mbox series

[v2,00/12] drm: bridge: Add Samsung MIPI DSIM bridge

Message ID 20220504114021.33265-1-jagan@amarulasolutions.com (mailing list archive)
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Series drm: bridge: Add Samsung MIPI DSIM bridge | expand

Message

Jagan Teki May 4, 2022, 11:40 a.m. UTC
This series supports common bridge support for Samsung MIPI DSIM
which is used in Exynos and i.MX8MM SoC's.

Previous v1 can be available here [1].

The final bridge supports both the Exynos and i.MX8MM DSI devices.

On, summary this patch-set break the entire DSIM driver into
- platform specific glue code for platform ops, component_ops.
- common bridge driver which handle platform glue init and invoke.

Patch 0000: 	Samsung DSIM bridge

Patch 0001:	Common lookup code for OF-graph or child

Patch 0002: 	platform init flag via driver_data

Patch 0003/10:  bridge fixes, atomic API's

Patch 0011:	document fsl,imx8mm-mipi-dsim

Patch 0012:	add i.MX8MM DSIM support

Tested in Engicam i.Core MX8M Mini SoM.

Anyone interested, please have a look on this repo [2]

[2] https://github.com/openedev/kernel/tree/imx8mm-dsi-v2 
[1] https://patchwork.kernel.org/project/dri-devel/cover/20220408162108.184583-1-jagan@amarulasolutions.com/

Any inputs?
Jagan.

Jagan Teki (12):
  drm: bridge: Add Samsung DSIM bridge driver
  drm: bridge: samsung-dsim: Lookup OF-graph or Child node devices
  drm: bridge: samsung-dsim: Handle platform init via driver_data
  drm: bridge: samsung-dsim: Mark PHY as optional
  drm: bridge: samsung-dsim: Add DSI init in bridge pre_enable()
  drm: bridge: samsung-dsim: Fix PLL_P (PMS_P) offset
  drm: bridge: samsung-dsim: Add module init, exit
  drm: bridge: samsung-dsim: Add atomic_check
  drm: bridge: samsung-dsim: Add atomic_get_input_bus_fmts
  drm: bridge: samsung-dsim: Add input_bus_flags
  dt-bindings: display: exynos: dsim: Add NXP i.MX8MM support
  drm: bridge: samsung-dsim: Add i.MX8MM support

 .../bindings/display/exynos/exynos_dsim.txt   |    1 +
 MAINTAINERS                                   |    8 +
 drivers/gpu/drm/bridge/Kconfig                |   12 +
 drivers/gpu/drm/bridge/Makefile               |    1 +
 drivers/gpu/drm/bridge/samsung-dsim.c         | 1847 +++++++++++++++++
 drivers/gpu/drm/exynos/Kconfig                |    1 +
 drivers/gpu/drm/exynos/exynos_drm_dsi.c       | 1724 +--------------
 include/drm/bridge/samsung-dsim.h             |   99 +
 8 files changed, 2032 insertions(+), 1661 deletions(-)
 create mode 100644 drivers/gpu/drm/bridge/samsung-dsim.c
 create mode 100644 include/drm/bridge/samsung-dsim.h

Comments

Alexander Stein May 5, 2022, 7:26 a.m. UTC | #1
Hello Jagan,

thanks for the second version of this patchset.

Am Mittwoch, 4. Mai 2022, 13:40:09 CEST schrieb Jagan Teki:
> This series supports common bridge support for Samsung MIPI DSIM
> which is used in Exynos and i.MX8MM SoC's.
> 
> Previous v1 can be available here [1].
> 
> The final bridge supports both the Exynos and i.MX8MM DSI devices.
> 
> On, summary this patch-set break the entire DSIM driver into
> - platform specific glue code for platform ops, component_ops.
> - common bridge driver which handle platform glue init and invoke.
> 
> Patch 0000: 	Samsung DSIM bridge
> 
> Patch 0001:	Common lookup code for OF-graph or child
> 
> Patch 0002: 	platform init flag via driver_data
> 
> Patch 0003/10:  bridge fixes, atomic API's
> 
> Patch 0011:	document fsl,imx8mm-mipi-dsim
> 
> Patch 0012:	add i.MX8MM DSIM support
> 
> Tested in Engicam i.Core MX8M Mini SoM.
> 
> Anyone interested, please have a look on this repo [2]
> 
> [2] https://github.com/openedev/kernel/tree/imx8mm-dsi-v2
> [1]
> https://patchwork.kernel.org/project/dri-devel/cover/20220408162108.184583-> 1-jagan@amarulasolutions.com/
> 
> Any inputs?

I was able to get my LVDS display running using this driver and an LVDS 
bridge. Actually my setup is similar to yours. My chain is like this:
MIPI-DSI -> sn65dsi83 -> LVDS panel
I noticed some things though:
My setup only works if I use less than 4 lanes. See [1]. When using 4 lanes 
the image is flickering, but the content is "visible". Your DT has only 2 
lanes configured, do you have the possibility to use 4 lanes? I have no idea 
how to tackle this. It might be the DSIM side or the bridge side.
Apparently the downstream kernel from NXP supports 4 lanes, if I can trust the 
config. I have no way to verify this though.

Another thing is I get the following warning
> sn65dsi83 2-002d: Unsupported LVDS bus format 0x100a, please check output 
bridge driver. Falling back to SPWG24.

This seems to be caused by a wrong bridge chain. Using commit 81e80429 at [2] 
I get the following output:
> bridge chain: /soc@0/bus@30800000/i2c@30a40000/dsi-lvds-bridge@2d -> /
panel_lvds0 -> /soc@0/bus@32c00000/dsi@32e10000 ->
Which seems weird. I would have expected something like
dsi@32e10000 -> dsi-lvds-bridge@2d -> panel_lvds0
Do you happen to see somthing similar? But this is completely unrelated to 
your patchset though.

Also unloading the samsung_dsim driver raises a regulator warning:
------------[ cut here ]------------                                                                                                 
WARNING: CPU: 2 PID: 381 at drivers/regulator/core.c:2275 _regulator_put.part.
0+0x38/0x40                                            
Modules linked in: caam_jr caamhash_desc caamalg_desc crypto_engine rng_core 
authenc libdes hantro_vpu(C) v4l2_vp9 v4l2_h264 snd_soc_
fsl_asoc_card crct10dif_ce snd_soc_tlv320aic32x4_spi videobuf2_dma_contig 
phy_fsl_imx8m_pcie v4l2_mem2mem samsung_dsim(-) snd_soc_tlv
320aic32x4_i2c snd_soc_tlv320aic32x4 caam error imx8mm_thermal imx_sdma 
pwm_beeper fuse ipv6                                         
CPU: 2 PID: 381 Comm: modprobe Tainted: G         C        5.18.0-rc5-
next-20220504+ #204 03c84d7b1600b734091c3159e797071c8f65061c   
Hardware name: TQ-Systems GmbH i.MX8MM TQMa8MxML on MBa8Mx (DT)                                                                      
pstate: 80000005 (Nzcv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--)                                                                      
pc : _regulator_put.part.0+0x38/0x40                                                                                                 
lr : regulator_bulk_free+0x58/0x80                                                                                                   
sp : ffff80000aeb3af0                                                                                                                
x29: ffff80000aeb3af0 x28: ffff00000360bb00 x27: 0000000000000000                                                                    
x26: ffff800009bad438 x25: ffff000000276890 x24: 0000000000000009                                                                    
x23: ffff00000360bb00 x22: ffff000003543268 x21: ffff800009b85280                                                                    
x20: ffff000005587800 x19: ffff000003543238 x18: 0000000000000000                                                                    
x17: 0000000000000000 x16: 0000000000000000 x15: 6d3d4d4554535953                                                                    
x14: 42555300302e6973 x13: 4553003338697364 x12: 0000000000000000                                                                    
x11: 0000000000000000 x10: 0000000000000ab0 x9 : ffff80000aeb38f0
x8 : ffff00000360c610 x7 : 0000000000000000 x6 : 0000000000000000
x5 : ffff8000092dc468 x4 : ffff00000360bb00 x3 : 0000000000000000
x2 : ffff00000360bb00 x1 : 0000000000000001 x0 : ffff000005587800
Call trace:
 _regulator_put.part.0+0x38/0x40
 regulator_bulk_free+0x58/0x80
 devm_regulator_bulk_release+0x18/0x20
 devres_release_all+0xa0/0x100
 device_unbind_cleanup+0x14/0x60
 device_release_driver_internal+0x214/0x2b4
 driver_detach+0x4c/0xe0
 bus_remove_driver+0x68/0x120
 driver_unregister+0x2c/0x5c
 platform_driver_unregister+0x10/0x20
 samsung_mipi_dsim_exit+0x18/0xd20 [samsung_dsim 
f08bbdb06ba3e4aef07da9615e8193297aa99358]
 __do_sys_delete_module.constprop.0+0x134/0x1e4
 __arm64_sys_delete_module+0x10/0x1c
 invoke_syscall+0x6c/0xf0
 el0_svc_common.constprop.0+0xc0/0xe0
 do_el0_svc+0x24/0x30
 el0_svc+0x3c/0xfc
 el0t_64_sync_handler+0xb0/0xb4
 el0t_64_sync+0x148/0x14c
---[ end trace 0000000000000000 ]---

Best regards,
Alexander

[1] https://github.com/tq-steina/linux/blob/imx8mm-dsi-lvds/arch/arm64/boot/
dts/freescale/imx8mm-tqma8mqml-mba8mx-lvds.dts#L45-L46
[2] https://github.com/tq-steina/linux/commit/
81e80429341cd0a4f119ec9cf50839498915443b
Jagan Teki May 5, 2022, 7:38 a.m. UTC | #2
On Thu, May 5, 2022 at 12:57 PM Alexander Stein
<alexander.stein@ew.tq-group.com> wrote:
>
> Hello Jagan,
>
> thanks for the second version of this patchset.
>
> Am Mittwoch, 4. Mai 2022, 13:40:09 CEST schrieb Jagan Teki:
> > This series supports common bridge support for Samsung MIPI DSIM
> > which is used in Exynos and i.MX8MM SoC's.
> >
> > Previous v1 can be available here [1].
> >
> > The final bridge supports both the Exynos and i.MX8MM DSI devices.
> >
> > On, summary this patch-set break the entire DSIM driver into
> > - platform specific glue code for platform ops, component_ops.
> > - common bridge driver which handle platform glue init and invoke.
> >
> > Patch 0000:   Samsung DSIM bridge
> >
> > Patch 0001:   Common lookup code for OF-graph or child
> >
> > Patch 0002:   platform init flag via driver_data
> >
> > Patch 0003/10:  bridge fixes, atomic API's
> >
> > Patch 0011:   document fsl,imx8mm-mipi-dsim
> >
> > Patch 0012:   add i.MX8MM DSIM support
> >
> > Tested in Engicam i.Core MX8M Mini SoM.
> >
> > Anyone interested, please have a look on this repo [2]
> >
> > [2] https://github.com/openedev/kernel/tree/imx8mm-dsi-v2
> > [1]
> > https://patchwork.kernel.org/project/dri-devel/cover/20220408162108.184583-> 1-jagan@amarulasolutions.com/
> >
> > Any inputs?
>
> I was able to get my LVDS display running using this driver and an LVDS
> bridge. Actually my setup is similar to yours. My chain is like this:
> MIPI-DSI -> sn65dsi83 -> LVDS panel
> I noticed some things though:
> My setup only works if I use less than 4 lanes. See [1]. When using 4 lanes
> the image is flickering, but the content is "visible". Your DT has only 2
> lanes configured, do you have the possibility to use 4 lanes? I have no idea
> how to tackle this. It might be the DSIM side or the bridge side.
> Apparently the downstream kernel from NXP supports 4 lanes, if I can trust the
> config. I have no way to verify this though.

What is dsi_lvds_bridge node? have you added your dts changes on top
of imx8mm-dsi-v2 branch I'm pointing it.

I will check 4 lanes and let you know.

>
> Another thing is I get the following warning
> > sn65dsi83 2-002d: Unsupported LVDS bus format 0x100a, please check output
> bridge driver. Falling back to SPWG24.

This couldn't be much affected but will fix it.

>
> This seems to be caused by a wrong bridge chain. Using commit 81e80429 at [2]
> I get the following output:
> > bridge chain: /soc@0/bus@30800000/i2c@30a40000/dsi-lvds-bridge@2d -> /
> panel_lvds0 -> /soc@0/bus@32c00000/dsi@32e10000 ->
> Which seems weird. I would have expected something like
> dsi@32e10000 -> dsi-lvds-bridge@2d -> panel_lvds0
> Do you happen to see somthing similar? But this is completely unrelated to
> your patchset though.

Can you share the link to the exact commit?

Thanks,
Jagan.
Alexander Stein May 5, 2022, 7:48 a.m. UTC | #3
Hello Jagan,

thanks for the quick response.

Am Donnerstag, 5. Mai 2022, 09:38:48 CEST schrieb Jagan Teki:
> On Thu, May 5, 2022 at 12:57 PM Alexander Stein
> 
> <alexander.stein@ew.tq-group.com> wrote:
> > Hello Jagan,
> > 
> > thanks for the second version of this patchset.
> > 
> > Am Mittwoch, 4. Mai 2022, 13:40:09 CEST schrieb Jagan Teki:
> > > This series supports common bridge support for Samsung MIPI DSIM
> > > which is used in Exynos and i.MX8MM SoC's.
> > > 
> > > Previous v1 can be available here [1].
> > > 
> > > The final bridge supports both the Exynos and i.MX8MM DSI devices.
> > > 
> > > On, summary this patch-set break the entire DSIM driver into
> > > - platform specific glue code for platform ops, component_ops.
> > > - common bridge driver which handle platform glue init and invoke.
> > > 
> > > Patch 0000:   Samsung DSIM bridge
> > > 
> > > Patch 0001:   Common lookup code for OF-graph or child
> > > 
> > > Patch 0002:   platform init flag via driver_data
> > > 
> > > Patch 0003/10:  bridge fixes, atomic API's
> > > 
> > > Patch 0011:   document fsl,imx8mm-mipi-dsim
> > > 
> > > Patch 0012:   add i.MX8MM DSIM support
> > > 
> > > Tested in Engicam i.Core MX8M Mini SoM.
> > > 
> > > Anyone interested, please have a look on this repo [2]
> > > 
> > > [2] https://github.com/openedev/kernel/tree/imx8mm-dsi-v2
> > > [1]
> > > https://patchwork.kernel.org/project/dri-devel/cover/20220408162108.1845
> > > 83-> 1-jagan@amarulasolutions.com/
> > > 
> > > Any inputs?
> > 
> > I was able to get my LVDS display running using this driver and an LVDS
> > bridge. Actually my setup is similar to yours. My chain is like this:
> > MIPI-DSI -> sn65dsi83 -> LVDS panel
> > I noticed some things though:
> > My setup only works if I use less than 4 lanes. See [1]. When using 4
> > lanes
> > the image is flickering, but the content is "visible". Your DT has only 2
> > lanes configured, do you have the possibility to use 4 lanes? I have no
> > idea how to tackle this. It might be the DSIM side or the bridge side.
> > Apparently the downstream kernel from NXP supports 4 lanes, if I can trust
> > the config. I have no way to verify this though.
> 
> What is dsi_lvds_bridge node? have you added your dts changes on top
> of imx8mm-dsi-v2 branch I'm pointing it.

I cherry-picked your commits and applied them on (currently) next-20220504.
Maybe you missed the links at the end of my mail. The branch I am talking 
about is https://github.com/tq-steina/linux/commits/imx8mm-dsi-lvds
This includes your commits as well as my additions.

> I will check 4 lanes and let you know.

Great, thanks.

