[PATCH v2 00/34] component: Make into an aggregate bus

[PATCH v2 00/34] component: Make into an aggregate bus

[Stephen Boyd]

This series is from discussion we had on reordering the device lists for
drm shutdown paths[1]. I've introduced an 'aggregate' bus that we put
the aggregate device onto and then we probe the aggregate device once
all the components are probed and call component_add(). The probe/remove
hooks are where the bind/unbind calls go, and then a shutdown hook is
added that can be used to shutdown the drm display pipeline at the right
time.

This works for me on my sc7180 board. I no longer get a warning from i2c
at shutdown that we're trying to make an i2c transaction after the i2c
bus has been shutdown. There's more work to do on the msm drm driver to
extract component device resources like clks, regulators, etc. out of
the component bind function into the driver probe but I wanted to move
everything over now in other component drivers before tackling that
problem.

I'll definitely be sending a v3 so this is partially a request for
testing to shake out any more problems. Tested-by tags would be appreciated,
and Acked-by/Reviewed-by tags too. I sent this to gregkh which may be
incorrect but I don't know what better tree to send it all through.
Maybe drm?

I'll be faster at resending this next time, sorry for the long delay!

Changes since v1 (https://lore.kernel.org/r/20210520002519.3538432-1-swboyd@chromium.org):
 - Use devlink to connect components to the aggregate device
 - Don't set the registering device as a parent of the aggregate device
 - New patch for bind_component/unbind_component ops that takes the
   aggregate device
 - Convert all drivers in the tree to use the aggregate driver approach
 - Allow one aggregate driver to be used for multiple aggregate devices

[1] https://lore.kernel.org/r/20210508074118.1621729-1-swboyd@chromium.org

Stephen Boyd (34):
  component: Introduce struct aggregate_device
  component: Introduce the aggregate bus_type
  component: Move struct aggregate_device out to header file
  drm/msm: Migrate to aggregate driver
  component: Add {bind,unbind}_component() ops that take aggregate
    device
  drm/of: Add a drm_of_aggregate_probe() API
  drm/komeda: Migrate to aggregate driver
  drm/arm/hdlcd: Migrate to aggregate driver
  drm/malidp: Migrate to aggregate driver
  drm/armada: Migrate to aggregate driver
  drm/etnaviv: Migrate to aggregate driver
  drm/kirin: Migrate to aggregate driver
  drm/exynos: Migrate to aggregate driver
  drm/imx: Migrate to aggregate driver
  drm/ingenic: Migrate to aggregate driver
  drm/mcde: Migrate to aggregate driver
  drm/mediatek: Migrate to aggregate driver
  drm/meson: Migrate to aggregate driver
  drm/omap: Migrate to aggregate driver
  drm/rockchip: Migrate to aggregate driver
  drm/sti: Migrate to aggregate driver
  drm/sun4i: Migrate to aggregate driver
  drm/tilcdc: Migrate to aggregate driver
  drm/vc4: Migrate to aggregate driver
  drm/zte: Migrate to aggregate driver
  iommu/mtk: Migrate to aggregate driver
  mei: Migrate to aggregate driver
  power: supply: ab8500: Migrate to aggregate driver
  fbdev: omap2: Migrate to aggregate driver
  sound: hdac: Migrate to aggregate driver
  ASoC: codecs: wcd938x: Migrate to aggregate driver
  component: Get rid of drm_of_component_probe()
  component: Remove component_master_ops and friends
  component: Remove all references to 'master'

Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Benjamin Gaignard <benjamin.gaignard@linaro.org>
Cc: Chen Feng <puck.chen@hisilicon.com>
Cc: Chen-Yu Tsai <wens@csie.org>
Cc: Christian Gmeiner <christian.gmeiner@gmail.com>
Cc: Chun-Kuang Hu <chunkuang.hu@kernel.org>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Emma Anholt <emma@anholt.net>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "Heiko Stübner" <heiko@sntech.de>
Cc: Inki Dae <inki.dae@samsung.com>
Cc: James Qian Wang (Arm Technology China) <james.qian.wang@arm.com>
Cc: Jaroslav Kysela <perex@perex.cz>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Joonyoung Shim <jy0922.shim@samsung.com>
Cc: Jyri Sarha <jyri.sarha@iki.fi>
Cc: Kai Vehmanen <kai.vehmanen@linux.intel.com>
Cc: Kyungmin Park <kyungmin.park@samsung.com>
Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc: <linux-fbdev@vger.kernel.org>
Cc: <linux-omap@vger.kernel.org>
Cc: <linux-pm@vger.kernel.org>
Cc: Liviu Dudau <liviu.dudau@arm.com>
Cc: Lucas Stach <l.stach@pengutronix.de>
Cc: Mark Brown <broonie@kernel.org>
Cc: Maxime Ripard <mripard@kernel.org>
Cc: Neil Armstrong <narmstrong@baylibre.com>
Cc: Paul Cercueil <paul@crapouillou.net>
Cc: Philipp Zabel <p.zabel@pengutronix.de>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Rob Clark <robdclark@gmail.com>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Russell King <linux+etnaviv@armlinux.org.uk>
Cc: Russell King <rmk+kernel@arm.linux.org.uk>
Cc: Sandy Huang <hjc@rock-chips.com>
Cc: Saravana Kannan <saravanak@google.com>
Cc: Sebastian Reichel <sre@kernel.org>
Cc: Seung-Woo Kim <sw0312.kim@samsung.com>
Cc: Takashi Iwai <tiwai@suse.com>
Cc: Tian Tao <tiantao6@hisilicon.com>
Cc: Tomas Winkler <tomas.winkler@intel.com>
Cc: Tomi Valkeinen <tomba@kernel.org>
Cc: Will Deacon <will@kernel.org>
Cc: Xinliang Liu <xinliang.liu@linaro.org>
Cc: Xinwei Kong <kong.kongxinwei@hisilicon.com>
Cc: Yong Wu <yong.wu@mediatek.com>

 drivers/base/component.c                      | 555 +++++++++++-------
 .../gpu/drm/arm/display/komeda/komeda_drv.c   |  20 +-
 drivers/gpu/drm/arm/hdlcd_drv.c               |  21 +-
 drivers/gpu/drm/arm/malidp_drv.c              |  21 +-
 drivers/gpu/drm/armada/armada_drv.c           |  23 +-
 drivers/gpu/drm/drm_drv.c                     |   2 +-
 drivers/gpu/drm/drm_of.c                      |  20 +-
 drivers/gpu/drm/etnaviv/etnaviv_drv.c         |  20 +-
 drivers/gpu/drm/exynos/exynos_drm_drv.c       |  21 +-
 .../gpu/drm/hisilicon/kirin/kirin_drm_drv.c   |  20 +-
 drivers/gpu/drm/imx/imx-drm-core.c            |  20 +-
 drivers/gpu/drm/ingenic/ingenic-drm-drv.c     |  24 +-
 drivers/gpu/drm/mcde/mcde_drv.c               |  23 +-
 drivers/gpu/drm/mediatek/mtk_drm_drv.c        |  20 +-
 drivers/gpu/drm/meson/meson_drv.c             |  21 +-
 drivers/gpu/drm/msm/msm_drv.c                 |  46 +-
 drivers/gpu/drm/omapdrm/dss/dss.c             |  17 +-
 drivers/gpu/drm/rockchip/rockchip_drm_drv.c   |  20 +-
 drivers/gpu/drm/sti/sti_drv.c                 |  20 +-
 drivers/gpu/drm/sun4i/sun4i_drv.c             |  26 +-
 drivers/gpu/drm/tilcdc/tilcdc_drv.c           |  28 +-
 drivers/gpu/drm/vc4/vc4_drv.c                 |  20 +-
 drivers/gpu/drm/zte/zx_drm_drv.c              |  20 +-
 drivers/iommu/mtk_iommu.c                     |  14 +-
 drivers/iommu/mtk_iommu.h                     |   6 +-
 drivers/iommu/mtk_iommu_v1.c                  |  14 +-
 drivers/misc/mei/hdcp/mei_hdcp.c              |  22 +-
 drivers/power/supply/ab8500_charger.c         |  22 +-
 drivers/video/fbdev/omap2/omapfb/dss/dss.c    |  20 +-
 include/drm/drm_of.h                          |   9 +-
 include/linux/component.h                     |  92 ++-
 sound/hda/hdac_component.c                    |  21 +-
 sound/soc/codecs/wcd938x.c                    |  20 +-
 33 files changed, 780 insertions(+), 488 deletions(-)


