[PATCH v4 4/6] media: synopsys: Add PHY stopstate wait for i.MX93
Alexander Stein
alexander.stein at ew.tq-group.com
Thu May 21 04:52:31 PDT 2026
Hi,
thanks for the replay.
Am Donnerstag, 21. Mai 2026, 11:29:39 CEST schrieb G.N. Zhou (OSS):
> Hi Alexander,
>
> > -----Original Message-----
> > From: Alexander Stein <alexander.stein at ew.tq-group.com>
> > Sent: Wednesday, May 20, 2026 7:12 PM
> > To: Michael Riesch <michael.riesch at collabora.com>; Mauro Carvalho Chehab
> > <mchehab at kernel.org>; Rob Herring <robh at kernel.org>; Krzysztof Kozlowski
> > <krzk+dt at kernel.org>; Conor Dooley <conor+dt at kernel.org>; Heiko Stuebner
> > <heiko at sntech.de>; Laurent Pinchart <laurent.pinchart at ideasonboard.com>;
> > Frank Li <frank.li at nxp.com>; Sakari Ailus <sakari.ailus at linux.intel.com>; Bryan
> > O'Donoghue <bryan.odonoghue at linaro.org>; Mehdi Djait
> > <mehdi.djait at linux.intel.com>; Hans Verkuil <hverkuil+cisco at kernel.org>;
> > G.N. Zhou (OSS) <guoniu.zhou at oss.nxp.com>
> > Cc: linux-media at vger.kernel.org; linux-kernel at vger.kernel.org;
> > devicetree at vger.kernel.org; imx at lists.linux.dev; linux-arm-
> > kernel at lists.infradead.org; linux-rockchip at lists.infradead.org; G.N. Zhou (OSS)
> > <guoniu.zhou at oss.nxp.com>
> > Subject: Re: [PATCH v4 4/6] media: synopsys: Add PHY stopstate wait for
> > i.MX93
> >
> > Hi,
> >
> > Am Dienstag, 19. Mai 2026, 04:07:41 CEST schrieb Guoniu Zhou:
> > > Implement waiting for D-PHY lanes to enter stop state on i.MX93. This
> > > ensures proper PHY initialization by verifying that the clock lane and
> > > all active data lanes have entered the stop state before proceeding
> > > with further operations.
> > >
> > > Reviewed-by: Frank Li <Frank.Li at nxp.com>
> > > Signed-off-by: Guoniu Zhou <guoniu.zhou at oss.nxp.com>
> > > ---
> > > Changes in v2:
> > > - Removes redundant register availability check
> > > - Uses read_poll_timeout() with dw_mipi_csi2rx_read() instead of
> > > readl_poll_timeout() with direct register address
> > > - Fixes stopstate condition logic
> > > - Check PHY stopstate after sensor enable instead of before to ensure
> > > correct timing.
> > > - Optimize PHY stopstate polling parameters (1000us->10us, 2s->1ms) to
> > > balance performance and responsiveness.
> > > ---
> > > drivers/media/platform/synopsys/dw-mipi-csi2rx.c | 36
> > > ++++++++++++++++++++++++
> > > 1 file changed, 36 insertions(+)
> > >
> > > diff --git a/drivers/media/platform/synopsys/dw-mipi-csi2rx.c
> > > b/drivers/media/platform/synopsys/dw-mipi-csi2rx.c
> > > index 92178a3dec5d..8a34aec550ad 100644
> > > --- a/drivers/media/platform/synopsys/dw-mipi-csi2rx.c
> > > +++ b/drivers/media/platform/synopsys/dw-mipi-csi2rx.c
> > > @@ -11,6 +11,7 @@
> > > #include <linux/clk.h>
> > > #include <linux/delay.h>
> > > #include <linux/io.h>
> > > +#include <linux/iopoll.h>
> > > #include <linux/module.h>
> > > #include <linux/of.h>
> > > #include <linux/phy/phy.h>
> > > @@ -35,6 +36,8 @@
> > > #define DW_REG_EXIST BIT(31)
> > > #define DW_REG(x) (DW_REG_EXIST | (x))
> > >
> > > +#define DPHY_STOPSTATE_CLK_LANE BIT(16)
> > > +
> > > #define DPHY_TEST_CTRL0_TEST_CLR BIT(0)
> > >