> > Another thing is I get the following warning
> > 
> > > sn65dsi83 2-002d: Unsupported LVDS bus format 0x100a, please check
> > > output
> > 
> > bridge driver. Falling back to SPWG24.
> 
> This couldn't be much affected but will fix it.
> 
> > This seems to be caused by a wrong bridge chain. Using commit 81e80429 at
> > [2]> 
> > I get the following output:
> > > bridge chain: /soc@0/bus@30800000/i2c@30a40000/dsi-lvds-bridge@2d -> /
> > 
> > panel_lvds0 -> /soc@0/bus@32c00000/dsi@32e10000 ->
> > Which seems weird. I would have expected something like
> > dsi@32e10000 -> dsi-lvds-bridge@2d -> panel_lvds0
> > Do you happen to see somthing similar? But this is completely unrelated to
> > your patchset though.
> 
> Can you share the link to the exact commit?

This is the commit introducing this output:
https://github.com/tq-steina/linux/commit/
81e80429341cd0a4f119ec9cf50839498915443b

Best regards,
Alexander
Alexander Stein May 5, 2022, 11:55 a.m. UTC | #4
Am Donnerstag, 5. Mai 2022, 09:38:48 CEST schrieb Jagan Teki:
> On Thu, May 5, 2022 at 12:57 PM Alexander Stein
> 
> <alexander.stein@ew.tq-group.com> wrote:
> > Hello Jagan,
> > 
> > thanks for the second version of this patchset.
> > 
> > Am Mittwoch, 4. Mai 2022, 13:40:09 CEST schrieb Jagan Teki:
> > > This series supports common bridge support for Samsung MIPI DSIM
> > > which is used in Exynos and i.MX8MM SoC's.
> > > 
> > > Previous v1 can be available here [1].
> > > 
> > > The final bridge supports both the Exynos and i.MX8MM DSI devices.
> > > 
> > > On, summary this patch-set break the entire DSIM driver into
> > > - platform specific glue code for platform ops, component_ops.
> > > - common bridge driver which handle platform glue init and invoke.
> > > 
> > > Patch 0000:   Samsung DSIM bridge
> > > 
> > > Patch 0001:   Common lookup code for OF-graph or child
> > > 
> > > Patch 0002:   platform init flag via driver_data
> > > 
> > > Patch 0003/10:  bridge fixes, atomic API's
> > > 
> > > Patch 0011:   document fsl,imx8mm-mipi-dsim
> > > 
> > > Patch 0012:   add i.MX8MM DSIM support
> > > 
> > > Tested in Engicam i.Core MX8M Mini SoM.
> > > 
> > > Anyone interested, please have a look on this repo [2]
> > > 
> > > [2] https://github.com/openedev/kernel/tree/imx8mm-dsi-v2
> > > [1]
> > > https://patchwork.kernel.org/project/dri-devel/cover/20220408162108.1845
> > > 83-> 1-jagan@amarulasolutions.com/
> > > 
> > > Any inputs?
> > 
> > I was able to get my LVDS display running using this driver and an LVDS
> > bridge. Actually my setup is similar to yours. My chain is like this:
> > MIPI-DSI -> sn65dsi83 -> LVDS panel
> > I noticed some things though:
> > My setup only works if I use less than 4 lanes. See [1]. When using 4
> > lanes
> > the image is flickering, but the content is "visible". Your DT has only 2
> > lanes configured, do you have the possibility to use 4 lanes? I have no
> > idea how to tackle this. It might be the DSIM side or the bridge side.
> > Apparently the downstream kernel from NXP supports 4 lanes, if I can trust
> > the config. I have no way to verify this though.
> 
> What is dsi_lvds_bridge node? have you added your dts changes on top
> of imx8mm-dsi-v2 branch I'm pointing it.
> 
> I will check 4 lanes and let you know.
> 
> > Another thing is I get the following warning
> > 
> > > sn65dsi83 2-002d: Unsupported LVDS bus format 0x100a, please check
> > > output
> > 
> > bridge driver. Falling back to SPWG24.
> 
> This couldn't be much affected but will fix it.

I found the cause. You need the following diff:
----8<-----
diff --git a/drivers/gpu/drm/bridge/samsung-dsim.c b/drivers/gpu/drm/bridge/
samsung-dsim.c
index 138323dec0eb..7fb96dc7bb2e 100644
--- a/drivers/gpu/drm/bridge/samsung-dsim.c
+++ b/drivers/gpu/drm/bridge/samsung-dsim.c
@@ -1427,7 +1427,7 @@ static int samsung_dsim_attach(struct drm_bridge 
*bridge,
 {
        struct samsung_dsim *dsi = bridge_to_dsi(bridge);
 
-       return drm_bridge_attach(bridge->encoder, dsi->out_bridge, NULL, 
flags);
+       return drm_bridge_attach(bridge->encoder, dsi->out_bridge, bridge, 
flags);
 }
 
 static const struct drm_bridge_funcs samsung_dsim_bridge_funcs = {
----8<-----

Best regards,
Alexander
Marek Szyprowski May 6, 2022, 8:57 a.m. UTC | #5
Hi Alexander,

On 05.05.2022 13:55, Alexander Stein wrote:
> Am Donnerstag, 5. Mai 2022, 09:38:48 CEST schrieb Jagan Teki:
>> On Thu, May 5, 2022 at 12:57 PM Alexander Stein
>>
>> <alexander.stein@ew.tq-group.com> wrote:
>>> Hello Jagan,
>>>
>>> thanks for the second version of this patchset.
>>>
>>> Am Mittwoch, 4. Mai 2022, 13:40:09 CEST schrieb Jagan Teki:
>>>> This series supports common bridge support for Samsung MIPI DSIM
>>>> which is used in Exynos and i.MX8MM SoC's.
>>>>
>>>> Previous v1 can be available here [1].
>>>>
>>>> The final bridge supports both the Exynos and i.MX8MM DSI devices.
>>>>
>>>> On, summary this patch-set break the entire DSIM driver into
>>>> - platform specific glue code for platform ops, component_ops.
>>>> - common bridge driver which handle platform glue init and invoke.
>>>>
>>>> Patch 0000:   Samsung DSIM bridge
>>>>
>>>> Patch 0001:   Common lookup code for OF-graph or child
>>>>
>>>> Patch 0002:   platform init flag via driver_data
>>>>
>>>> Patch 0003/10:  bridge fixes, atomic API's
>>>>
>>>> Patch 0011:   document fsl,imx8mm-mipi-dsim
>>>>
>>>> Patch 0012:   add i.MX8MM DSIM support
>>>>
>>>> Tested in Engicam i.Core MX8M Mini SoM.
>>>>
>>>> Anyone interested, please have a look on this repo [2]
>>>>
>>>> [2] https://protect2.fireeye.com/v1/url?k=569d5207-09066afa-569cd948-000babff317b-7f7572918a36c54e&q=1&e=1305c5cc-33c8-467e-a498-6862a854cf94&u=https%3A%2F%2Fgithub.com%2Fopenedev%2Fkernel%2Ftree%2Fimx8mm-dsi-v2
>>>> [1]
>>>> https://patchwork.kernel.org/project/dri-devel/cover/20220408162108.1845
>>>> 83-> 1-jagan@amarulasolutions.com/
>>>>
>>>> Any inputs?
>>> I was able to get my LVDS display running using this driver and an LVDS
>>> bridge. Actually my setup is similar to yours. My chain is like this:
>>> MIPI-DSI -> sn65dsi83 -> LVDS panel
>>> I noticed some things though:
>>> My setup only works if I use less than 4 lanes. See [1]. When using 4
>>> lanes
>>> the image is flickering, but the content is "visible". Your DT has only 2
>>> lanes configured, do you have the possibility to use 4 lanes? I have no
>>> idea how to tackle this. It might be the DSIM side or the bridge side.
>>> Apparently the downstream kernel from NXP supports 4 lanes, if I can trust
>>> the config. I have no way to verify this though.
>> What is dsi_lvds_bridge node? have you added your dts changes on top
>> of imx8mm-dsi-v2 branch I'm pointing it.
>>
>> I will check 4 lanes and let you know.
>>
>>> Another thing is I get the following warning
>>>
>>>> sn65dsi83 2-002d: Unsupported LVDS bus format 0x100a, please check
>>>> output
>>> bridge driver. Falling back to SPWG24.
>> This couldn't be much affected but will fix it.
> I found the cause. You need the following diff:
> ----8<-----
> diff --git a/drivers/gpu/drm/bridge/samsung-dsim.c b/drivers/gpu/drm/bridge/
> samsung-dsim.c
> index 138323dec0eb..7fb96dc7bb2e 100644
> --- a/drivers/gpu/drm/bridge/samsung-dsim.c
> +++ b/drivers/gpu/drm/bridge/samsung-dsim.c
> @@ -1427,7 +1427,7 @@ static int samsung_dsim_attach(struct drm_bridge
> *bridge,
>   {
>          struct samsung_dsim *dsi = bridge_to_dsi(bridge);
>   
> -       return drm_bridge_attach(bridge->encoder, dsi->out_bridge, NULL,
> flags);
> +       return drm_bridge_attach(bridge->encoder, dsi->out_bridge, bridge,
> flags);
>   }
>   
>   static const struct drm_bridge_funcs samsung_dsim_bridge_funcs = {
> ----8<-----

Well, basically, the above change breaks DSI panels. :(

I've spent another evening playing with that code and I have some more 
thoughts...

I agree that logically this should be like you pointed. However the the 
code has been hacked in such a way, that it forces a proper order of 
pre-enable operations of the DSI and the client (panel, next bridge). 
This works somehow with a chain of 2 entities (Trats board: DSI and a 
panel) or even 3 entities (Arndale board: DSI, TC358764 bridge, panel), 
but probably it fails in your case.

I really have no clue how to fix this mess. It has been pointed many 
times that this insane per-order call chain of the pre_enable() 
operations is completely useless for the DSI hardware and noone pointed 
how to solve this. Exynos DSI (and VC4) called those operations directly 
to achieve proper order. So what happened? Now Exynos DSI got converted 
to the generic bridge call chain. To get it working with existing hw, 
the order of the bridges has been hacked. Probably in the next few 
releases more mess will come to get around this known issue, especially 
when support for the next set of imx boards is added.

I'm really open to help fixing this issue. I've spent a lot of time 
analyzing this code and I have boards to test. Just please give me some 
advice how to avoid this reverse-order call chain of the pre_enable() 
operations in the widely accepted, non-hacky way.


Best regards
Alexander Stein May 6, 2022, 10:38 a.m. UTC | #6
Hi Marek,

Am Freitag, 6. Mai 2022, 10:57:05 CEST schrieb Marek Szyprowski:
> Hi Alexander,
> 
> On 05.05.2022 13:55, Alexander Stein wrote:
> > Am Donnerstag, 5. Mai 2022, 09:38:48 CEST schrieb Jagan Teki:
> >> On Thu, May 5, 2022 at 12:57 PM Alexander Stein
> >> 
> >> <alexander.stein@ew.tq-group.com> wrote:
> >>> Hello Jagan,
> >>> 
> >>> thanks for the second version of this patchset.
> >>> 
> >>> Am Mittwoch, 4. Mai 2022, 13:40:09 CEST schrieb Jagan Teki:
> >>>> This series supports common bridge support for Samsung MIPI DSIM
> >>>> which is used in Exynos and i.MX8MM SoC's.
> >>>> 
> >>>> Previous v1 can be available here [1].
> >>>> 
> >>>> The final bridge supports both the Exynos and i.MX8MM DSI devices.
> >>>> 
> >>>> On, summary this patch-set break the entire DSIM driver into
> >>>> - platform specific glue code for platform ops, component_ops.
> >>>> - common bridge driver which handle platform glue init and invoke.
> >>>> 
> >>>> Patch 0000:   Samsung DSIM bridge
> >>>> 
> >>>> Patch 0001:   Common lookup code for OF-graph or child
> >>>> 
> >>>> Patch 0002:   platform init flag via driver_data
> >>>> 
> >>>> Patch 0003/10:  bridge fixes, atomic API's
> >>>> 
> >>>> Patch 0011:   document fsl,imx8mm-mipi-dsim
> >>>> 
> >>>> Patch 0012:   add i.MX8MM DSIM support
> >>>> 
> >>>> Tested in Engicam i.Core MX8M Mini SoM.
> >>>> 
> >>>> Anyone interested, please have a look on this repo [2]
> >>>> 
> >>>> [2]
> >>>> https://protect2.fireeye.com/v1/url?k=569d5207-09066afa-569cd948-000ba
> >>>> bff317b-7f7572918a36c54e&q=1&e=1305c5cc-33c8-467e-a498-6862a854cf94&u=h
> >>>> ttps%3A%2F%2Fgithub.com%2Fopenedev%2Fkernel%2Ftree%2Fimx8mm-dsi-v2 [1]
> >>>> https://patchwork.kernel.org/project/dri-devel/cover/20220408162108.184
> >>>> 5
> >>>> 83-> 1-jagan@amarulasolutions.com/
> >>>> 
> >>>> Any inputs?
> >>> 
> >>> I was able to get my LVDS display running using this driver and an LVDS
> >>> bridge. Actually my setup is similar to yours. My chain is like this:
> >>> MIPI-DSI -> sn65dsi83 -> LVDS panel
> >>> I noticed some things though:
> >>> My setup only works if I use less than 4 lanes. See [1]. When using 4
> >>> lanes
> >>> the image is flickering, but the content is "visible". Your DT has only
> >>> 2
> >>> lanes configured, do you have the possibility to use 4 lanes? I have no
> >>> idea how to tackle this. It might be the DSIM side or the bridge side.
> >>> Apparently the downstream kernel from NXP supports 4 lanes, if I can
> >>> trust
> >>> the config. I have no way to verify this though.
> >> 
> >> What is dsi_lvds_bridge node? have you added your dts changes on top
> >> of imx8mm-dsi-v2 branch I'm pointing it.
> >> 
> >> I will check 4 lanes and let you know.
> >> 
> >>> Another thing is I get the following warning
> >>> 
> >>>> sn65dsi83 2-002d: Unsupported LVDS bus format 0x100a, please check
> >>>> output
> >>> 
> >>> bridge driver. Falling back to SPWG24.
> >> 
> >> This couldn't be much affected but will fix it.
> > 
> > I found the cause. You need the following diff:
> > ----8<-----
> > diff --git a/drivers/gpu/drm/bridge/samsung-dsim.c
> > b/drivers/gpu/drm/bridge/ samsung-dsim.c
> > index 138323dec0eb..7fb96dc7bb2e 100644
> > --- a/drivers/gpu/drm/bridge/samsung-dsim.c
> > +++ b/drivers/gpu/drm/bridge/samsung-dsim.c
> > @@ -1427,7 +1427,7 @@ static int samsung_dsim_attach(struct drm_bridge
> > *bridge,
> > 
> >   {
> >   
> >          struct samsung_dsim *dsi = bridge_to_dsi(bridge);
> > 
> > -       return drm_bridge_attach(bridge->encoder, dsi->out_bridge, NULL,
> > flags);
> > +       return drm_bridge_attach(bridge->encoder, dsi->out_bridge, bridge,
> > flags);
> > 
> >   }
> >   
> >   static const struct drm_bridge_funcs samsung_dsim_bridge_funcs = {
> > 
> > ----8<-----
> 
> Well, basically, the above change breaks DSI panels. :(

That's too bad :( I wonder why actually this breaks DSI setups. From my 
understanding, the diff above seems correct, even for DSI panels.
But I don't know a DSI setup in detail or the bridge/panel code involved or 
which part breaks with this change.

> I've spent another evening playing with that code and I have some more
> thoughts...
> 
> I agree that logically this should be like you pointed. However the the
> code has been hacked in such a way, that it forces a proper order of
> pre-enable operations of the DSI and the client (panel, next bridge).
> This works somehow with a chain of 2 entities (Trats board: DSI and a
> panel) or even 3 entities (Arndale board: DSI, TC358764 bridge, panel),
> but probably it fails in your case.