base-commit: e4e737bb5c170df6135a127739a9e6148ee3da82
-- 
https://chromeos.dev

[PATCH v2 29/34] fbdev: omap2: Migrate to aggregate driver

[Stephen Boyd]

Use an aggregate driver instead of component ops so that we can get
proper driver probe ordering of the aggregate device with respect to all
the component devices that make up the aggregate device.

Cc: <linux-omap@vger.kernel.org>
Cc: <linux-fbdev@vger.kernel.org>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Rob Clark <robdclark@gmail.com>
Cc: Russell King <rmk+kernel@arm.linux.org.uk>
Cc: Saravana Kannan <saravanak@google.com>
Signed-off-by: Stephen Boyd <swboyd@chromium.org>
---
 drivers/video/fbdev/omap2/omapfb/dss/dss.c | 20 +++++++++++++-------
 1 file changed, 13 insertions(+), 7 deletions(-)

diff --git a/drivers/video/fbdev/omap2/omapfb/dss/dss.c b/drivers/video/fbdev/omap2/omapfb/dss/dss.c
index a6b1c1598040..f12663c39ceb 100644
--- a/drivers/video/fbdev/omap2/omapfb/dss/dss.c
+++ b/drivers/video/fbdev/omap2/omapfb/dss/dss.c
@@ -1067,8 +1067,9 @@ static int dss_video_pll_probe(struct platform_device *pdev)
 }
 
 /* DSS HW IP initialisation */
-static int dss_bind(struct device *dev)
+static int dss_bind(struct aggregate_device *adev)
 {
+	struct device *dev = adev->parent;
 	struct platform_device *pdev = to_platform_device(dev);
 	struct resource *dss_mem;
 	u32 rev;
@@ -1167,8 +1168,9 @@ static int dss_bind(struct device *dev)
 	return r;
 }
 
-static void dss_unbind(struct device *dev)
+static void dss_unbind(struct aggregate_device *adev)
 {
+	struct device *dev = adev->parent;
 	struct platform_device *pdev = to_platform_device(dev);
 
 	dss_initialized = false;
@@ -1188,9 +1190,13 @@ static void dss_unbind(struct device *dev)
 	dss_put_clocks();
 }
 
-static const struct component_master_ops dss_component_ops = {
-	.bind = dss_bind,
-	.unbind = dss_unbind,
+static struct aggregate_driver dss_aggregate_driver = {
+	.probe = dss_bind,
+	.remove = dss_unbind,
+	.driver = {
+		.name = "dss_fbdev",
+		.owner = THIS_MODULE,
+	},
 };
 
 static int dss_component_compare(struct device *dev, void *data)
@@ -1225,7 +1231,7 @@ static int dss_probe(struct platform_device *pdev)
 	/* add all the child devices as components */
 	device_for_each_child(&pdev->dev, &match, dss_add_child_component);
 
-	r = component_master_add_with_match(&pdev->dev, &dss_component_ops, match);
+	r = component_aggregate_register(&pdev->dev, &dss_aggregate_driver, match);
 	if (r)
 		return r;
 
@@ -1234,7 +1240,7 @@ static int dss_probe(struct platform_device *pdev)
 
 static int dss_remove(struct platform_device *pdev)
 {
-	component_master_del(&pdev->dev, &dss_component_ops);
+	component_aggregate_unregister(&pdev->dev, &dss_aggregate_driver);
 	return 0;
 }
 
