3000, 0x00, 0, 0},
> >  	{0x3002, 0x1c, 0, 0}, {0x3004, 0xff, 0, 0}, {0x3006, 0xc3, 0, 0},
> >-	{0x300e, 0x45, 0, 0}, {0x302e, 0x08, 0, 0}, {0x4300, 0x3f, 0, 0},
> >+	{0x302e, 0x08, 0, 0}, {0x4300, 0x3f, 0, 0},
> >  	{0x501f, 0x00, 0, 0}, {0x4713, 0x03, 0, 0}, {0x4407, 0x04, 0, 0},
> >  	{0x440e, 0x00, 0, 0}, {0x460b, 0x35, 0, 0}, {0x460c, 0x22, 0, 0},
> >-	{0x4837, 0x0a, 0, 0}, {0x4800, 0x04, 0, 0}, {0x3824, 0x02, 0, 0},
> >+	{0x4837, 0x0a, 0, 0}, {0x3824, 0x02, 0, 0},
> >  	{0x5000, 0xa7, 0, 0}, {0x5001, 0xa3, 0, 0}, {0x5180, 0xff, 0, 0},
> >  	{0x5181, 0xf2, 0, 0}, {0x5182, 0x00, 0, 0}, {0x5183, 0x14, 0, 0},
> >  	{0x5184, 0x25, 0, 0}, {0x5185, 0x24, 0, 0}, {0x5186, 0x09, 0, 0},
> >@@ -1102,12 +1102,18 @@ static int ov5640_set_stream_mipi(struct ov5640_dev *sensor, bool on)
> >  {
> >  	int ret;
> >
> >-	ret = ov5640_mod_reg(sensor, OV5640_REG_MIPI_CTRL00, BIT(5),
> >-			     on ? 0 : BIT(5));
> >-	if (ret)
> >-		return ret;
> >-	ret = ov5640_write_reg(sensor, OV5640_REG_PAD_OUTPUT00,
> >-			       on ? 0x00 : 0x70);
> >+	/*
> >+	 * Enable/disable the MIPI interface
> >+	 *
> >+	 * 0x300e = on ? 0x45 : 0x40
> >+	 * [7:5] = 001	: 2 data lanes mode
> >+	 * [4] = 0	: Power up MIPI HS Tx
> >+	 * [3] = 0	: Power up MIPI LS Rx
> >+	 * [2] = 1/0	: MIPI interface enable/disable
> >+	 * [1:0] = 01/00: FIXME: 'debug'
> >+	 */
> >+	ret = ov5640_write_reg(sensor, OV5640_REG_IO_MIPI_CTRL00,
> >+			       on ? 0x45 : 0x40);
> >  	if (ret)
> >  		return ret;
> >
> >@@ -1786,23 +1792,68 @@ static int ov5640_set_power(struct ov5640_dev *sensor, bool on)
> >  		if (ret)
> >  			goto power_off;
> >
> >+		/* We're done here for DVP bus, while CSI-2 needs setup. */
> >+		if (sensor->ep.bus_type != V4L2_MBUS_CSI2)
> >+			return 0;
> >+
> >+		/*
> >+		 * Power up MIPI HS Tx and LS Rx; 2 data lanes mode
> >+		 *
> >+		 * 0x300e = 0x40
> >+		 * [7:5] = 001	: 2 data lanes mode
> >+		 * [4] = 0	: Power up MIPI HS Tx
> >+		 * [3] = 0	: Power up MIPI LS Rx
> >+		 * [2] = 0	: MIPI interface disabled
> >+		 */
> >+		ret = ov5640_write_reg(sensor,
> >+				       OV5640_REG_IO_MIPI_CTRL00, 0x40);
> >+		if (ret)
> >+			goto power_off;
> >+
> >+		/*
> >+		 * Gate clock and set LP11 in 'no packets mode' (idle)
> >+		 *
> >+		 * 0x4800 = 0x24
> >+		 * [5] = 1	: Gate clock when 'no packets'
> >+		 * [2] = 1	: MIPI bus in LP11 when 'no packets'
> >+		 */
> >+		ret = ov5640_write_reg(sensor,
> >+				       OV5640_REG_MIPI_CTRL00, 0x24);
> >+		if (ret)
> >+			goto power_off;
> >+
> >+		/*
> >+		 * Set data lanes and clock in LP11 when 'sleeping'
> >+		 *
> >+		 * 0x3019 = 0x70
> >+		 * [6] = 1	: MIPI data lane 2 in LP11 when 'sleeping'
> >+		 * [5] = 1	: MIPI data lane 1 in LP11 when 'sleeping'
> >+		 * [4] = 1	: MIPI clock lane in LP11 when 'sleeping'
> >+		 */
> >+		ret = ov5640_write_reg(sensor,
> >+				       OV5640_REG_PAD_OUTPUT00, 0x70);
> >+		if (ret)
> >+			goto power_off;
> >+
> >+		/* Give lanes some time to coax into LP11 state. */
> >+		usleep_range(500, 1000);
> >+
> >+	} else {
> >  		if (sensor->ep.bus_type == V4L2_MBUS_CSI2) {
> >-			/*
> >-			 * start streaming briefly followed by stream off in
> >-			 * order to coax the clock lane into LP-11 state.
> >-			 */
> >-			ret = ov5640_set_stream_mipi(sensor, true);
> >-			if (ret)
> >-				goto power_off;
> >-			usleep_range(1000, 2000);
> >-			ret = ov5640_set_stream_mipi(sensor, false);
> >-			if (ret)
> >-				goto power_off;
> >+			/* Reset MIPI bus settings to their default values. */
> >+			ov5640_write_reg(sensor,
> >+					 OV5640_REG_IO_MIPI_CTRL00, 0x58);
> >+			ov5640_write_reg(sensor,
> >+					 OV5640_REG_MIPI_CTRL00, 0x04);
> >+			ov5640_write_reg(sensor,
> >+					 OV5640_REG_PAD_OUTPUT00, 0x00);
> >  		}
> >
> >-		return 0;
> >+		ov5640_set_power_off(sensor);
> >  	}
> >
> >+	return 0;
> >+
> >  power_off:
> >  	ov5640_set_power_off(sensor);
> >  	return ret;
> >--
> >2.7.4
> >
>

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