> > > #define IPI_VCID_VC(x) FIELD_PREP(GENMASK(1, 0),
> > (x))
> > > @@ -65,6 +68,7 @@ enum dw_mipi_csi2rx_regs_index {
> > > DW_MIPI_CSI2RX_PHY_TST_CTRL0,
> > > DW_MIPI_CSI2RX_PHY_TST_CTRL1,
> > > DW_MIPI_CSI2RX_PHY_SHUTDOWNZ,
> > > + DW_MIPI_CSI2RX_PHY_STOPSTATE,
> > > DW_MIPI_CSI2RX_IPI_DATATYPE,
> > > DW_MIPI_CSI2RX_IPI_MEM_FLUSH,
> > > DW_MIPI_CSI2RX_IPI_MODE,
> > > @@ -87,6 +91,7 @@ struct dw_mipi_csi2rx_drvdata {
> > > void (*dphy_assert_reset)(struct dw_mipi_csi2rx_device *csi2);
> > > void (*dphy_deassert_reset)(struct dw_mipi_csi2rx_device *csi2);
> > > void (*ipi_enable)(struct dw_mipi_csi2rx_device *csi2);
> > > + int (*wait_for_phy_stopstate)(struct dw_mipi_csi2rx_device *csi2);
> > > };
> > >
> > > struct dw_mipi_csi2rx_format {
> > > @@ -139,6 +144,7 @@ static const u32 imx93_regs[DW_MIPI_CSI2RX_MAX]
> > = {
> > > [DW_MIPI_CSI2RX_PHY_SHUTDOWNZ] = DW_REG(0x40),
> > > [DW_MIPI_CSI2RX_DPHY_RSTZ] = DW_REG(0x44),
> > > [DW_MIPI_CSI2RX_PHY_STATE] = DW_REG(0x48),
> > > + [DW_MIPI_CSI2RX_PHY_STOPSTATE] = DW_REG(0x4c),
> > > [DW_MIPI_CSI2RX_PHY_TST_CTRL0] = DW_REG(0x50),
> > > [DW_MIPI_CSI2RX_PHY_TST_CTRL1] = DW_REG(0x54),
> > > [DW_MIPI_CSI2RX_IPI_MODE] = DW_REG(0x80), @@ -556,10 +562,19
> > @@
> > > static int dw_mipi_csi2rx_enable_streams(struct v4l2_subdev *sd,
> > > if (ret)
> > > goto err_csi_stop;
> > >
> > > + if (!csi2->enabled_streams &&
> > > + csi2->drvdata->wait_for_phy_stopstate) {
> > > + ret = csi2->drvdata->wait_for_phy_stopstate(csi2);
> > > + if (ret)
> > > + goto err_disable_streams;
> > > + }
> > > +
> > > csi2->enabled_streams |= streams_mask;
> > >
> > > return 0;
> > >
> > > +err_disable_streams:
> > > + v4l2_subdev_disable_streams(remote_sd, remote_pad->index, mask);
> > > err_csi_stop:
> > > /* Stop CSI hardware if no streams are enabled */
> > > if (!csi2->enabled_streams)
> > > @@ -871,11 +886,32 @@ static void imx93_csi2rx_dphy_ipi_enable(struct
> > dw_mipi_csi2rx_device *csi2)
> > > dw_mipi_csi2rx_write(csi2, DW_MIPI_CSI2RX_IPI_MODE, val); }
> > >
> > > +static int imx93_csi2rx_wait_for_phy_stopstate(struct
> > > +dw_mipi_csi2rx_device *csi2) {
> > > + struct device *dev = csi2->dev;
> > > + u32 stopstate_mask;
> > > + u32 val;
> > > + int ret;
> > > +
> > > + stopstate_mask = DPHY_STOPSTATE_CLK_LANE | GENMASK(csi2-
> > >lanes_num -
> > > +1, 0);
> > > +
> > > + ret = read_poll_timeout(dw_mipi_csi2rx_read, val,
> > > + (val & stopstate_mask) == stopstate_mask,
> > > + 10, 1000, true,
> > > + csi2, DW_MIPI_CSI2RX_PHY_STOPSTATE);
> > > + if (ret)
> > > + dev_err(dev, "lanes are not in stop state: %#x,
> > expected %#x\n",
> > > + val, stopstate_mask);
> >
> > Did you actually test this on imx93? I'm trying to get my imx327 sensor to run,
> > but only run into this error message:
> > dw-mipi-csi2rx 4ae00000.mipi-csi: lanes are not in stop state: 0x0, expected
> > 0x10003
>
> Thanks for testing. Regarding the lane stop state error on i.MX93 with imx327:
>
> This error indicates the CSI-2 lanes are not in LP-11 (stop) state when
> expected. Please check:
>
> 1) Verify the sensor PHY is in LP-11 state before returning from the sensor's
> s_stream(1) call. The CSI-2 receiver expects lanes to be in stop state
> initially.