-- 
https://chromeos.dev

Re: [PATCH v2 00/34] component: Make into an aggregate bus

[Andrzej Hajda]

Hi Stephen,

On 06.10.2021 21:37, Stephen Boyd wrote:
> This series is from discussion we had on reordering the device lists for
> drm shutdown paths[1]. I've introduced an 'aggregate' bus that we put
> the aggregate device onto and then we probe the aggregate device once
> all the components are probed and call component_add(). The probe/remove
> hooks are where the bind/unbind calls go, and then a shutdown hook is
> added that can be used to shutdown the drm display pipeline at the right
> time.
> 
> This works for me on my sc7180 board. I no longer get a warning from i2c
> at shutdown that we're trying to make an i2c transaction after the i2c
> bus has been shutdown. There's more work to do on the msm drm driver to
> extract component device resources like clks, regulators, etc. out of
> the component bind function into the driver probe but I wanted to move
> everything over now in other component drivers before tackling that
> problem.


As I understand you have DSI host with i2c-controlled DSI bridge. And 
there is an issue that bridge is shutdown before msmdrm. Your solution 
is to 'adjust' device order on pm list.
I had similar issue and solved it locally by adding notification from 
DSI bridge to DSI host that is has to be removed: mipi_dsi_detach, this 
notification escalates in DSI host to component_del and this allow to 
react properly.

Advantages:
- it is local (only involves DSI host and DSI device),
- it does not depend on PM internals,
- it can be used in other scenarios as well - unbinding DSI device driver

Disadvantage:
- It is DSI specific (but this is your case), I have advertised some 
time ago more general approach [1][2].

[1]: https://static.sched.com/hosted_files/osseu18/0f/deferred_problem.pdf
[2]: https://lwn.net/Articles/625454/


Regards
Andrzej

Re: [PATCH v2 00/34] component: Make into an aggregate bus

[Andrzej Hajda]

On 07.10.2021 13:22, Andy Shevchenko wrote:
> 
> 
> On Wednesday, October 6, 2021, Stephen Boyd <swboyd@chromium.org 
> <mailto:swboyd@chromium.org>> wrote:
> 
>     This series is from discussion we had on reordering the device lists for
>     drm shutdown paths[1]. I've introduced an 'aggregate' bus that we put
>     the aggregate device onto and then we probe the aggregate device once
>     all the components are probed and call component_add(). The probe/remove
>     hooks are where the bind/unbind calls go, and then a shutdown hook is
>     added that can be used to shutdown the drm display pipeline at the right
>     time.
> 
>     This works for me on my sc7180 board. I no longer get a warning from i2c
>     at shutdown that we're trying to make an i2c transaction after the i2c
>     bus has been shutdown. There's more work to do on the msm drm driver to
>     extract component device resources like clks, regulators, etc. out of
>     the component bind function into the driver probe but I wanted to move
>     everything over now in other component drivers before tackling that
>     problem.
> 
>     I'll definitely be sending a v3 so this is partially a request for
>     testing to shake out any more problems. Tested-by tags would be
>     appreciated,
>     and Acked-by/Reviewed-by tags too. I sent this to gregkh which may be
>     incorrect but I don't know what better tree to send it all through.
>     Maybe drm?
> 
>     I'll be faster at resending this next time, sorry for the long delay!
> 
> 
> Yet another avoidance of mathematically proven device dependency graph...
> 
> 
> Can we actually find and ask a mathematician to look into the problem 
> and suggest real solution instead of all these ugly hacks: deferred 
> probe (ugliest hack, how it even came into kernel?), component 
> framework, custom approaches on how to see if devices are in the system 
> (ASoC hack).

Master of Science in Math is OK? :)
The solution is simple - topological sort - this is what PM device list 
does, but it is possible only if there are no circular dependencies.

And in this case we have circular dependency.
In such case the solution in case of initialization is to split it to 
two phases - probe/bind (component framework), probe/attach (DSI bus) 
and it works. But PM still relies on topological sort. To make PM 
working with circular deps you can try to extend PM somehow (maybe 
replace list of devices with list of pairs (device, phase) ??? ), or to 
add notifiers to frameworks allowing providers to informs its consumers 
about state change. The latter approach I have advertised several times, 
even on OSS.