Well, setting e.g. the bus format from panel -> bridge -> bridge ->... -> 
encoder seems sensible to me. It should be similar for both names setups as 
well. Essentially the Arndale is quite a similar setup to my and Jagan's one.
The actual reason it fails for me is that this list is created incorrectly, 
which should also be the case for Arndale.

> I really have no clue how to fix this mess. It has been pointed many
> times that this insane per-order call chain of the pre_enable()
> operations is completely useless for the DSI hardware and noone pointed
> how to solve this. Exynos DSI (and VC4) called those operations directly
> to achieve proper order. So what happened? Now Exynos DSI got converted
> to the generic bridge call chain. To get it working with existing hw,
> the order of the bridges has been hacked. Probably in the next few
> releases more mess will come to get around this known issue, especially
> when support for the next set of imx boards is added.
> 
> I'm really open to help fixing this issue. I've spent a lot of time
> analyzing this code and I have boards to test. Just please give me some
> advice how to avoid this reverse-order call chain of the pre_enable()
> operations in the widely accepted, non-hacky way.

In the first place I'm inclined to raise a warning in drm_bridge_attach() if 
previous is NULL and encoder->bridge_chain is not empty. This means that you 
are adding two "root"-bridges which seems wrong to me.

There is also some documentation regarding 'special care dsi' in drivers/gpu/
drm/drm_bridge.c. There is some distinction between a DSI host using 
components or not. But I have no knowledge about those components. 
That being said, I would assume that the Exynos conversion using a DRM bridge 
now might needs some additional changes.

Best regards,
Alexander
Dave Stevenson May 6, 2022, 10:50 a.m. UTC | #7
Hi Marek

On Fri, 6 May 2022 at 09:57, Marek Szyprowski <m.szyprowski@samsung.com> wrote:
>
> Hi Alexander,
>
> On 05.05.2022 13:55, Alexander Stein wrote:
> > Am Donnerstag, 5. Mai 2022, 09:38:48 CEST schrieb Jagan Teki:
> >> On Thu, May 5, 2022 at 12:57 PM Alexander Stein
> >>
> >> <alexander.stein@ew.tq-group.com> wrote:
> >>> Hello Jagan,
> >>>
> >>> thanks for the second version of this patchset.
> >>>
> >>> Am Mittwoch, 4. Mai 2022, 13:40:09 CEST schrieb Jagan Teki:
> >>>> This series supports common bridge support for Samsung MIPI DSIM
> >>>> which is used in Exynos and i.MX8MM SoC's.
> >>>>
> >>>> Previous v1 can be available here [1].
> >>>>
> >>>> The final bridge supports both the Exynos and i.MX8MM DSI devices.
> >>>>
> >>>> On, summary this patch-set break the entire DSIM driver into
> >>>> - platform specific glue code for platform ops, component_ops.
> >>>> - common bridge driver which handle platform glue init and invoke.
> >>>>
> >>>> Patch 0000:   Samsung DSIM bridge
> >>>>
> >>>> Patch 0001:   Common lookup code for OF-graph or child
> >>>>
> >>>> Patch 0002:   platform init flag via driver_data
> >>>>
> >>>> Patch 0003/10:  bridge fixes, atomic API's
> >>>>
> >>>> Patch 0011:   document fsl,imx8mm-mipi-dsim
> >>>>
> >>>> Patch 0012:   add i.MX8MM DSIM support
> >>>>
> >>>> Tested in Engicam i.Core MX8M Mini SoM.
> >>>>
> >>>> Anyone interested, please have a look on this repo [2]
> >>>>
> >>>> [2] https://protect2.fireeye.com/v1/url?k=569d5207-09066afa-569cd948-000babff317b-7f7572918a36c54e&q=1&e=1305c5cc-33c8-467e-a498-6862a854cf94&u=https%3A%2F%2Fgithub.com%2Fopenedev%2Fkernel%2Ftree%2Fimx8mm-dsi-v2
> >>>> [1]
> >>>> https://patchwork.kernel.org/project/dri-devel/cover/20220408162108.1845
> >>>> 83-> 1-jagan@amarulasolutions.com/
> >>>>
> >>>> Any inputs?
> >>> I was able to get my LVDS display running using this driver and an LVDS
> >>> bridge. Actually my setup is similar to yours. My chain is like this:
> >>> MIPI-DSI -> sn65dsi83 -> LVDS panel
> >>> I noticed some things though:
> >>> My setup only works if I use less than 4 lanes. See [1]. When using 4
> >>> lanes
> >>> the image is flickering, but the content is "visible". Your DT has only 2
> >>> lanes configured, do you have the possibility to use 4 lanes? I have no
> >>> idea how to tackle this. It might be the DSIM side or the bridge side.
> >>> Apparently the downstream kernel from NXP supports 4 lanes, if I can trust
> >>> the config. I have no way to verify this though.
> >> What is dsi_lvds_bridge node? have you added your dts changes on top
> >> of imx8mm-dsi-v2 branch I'm pointing it.
> >>
> >> I will check 4 lanes and let you know.
> >>
> >>> Another thing is I get the following warning
> >>>
> >>>> sn65dsi83 2-002d: Unsupported LVDS bus format 0x100a, please check
> >>>> output
> >>> bridge driver. Falling back to SPWG24.
> >> This couldn't be much affected but will fix it.
> > I found the cause. You need the following diff:
> > ----8<-----
> > diff --git a/drivers/gpu/drm/bridge/samsung-dsim.c b/drivers/gpu/drm/bridge/
> > samsung-dsim.c
> > index 138323dec0eb..7fb96dc7bb2e 100644
> > --- a/drivers/gpu/drm/bridge/samsung-dsim.c
> > +++ b/drivers/gpu/drm/bridge/samsung-dsim.c
> > @@ -1427,7 +1427,7 @@ static int samsung_dsim_attach(struct drm_bridge
> > *bridge,
> >   {
> >          struct samsung_dsim *dsi = bridge_to_dsi(bridge);
> >
> > -       return drm_bridge_attach(bridge->encoder, dsi->out_bridge, NULL,
> > flags);
> > +       return drm_bridge_attach(bridge->encoder, dsi->out_bridge, bridge,
> > flags);
> >   }
> >
> >   static const struct drm_bridge_funcs samsung_dsim_bridge_funcs = {
> > ----8<-----
>
> Well, basically, the above change breaks DSI panels. :(
>
> I've spent another evening playing with that code and I have some more
> thoughts...
>
> I agree that logically this should be like you pointed. However the the
> code has been hacked in such a way, that it forces a proper order of
> pre-enable operations of the DSI and the client (panel, next bridge).
> This works somehow with a chain of 2 entities (Trats board: DSI and a
> panel) or even 3 entities (Arndale board: DSI, TC358764 bridge, panel),
> but probably it fails in your case.
>
> I really have no clue how to fix this mess. It has been pointed many
> times that this insane per-order call chain of the pre_enable()
> operations is completely useless for the DSI hardware and noone pointed
> how to solve this. Exynos DSI (and VC4) called those operations directly
> to achieve proper order. So what happened? Now Exynos DSI got converted
> to the generic bridge call chain. To get it working with existing hw,
> the order of the bridges has been hacked. Probably in the next few
> releases more mess will come to get around this known issue, especially
> when support for the next set of imx boards is added.
>
> I'm really open to help fixing this issue. I've spent a lot of time
> analyzing this code and I have boards to test. Just please give me some
> advice how to avoid this reverse-order call chain of the pre_enable()
> operations in the widely accepted, non-hacky way.

I sent [1] to try and offer a solution for DSI back in March, but no
one has responded to it at all. Care to review it?

As noted in the cover letter for that series, splitting the
bridge_chain (as Exynos and vc4 do) does not work with atomic
operations due to the bridges beyond the split never being added to
the state. That approach is a dead end, and I'm trying to move vc4
away from it. That's not possible until the framework issue is
resolved, unless you adopt the hack done by dw-mipi and msm to power
up the DSI host in mode_set.

Thanks.
  Dave

[1] https://patchwork.kernel.org/project/dri-devel/cover/cover.1646406653.git.dave.stevenson@raspberrypi.com/

> Best regards
> --
> Marek Szyprowski, PhD
> Samsung R&D Institute Poland
>
Marek Szyprowski May 9, 2022, 9 a.m. UTC | #8
Hi Dave,

On 06.05.2022 12:50, Dave Stevenson wrote:
> On Fri, 6 May 2022 at 09:57, Marek Szyprowski <m.szyprowski@samsung.com> wrote:
>> On 05.05.2022 13:55, Alexander Stein wrote:
>>> Am Donnerstag, 5. Mai 2022, 09:38:48 CEST schrieb Jagan Teki:
>>>> On Thu, May 5, 2022 at 12:57 PM Alexander Stein
>>>>
>>>> <alexander.stein@ew.tq-group.com> wrote:
>>>>> Hello Jagan,
>>>>>
>>>>> thanks for the second version of this patchset.
>>>>>
>>>>> Am Mittwoch, 4. Mai 2022, 13:40:09 CEST schrieb Jagan Teki:
>>>>>> This series supports common bridge support for Samsung MIPI DSIM
>>>>>> which is used in Exynos and i.MX8MM SoC's.
>>>>>>
>>>>>> Previous v1 can be available here [1].
>>>>>>
>>>>>> The final bridge supports both the Exynos and i.MX8MM DSI devices.
>>>>>>
>>>>>> On, summary this patch-set break the entire DSIM driver into
>>>>>> - platform specific glue code for platform ops, component_ops.
>>>>>> - common bridge driver which handle platform glue init and invoke.
>>>>>>
>>>>>> Patch 0000:   Samsung DSIM bridge
>>>>>>
>>>>>> Patch 0001:   Common lookup code for OF-graph or child
>>>>>>
>>>>>> Patch 0002:   platform init flag via driver_data
>>>>>>
>>>>>> Patch 0003/10:  bridge fixes, atomic API's
>>>>>>
>>>>>> Patch 0011:   document fsl,imx8mm-mipi-dsim
>>>>>>
>>>>>> Patch 0012:   add i.MX8MM DSIM support
>>>>>>
>>>>>> Tested in Engicam i.Core MX8M Mini SoM.
>>>>>>
>>>>>> Anyone interested, please have a look on this repo [2]
>>>>>>
>>>>>> [2] https://protect2.fireeye.com/v1/url?k=569d5207-09066afa-569cd948-000babff317b-7f7572918a36c54e&q=1&e=1305c5cc-33c8-467e-a498-6862a854cf94&u=https%3A%2F%2Fgithub.com%2Fopenedev%2Fkernel%2Ftree%2Fimx8mm-dsi-v2
>>>>>> [1]
>>>>>> https://patchwork.kernel.org/project/dri-devel/cover/20220408162108.1845
>>>>>> 83-> 1-jagan@amarulasolutions.com/
>>>>>>
>>>>>> Any inputs?
>>>>> I was able to get my LVDS display running using this driver and an LVDS
>>>>> bridge. Actually my setup is similar to yours. My chain is like this:
>>>>> MIPI-DSI -> sn65dsi83 -> LVDS panel
>>>>> I noticed some things though:
>>>>> My setup only works if I use less than 4 lanes. See [1]. When using 4
>>>>> lanes
>>>>> the image is flickering, but the content is "visible". Your DT has only 2
>>>>> lanes configured, do you have the possibility to use 4 lanes? I have no
>>>>> idea how to tackle this. It might be the DSIM side or the bridge side.
>>>>> Apparently the downstream kernel from NXP supports 4 lanes, if I can trust
>>>>> the config. I have no way to verify this though.
>>>> What is dsi_lvds_bridge node? have you added your dts changes on top
>>>> of imx8mm-dsi-v2 branch I'm pointing it.
>>>>
>>>> I will check 4 lanes and let you know.
>>>>
>>>>> Another thing is I get the following warning
>>>>>
>>>>>> sn65dsi83 2-002d: Unsupported LVDS bus format 0x100a, please check
>>>>>> output
>>>>> bridge driver. Falling back to SPWG24.
>>>> This couldn't be much affected but will fix it.
>>> I found the cause. You need the following diff:
>>> ----8<-----
>>> diff --git a/drivers/gpu/drm/bridge/samsung-dsim.c b/drivers/gpu/drm/bridge/
>>> samsung-dsim.c
>>> index 138323dec0eb..7fb96dc7bb2e 100644
>>> --- a/drivers/gpu/drm/bridge/samsung-dsim.c
>>> +++ b/drivers/gpu/drm/bridge/samsung-dsim.c
>>> @@ -1427,7 +1427,7 @@ static int samsung_dsim_attach(struct drm_bridge
>>> *bridge,
>>>    {
>>>           struct samsung_dsim *dsi = bridge_to_dsi(bridge);
>>>
>>> -       return drm_bridge_attach(bridge->encoder, dsi->out_bridge, NULL,
>>> flags);
>>> +       return drm_bridge_attach(bridge->encoder, dsi->out_bridge, bridge,
>>> flags);
>>>    }
>>>
>>>    static const struct drm_bridge_funcs samsung_dsim_bridge_funcs = {
>>> ----8<-----
>> Well, basically, the above change breaks DSI panels. :(
>>
>> I've spent another evening playing with that code and I have some more
>> thoughts...
>>
>> I agree that logically this should be like you pointed. However the the
>> code has been hacked in such a way, that it forces a proper order of
>> pre-enable operations of the DSI and the client (panel, next bridge).
>> This works somehow with a chain of 2 entities (Trats board: DSI and a
>> panel) or even 3 entities (Arndale board: DSI, TC358764 bridge, panel),
>> but probably it fails in your case.
>>
>> I really have no clue how to fix this mess. It has been pointed many
>> times that this insane per-order call chain of the pre_enable()
>> operations is completely useless for the DSI hardware and noone pointed
>> how to solve this. Exynos DSI (and VC4) called those operations directly
>> to achieve proper order. So what happened? Now Exynos DSI got converted
>> to the generic bridge call chain. To get it working with existing hw,
>> the order of the bridges has been hacked. Probably in the next few
>> releases more mess will come to get around this known issue, especially
>> when support for the next set of imx boards is added.
>>
>> I'm really open to help fixing this issue. I've spent a lot of time
>> analyzing this code and I have boards to test. Just please give me some
>> advice how to avoid this reverse-order call chain of the pre_enable()
>> operations in the widely accepted, non-hacky way.
> I sent [1] to try and offer a solution for DSI back in March, but no
> one has responded to it at all. Care to review it?

Thanks, I will post my comments there soon. It finally resolves all the 
issues I found with the Exynos DSI driver converted to DRM bridge.

> As noted in the cover letter for that series, splitting the
> bridge_chain (as Exynos and vc4 do) does not work with atomic
> operations due to the bridges beyond the split never being added to
> the state. That approach is a dead end, and I'm trying to move vc4
> away from it. That's not possible until the framework issue is
> resolved, unless you adopt the hack done by dw-mipi and msm to power
> up the DSI host in mode_set.

Well, it is the first time one has pointed me WHY moving the bridge 
chain management to DRM core is really needed and what are the drawbacks 
of the old approach! Thanks again!