Well, this might be tricky as I don't have D-PHY capable scopes.
I can successfully use this sensor on a imx8mp, so I am expecting this to be
okay.
> 2) Check if the imx327 driver has a delay between starting the stream and
> returning from s_stream(). If the sensor transitions PHY out of LP-11
> state during this delay, the CSI driver's lane state check will fail
> when it runs later. The sensor should remain in LP-11 until the CSI
> controller completes its initialization.
In imx290_set_stream() and subsequently imx290_start_streaming() setting
IMX290_XMSTA starts the stream. I expect this is the point when the sensors
switches from LP-11 to HS. But again, I can't verify.
With enabling debug
> echo "module videodev +p" > /sys/kernel/debug/dynamic_debug/control
> echo 0xff > /sys/class/video4linux/video0/dev_debug
After I setup the media pipeline, running the command
> v4l2-ctl -z "platform:4ae40000.isi" -d "mxc_isi.0.capture" --stream-mmap --stream-count=1 --stream-to=imx93.raw
I get the following debug output:
--8<--
plane 0: bytesperline=3840 sizeimage=4147200
mxc-isi 4ae40000.isi: validating link "crossbar":2 -> "mxc_isi.0":0
mxc-isi 4ae40000.isi: validating stream "crossbar":2:0 -> "mxc_isi.0":0:0
mxc-isi 4ae40000.isi: validating link "dw-mipi-csi2rx 4ae00000.mipi-csi":1 -> "crossbar":0
mxc-isi 4ae40000.isi: validating stream "dw-mipi-csi2rx 4ae00000.mipi-csi":1:0 -> "crossbar":0:0
mxc-isi 4ae40000.isi: validating link "imx327 4-001a":0 -> "dw-mipi-csi2rx 4ae00000.mipi-csi":0
mxc-isi 4ae40000.isi: validating stream "imx327 4-001a":0:0 -> "dw-mipi-csi2rx 4ae00000.mipi-csi":0:0
mxc-isi 4ae40000.isi: enable streams "crossbar":2/0x1
mxc-isi 4ae40000.isi: collect_streams: "crossbar":2: found 0x1 enabled 0x0
imx290 4-001a: Frame descriptor on pad 0, type CSI-2
imx290 4-001a: stream 0, code 0x300f, length 0, flags 0x0000, vc 0, dt 0x2b
dw-mipi-csi2rx 4ae00000.mipi-csi: Frame descriptor on pad 1, type CSI-2
dw-mipi-csi2rx 4ae00000.mipi-csi: stream 0, code 0x300f, length 0, flags 0x0000, vc 0, dt 0x2b
mxc-isi 4ae40000.isi: enable streams "dw-mipi-csi2rx 4ae00000.mipi-csi":1/0x1
dw-mipi-csi2rx 4ae00000.mipi-csi: collect_streams: "dw-mipi-csi2rx 4ae00000.mipi-csi":1: found 0x1 enabled 0x0
mxc-isi 4ae40000.isi: enable streams "imx327 4-001a":0/0x1
imx290 4-001a: collect_streams: sub-device "imx327 4-001a" does not support streams
dw-mipi-csi2rx 4ae00000.mipi-csi: lanes are not in stop state: 0x0, expected 0x10003
mxc-isi 4ae40000.isi: disable streams "imx327 4-001a":0/0x1
imx290 4-001a: collect_streams: sub-device "imx327 4-001a" does not support streams
mxc-isi 4ae40000.isi: enable streams 1:0x1 failed: -110
mxc-isi 4ae40000.isi: failed to enable streams 0x1 on 'dw-mipi-csi2rx 4ae00000.mipi-csi':1: -110
mxc-isi 4ae40000.isi: enable streams 2:0x1 failed: -110
mxc-isi 4ae40000.isi: Failed to enable pipe 0
video0: VIDIOC_STREAMON: error -110: type=vid-cap-mplane
videodev: v4l2_release: video0: release
--8<--
For completeness this is my media device config
--8<--
# media-ctl -p
Media controller API version 7.1.0
Media device information
------------------------
driver mxc-isi
model FSL Capture Media Device
serial
bus info platform:4ae40000.isi
hw revision 0x0
driver version 7.1.0