[1]: https://static.sched.com/hosted_files/osseu18/0f/deferred_problem.pdf
[2]: https://lwn.net/Articles/625454/


Regards
Andrzej


> 
>     Changes since v1
>     (https://lore.kernel.org/r/20210520002519.3538432-1-swboyd@chromium.org
>     <https://lore.kernel.org/r/20210520002519.3538432-1-swboyd@chromium.org>):
>       - Use devlink to connect components to the aggregate device
>       - Don't set the registering device as a parent of the aggregate device
>       - New patch for bind_component/unbind_component ops that takes the
>         aggregate device
>       - Convert all drivers in the tree to use the aggregate driver approach
>       - Allow one aggregate driver to be used for multiple aggregate devices
> 
>     [1]
>     https://lore.kernel.org/r/20210508074118.1621729-1-swboyd@chromium.org
>     <https://lore.kernel.org/r/20210508074118.1621729-1-swboyd@chromium.org>
> 
>     Stephen Boyd (34):
>        component: Introduce struct aggregate_device
>        component: Introduce the aggregate bus_type
>        component: Move struct aggregate_device out to header file
>        drm/msm: Migrate to aggregate driver
>        component: Add {bind,unbind}_component() ops that take aggregate
>          device
>        drm/of: Add a drm_of_aggregate_probe() API
>        drm/komeda: Migrate to aggregate driver
>        drm/arm/hdlcd: Migrate to aggregate driver
>        drm/malidp: Migrate to aggregate driver
>        drm/armada: Migrate to aggregate driver
>        drm/etnaviv: Migrate to aggregate driver
>        drm/kirin: Migrate to aggregate driver
>        drm/exynos: Migrate to aggregate driver
>        drm/imx: Migrate to aggregate driver
>        drm/ingenic: Migrate to aggregate driver
>        drm/mcde: Migrate to aggregate driver
>        drm/mediatek: Migrate to aggregate driver
>        drm/meson: Migrate to aggregate driver
>        drm/omap: Migrate to aggregate driver
>        drm/rockchip: Migrate to aggregate driver
>        drm/sti: Migrate to aggregate driver
>        drm/sun4i: Migrate to aggregate driver
>        drm/tilcdc: Migrate to aggregate driver
>        drm/vc4: Migrate to aggregate driver
>        drm/zte: Migrate to aggregate driver
>        iommu/mtk: Migrate to aggregate driver
>        mei: Migrate to aggregate driver
>        power: supply: ab8500: Migrate to aggregate driver
>        fbdev: omap2: Migrate to aggregate driver
>        sound: hdac: Migrate to aggregate driver
>        ASoC: codecs: wcd938x: Migrate to aggregate driver
>        component: Get rid of drm_of_component_probe()
>        component: Remove component_master_ops and friends
>        component: Remove all references to 'master'
> 
>     Cc: Arnd Bergmann <arnd@arndb.de <mailto:arnd@arndb.de>>
>     Cc: Benjamin Gaignard <benjamin.gaignard@linaro.org
>     <mailto:benjamin.gaignard@linaro.org>>
>     Cc: Chen Feng <puck.chen@hisilicon.com <mailto:puck.chen@hisilicon.com>>