Best regards
Marek Szyprowski May 9, 2022, 12:44 p.m. UTC | #9
On 04.05.2022 13:40, Jagan Teki wrote:
> Samsung MIPI DSIM controller is common DSI IP that can be used in various
> SoCs like Exynos, i.MX8M Mini/Nano.
>
> In order to access this DSI controller between various platform SoCs,
> the ideal way to incorporate this in the drm stack is via the drm bridge
> driver.
>
> This patch is trying to differentiate platform-specific and bridge driver
> code and keep maintaining the exynos_drm_dsi.c code as platform-specific
> glue code and samsung-dsim.c as a common bridge driver code.
>
> - Exynos specific glue code is exynos specific te_irq, host_attach, and
>    detach code along with conventional component_ops.
>
> - Samsung DSIM is a bridge driver which is common across all platforms and
>    the respective platform-specific glue will initialize at the end of the
>    probe. The platform-specific operations and other glue calls will invoke
>    on associate code areas.
>
> v2:
> * fixed exynos dsi driver conversion (Marek Szyprowski)
> * updated commit message
> * updated MAINTAINERS file
>
> v1:
> * Don't maintain component_ops in bridge driver
> * Don't maintain platform glue code in bridge driver
> * Add platform-specific glue code and make a common bridge
>
> Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
> Signed-off-by: Jagan Teki <jagan@amarulasolutions.com>
> ---
>   MAINTAINERS                             |    8 +
>   drivers/gpu/drm/bridge/Kconfig          |   12 +
>   drivers/gpu/drm/bridge/Makefile         |    1 +
>   drivers/gpu/drm/bridge/samsung-dsim.c   | 1687 ++++++++++++++++++++++
>   drivers/gpu/drm/exynos/Kconfig          |    1 +
>   drivers/gpu/drm/exynos/exynos_drm_dsi.c | 1724 +----------------------
>   include/drm/bridge/samsung-dsim.h       |   97 ++
>   7 files changed, 1869 insertions(+), 1661 deletions(-)
>   create mode 100644 drivers/gpu/drm/bridge/samsung-dsim.c
>   create mode 100644 include/drm/bridge/samsung-dsim.h

> ...

> -static int exynos_dsi_register_te_irq(struct exynos_dsi *dsi,
> -				      struct device *panel)
> +static int exynos_dsi_register_te_irq(struct exynos_dsi *dsi, struct device *panel)
>   {
> -	int ret;
> +	struct samsung_dsim *priv = dsi->priv;
>   	int te_gpio_irq;
> +	int ret;
> -	dsi->te_gpio = gpiod_get_optional(panel, "te", GPIOD_IN);
> -	if (!dsi->te_gpio) {
> -		return 0;
> -	} else if (IS_ERR(dsi->te_gpio)) {
> -		dev_err(dsi->dev, "gpio request failed with %ld\n",
> +	dsi->te_gpio = devm_gpiod_get_optional(priv->dev, "te", GPIOD_IN);
> +	if (IS_ERR(dsi->te_gpio)) {

The above change is basically a revert to the old broken code, which has 
been fixed by the following commits:

fedc89821990 drm/exynos: Search for TE-gpio in DSI panel's node
8e3fa9d841db drm/exynos: Don't fail if no TE-gpio is defined for DSI driver

Please update it to the current mainline state by removing the above change.

 > ...