Device topology
- entity 1: crossbar (3 pads, 2 links, 1 route)
type V4L2 subdev subtype Unknown flags 0
device node name /dev/v4l-subdev0
routes:
0/0 -> 2/0 [ACTIVE]
pad0: SINK,MUST_CONNECT
[stream:0 fmt:SRGGB10_1X10/1920x1080 field:none colorspace:raw]
<- "dw-mipi-csi2rx 4ae00000.mipi-cs":1 [ENABLED,IMMUTABLE]
pad1: SINK,MUST_CONNECT
pad2: SOURCE
[stream:0 fmt:SRGGB10_1X10/1920x1080 field:none colorspace:raw]
-> "mxc_isi.0":0 [ENABLED,IMMUTABLE]
- entity 5: mxc_isi.0 (2 pads, 2 links, 0 routes)
type V4L2 subdev subtype Unknown flags 0
device node name /dev/v4l-subdev1
pad0: SINK
[stream:0 fmt:SRGGB10_1X10/1920x1080 field:none colorspace:raw
compose.bounds:(0,0)/1920x1080
compose:(0,0)/1920x1080]
<- "crossbar":2 [ENABLED,IMMUTABLE]
pad1: SOURCE
[stream:0 fmt:SRGGB10_1X10/1920x1080 field:none colorspace:jpeg xfer:srgb ycbcr:601 quantization:full-range
crop.bounds:(0,0)/1920x1080
crop:(0,0)/1920x1080]
-> "mxc_isi.0.capture":0 [ENABLED,IMMUTABLE]
- entity 8: mxc_isi.0.capture (1 pad, 1 link)
type Node subtype V4L flags 0
device node name /dev/video0
pad0: SINK
<- "mxc_isi.0":1 [ENABLED,IMMUTABLE]
- entity 16: dw-mipi-csi2rx 4ae00000.mipi-cs (2 pads, 2 links, 1 route)
type V4L2 subdev subtype Unknown flags 0
device node name /dev/v4l-subdev2
routes:
0/0 -> 1/0 [ACTIVE]
pad0: SINK,MUST_CONNECT
[stream:0 fmt:SRGGB10_1X10/1920x1080 field:none colorspace:raw xfer:none ycbcr:601 quantization:full-range]
<- "imx327 4-001a":0 [ENABLED]
pad1: SOURCE
[stream:0 fmt:SRGGB10_1X10/1920x1080 field:none colorspace:raw xfer:none ycbcr:601 quantization:full-range]
-> "crossbar":0 [ENABLED,IMMUTABLE]
- entity 21: imx327 4-001a (1 pad, 1 link, 0 routes)
type V4L2 subdev subtype Sensor flags 0
device node name /dev/v4l-subdev3
pad0: SOURCE
[stream:0 fmt:SRGGB10_1X10/1920x1080 field:none colorspace:raw xfer:none ycbcr:601 quantization:full-range
crop.bounds:(0,0)/1945x1097
crop:(12,8)/1920x1080]
-> "dw-mipi-csi2rx 4ae00000.mipi-cs":0 [ENABLED]
--8<--
Anything odd here?
> You may need to remove any delays in the imx327 s_stream implementation, or
> ensure the sensor stays in LP-11 state until the CSI receiver is ready.
>
> If possible, could you share the imx327 driver code or check its s_stream implementation?
It's essentially upstream in drivers/media/i2c/imx290.c.
I only have a dummy implementation for get_frame_desc and a small adjustement
for my camera module regarding i2c access.
--8<--
static int imx290_get_frame_desc(struct v4l2_subdev *sd, unsigned int pad,
struct v4l2_mbus_frame_desc *fd)
{
const struct v4l2_mbus_framefmt *format;
struct v4l2_subdev_state *state;
state = v4l2_subdev_lock_and_get_active_state(sd);
format = v4l2_subdev_state_get_format(state, pad);
v4l2_subdev_unlock_state(state);
fd->type = V4L2_MBUS_FRAME_DESC_TYPE_CSI2;
fd->num_entries = 1;
fd->entry[0].pixelcode = format->code;
fd->entry[0].stream = 0;
fd->entry[0].bus.csi2.vc = 0;
fd->entry[0].bus.csi2.dt = MIPI_CSI2_DT_RAW10; //TODO: get_data_type_by_code(format->code);
return 0;
}
--8<--
Another thing. I use https://lore.kernel.org/imx/20250701-95_cam-v1-2-c5172bab387b@nxp.com/
for the D-PHY. Is there any update/progress on that driver?
Best regards,
Alexander
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