>     Cc: Chen-Yu Tsai <wens@csie.org <mailto:wens@csie.org>>
>     Cc: Christian Gmeiner <christian.gmeiner@gmail.com
>     <mailto:christian.gmeiner@gmail.com>>
>     Cc: Chun-Kuang Hu <chunkuang.hu@kernel.org
>     <mailto:chunkuang.hu@kernel.org>>
>     Cc: Daniel Vetter <daniel.vetter@ffwll.ch
>     <mailto:daniel.vetter@ffwll.ch>>
>     Cc: Emma Anholt <emma@anholt.net <mailto:emma@anholt.net>>
>     Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org
>     <mailto:gregkh@linuxfoundation.org>>
>     Cc: "Heiko Stübner" <heiko@sntech.de <mailto:heiko@sntech.de>>
>     Cc: Inki Dae <inki.dae@samsung.com <mailto:inki.dae@samsung.com>>
>     Cc: James Qian Wang (Arm Technology China) <james.qian.wang@arm.com
>     <mailto:james.qian.wang@arm.com>>
>     Cc: Jaroslav Kysela <perex@perex.cz <mailto:perex@perex.cz>>
>     Cc: Joerg Roedel <joro@8bytes.org <mailto:joro@8bytes.org>>
>     Cc: John Stultz <john.stultz@linaro.org <mailto:john.stultz@linaro.org>>
>     Cc: Joonyoung Shim <jy0922.shim@samsung.com
>     <mailto:jy0922.shim@samsung.com>>
>     Cc: Jyri Sarha <jyri.sarha@iki.fi <mailto:jyri.sarha@iki.fi>>
>     Cc: Kai Vehmanen <kai.vehmanen@linux.intel.com
>     <mailto:kai.vehmanen@linux.intel.com>>
>     Cc: Kyungmin Park <kyungmin.park@samsung.com
>     <mailto:kyungmin.park@samsung.com>>
>     Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com
>     <mailto:laurent.pinchart@ideasonboard.com>>
>     Cc: <linux-fbdev@vger.kernel.org <mailto:linux-fbdev@vger.kernel.org>>
>     Cc: <linux-omap@vger.kernel.org <mailto:linux-omap@vger.kernel.org>>
>     Cc: <linux-pm@vger.kernel.org <mailto:linux-pm@vger.kernel.org>>
>     Cc: Liviu Dudau <liviu.dudau@arm.com <mailto:liviu.dudau@arm.com>>
>     Cc: Lucas Stach <l.stach@pengutronix.de <mailto:l.stach@pengutronix.de>>
>     Cc: Mark Brown <broonie@kernel.org <mailto:broonie@kernel.org>>
>     Cc: Maxime Ripard <mripard@kernel.org <mailto:mripard@kernel.org>>
>     Cc: Neil Armstrong <narmstrong@baylibre.com
>     <mailto:narmstrong@baylibre.com>>
>     Cc: Paul Cercueil <paul@crapouillou.net <mailto:paul@crapouillou.net>>
>     Cc: Philipp Zabel <p.zabel@pengutronix.de
>     <mailto:p.zabel@pengutronix.de>>
>     Cc: "Rafael J. Wysocki" <rafael@kernel.org <mailto:rafael@kernel.org>>
>     Cc: Rob Clark <robdclark@gmail.com <mailto:robdclark@gmail.com>>
>     Cc: Russell King <linux@armlinux.org.uk <mailto:linux@armlinux.org.uk>>
>     Cc: Russell King <linux+etnaviv@armlinux.org.uk
>     <mailto:linux+etnaviv@armlinux.org.uk>>
>     Cc: Russell King <rmk+kernel@arm.linux.org.uk
>     <mailto:rmk+kernel@arm.linux.org.uk>>
>     Cc: Sandy Huang <hjc@rock-chips.com <mailto:hjc@rock-chips.com>>
>     Cc: Saravana Kannan <saravanak@google.com <mailto:saravanak@google.com>>
>     Cc: Sebastian Reichel <sre@kernel.org <mailto:sre@kernel.org>>
>     Cc: Seung-Woo Kim <sw0312.kim@samsung.com
>     <mailto:sw0312.kim@samsung.com>>