Best regards
Marek Szyprowski May 11, 2022, 12:21 p.m. UTC | #10
On 04.05.2022 13:40, Jagan Teki wrote:
> Samsung MIPI DSIM controller is common DSI IP that can be used in various
> SoCs like Exynos, i.MX8M Mini/Nano.
>
> In order to access this DSI controller between various platform SoCs,
> the ideal way to incorporate this in the drm stack is via the drm bridge
> driver.
>
> This patch is trying to differentiate platform-specific and bridge driver
> code and keep maintaining the exynos_drm_dsi.c code as platform-specific
> glue code and samsung-dsim.c as a common bridge driver code.
>
> - Exynos specific glue code is exynos specific te_irq, host_attach, and
>    detach code along with conventional component_ops.
>
> - Samsung DSIM is a bridge driver which is common across all platforms and
>    the respective platform-specific glue will initialize at the end of the
>    probe. The platform-specific operations and other glue calls will invoke
>    on associate code areas.
>
> v2:
> * fixed exynos dsi driver conversion (Marek Szyprowski)
> * updated commit message
> * updated MAINTAINERS file
>
> v1:
> * Don't maintain component_ops in bridge driver
> * Don't maintain platform glue code in bridge driver
> * Add platform-specific glue code and make a common bridge
>
> Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
> Signed-off-by: Jagan Teki <jagan@amarulasolutions.com>
> ---
>   MAINTAINERS                             |    8 +
>   drivers/gpu/drm/bridge/Kconfig          |   12 +
>   drivers/gpu/drm/bridge/Makefile         |    1 +
>   drivers/gpu/drm/bridge/samsung-dsim.c   | 1687 ++++++++++++++++++++++
>   drivers/gpu/drm/exynos/Kconfig          |    1 +
>   drivers/gpu/drm/exynos/exynos_drm_dsi.c | 1724 +----------------------
>   include/drm/bridge/samsung-dsim.h       |   97 ++
>   7 files changed, 1869 insertions(+), 1661 deletions(-)
>   create mode 100644 drivers/gpu/drm/bridge/samsung-dsim.c
>   create mode 100644 include/drm/bridge/samsung-dsim.h
>
>
> diff --git a/drivers/gpu/drm/bridge/samsung-dsim.c b/drivers/gpu/drm/bridge/samsung-dsim.c
> new file mode 100644
> index 000000000000..7745902f3f1e
> --- /dev/null
> +++ b/drivers/gpu/drm/bridge/samsung-dsim.c
> @@ -0,0 +1,1687 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * Samsung MIPI DSIM bridge driver.
> + *
> + * Copyright (C) 2021 Amarula Solutions(India)
> + * Copyright (c) 2014 Samsung Electronics Co., Ltd
> + * Author: Jagan Teki <jagan@amarulasolutions.com>
> + *
> + * Based on exynos_drm_dsi from
> + * Tomasz Figa <t.figa@samsung.com>
> + */
> +
> +#include <asm/unaligned.h>
> +
> +#include <drm/bridge/samsung-dsim.h>
> +#include <drm/drm_panel.h>
> +#include <drm/drm_print.h>
> +
> +#include <linux/clk.h>
> +#include <linux/delay.h>
> +#include <linux/irq.h>
> +#include <linux/of_device.h>
> +#include <linux/phy/phy.h>
> +#include <linux/regulator/consumer.h>
> +
> +#include <video/mipi_display.h>
> +
> +/* returns true iff both arguments logically differs */
> +#define NEQV(a, b) (!(a) ^ !(b))
> +
> +/* DSIM_STATUS */
> +#define DSIM_STOP_STATE_DAT(x)		(((x) & 0xf) << 0)
> +#define DSIM_STOP_STATE_CLK		(1 << 8)
> +#define DSIM_TX_READY_HS_CLK		(1 << 10)
> +#define DSIM_PLL_STABLE			(1 << 31)
> +
> +/* DSIM_SWRST */
> +#define DSIM_FUNCRST			(1 << 16)
> +#define DSIM_SWRST			(1 << 0)
> +
> +/* DSIM_TIMEOUT */
> +#define DSIM_LPDR_TIMEOUT(x)		((x) << 0)
> +#define DSIM_BTA_TIMEOUT(x)		((x) << 16)
> +
> +/* DSIM_CLKCTRL */
> +#define DSIM_ESC_PRESCALER(x)		(((x) & 0xffff) << 0)
> +#define DSIM_ESC_PRESCALER_MASK		(0xffff << 0)
> +#define DSIM_LANE_ESC_CLK_EN_CLK	(1 << 19)
> +#define DSIM_LANE_ESC_CLK_EN_DATA(x)	(((x) & 0xf) << 20)
> +#define DSIM_LANE_ESC_CLK_EN_DATA_MASK	(0xf << 20)
> +#define DSIM_BYTE_CLKEN			(1 << 24)
> +#define DSIM_BYTE_CLK_SRC(x)		(((x) & 0x3) << 25)
> +#define DSIM_BYTE_CLK_SRC_MASK		(0x3 << 25)
> +#define DSIM_PLL_BYPASS			(1 << 27)
> +#define DSIM_ESC_CLKEN			(1 << 28)
> +#define DSIM_TX_REQUEST_HSCLK		(1 << 31)
> +
> +/* DSIM_CONFIG */
> +#define DSIM_LANE_EN_CLK		(1 << 0)
> +#define DSIM_LANE_EN(x)			(((x) & 0xf) << 1)
> +#define DSIM_NUM_OF_DATA_LANE(x)	(((x) & 0x3) << 5)
> +#define DSIM_SUB_PIX_FORMAT(x)		(((x) & 0x7) << 8)
> +#define DSIM_MAIN_PIX_FORMAT_MASK	(0x7 << 12)
> +#define DSIM_MAIN_PIX_FORMAT_RGB888	(0x7 << 12)
> +#define DSIM_MAIN_PIX_FORMAT_RGB666	(0x6 << 12)
> +#define DSIM_MAIN_PIX_FORMAT_RGB666_P	(0x5 << 12)
> +#define DSIM_MAIN_PIX_FORMAT_RGB565	(0x4 << 12)
> +#define DSIM_SUB_VC			(((x) & 0x3) << 16)
> +#define DSIM_MAIN_VC			(((x) & 0x3) << 18)
> +#define DSIM_HSA_MODE			(1 << 20)
> +#define DSIM_HBP_MODE			(1 << 21)
> +#define DSIM_HFP_MODE			(1 << 22)
> +#define DSIM_HSE_MODE			(1 << 23)
> +#define DSIM_AUTO_MODE			(1 << 24)
> +#define DSIM_VIDEO_MODE			(1 << 25)
> +#define DSIM_BURST_MODE			(1 << 26)
> +#define DSIM_SYNC_INFORM		(1 << 27)
> +#define DSIM_EOT_DISABLE		(1 << 28)
> +#define DSIM_MFLUSH_VS			(1 << 29)
> +/* This flag is valid only for exynos3250/3472/5260/5430 */
> +#define DSIM_CLKLANE_STOP		(1 << 30)
> +
> +/* DSIM_ESCMODE */
> +#define DSIM_TX_TRIGGER_RST		(1 << 4)
> +#define DSIM_TX_LPDT_LP			(1 << 6)
> +#define DSIM_CMD_LPDT_LP		(1 << 7)
> +#define DSIM_FORCE_BTA			(1 << 16)
> +#define DSIM_FORCE_STOP_STATE		(1 << 20)
> +#define DSIM_STOP_STATE_CNT(x)		(((x) & 0x7ff) << 21)
> +#define DSIM_STOP_STATE_CNT_MASK	(0x7ff << 21)
> +
> +/* DSIM_MDRESOL */
> +#define DSIM_MAIN_STAND_BY		(1 << 31)
> +#define DSIM_MAIN_VRESOL(x, num_bits)	(((x) & ((1 << (num_bits)) - 1)) << 16)
> +#define DSIM_MAIN_HRESOL(x, num_bits)	(((x) & ((1 << (num_bits)) - 1)) << 0)
> +
> +/* DSIM_MVPORCH */
> +#define DSIM_CMD_ALLOW(x)		((x) << 28)
> +#define DSIM_STABLE_VFP(x)		((x) << 16)
> +#define DSIM_MAIN_VBP(x)		((x) << 0)
> +#define DSIM_CMD_ALLOW_MASK		(0xf << 28)
> +#define DSIM_STABLE_VFP_MASK		(0x7ff << 16)
> +#define DSIM_MAIN_VBP_MASK		(0x7ff << 0)
> +
> +/* DSIM_MHPORCH */
> +#define DSIM_MAIN_HFP(x)		((x) << 16)
> +#define DSIM_MAIN_HBP(x)		((x) << 0)
> +#define DSIM_MAIN_HFP_MASK		((0xffff) << 16)
> +#define DSIM_MAIN_HBP_MASK		((0xffff) << 0)
> +
> +/* DSIM_MSYNC */
> +#define DSIM_MAIN_VSA(x)		((x) << 22)
> +#define DSIM_MAIN_HSA(x)		((x) << 0)
> +#define DSIM_MAIN_VSA_MASK		((0x3ff) << 22)
> +#define DSIM_MAIN_HSA_MASK		((0xffff) << 0)
> +
> +/* DSIM_SDRESOL */
> +#define DSIM_SUB_STANDY(x)		((x) << 31)
> +#define DSIM_SUB_VRESOL(x)		((x) << 16)
> +#define DSIM_SUB_HRESOL(x)		((x) << 0)
> +#define DSIM_SUB_STANDY_MASK		((0x1) << 31)
> +#define DSIM_SUB_VRESOL_MASK		((0x7ff) << 16)
> +#define DSIM_SUB_HRESOL_MASK		((0x7ff) << 0)
> +
> +/* DSIM_INTSRC */
> +#define DSIM_INT_PLL_STABLE		(1 << 31)
> +#define DSIM_INT_SW_RST_RELEASE		(1 << 30)
> +#define DSIM_INT_SFR_FIFO_EMPTY		(1 << 29)
> +#define DSIM_INT_SFR_HDR_FIFO_EMPTY	(1 << 28)
> +#define DSIM_INT_BTA			(1 << 25)
> +#define DSIM_INT_FRAME_DONE		(1 << 24)
> +#define DSIM_INT_RX_TIMEOUT		(1 << 21)
> +#define DSIM_INT_BTA_TIMEOUT		(1 << 20)
> +#define DSIM_INT_RX_DONE		(1 << 18)
> +#define DSIM_INT_RX_TE			(1 << 17)
> +#define DSIM_INT_RX_ACK			(1 << 16)
> +#define DSIM_INT_RX_ECC_ERR		(1 << 15)
> +#define DSIM_INT_RX_CRC_ERR		(1 << 14)
> +
> +/* DSIM_FIFOCTRL */
> +#define DSIM_RX_DATA_FULL		(1 << 25)
> +#define DSIM_RX_DATA_EMPTY		(1 << 24)
> +#define DSIM_SFR_HEADER_FULL		(1 << 23)
> +#define DSIM_SFR_HEADER_EMPTY		(1 << 22)
> +#define DSIM_SFR_PAYLOAD_FULL		(1 << 21)
> +#define DSIM_SFR_PAYLOAD_EMPTY		(1 << 20)
> +#define DSIM_I80_HEADER_FULL		(1 << 19)
> +#define DSIM_I80_HEADER_EMPTY		(1 << 18)
> +#define DSIM_I80_PAYLOAD_FULL		(1 << 17)
> +#define DSIM_I80_PAYLOAD_EMPTY		(1 << 16)
> +#define DSIM_SD_HEADER_FULL		(1 << 15)
> +#define DSIM_SD_HEADER_EMPTY		(1 << 14)
> +#define DSIM_SD_PAYLOAD_FULL		(1 << 13)
> +#define DSIM_SD_PAYLOAD_EMPTY		(1 << 12)
> +#define DSIM_MD_HEADER_FULL		(1 << 11)
> +#define DSIM_MD_HEADER_EMPTY		(1 << 10)
> +#define DSIM_MD_PAYLOAD_FULL		(1 << 9)
> +#define DSIM_MD_PAYLOAD_EMPTY		(1 << 8)
> +#define DSIM_RX_FIFO			(1 << 4)
> +#define DSIM_SFR_FIFO			(1 << 3)
> +#define DSIM_I80_FIFO			(1 << 2)
> +#define DSIM_SD_FIFO			(1 << 1)
> +#define DSIM_MD_FIFO			(1 << 0)
> +
> +/* DSIM_PHYACCHR */
> +#define DSIM_AFC_EN			(1 << 14)
> +#define DSIM_AFC_CTL(x)			(((x) & 0x7) << 5)
> +
> +/* DSIM_PLLCTRL */
> +#define DSIM_FREQ_BAND(x)		((x) << 24)
> +#define DSIM_PLL_EN			(1 << 23)
> +#define DSIM_PLL_P(x)			((x) << 13)
> +#define DSIM_PLL_M(x)			((x) << 4)
> +#define DSIM_PLL_S(x)			((x) << 1)
> +
> +/* DSIM_PHYCTRL */
> +#define DSIM_PHYCTRL_ULPS_EXIT(x)	(((x) & 0x1ff) << 0)
> +#define DSIM_PHYCTRL_B_DPHYCTL_VREG_LP	(1 << 30)
> +#define DSIM_PHYCTRL_B_DPHYCTL_SLEW_UP	(1 << 14)
> +
> +/* DSIM_PHYTIMING */
> +#define DSIM_PHYTIMING_LPX(x)		((x) << 8)
> +#define DSIM_PHYTIMING_HS_EXIT(x)	((x) << 0)
> +
> +/* DSIM_PHYTIMING1 */
> +#define DSIM_PHYTIMING1_CLK_PREPARE(x)	((x) << 24)
> +#define DSIM_PHYTIMING1_CLK_ZERO(x)	((x) << 16)
> +#define DSIM_PHYTIMING1_CLK_POST(x)	((x) << 8)
> +#define DSIM_PHYTIMING1_CLK_TRAIL(x)	((x) << 0)
> +
> +/* DSIM_PHYTIMING2 */
> +#define DSIM_PHYTIMING2_HS_PREPARE(x)	((x) << 16)
> +#define DSIM_PHYTIMING2_HS_ZERO(x)	((x) << 8)
> +#define DSIM_PHYTIMING2_HS_TRAIL(x)	((x) << 0)
> +
> +#define DSI_MAX_BUS_WIDTH		4
> +#define DSI_NUM_VIRTUAL_CHANNELS	4
> +#define DSI_TX_FIFO_SIZE		2048
> +#define DSI_RX_FIFO_SIZE		256
> +#define DSI_XFER_TIMEOUT_MS		100
> +#define DSI_RX_FIFO_EMPTY		0x30800002
> +
> +#define OLD_SCLK_MIPI_CLK_NAME		"pll_clk"
> +
> +static const char *const clk_names[5] = {
> +	"bus_clk",
> +	"sclk_mipi",
> +	"phyclk_mipidphy0_bitclkdiv8",
> +	"phyclk_mipidphy0_rxclkesc0",
> +	"sclk_rgb_vclk_to_dsim0"
> +};
> +
> +enum samsung_dsim_transfer_type {
> +	EXYNOS_DSI_TX,
> +	EXYNOS_DSI_RX,
> +};
> +
> +enum reg_idx {
> +	DSIM_STATUS_REG,	/* Status register */
> +	DSIM_SWRST_REG,		/* Software reset register */
> +	DSIM_CLKCTRL_REG,	/* Clock control register */
> +	DSIM_TIMEOUT_REG,	/* Time out register */
> +	DSIM_CONFIG_REG,	/* Configuration register */
> +	DSIM_ESCMODE_REG,	/* Escape mode register */
> +	DSIM_MDRESOL_REG,
> +	DSIM_MVPORCH_REG,	/* Main display Vporch register */
> +	DSIM_MHPORCH_REG,	/* Main display Hporch register */
> +	DSIM_MSYNC_REG,		/* Main display sync area register */
> +	DSIM_INTSRC_REG,	/* Interrupt source register */
> +	DSIM_INTMSK_REG,	/* Interrupt mask register */
> +	DSIM_PKTHDR_REG,	/* Packet Header FIFO register */
> +	DSIM_PAYLOAD_REG,	/* Payload FIFO register */
> +	DSIM_RXFIFO_REG,	/* Read FIFO register */
> +	DSIM_FIFOCTRL_REG,	/* FIFO status and control register */
> +	DSIM_PLLCTRL_REG,	/* PLL control register */
> +	DSIM_PHYCTRL_REG,
> +	DSIM_PHYTIMING_REG,
> +	DSIM_PHYTIMING1_REG,
> +	DSIM_PHYTIMING2_REG,
> +	NUM_REGS
> +};
> +
> +static const unsigned int exynos_reg_ofs[] = {
> +	[DSIM_STATUS_REG] =  0x00,
> +	[DSIM_SWRST_REG] =  0x04,
> +	[DSIM_CLKCTRL_REG] =  0x08,
> +	[DSIM_TIMEOUT_REG] =  0x0c,
> +	[DSIM_CONFIG_REG] =  0x10,
> +	[DSIM_ESCMODE_REG] =  0x14,
> +	[DSIM_MDRESOL_REG] =  0x18,
> +	[DSIM_MVPORCH_REG] =  0x1c,
> +	[DSIM_MHPORCH_REG] =  0x20,
> +	[DSIM_MSYNC_REG] =  0x24,
> +	[DSIM_INTSRC_REG] =  0x2c,
> +	[DSIM_INTMSK_REG] =  0x30,
> +	[DSIM_PKTHDR_REG] =  0x34,
> +	[DSIM_PAYLOAD_REG] =  0x38,
> +	[DSIM_RXFIFO_REG] =  0x3c,
> +	[DSIM_FIFOCTRL_REG] =  0x44,
> +	[DSIM_PLLCTRL_REG] =  0x4c,
> +	[DSIM_PHYCTRL_REG] =  0x5c,
> +	[DSIM_PHYTIMING_REG] =  0x64,
> +	[DSIM_PHYTIMING1_REG] =  0x68,
> +	[DSIM_PHYTIMING2_REG] =  0x6c,
> +};
> +
> +static const unsigned int exynos5433_reg_ofs[] = {
> +	[DSIM_STATUS_REG] = 0x04,
> +	[DSIM_SWRST_REG] = 0x0C,
> +	[DSIM_CLKCTRL_REG] = 0x10,
> +	[DSIM_TIMEOUT_REG] = 0x14,
> +	[DSIM_CONFIG_REG] = 0x18,
> +	[DSIM_ESCMODE_REG] = 0x1C,
> +	[DSIM_MDRESOL_REG] = 0x20,
> +	[DSIM_MVPORCH_REG] = 0x24,
> +	[DSIM_MHPORCH_REG] = 0x28,
> +	[DSIM_MSYNC_REG] = 0x2C,
> +	[DSIM_INTSRC_REG] = 0x34,
> +	[DSIM_INTMSK_REG] = 0x38,
> +	[DSIM_PKTHDR_REG] = 0x3C,
> +	[DSIM_PAYLOAD_REG] = 0x40,
> +	[DSIM_RXFIFO_REG] = 0x44,
> +	[DSIM_FIFOCTRL_REG] = 0x4C,
> +	[DSIM_PLLCTRL_REG] = 0x94,
> +	[DSIM_PHYCTRL_REG] = 0xA4,
> +	[DSIM_PHYTIMING_REG] = 0xB4,
> +	[DSIM_PHYTIMING1_REG] = 0xB8,
> +	[DSIM_PHYTIMING2_REG] = 0xBC,
> +};
> +
> +enum reg_value_idx {
> +	RESET_TYPE,
> +	PLL_TIMER,
> +	STOP_STATE_CNT,
> +	PHYCTRL_ULPS_EXIT,
> +	PHYCTRL_VREG_LP,
> +	PHYCTRL_SLEW_UP,
> +	PHYTIMING_LPX,
> +	PHYTIMING_HS_EXIT,
> +	PHYTIMING_CLK_PREPARE,
> +	PHYTIMING_CLK_ZERO,
> +	PHYTIMING_CLK_POST,
> +	PHYTIMING_CLK_TRAIL,
> +	PHYTIMING_HS_PREPARE,
> +	PHYTIMING_HS_ZERO,
> +	PHYTIMING_HS_TRAIL
> +};
> +
> +static const unsigned int reg_values[] = {
> +	[RESET_TYPE] = DSIM_SWRST,
> +	[PLL_TIMER] = 500,
> +	[STOP_STATE_CNT] = 0xf,
> +	[PHYCTRL_ULPS_EXIT] = DSIM_PHYCTRL_ULPS_EXIT(0x0af),
> +	[PHYCTRL_VREG_LP] = 0,
> +	[PHYCTRL_SLEW_UP] = 0,
> +	[PHYTIMING_LPX] = DSIM_PHYTIMING_LPX(0x06),
> +	[PHYTIMING_HS_EXIT] = DSIM_PHYTIMING_HS_EXIT(0x0b),
> +	[PHYTIMING_CLK_PREPARE] = DSIM_PHYTIMING1_CLK_PREPARE(0x07),
> +	[PHYTIMING_CLK_ZERO] = DSIM_PHYTIMING1_CLK_ZERO(0x27),
> +	[PHYTIMING_CLK_POST] = DSIM_PHYTIMING1_CLK_POST(0x0d),
> +	[PHYTIMING_CLK_TRAIL] = DSIM_PHYTIMING1_CLK_TRAIL(0x08),
> +	[PHYTIMING_HS_PREPARE] = DSIM_PHYTIMING2_HS_PREPARE(0x09),
> +	[PHYTIMING_HS_ZERO] = DSIM_PHYTIMING2_HS_ZERO(0x0d),
> +	[PHYTIMING_HS_TRAIL] = DSIM_PHYTIMING2_HS_TRAIL(0x0b),
> +};
> +
> +static const unsigned int exynos5422_reg_values[] = {
> +	[RESET_TYPE] = DSIM_SWRST,
> +	[PLL_TIMER] = 500,
> +	[STOP_STATE_CNT] = 0xf,
> +	[PHYCTRL_ULPS_EXIT] = DSIM_PHYCTRL_ULPS_EXIT(0xaf),
> +	[PHYCTRL_VREG_LP] = 0,
> +	[PHYCTRL_SLEW_UP] = 0,
> +	[PHYTIMING_LPX] = DSIM_PHYTIMING_LPX(0x08),
> +	[PHYTIMING_HS_EXIT] = DSIM_PHYTIMING_HS_EXIT(0x0d),
> +	[PHYTIMING_CLK_PREPARE] = DSIM_PHYTIMING1_CLK_PREPARE(0x09),
> +	[PHYTIMING_CLK_ZERO] = DSIM_PHYTIMING1_CLK_ZERO(0x30),
> +	[PHYTIMING_CLK_POST] = DSIM_PHYTIMING1_CLK_POST(0x0e),
> +	[PHYTIMING_CLK_TRAIL] = DSIM_PHYTIMING1_CLK_TRAIL(0x0a),
> +	[PHYTIMING_HS_PREPARE] = DSIM_PHYTIMING2_HS_PREPARE(0x0c),
> +	[PHYTIMING_HS_ZERO] = DSIM_PHYTIMING2_HS_ZERO(0x11),
> +	[PHYTIMING_HS_TRAIL] = DSIM_PHYTIMING2_HS_TRAIL(0x0d),
> +};
> +
> +static const unsigned int exynos5433_reg_values[] = {
> +	[RESET_TYPE] = DSIM_FUNCRST,
> +	[PLL_TIMER] = 22200,
> +	[STOP_STATE_CNT] = 0xa,
> +	[PHYCTRL_ULPS_EXIT] = DSIM_PHYCTRL_ULPS_EXIT(0x190),
> +	[PHYCTRL_VREG_LP] = DSIM_PHYCTRL_B_DPHYCTL_VREG_LP,
> +	[PHYCTRL_SLEW_UP] = DSIM_PHYCTRL_B_DPHYCTL_SLEW_UP,
> +	[PHYTIMING_LPX] = DSIM_PHYTIMING_LPX(0x07),
> +	[PHYTIMING_HS_EXIT] = DSIM_PHYTIMING_HS_EXIT(0x0c),
> +	[PHYTIMING_CLK_PREPARE] = DSIM_PHYTIMING1_CLK_PREPARE(0x09),
> +	[PHYTIMING_CLK_ZERO] = DSIM_PHYTIMING1_CLK_ZERO(0x2d),
> +	[PHYTIMING_CLK_POST] = DSIM_PHYTIMING1_CLK_POST(0x0e),
> +	[PHYTIMING_CLK_TRAIL] = DSIM_PHYTIMING1_CLK_TRAIL(0x09),
> +	[PHYTIMING_HS_PREPARE] = DSIM_PHYTIMING2_HS_PREPARE(0x0b),
> +	[PHYTIMING_HS_ZERO] = DSIM_PHYTIMING2_HS_ZERO(0x10),
> +	[PHYTIMING_HS_TRAIL] = DSIM_PHYTIMING2_HS_TRAIL(0x0c),
> +};
> +
> +static const struct samsung_dsim_driver_data exynos3_dsi_driver_data = {
> +	.reg_ofs = exynos_reg_ofs,
> +	.plltmr_reg = 0x50,
> +	.has_freqband = 1,
> +	.has_clklane_stop = 1,
> +	.num_clks = 2,
> +	.max_freq = 1000,
> +	.wait_for_reset = 1,
> +	.num_bits_resol = 11,
> +	.reg_values = reg_values,
> +};
> +
> +static const struct samsung_dsim_driver_data exynos4_dsi_driver_data = {
> +	.reg_ofs = exynos_reg_ofs,
> +	.plltmr_reg = 0x50,
> +	.has_freqband = 1,
> +	.has_clklane_stop = 1,
> +	.num_clks = 2,
> +	.max_freq = 1000,
> +	.wait_for_reset = 1,
> +	.num_bits_resol = 11,
> +	.reg_values = reg_values,
> +};
> +
> +static const struct samsung_dsim_driver_data exynos5_dsi_driver_data = {
> +	.reg_ofs = exynos_reg_ofs,
> +	.plltmr_reg = 0x58,
> +	.num_clks = 2,
> +	.max_freq = 1000,
> +	.wait_for_reset = 1,
> +	.num_bits_resol = 11,
> +	.reg_values = reg_values,
> +};
> +
> +static const struct samsung_dsim_driver_data exynos5433_dsi_driver_data = {
> +	.reg_ofs = exynos5433_reg_ofs,
> +	.plltmr_reg = 0xa0,
> +	.has_clklane_stop = 1,
> +	.num_clks = 5,
> +	.max_freq = 1500,
> +	.wait_for_reset = 0,
> +	.num_bits_resol = 12,
> +	.reg_values = exynos5433_reg_values,
> +};
> +
> +static const struct samsung_dsim_driver_data exynos5422_dsi_driver_data = {
> +	.reg_ofs = exynos5433_reg_ofs,
> +	.plltmr_reg = 0xa0,
> +	.has_clklane_stop = 1,
> +	.num_clks = 2,
> +	.max_freq = 1500,
> +	.wait_for_reset = 1,
> +	.num_bits_resol = 12,
> +	.reg_values = exynos5422_reg_values,
> +};
> +
> +static const struct of_device_id samsung_dsim_of_match[] = {
> +	{
> +		.compatible = "samsung,exynos3250-mipi-dsi",
> +		.data = &exynos3_dsi_driver_data
> +	},
> +	{
> +		.compatible = "samsung,exynos4210-mipi-dsi",
> +		.data = &exynos4_dsi_driver_data
> +	},
> +	{
> +		.compatible = "samsung,exynos5410-mipi-dsi",
> +		.data = &exynos5_dsi_driver_data
> +	},
> +	{
> +		.compatible = "samsung,exynos5422-mipi-dsi",
> +		.data = &exynos5422_dsi_driver_data
> +	},
> +	{
> +		.compatible = "samsung,exynos5433-mipi-dsi",
> +		.data = &exynos5433_dsi_driver_data
> +	},
> +	{ /* sentinel. */ }
> +};
> +
> +static inline struct samsung_dsim *host_to_dsi(struct mipi_dsi_host *h)
> +{
> +	return container_of(h, struct samsung_dsim, dsi_host);
> +}
> +
> +static inline struct samsung_dsim *bridge_to_dsi(struct drm_bridge *b)
> +{
> +	return container_of(b, struct samsung_dsim, bridge);
> +}
> +
> +static inline void samsung_dsim_write(struct samsung_dsim *dsi,
> +				      enum reg_idx idx, u32 val)
> +{
> +	writel(val, dsi->reg_base + dsi->driver_data->reg_ofs[idx]);
> +}
> +
> +static inline u32 samsung_dsim_read(struct samsung_dsim *dsi, enum reg_idx idx)
> +{
> +	return readl(dsi->reg_base + dsi->driver_data->reg_ofs[idx]);
> +}
> +
> +static void samsung_dsim_wait_for_reset(struct samsung_dsim *dsi)
> +{
> +	if (wait_for_completion_timeout(&dsi->completed, msecs_to_jiffies(300)))
> +		return;
> +
> +	dev_err(dsi->dev, "timeout waiting for reset\n");
> +}
> +
> +static void samsung_dsim_reset(struct samsung_dsim *dsi)
> +{
> +	u32 reset_val = dsi->driver_data->reg_values[RESET_TYPE];
> +
> +	reinit_completion(&dsi->completed);
> +	samsung_dsim_write(dsi, DSIM_SWRST_REG, reset_val);
> +}
> +
> +#ifndef MHZ
> +#define MHZ	(1000*1000)
> +#endif
> +
> +static unsigned long samsung_dsim_pll_find_pms(struct samsung_dsim *dsi,
> +					       unsigned long fin,
> +					       unsigned long fout,
> +					       u8 *p, u16 *m, u8 *s)
> +{
> +	const struct samsung_dsim_driver_data *driver_data = dsi->driver_data;
> +	unsigned long best_freq = 0;
> +	u32 min_delta = 0xffffffff;
> +	u8 p_min, p_max;
> +	u8 _p, best_p;
> +	u16 _m, best_m;
> +	u8 _s, best_s;
> +
> +	p_min = DIV_ROUND_UP(fin, (12 * MHZ));
> +	p_max = fin / (6 * MHZ);
> +
> +	for (_p = p_min; _p <= p_max; ++_p) {
> +		for (_s = 0; _s <= 5; ++_s) {
> +			u64 tmp;
> +			u32 delta;
> +
> +			tmp = (u64)fout * (_p << _s);
> +			do_div(tmp, fin);
> +			_m = tmp;
> +			if (_m < 41 || _m > 125)
> +				continue;
> +
> +			tmp = (u64)_m * fin;
> +			do_div(tmp, _p);
> +			if (tmp < 500 * MHZ ||
> +					tmp > driver_data->max_freq * MHZ)
> +				continue;
> +
> +			tmp = (u64)_m * fin;
> +			do_div(tmp, _p << _s);
> +
> +			delta = abs(fout - tmp);
> +			if (delta < min_delta) {
> +				best_p = _p;
> +				best_m = _m;
> +				best_s = _s;
> +				min_delta = delta;
> +				best_freq = tmp;
> +			}
> +		}
> +	}
> +
> +	if (best_freq) {
> +		*p = best_p;
> +		*m = best_m;
> +		*s = best_s;
> +	}
> +
> +	return best_freq;
> +}
> +
> +static unsigned long samsung_dsim_set_pll(struct samsung_dsim *dsi,
> +					  unsigned long freq)
> +{
> +	const struct samsung_dsim_driver_data *driver_data = dsi->driver_data;
> +	unsigned long fin, fout;
> +	int timeout;
> +	u8 p, s;
> +	u16 m;
> +	u32 reg;
> +
> +	fin = dsi->pll_clk_rate;
> +	fout = samsung_dsim_pll_find_pms(dsi, fin, freq, &p, &m, &s);
> +	if (!fout) {
> +		dev_err(dsi->dev,
> +			"failed to find PLL PMS for requested frequency\n");
> +		return 0;
> +	}
> +	dev_dbg(dsi->dev, "PLL freq %lu, (p %d, m %d, s %d)\n", fout, p, m, s);
> +
> +	writel(driver_data->reg_values[PLL_TIMER],
> +			dsi->reg_base + driver_data->plltmr_reg);
> +
> +	reg = DSIM_PLL_EN | DSIM_PLL_P(p) | DSIM_PLL_M(m) | DSIM_PLL_S(s);
> +
> +	if (driver_data->has_freqband) {
> +		static const unsigned long freq_bands[] = {
> +			100 * MHZ, 120 * MHZ, 160 * MHZ, 200 * MHZ,
> +			270 * MHZ, 320 * MHZ, 390 * MHZ, 450 * MHZ,
> +			510 * MHZ, 560 * MHZ, 640 * MHZ, 690 * MHZ,
> +			770 * MHZ, 870 * MHZ, 950 * MHZ,
> +		};
> +		int band;
> +
> +		for (band = 0; band < ARRAY_SIZE(freq_bands); ++band)
> +			if (fout < freq_bands[band])
> +				break;
> +
> +		dev_dbg(dsi->dev, "band %d\n", band);
> +
> +		reg |= DSIM_FREQ_BAND(band);
> +	}
> +
> +	samsung_dsim_write(dsi, DSIM_PLLCTRL_REG, reg);
> +
> +	timeout = 1000;
> +	do {
> +		if (timeout-- == 0) {
> +			dev_err(dsi->dev, "PLL failed to stabilize\n");
> +			return 0;
> +		}
> +		reg = samsung_dsim_read(dsi, DSIM_STATUS_REG);
> +	} while ((reg & DSIM_PLL_STABLE) == 0);
> +
> +	return fout;
> +}
> +
> +static int samsung_dsim_enable_clock(struct samsung_dsim *dsi)
> +{
> +	unsigned long hs_clk, byte_clk, esc_clk;
> +	unsigned long esc_div;
> +	u32 reg;
> +
> +	hs_clk = samsung_dsim_set_pll(dsi, dsi->burst_clk_rate);
> +	if (!hs_clk) {
> +		dev_err(dsi->dev, "failed to configure DSI PLL\n");
> +		return -EFAULT;
> +	}
> +
> +	byte_clk = hs_clk / 8;
> +	esc_div = DIV_ROUND_UP(byte_clk, dsi->esc_clk_rate);
> +	esc_clk = byte_clk / esc_div;
> +
> +	if (esc_clk > 20 * MHZ) {
> +		++esc_div;
> +		esc_clk = byte_clk / esc_div;
> +	}
> +
> +	dev_dbg(dsi->dev, "hs_clk = %lu, byte_clk = %lu, esc_clk = %lu\n",
> +		hs_clk, byte_clk, esc_clk);
> +
> +	reg = samsung_dsim_read(dsi, DSIM_CLKCTRL_REG);
> +	reg &= ~(DSIM_ESC_PRESCALER_MASK | DSIM_LANE_ESC_CLK_EN_CLK
> +			| DSIM_LANE_ESC_CLK_EN_DATA_MASK | DSIM_PLL_BYPASS
> +			| DSIM_BYTE_CLK_SRC_MASK);
> +	reg |= DSIM_ESC_CLKEN | DSIM_BYTE_CLKEN
> +			| DSIM_ESC_PRESCALER(esc_div)
> +			| DSIM_LANE_ESC_CLK_EN_CLK
> +			| DSIM_LANE_ESC_CLK_EN_DATA(BIT(dsi->lanes) - 1)
> +			| DSIM_BYTE_CLK_SRC(0)
> +			| DSIM_TX_REQUEST_HSCLK;
> +	samsung_dsim_write(dsi, DSIM_CLKCTRL_REG, reg);
> +
> +	return 0;
> +}
> +
> +static void samsung_dsim_set_phy_ctrl(struct samsung_dsim *dsi)
> +{
> +	const struct samsung_dsim_driver_data *driver_data = dsi->driver_data;
> +	const unsigned int *reg_values = driver_data->reg_values;
> +	u32 reg;
> +
> +	if (driver_data->has_freqband)
> +		return;
> +
> +	/* B D-PHY: D-PHY Master & Slave Analog Block control */
> +	reg = reg_values[PHYCTRL_ULPS_EXIT] | reg_values[PHYCTRL_VREG_LP] |
> +		reg_values[PHYCTRL_SLEW_UP];
> +	samsung_dsim_write(dsi, DSIM_PHYCTRL_REG, reg);
> +
> +	/*
> +	 * T LPX: Transmitted length of any Low-Power state period
> +	 * T HS-EXIT: Time that the transmitter drives LP-11 following a HS
> +	 *	burst
> +	 */
> +	reg = reg_values[PHYTIMING_LPX] | reg_values[PHYTIMING_HS_EXIT];
> +	samsung_dsim_write(dsi, DSIM_PHYTIMING_REG, reg);
> +
> +	/*
> +	 * T CLK-PREPARE: Time that the transmitter drives the Clock Lane LP-00
> +	 *	Line state immediately before the HS-0 Line state starting the
> +	 *	HS transmission
> +	 * T CLK-ZERO: Time that the transmitter drives the HS-0 state prior to
> +	 *	transmitting the Clock.
> +	 * T CLK_POST: Time that the transmitter continues to send HS clock
> +	 *	after the last associated Data Lane has transitioned to LP Mode
> +	 *	Interval is defined as the period from the end of T HS-TRAIL to
> +	 *	the beginning of T CLK-TRAIL
> +	 * T CLK-TRAIL: Time that the transmitter drives the HS-0 state after
> +	 *	the last payload clock bit of a HS transmission burst
> +	 */
> +	reg = reg_values[PHYTIMING_CLK_PREPARE] |
> +		reg_values[PHYTIMING_CLK_ZERO] |
> +		reg_values[PHYTIMING_CLK_POST] |
> +		reg_values[PHYTIMING_CLK_TRAIL];
> +
> +	samsung_dsim_write(dsi, DSIM_PHYTIMING1_REG, reg);
> +
> +	/*
> +	 * T HS-PREPARE: Time that the transmitter drives the Data Lane LP-00
> +	 *	Line state immediately before the HS-0 Line state starting the
> +	 *	HS transmission
> +	 * T HS-ZERO: Time that the transmitter drives the HS-0 state prior to
> +	 *	transmitting the Sync sequence.
> +	 * T HS-TRAIL: Time that the transmitter drives the flipped differential
> +	 *	state after last payload data bit of a HS transmission burst
> +	 */
> +	reg = reg_values[PHYTIMING_HS_PREPARE] | reg_values[PHYTIMING_HS_ZERO] |
> +		reg_values[PHYTIMING_HS_TRAIL];
> +	samsung_dsim_write(dsi, DSIM_PHYTIMING2_REG, reg);
> +}
> +
> +static void samsung_dsim_disable_clock(struct samsung_dsim *dsi)
> +{
> +	u32 reg;
> +
> +	reg = samsung_dsim_read(dsi, DSIM_CLKCTRL_REG);
> +	reg &= ~(DSIM_LANE_ESC_CLK_EN_CLK | DSIM_LANE_ESC_CLK_EN_DATA_MASK
> +			| DSIM_ESC_CLKEN | DSIM_BYTE_CLKEN);
> +	samsung_dsim_write(dsi, DSIM_CLKCTRL_REG, reg);
> +
> +	reg = samsung_dsim_read(dsi, DSIM_PLLCTRL_REG);
> +	reg &= ~DSIM_PLL_EN;
> +	samsung_dsim_write(dsi, DSIM_PLLCTRL_REG, reg);
> +}
> +
> +static void samsung_dsim_enable_lane(struct samsung_dsim *dsi, u32 lane)
> +{