>     Cc: Takashi Iwai <tiwai@suse.com <mailto:tiwai@suse.com>>
>     Cc: Tian Tao <tiantao6@hisilicon.com <mailto:tiantao6@hisilicon.com>>
>     Cc: Tomas Winkler <tomas.winkler@intel.com
>     <mailto:tomas.winkler@intel.com>>
>     Cc: Tomi Valkeinen <tomba@kernel.org <mailto:tomba@kernel.org>>
>     Cc: Will Deacon <will@kernel.org <mailto:will@kernel.org>>
>     Cc: Xinliang Liu <xinliang.liu@linaro.org
>     <mailto:xinliang.liu@linaro.org>>
>     Cc: Xinwei Kong <kong.kongxinwei@hisilicon.com
>     <mailto:kong.kongxinwei@hisilicon.com>>
>     Cc: Yong Wu <yong.wu@mediatek.com <mailto:yong.wu@mediatek.com>>
> 
>       drivers/base/component.c                      | 555 +++++++++++-------
>       .../gpu/drm/arm/display/komeda/komeda_drv.c   |  20 +-
>       drivers/gpu/drm/arm/hdlcd_drv.c               |  21 +-
>       drivers/gpu/drm/arm/malidp_drv.c              |  21 +-
>       drivers/gpu/drm/armada/armada_drv.c           |  23 +-
>       drivers/gpu/drm/drm_drv.c                     |   2 +-
>       drivers/gpu/drm/drm_of.c                      |  20 +-
>       drivers/gpu/drm/etnaviv/etnaviv_drv.c         |  20 +-
>       drivers/gpu/drm/exynos/exynos_drm_drv.c       |  21 +-
>       .../gpu/drm/hisilicon/kirin/kirin_drm_drv.c   |  20 +-
>       drivers/gpu/drm/imx/imx-drm-core.c            |  20 +-
>       drivers/gpu/drm/ingenic/ingenic-drm-drv.c     |  24 +-
>       drivers/gpu/drm/mcde/mcde_drv.c               |  23 +-
>       drivers/gpu/drm/mediatek/mtk_drm_drv.c        |  20 +-
>       drivers/gpu/drm/meson/meson_drv.c             |  21 +-
>       drivers/gpu/drm/msm/msm_drv.c                 |  46 +-
>       drivers/gpu/drm/omapdrm/dss/dss.c             |  17 +-
>       drivers/gpu/drm/rockchip/rockchip_drm_drv.c   |  20 +-
>       drivers/gpu/drm/sti/sti_drv.c                 |  20 +-
>       drivers/gpu/drm/sun4i/sun4i_drv.c             |  26 +-
>       drivers/gpu/drm/tilcdc/tilcdc_drv.c           |  28 +-
>       drivers/gpu/drm/vc4/vc4_drv.c                 |  20 +-
>       drivers/gpu/drm/zte/zx_drm_drv.c              |  20 +-
>       drivers/iommu/mtk_iommu.c                     |  14 +-
>       drivers/iommu/mtk_iommu.h                     |   6 +-
>       drivers/iommu/mtk_iommu_v1.c                  |  14 +-
>       drivers/misc/mei/hdcp/mei_hdcp.c              |  22 +-
>       drivers/power/supply/ab8500_charger.c         |  22 +-
>       drivers/video/fbdev/omap2/omapfb/dss/dss.c    |  20 +-
>       include/drm/drm_of.h                          |   9 +-
>       include/linux/component.h                     |  92 ++-
>       sound/hda/hdac_component.c                    |  21 +-
>       sound/soc/codecs/wcd938x.c                    |  20 +-
>       33 files changed, 780 insertions(+), 488 deletions(-)
> 
> 
>     base-commit: e4e737bb5c170df6135a127739a9e6148ee3da82
>     -- 
>     https://chromeos.dev <https://chromeos.dev>
> 
> 
> 
> -- 
> With Best Regards,
> Andy Shevchenko
> 
> 