> +	u32 reg = samsung_dsim_read(dsi, DSIM_CONFIG_REG);
> +
> +	reg |= (DSIM_NUM_OF_DATA_LANE(dsi->lanes - 1) | DSIM_LANE_EN_CLK |
> +			DSIM_LANE_EN(lane));
> +	samsung_dsim_write(dsi, DSIM_CONFIG_REG, reg);
> +}
> +
> +static int samsung_dsim_init_link(struct samsung_dsim *dsi)
> +{
> +	const struct samsung_dsim_driver_data *driver_data = dsi->driver_data;
> +	int timeout;
> +	u32 reg;
> +	u32 lanes_mask;
> +
> +	/* Initialize FIFO pointers */
> +	reg = samsung_dsim_read(dsi, DSIM_FIFOCTRL_REG);
> +	reg &= ~0x1f;
> +	samsung_dsim_write(dsi, DSIM_FIFOCTRL_REG, reg);
> +
> +	usleep_range(9000, 11000);
> +
> +	reg |= 0x1f;
> +	samsung_dsim_write(dsi, DSIM_FIFOCTRL_REG, reg);
> +	usleep_range(9000, 11000);
> +
> +	/* DSI configuration */
> +	reg = 0;
> +
> +	/*
> +	 * The first bit of mode_flags specifies display configuration.
> +	 * If this bit is set[= MIPI_DSI_MODE_VIDEO], dsi will support video
> +	 * mode, otherwise it will support command mode.
> +	 */
> +	if (dsi->mode_flags & MIPI_DSI_MODE_VIDEO) {
> +		reg |= DSIM_VIDEO_MODE;
> +
> +		/*
> +		 * The user manual describes that following bits are ignored in
> +		 * command mode.
> +		 */
> +		if (!(dsi->mode_flags & MIPI_DSI_MODE_VSYNC_FLUSH))
> +			reg |= DSIM_MFLUSH_VS;
> +		if (dsi->mode_flags & MIPI_DSI_MODE_VIDEO_SYNC_PULSE)
> +			reg |= DSIM_SYNC_INFORM;
> +		if (dsi->mode_flags & MIPI_DSI_MODE_VIDEO_BURST)
> +			reg |= DSIM_BURST_MODE;
> +		if (dsi->mode_flags & MIPI_DSI_MODE_VIDEO_AUTO_VERT)
> +			reg |= DSIM_AUTO_MODE;
> +		if (dsi->mode_flags & MIPI_DSI_MODE_VIDEO_HSE)
> +			reg |= DSIM_HSE_MODE;
> +		if (!(dsi->mode_flags & MIPI_DSI_MODE_VIDEO_NO_HFP))
> +			reg |= DSIM_HFP_MODE;
> +		if (!(dsi->mode_flags & MIPI_DSI_MODE_VIDEO_NO_HBP))
> +			reg |= DSIM_HBP_MODE;
> +		if (!(dsi->mode_flags & MIPI_DSI_MODE_VIDEO_NO_HSA))
> +			reg |= DSIM_HSA_MODE;
> +	}
> +
> +	if (!(dsi->mode_flags & MIPI_DSI_MODE_NO_EOT_PACKET))
> +		reg |= DSIM_EOT_DISABLE;
> +
> +	switch (dsi->format) {
> +	case MIPI_DSI_FMT_RGB888:
> +		reg |= DSIM_MAIN_PIX_FORMAT_RGB888;
> +		break;
> +	case MIPI_DSI_FMT_RGB666:
> +		reg |= DSIM_MAIN_PIX_FORMAT_RGB666;
> +		break;
> +	case MIPI_DSI_FMT_RGB666_PACKED:
> +		reg |= DSIM_MAIN_PIX_FORMAT_RGB666_P;
> +		break;
> +	case MIPI_DSI_FMT_RGB565:
> +		reg |= DSIM_MAIN_PIX_FORMAT_RGB565;
> +		break;
> +	default:
> +		dev_err(dsi->dev, "invalid pixel format\n");
> +		return -EINVAL;
> +	}
> +
> +	/*
> +	 * Use non-continuous clock mode if the periparal wants and
> +	 * host controller supports
> +	 *
> +	 * In non-continous clock mode, host controller will turn off
> +	 * the HS clock between high-speed transmissions to reduce
> +	 * power consumption.
> +	 */
> +	if (driver_data->has_clklane_stop &&
> +			dsi->mode_flags & MIPI_DSI_CLOCK_NON_CONTINUOUS) {
> +		reg |= DSIM_CLKLANE_STOP;
> +	}
> +	samsung_dsim_write(dsi, DSIM_CONFIG_REG, reg);
> +
> +	lanes_mask = BIT(dsi->lanes) - 1;
> +	samsung_dsim_enable_lane(dsi, lanes_mask);
> +
> +	/* Check clock and data lane state are stop state */
> +	timeout = 100;
> +	do {
> +		if (timeout-- == 0) {
> +			dev_err(dsi->dev, "waiting for bus lanes timed out\n");
> +			return -EFAULT;
> +		}
> +
> +		reg = samsung_dsim_read(dsi, DSIM_STATUS_REG);
> +		if ((reg & DSIM_STOP_STATE_DAT(lanes_mask))
> +		    != DSIM_STOP_STATE_DAT(lanes_mask))
> +			continue;
> +	} while (!(reg & (DSIM_STOP_STATE_CLK | DSIM_TX_READY_HS_CLK)));
> +
> +	reg = samsung_dsim_read(dsi, DSIM_ESCMODE_REG);
> +	reg &= ~DSIM_STOP_STATE_CNT_MASK;
> +	reg |= DSIM_STOP_STATE_CNT(driver_data->reg_values[STOP_STATE_CNT]);
> +	samsung_dsim_write(dsi, DSIM_ESCMODE_REG, reg);
> +
> +	reg = DSIM_BTA_TIMEOUT(0xff) | DSIM_LPDR_TIMEOUT(0xffff);
> +	samsung_dsim_write(dsi, DSIM_TIMEOUT_REG, reg);
> +
> +	return 0;
> +}
> +
> +static void samsung_dsim_set_display_mode(struct samsung_dsim *dsi)
> +{
> +	struct drm_display_mode *m = &dsi->mode;
> +	unsigned int num_bits_resol = dsi->driver_data->num_bits_resol;
> +	u32 reg;
> +
> +	if (dsi->mode_flags & MIPI_DSI_MODE_VIDEO) {
> +		reg = DSIM_CMD_ALLOW(0xf)
> +			| DSIM_STABLE_VFP(m->vsync_start - m->vdisplay)
> +			| DSIM_MAIN_VBP(m->vtotal - m->vsync_end);
> +		samsung_dsim_write(dsi, DSIM_MVPORCH_REG, reg);
> +
> +		reg = DSIM_MAIN_HFP(m->hsync_start - m->hdisplay)
> +			| DSIM_MAIN_HBP(m->htotal - m->hsync_end);
> +		samsung_dsim_write(dsi, DSIM_MHPORCH_REG, reg);
> +
> +		reg = DSIM_MAIN_VSA(m->vsync_end - m->vsync_start)
> +			| DSIM_MAIN_HSA(m->hsync_end - m->hsync_start);
> +		samsung_dsim_write(dsi, DSIM_MSYNC_REG, reg);
> +	}
> +	reg =  DSIM_MAIN_HRESOL(m->hdisplay, num_bits_resol) |
> +		DSIM_MAIN_VRESOL(m->vdisplay, num_bits_resol);
> +
> +	samsung_dsim_write(dsi, DSIM_MDRESOL_REG, reg);
> +
> +	dev_dbg(dsi->dev, "LCD size = %dx%d\n", m->hdisplay, m->vdisplay);
> +}
> +
> +static void samsung_dsim_set_display_enable(struct samsung_dsim *dsi, bool enable)
> +{
> +	u32 reg;
> +
> +	reg = samsung_dsim_read(dsi, DSIM_MDRESOL_REG);
> +	if (enable)
> +		reg |= DSIM_MAIN_STAND_BY;
> +	else
> +		reg &= ~DSIM_MAIN_STAND_BY;
> +	samsung_dsim_write(dsi, DSIM_MDRESOL_REG, reg);
> +}
> +
> +static int samsung_dsim_wait_for_hdr_fifo(struct samsung_dsim *dsi)
> +{
> +	int timeout = 2000;
> +
> +	do {
> +		u32 reg = samsung_dsim_read(dsi, DSIM_FIFOCTRL_REG);
> +
> +		if (!(reg & DSIM_SFR_HEADER_FULL))
> +			return 0;
> +
> +		if (!cond_resched())
> +			usleep_range(950, 1050);
> +	} while (--timeout);
> +
> +	return -ETIMEDOUT;
> +}
> +
> +static void samsung_dsim_set_cmd_lpm(struct samsung_dsim *dsi, bool lpm)
> +{
> +	u32 v = samsung_dsim_read(dsi, DSIM_ESCMODE_REG);
> +
> +	if (lpm)
> +		v |= DSIM_CMD_LPDT_LP;
> +	else
> +		v &= ~DSIM_CMD_LPDT_LP;
> +
> +	samsung_dsim_write(dsi, DSIM_ESCMODE_REG, v);
> +}
> +
> +static void samsung_dsim_force_bta(struct samsung_dsim *dsi)
> +{
> +	u32 v = samsung_dsim_read(dsi, DSIM_ESCMODE_REG);
> +
> +	v |= DSIM_FORCE_BTA;
> +	samsung_dsim_write(dsi, DSIM_ESCMODE_REG, v);
> +}
> +
> +static void samsung_dsim_send_to_fifo(struct samsung_dsim *dsi,
> +				      struct samsung_dsim_transfer *xfer)
> +{
> +	struct device *dev = dsi->dev;
> +	struct mipi_dsi_packet *pkt = &xfer->packet;
> +	const u8 *payload = pkt->payload + xfer->tx_done;
> +	u16 length = pkt->payload_length - xfer->tx_done;
> +	bool first = !xfer->tx_done;
> +	u32 reg;
> +
> +	dev_dbg(dev, "< xfer %pK: tx len %u, done %u, rx len %u, done %u\n",
> +		xfer, length, xfer->tx_done, xfer->rx_len, xfer->rx_done);
> +
> +	if (length > DSI_TX_FIFO_SIZE)
> +		length = DSI_TX_FIFO_SIZE;
> +
> +	xfer->tx_done += length;
> +
> +	/* Send payload */
> +	while (length >= 4) {
> +		reg = get_unaligned_le32(payload);
> +		samsung_dsim_write(dsi, DSIM_PAYLOAD_REG, reg);
> +		payload += 4;
> +		length -= 4;
> +	}
> +
> +	reg = 0;
> +	switch (length) {
> +	case 3:
> +		reg |= payload[2] << 16;
> +		fallthrough;
> +	case 2:
> +		reg |= payload[1] << 8;
> +		fallthrough;
> +	case 1:
> +		reg |= payload[0];
> +		samsung_dsim_write(dsi, DSIM_PAYLOAD_REG, reg);
> +		break;
> +	}
> +
> +	/* Send packet header */
> +	if (!first)
> +		return;
> +
> +	reg = get_unaligned_le32(pkt->header);
> +	if (samsung_dsim_wait_for_hdr_fifo(dsi)) {
> +		dev_err(dev, "waiting for header FIFO timed out\n");
> +		return;
> +	}
> +
> +	if (NEQV(xfer->flags & MIPI_DSI_MSG_USE_LPM,
> +		 dsi->state & DSIM_STATE_CMD_LPM)) {
> +		samsung_dsim_set_cmd_lpm(dsi, xfer->flags & MIPI_DSI_MSG_USE_LPM);
> +		dsi->state ^= DSIM_STATE_CMD_LPM;
> +	}
> +
> +	samsung_dsim_write(dsi, DSIM_PKTHDR_REG, reg);
> +
> +	if (xfer->flags & MIPI_DSI_MSG_REQ_ACK)
> +		samsung_dsim_force_bta(dsi);
> +}
> +
> +static void samsung_dsim_read_from_fifo(struct samsung_dsim *dsi,
> +					struct samsung_dsim_transfer *xfer)
> +{
> +	u8 *payload = xfer->rx_payload + xfer->rx_done;
> +	bool first = !xfer->rx_done;
> +	struct device *dev = dsi->dev;
> +	u16 length;
> +	u32 reg;
> +
> +	if (first) {
> +		reg = samsung_dsim_read(dsi, DSIM_RXFIFO_REG);
> +
> +		switch (reg & 0x3f) {
> +		case MIPI_DSI_RX_GENERIC_SHORT_READ_RESPONSE_2BYTE:
> +		case MIPI_DSI_RX_DCS_SHORT_READ_RESPONSE_2BYTE:
> +			if (xfer->rx_len >= 2) {
> +				payload[1] = reg >> 16;
> +				++xfer->rx_done;
> +			}
> +			fallthrough;
> +		case MIPI_DSI_RX_GENERIC_SHORT_READ_RESPONSE_1BYTE:
> +		case MIPI_DSI_RX_DCS_SHORT_READ_RESPONSE_1BYTE:
> +			payload[0] = reg >> 8;
> +			++xfer->rx_done;
> +			xfer->rx_len = xfer->rx_done;
> +			xfer->result = 0;
> +			goto clear_fifo;
> +		case MIPI_DSI_RX_ACKNOWLEDGE_AND_ERROR_REPORT:
> +			dev_err(dev, "DSI Error Report: 0x%04x\n", (reg >> 8) & 0xffff);
> +			xfer->result = 0;
> +			goto clear_fifo;
> +		}
> +
> +		length = (reg >> 8) & 0xffff;
> +		if (length > xfer->rx_len) {
> +			dev_err(dev,
> +				"response too long (%u > %u bytes), stripping\n",
> +				xfer->rx_len, length);
> +			length = xfer->rx_len;
> +		} else if (length < xfer->rx_len)
> +			xfer->rx_len = length;
> +	}
> +
> +	length = xfer->rx_len - xfer->rx_done;
> +	xfer->rx_done += length;
> +
> +	/* Receive payload */
> +	while (length >= 4) {
> +		reg = samsung_dsim_read(dsi, DSIM_RXFIFO_REG);
> +		payload[0] = (reg >>  0) & 0xff;
> +		payload[1] = (reg >>  8) & 0xff;
> +		payload[2] = (reg >> 16) & 0xff;
> +		payload[3] = (reg >> 24) & 0xff;
> +		payload += 4;
> +		length -= 4;
> +	}
> +
> +	if (length) {
> +		reg = samsung_dsim_read(dsi, DSIM_RXFIFO_REG);
> +		switch (length) {
> +		case 3:
> +			payload[2] = (reg >> 16) & 0xff;
> +			fallthrough;
> +		case 2:
> +			payload[1] = (reg >> 8) & 0xff;
> +			fallthrough;
> +		case 1:
> +			payload[0] = reg & 0xff;
> +		}
> +	}
> +
> +	if (xfer->rx_done == xfer->rx_len)
> +		xfer->result = 0;
> +
> +clear_fifo:
> +	length = DSI_RX_FIFO_SIZE / 4;
> +	do {
> +		reg = samsung_dsim_read(dsi, DSIM_RXFIFO_REG);
> +		if (reg == DSI_RX_FIFO_EMPTY)
> +			break;
> +	} while (--length);
> +}
> +
> +static void samsung_dsim_transfer_start(struct samsung_dsim *dsi)
> +{
> +	unsigned long flags;
> +	struct samsung_dsim_transfer *xfer;
> +	bool start = false;
> +
> +again:
> +	spin_lock_irqsave(&dsi->transfer_lock, flags);
> +
> +	if (list_empty(&dsi->transfer_list)) {
> +		spin_unlock_irqrestore(&dsi->transfer_lock, flags);
> +		return;
> +	}
> +
> +	xfer = list_first_entry(&dsi->transfer_list,
> +				struct samsung_dsim_transfer, list);
> +
> +	spin_unlock_irqrestore(&dsi->transfer_lock, flags);
> +
> +	if (xfer->packet.payload_length &&
> +	    xfer->tx_done == xfer->packet.payload_length)
> +		/* waiting for RX */
> +		return;
> +
> +	samsung_dsim_send_to_fifo(dsi, xfer);
> +
> +	if (xfer->packet.payload_length || xfer->rx_len)
> +		return;
> +
> +	xfer->result = 0;
> +	complete(&xfer->completed);
> +
> +	spin_lock_irqsave(&dsi->transfer_lock, flags);
> +
> +	list_del_init(&xfer->list);
> +	start = !list_empty(&dsi->transfer_list);
> +
> +	spin_unlock_irqrestore(&dsi->transfer_lock, flags);
> +
> +	if (start)
> +		goto again;
> +}
> +
> +static bool samsung_dsim_transfer_finish(struct samsung_dsim *dsi)
> +{
> +	struct samsung_dsim_transfer *xfer;
> +	unsigned long flags;
> +	bool start = true;
> +
> +	spin_lock_irqsave(&dsi->transfer_lock, flags);
> +
> +	if (list_empty(&dsi->transfer_list)) {
> +		spin_unlock_irqrestore(&dsi->transfer_lock, flags);
> +		return false;
> +	}
> +
> +	xfer = list_first_entry(&dsi->transfer_list,
> +				struct samsung_dsim_transfer, list);
> +
> +	spin_unlock_irqrestore(&dsi->transfer_lock, flags);
> +
> +	dev_dbg(dsi->dev,
> +		"> xfer %pK, tx_len %zu, tx_done %u, rx_len %u, rx_done %u\n",
> +		xfer, xfer->packet.payload_length, xfer->tx_done, xfer->rx_len,
> +		xfer->rx_done);
> +
> +	if (xfer->tx_done != xfer->packet.payload_length)
> +		return true;
> +
> +	if (xfer->rx_done != xfer->rx_len)
> +		samsung_dsim_read_from_fifo(dsi, xfer);
> +
> +	if (xfer->rx_done != xfer->rx_len)
> +		return true;
> +
> +	spin_lock_irqsave(&dsi->transfer_lock, flags);
> +
> +	list_del_init(&xfer->list);
> +	start = !list_empty(&dsi->transfer_list);
> +
> +	spin_unlock_irqrestore(&dsi->transfer_lock, flags);
> +
> +	if (!xfer->rx_len)
> +		xfer->result = 0;
> +	complete(&xfer->completed);
> +
> +	return start;
> +}
> +
> +static void samsung_dsim_remove_transfer(struct samsung_dsim *dsi,
> +					 struct samsung_dsim_transfer *xfer)
> +{
> +	unsigned long flags;
> +	bool start;
> +
> +	spin_lock_irqsave(&dsi->transfer_lock, flags);
> +
> +	if (!list_empty(&dsi->transfer_list) &&
> +	    xfer == list_first_entry(&dsi->transfer_list,
> +				     struct samsung_dsim_transfer, list)) {
> +		list_del_init(&xfer->list);
> +		start = !list_empty(&dsi->transfer_list);
> +		spin_unlock_irqrestore(&dsi->transfer_lock, flags);
> +		if (start)
> +			samsung_dsim_transfer_start(dsi);
> +		return;
> +	}
> +
> +	list_del_init(&xfer->list);
> +
> +	spin_unlock_irqrestore(&dsi->transfer_lock, flags);
> +}
> +
> +static int samsung_dsim_transfer(struct samsung_dsim *dsi,
> +				 struct samsung_dsim_transfer *xfer)
> +{
> +	unsigned long flags;
> +	bool stopped;
> +
> +	xfer->tx_done = 0;
> +	xfer->rx_done = 0;
> +	xfer->result = -ETIMEDOUT;
> +	init_completion(&xfer->completed);
> +
> +	spin_lock_irqsave(&dsi->transfer_lock, flags);
> +
> +	stopped = list_empty(&dsi->transfer_list);
> +	list_add_tail(&xfer->list, &dsi->transfer_list);
> +
> +	spin_unlock_irqrestore(&dsi->transfer_lock, flags);
> +
> +	if (stopped)
> +		samsung_dsim_transfer_start(dsi);
> +
> +	wait_for_completion_timeout(&xfer->completed,
> +				    msecs_to_jiffies(DSI_XFER_TIMEOUT_MS));
> +	if (xfer->result == -ETIMEDOUT) {
> +		struct mipi_dsi_packet *pkt = &xfer->packet;
> +
> +		samsung_dsim_remove_transfer(dsi, xfer);
> +		dev_err(dsi->dev, "xfer timed out: %*ph %*ph\n", 4, pkt->header,
> +			(int)pkt->payload_length, pkt->payload);
> +		return -ETIMEDOUT;
> +	}
> +
> +	/* Also covers hardware timeout condition */
> +	return xfer->result;
> +}
> +
> +static irqreturn_t samsung_dsim_irq(int irq, void *dev_id)
> +{
> +	struct samsung_dsim *dsi = dev_id;
> +	u32 status;
> +
> +	status = samsung_dsim_read(dsi, DSIM_INTSRC_REG);
> +	if (!status) {
> +		static unsigned long j;
> +
> +		if (printk_timed_ratelimit(&j, 500))
> +			dev_warn(dsi->dev, "spurious interrupt\n");
> +		return IRQ_HANDLED;
> +	}
> +	samsung_dsim_write(dsi, DSIM_INTSRC_REG, status);
> +
> +	if (status & DSIM_INT_SW_RST_RELEASE) {
> +		u32 mask = ~(DSIM_INT_RX_DONE | DSIM_INT_SFR_FIFO_EMPTY |
> +			DSIM_INT_SFR_HDR_FIFO_EMPTY | DSIM_INT_RX_ECC_ERR |
> +			DSIM_INT_SW_RST_RELEASE);
> +		samsung_dsim_write(dsi, DSIM_INTMSK_REG, mask);
> +		complete(&dsi->completed);
> +		return IRQ_HANDLED;
> +	}
> +
> +	if (!(status & (DSIM_INT_RX_DONE | DSIM_INT_SFR_FIFO_EMPTY |
> +			DSIM_INT_PLL_STABLE)))
> +		return IRQ_HANDLED;
> +
> +	if (samsung_dsim_transfer_finish(dsi))
> +		samsung_dsim_transfer_start(dsi);
> +
> +	return IRQ_HANDLED;
> +}
> +
> +static void samsung_dsim_enable_irq(struct samsung_dsim *dsi)
> +{
> +	const struct samsung_dsim_plat_data *pdata = dsi->plat_data;
> +
> +	enable_irq(dsi->irq);
> +
> +	if (pdata && pdata->irq_ops && pdata->irq_ops->enable)
> +		pdata->irq_ops->enable(dsi);
> +}
> +
> +static void samsung_dsim_disable_irq(struct samsung_dsim *dsi)
> +{
> +	const struct samsung_dsim_plat_data *pdata = dsi->plat_data;
> +
> +	if (pdata && pdata->irq_ops && pdata->irq_ops->disable)
> +		pdata->irq_ops->disable(dsi);
> +
> +	disable_irq(dsi->irq);
> +}
> +
> +static int samsung_dsim_init(struct samsung_dsim *dsi)
> +{
> +	const struct samsung_dsim_driver_data *driver_data = dsi->driver_data;
> +
> +	samsung_dsim_reset(dsi);
> +	samsung_dsim_enable_irq(dsi);
> +
> +	if (driver_data->reg_values[RESET_TYPE] == DSIM_FUNCRST)
> +		samsung_dsim_enable_lane(dsi, BIT(dsi->lanes) - 1);
> +
> +	samsung_dsim_enable_clock(dsi);
> +	if (driver_data->wait_for_reset)
> +		samsung_dsim_wait_for_reset(dsi);
> +	samsung_dsim_set_phy_ctrl(dsi);
> +	samsung_dsim_init_link(dsi);
> +
> +	return 0;
> +}
> +
> +static void samsung_dsim_atomic_pre_enable(struct drm_bridge *bridge,
> +					   struct drm_bridge_state *old_bridge_state)
> +{
> +	struct samsung_dsim *dsi = bridge_to_dsi(bridge);
> +	int ret;
> +
> +	if (dsi->state & DSIM_STATE_ENABLED)
> +		return;
> +
> +	ret = pm_runtime_resume_and_get(dsi->dev);
> +	if (ret < 0) {
> +		dev_err(dsi->dev, "failed to enable DSI device.\n");
> +		return;
> +	}
> +
> +	dsi->state |= DSIM_STATE_ENABLED;
> +}
> +
> +static void samsung_dsim_atomic_enable(struct drm_bridge *bridge,
> +				       struct drm_bridge_state *old_bridge_state)
> +{
> +	struct samsung_dsim *dsi = bridge_to_dsi(bridge);
> +
> +	samsung_dsim_set_display_mode(dsi);
> +	samsung_dsim_set_display_enable(dsi, true);
> +
> +	dsi->state |= DSIM_STATE_VIDOUT_AVAILABLE;
> +}
> +
> +static void samsung_dsim_atomic_disable(struct drm_bridge *bridge,
> +					struct drm_bridge_state *old_bridge_state)
> +{
> +	struct samsung_dsim *dsi = bridge_to_dsi(bridge);
> +
> +	if (!(dsi->state & DSIM_STATE_ENABLED))
> +		return;
> +
> +	dsi->state &= ~DSIM_STATE_VIDOUT_AVAILABLE;
> +}
> +
> +static void samsung_dsim_atomic_post_disable(struct drm_bridge *bridge,
> +					     struct drm_bridge_state *old_bridge_state)
> +{
> +	struct samsung_dsim *dsi = bridge_to_dsi(bridge);
> +
> +	samsung_dsim_set_display_enable(dsi, false);
> +
> +	dsi->state &= ~DSIM_STATE_ENABLED;
> +	pm_runtime_put_sync(dsi->dev);
> +}
> +
> +static void samsung_dsim_mode_set(struct drm_bridge *bridge,
> +				  const struct drm_display_mode *mode,
> +				  const struct drm_display_mode *adjusted_mode)
> +{
> +	struct samsung_dsim *dsi = bridge_to_dsi(bridge);
> +
> +	drm_mode_copy(&dsi->mode, adjusted_mode);
> +}
> +
> +static int samsung_dsim_attach(struct drm_bridge *bridge,
> +			       enum drm_bridge_attach_flags flags)
> +{
> +	struct samsung_dsim *dsi = bridge_to_dsi(bridge);
> +
> +	return drm_bridge_attach(bridge->encoder, dsi->out_bridge, NULL, flags);
> +}
> +
> +static const struct drm_bridge_funcs samsung_dsim_bridge_funcs = {
> +	.atomic_duplicate_state		= drm_atomic_helper_bridge_duplicate_state,
> +	.atomic_destroy_state		= drm_atomic_helper_bridge_destroy_state,
> +	.atomic_reset			= drm_atomic_helper_bridge_reset,
> +	.atomic_pre_enable		= samsung_dsim_atomic_pre_enable,
> +	.atomic_enable			= samsung_dsim_atomic_enable,
> +	.atomic_disable			= samsung_dsim_atomic_disable,
> +	.atomic_post_disable		= samsung_dsim_atomic_post_disable,
> +	.mode_set			= samsung_dsim_mode_set,
> +	.attach				= samsung_dsim_attach,
> +};
> +
> +MODULE_DEVICE_TABLE(of, samsung_dsim_of_match);
> +
> +static int samsung_dsim_host_attach(struct mipi_dsi_host *host,
> +				    struct mipi_dsi_device *device)
> +{
> +	struct samsung_dsim *dsi = host_to_dsi(host);
> +	const struct samsung_dsim_plat_data *pdata = dsi->plat_data;
> +	struct device *dev = dsi->dev;
> +	struct drm_panel *panel;
> +	int ret;
> +
> +	panel = of_drm_find_panel(device->dev.of_node);
> +	if (!IS_ERR(panel)) {
> +		dsi->out_bridge = devm_drm_panel_bridge_add(dev, panel);
> +	} else {
> +		dsi->out_bridge = of_drm_find_bridge(device->dev.of_node);
> +		if (!dsi->out_bridge)
> +			dsi->out_bridge = ERR_PTR(-EINVAL);
> +	}
> +
> +	if (IS_ERR(dsi->out_bridge)) {
> +		ret = PTR_ERR(dsi->out_bridge);
> +		DRM_DEV_ERROR(dev, "failed to find the bridge: %d\n", ret);
> +		return ret;
> +	}
> +
> +	DRM_DEV_INFO(dev, "Attached %s device\n", device->name);
> +
> +	drm_bridge_add(&dsi->bridge);
> +
> +	if (pdata && pdata->host_ops && pdata->host_ops->attach) {
> +		ret = pdata->host_ops->attach(dsi, device);
> +		if (ret < 0)
> +			return ret;
> +	}
> +
> +	dsi->lanes = device->lanes;
> +	dsi->format = device->format;
> +	dsi->mode_flags = device->mode_flags;
> +
> +	return 0;
> +}
> +
> +static int samsung_dsim_host_detach(struct mipi_dsi_host *host,
> +				    struct mipi_dsi_device *device)
> +{
> +	struct samsung_dsim *dsi = host_to_dsi(host);
> +	const struct samsung_dsim_plat_data *pdata = dsi->plat_data;
> +	int ret;
> +
> +	if (dsi->out_bridge->funcs->detach)
> +		dsi->out_bridge->funcs->detach(dsi->out_bridge);
> +
> +	dsi->out_bridge = NULL;
> +
> +	if (pdata && pdata->host_ops && pdata->host_ops->detach) {
> +		ret = pdata->host_ops->detach(dsi, device);
> +		if (ret < 0)
> +			return ret;
> +	}
> +
> +	drm_bridge_remove(&dsi->bridge);
> +
> +	return 0;
> +}
> +
> +static ssize_t samsung_dsim_host_transfer(struct mipi_dsi_host *host,
> +					  const struct mipi_dsi_msg *msg)
> +{
> +	struct samsung_dsim *dsi = host_to_dsi(host);
> +	struct samsung_dsim_transfer xfer;
> +	int ret;
> +
> +	if (!(dsi->state & DSIM_STATE_ENABLED))
> +		return -EINVAL;
> +
> +	if (!(dsi->state & DSIM_STATE_INITIALIZED)) {
> +		ret = samsung_dsim_init(dsi);
> +		if (ret)
> +			return ret;
> +		dsi->state |= DSIM_STATE_INITIALIZED;
> +	}
> +
> +	ret = mipi_dsi_create_packet(&xfer.packet, msg);
> +	if (ret < 0)
> +		return ret;
> +
> +	xfer.rx_len = msg->rx_len;
> +	xfer.rx_payload = msg->rx_buf;
> +	xfer.flags = msg->flags;
> +
> +	ret = samsung_dsim_transfer(dsi, &xfer);
> +	return (ret < 0) ? ret : xfer.rx_done;
> +}
> +
> +static const struct mipi_dsi_host_ops samsung_dsim_ops = {
> +	.attach = samsung_dsim_host_attach,
> +	.detach = samsung_dsim_host_detach,
> +	.transfer = samsung_dsim_host_transfer,
> +};
> +
> +static int samsung_dsim_of_read_u32(const struct device_node *np,
> +				    const char *propname, u32 *out_value)
> +{
> +	int ret = of_property_read_u32(np, propname, out_value);
> +
> +	if (ret < 0)
> +		pr_err("%pOF: failed to get '%s' property\n", np, propname);
> +
> +	return ret;
> +}
> +
> +static int samsung_dsim_parse_dt(struct samsung_dsim *dsi)
> +{
> +	struct device *dev = dsi->dev;
> +	struct device_node *node = dev->of_node;
> +	int ret;
> +
> +	ret = samsung_dsim_of_read_u32(node, "samsung,pll-clock-frequency",
> +				       &dsi->pll_clk_rate);
> +	if (ret < 0)
> +		return ret;
> +
> +	ret = samsung_dsim_of_read_u32(node, "samsung,burst-clock-frequency",
> +				       &dsi->burst_clk_rate);
> +	if (ret < 0)
> +		return ret;
> +
> +	ret = samsung_dsim_of_read_u32(node, "samsung,esc-clock-frequency",
> +				       &dsi->esc_clk_rate);
> +	if (ret < 0)
> +		return ret;
> +
> +	return 0;
> +}
> +
> +__weak const struct samsung_dsim_plat_data *
> +samsung_dsim_plat_probe(struct samsung_dsim *priv)
> +{
> +	return NULL;
> +}
> +
> +__weak void samsung_dsim_plat_remove(struct samsung_dsim *priv)
> +{
> +}
> +
> +static int samsung_dsim_probe(struct platform_device *pdev)
> +{
> +	struct device *dev = &pdev->dev;
> +	struct samsung_dsim *dsi;
> +	int ret, i;
> +
> +	dsi = devm_kzalloc(dev, sizeof(*dsi), GFP_KERNEL);
> +	if (!dsi)
> +		return -ENOMEM;
> +
> +	init_completion(&dsi->completed);
> +	spin_lock_init(&dsi->transfer_lock);
> +	INIT_LIST_HEAD(&dsi->transfer_list);
> +
> +	dsi->dsi_host.ops = &samsung_dsim_ops;
> +	dsi->dsi_host.dev = dev;
> +
> +	dsi->dev = dev;
> +	dsi->driver_data = of_device_get_match_data(dev);
> +
> +	dsi->supplies[0].supply = "vddcore";
> +	dsi->supplies[1].supply = "vddio";
> +	ret = devm_regulator_bulk_get(dev, ARRAY_SIZE(dsi->supplies),
> +				      dsi->supplies);
> +	if (ret)
> +		return dev_err_probe(dev, ret, "failed to get regulators\n");
> +
> +	dsi->clks = devm_kcalloc(dev, dsi->driver_data->num_clks,
> +				 sizeof(*dsi->clks), GFP_KERNEL);
> +	if (!dsi->clks)
> +		return -ENOMEM;
> +
> +	for (i = 0; i < dsi->driver_data->num_clks; i++) {
> +		dsi->clks[i] = devm_clk_get(dev, clk_names[i]);
> +		if (IS_ERR(dsi->clks[i])) {
> +			if (strcmp(clk_names[i], "sclk_mipi") == 0) {
> +				dsi->clks[i] = devm_clk_get(dev, OLD_SCLK_MIPI_CLK_NAME);
> +				if (!IS_ERR(dsi->clks[i]))
> +					continue;
> +			}
> +
> +			dev_info(dev, "failed to get the clock: %s\n", clk_names[i]);
> +			return PTR_ERR(dsi->clks[i]);
> +		}
> +	}
> +
> +	dsi->reg_base = devm_platform_ioremap_resource(pdev, 0);
> +	if (IS_ERR(dsi->reg_base))
> +		return PTR_ERR(dsi->reg_base);
> +
> +	dsi->phy = devm_phy_get(dev, "dsim");
> +	if (IS_ERR(dsi->phy)) {
> +		dev_info(dev, "failed to get dsim phy\n");
> +		return PTR_ERR(dsi->phy);
> +	}
> +
> +	dsi->irq = platform_get_irq(pdev, 0);
> +	if (dsi->irq < 0)
> +		return dsi->irq;
> +
> +	ret = devm_request_threaded_irq(dev, dsi->irq, NULL,
> +					samsung_dsim_irq,
> +					IRQF_ONESHOT | IRQF_NO_AUTOEN,
> +					dev_name(dev), dsi);
> +	if (ret) {
> +		dev_err(dev, "failed to request dsi irq\n");
> +		return ret;
> +	}
> +
> +	ret = samsung_dsim_parse_dt(dsi);
> +	if (ret)
> +		return ret;
> +
> +	platform_set_drvdata(pdev, dsi);
> +
> +	pm_runtime_enable(dev);
> +
> +	dsi->bridge.funcs = &samsung_dsim_bridge_funcs;
> +	dsi->bridge.of_node = dev->of_node;
> +	dsi->bridge.type = DRM_MODE_CONNECTOR_DSI;
> +
> +	dsi->plat_data = samsung_dsim_plat_probe(dsi);

The above it a source of the funny race. samsung_dsim_plat_probe() calls 
component_add(). If DSI is the last needed device of the component drm 
device, then this will immediately call bind(), what causes to enter 
exynos_dsi_bind() with dsi->plat_data being NULL. It must be assigned 
inside samsung_dsim_plat_probe(), before calling component_add()

 > ...

Best regards