Re: [PATCH v2 00/34] component: Make into an aggregate bus

[Stephen Boyd]

Quoting Andrzej Hajda (2021-10-07 03:16:27)
> Hi Stephen,
>
> On 06.10.2021 21:37, Stephen Boyd wrote:
> > This series is from discussion we had on reordering the device lists for
> > drm shutdown paths[1]. I've introduced an 'aggregate' bus that we put
> > the aggregate device onto and then we probe the aggregate device once
> > all the components are probed and call component_add(). The probe/remove
> > hooks are where the bind/unbind calls go, and then a shutdown hook is
> > added that can be used to shutdown the drm display pipeline at the right
> > time.
> >
> > This works for me on my sc7180 board. I no longer get a warning from i2c
> > at shutdown that we're trying to make an i2c transaction after the i2c
> > bus has been shutdown. There's more work to do on the msm drm driver to
> > extract component device resources like clks, regulators, etc. out of
> > the component bind function into the driver probe but I wanted to move
> > everything over now in other component drivers before tackling that
> > problem.
>
>
> As I understand you have DSI host with i2c-controlled DSI bridge. And
> there is an issue that bridge is shutdown before msmdrm. Your solution
> is to 'adjust' device order on pm list.
> I had similar issue and solved it locally by adding notification from
> DSI bridge to DSI host that is has to be removed: mipi_dsi_detach, this
> notification escalates in DSI host to component_del and this allow to
> react properly.
>
> Advantages:
> - it is local (only involves DSI host and DSI device),
> - it does not depend on PM internals,
> - it can be used in other scenarios as well - unbinding DSI device driver
>
> Disadvantage:
> - It is DSI specific (but this is your case), I have advertised some
> time ago more general approach [1][2].
>
> [1]: https://static.sched.com/hosted_files/osseu18/0f/deferred_problem.pdf
> [2]: https://lwn.net/Articles/625454/
>

I think these are all points for or against using the component code in
general? Maybe you can send patches that you think can solve the problem
I'm experiencing and we can review them on the list.

Re: [PATCH v2 00/34] component: Make into an aggregate bus

[Daniel Vetter]

On Thu, Oct 07, 2021 at 04:46:22PM -0400, Stephen Boyd wrote:
> Quoting Andrzej Hajda (2021-10-07 03:16:27)
> > Hi Stephen,
> >
> > On 06.10.2021 21:37, Stephen Boyd wrote:
> > > This series is from discussion we had on reordering the device lists for
> > > drm shutdown paths[1]. I've introduced an 'aggregate' bus that we put
> > > the aggregate device onto and then we probe the aggregate device once
> > > all the components are probed and call component_add(). The probe/remove
> > > hooks are where the bind/unbind calls go, and then a shutdown hook is
> > > added that can be used to shutdown the drm display pipeline at the right
> > > time.
> > >
> > > This works for me on my sc7180 board. I no longer get a warning from i2c
> > > at shutdown that we're trying to make an i2c transaction after the i2c
> > > bus has been shutdown. There's more work to do on the msm drm driver to
> > > extract component device resources like clks, regulators, etc. out of
> > > the component bind function into the driver probe but I wanted to move
> > > everything over now in other component drivers before tackling that
> > > problem.
> >
> >
> > As I understand you have DSI host with i2c-controlled DSI bridge. And
> > there is an issue that bridge is shutdown before msmdrm. Your solution
> > is to 'adjust' device order on pm list.
> > I had similar issue and solved it locally by adding notification from
> > DSI bridge to DSI host that is has to be removed: mipi_dsi_detach, this
> > notification escalates in DSI host to component_del and this allow to
> > react properly.
> >
> > Advantages:
> > - it is local (only involves DSI host and DSI device),
> > - it does not depend on PM internals,
> > - it can be used in other scenarios as well - unbinding DSI device driver
> >
> > Disadvantage:
> > - It is DSI specific (but this is your case), I have advertised some
> > time ago more general approach [1][2].
> >
> > [1]: https://static.sched.com/hosted_files/osseu18/0f/deferred_problem.pdf
> > [2]: https://lwn.net/Articles/625454/
> >
> 
> I think these are all points for or against using the component code in
> general? Maybe you can send patches that you think can solve the problem
> I'm experiencing and we can review them on the list.

Yeah I think this is entirely orthogonal. If you use component, then
component should provide a way to handle this.

If you use something else, like drm_bridge or dsi or whatever, then that
part should provide a solution to stage stuff correctly and handle all the
ordering.

Now there's a bunch of drivers which mix up component with bridge use and
hilarity ensues, but since there's no real effort to fix that I think it's
toally fine to just improve component.c meanwhile.
-Daniel
-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch