Currently, mode_valid is defined only in drm_connector_helper_funcs.
When the bridge is attached with the 'DRM_BRIDGE_ATTACH_NO_CONNECTOR'
flag, the connector is not initialized, and so is the mode_valid
hook under connector helper funcs.
It also returns MODE_OK for all modes without actually checking the
modes.
So move the mode_valid hook to drm_bridge_funcs with proper clock
checks for maximum and minimum pixel clock supported by the bridge.
Signed-off-by: Jayesh Choudhary <j-choudhary@ti.com>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Acked-by: Sui Jingfeng <sui.jingfeng@linux.dev>
Reviewed-by: Aradhya Bhatia <a-bhatia1@ti.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240613083805.439337-2-j-choudhary@ti.com
Signed-off-by: Maxime Ripard <mripard@kernel.org>
The VFP, HBP, and HSA are divided between the available lanes if
there is more than one lane. For certain timings and lane
configurations, the HFP may not be evenly divisible. If the HFP
is rounded down, it ends up being too small which can cause some
monitors to not sync properly. In these instances, adjust htotal
and hsync to round the HFP up, and recalculate the htotal.
This allows 720P-60 to operation on an i.MX8MP with a four-lane
configuration.
Tested-by: Frieder Schrempf <frieder.schrempf@kontron.de> # Kontron BL i.MX8MM with HDMI monitor
Signed-off-by: Adam Ford <aford173@gmail.com>
Signed-off-by: Robert Foss <rfoss@kernel.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20240601144103.198299-2-aford173@gmail.com
The P divider should be set based on the min and max values of
the fin pll which may vary between different platforms.
These ranges are defined per platform, but hard-coded values
were used instead which resulted in a smaller range available
on the i.MX8M[MNP] than what was possible.
As noted by Frieder, there are descripencies between the reference
manuals of the Mini, Nano and Plus, so I reached out to my NXP
rep and got the following response regarding the varing notes
in the documentation.
"Yes it is definitely wrong, the one that is part of the NOTE in
MIPI_DPHY_M_PLLPMS register table against PMS_P, PMS_M and PMS_S is
not correct. I will report this to Doc team, the one customer should
be take into account is the Table 13-40 DPHY PLL Parameters and the
Note above."
With this patch, the clock rates now match the values used in NXP's
downstream kernel.
Fixes: 846307185f ("drm/bridge: samsung-dsim: update PLL reference clock")
Signed-off-by: Adam Ford <aford173@gmail.com>
Reviewed-by: Frieder Schrempf <frieder.schrempf@kontron.de>
Tested-by: Frieder Schrempf <frieder.schrempf@kontron.de>
Reviewed-by: Marek Vasut <marex@denx.de>
Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Robert Foss <rfoss@kernel.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20240601144103.198299-1-aford173@gmail.com
make allmodconfig && make W=1 C=1 reports:
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/gpu/drm/bridge/lontium-lt9611.o
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/gpu/drm/bridge/lontium-lt9611uxc.o
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/gpu/drm/bridge/sil-sii8620.o
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/gpu/drm/bridge/sii9234.o
Add the missing invocations of the MODULE_DESCRIPTION() macro.
Signed-off-by: Jeff Johnson <quic_jjohnson@quicinc.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Maxime Ripard <mripard@kernel.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20240609-md-drivers-gpu-drm-bridge-v1-1-b582c5c815d7@quicinc.com
Pull drm fixes from Dave Airlie:
"Some fixes for the end of the merge window, mostly amdgpu and panthor,
with one nouveau uAPI change that fixes a bad decision we made a few
months back.
nouveau:
- fix bo metadata uAPI for vm bind
panthor:
- Fixes for panthor's heap logical block.
- Reset on unrecoverable fault
- Fix VM references.
- Reset fix.
xlnx:
- xlnx compile and doc fixes.
amdgpu:
- Handle vbios table integrated info v2.3
amdkfd:
- Handle duplicate BOs in reserve_bo_and_cond_vms
- Handle memory limitations on small APUs
dp/mst:
- MST null deref fix.
bridge:
- Don't let next bridge create connector in adv7511 to make probe
work"
* tag 'drm-next-2024-05-25' of https://gitlab.freedesktop.org/drm/kernel:
drm/amdgpu/atomfirmware: add intergrated info v2.3 table
drm/mst: Fix NULL pointer dereference at drm_dp_add_payload_part2
drm/amdkfd: Let VRAM allocations go to GTT domain on small APUs
drm/amdkfd: handle duplicate BOs in reserve_bo_and_cond_vms
drm/bridge: adv7511: Attach next bridge without creating connector
drm/buddy: Fix the warn on's during force merge
drm/nouveau: use tile_mode and pte_kind for VM_BIND bo allocations
drm/panthor: Call panthor_sched_post_reset() even if the reset failed
drm/panthor: Reset the FW VM to NULL on unplug
drm/panthor: Keep a ref to the VM at the panthor_kernel_bo level
drm/panthor: Force an immediate reset on unrecoverable faults
drm/panthor: Document drm_panthor_tiler_heap_destroy::handle validity constraints
drm/panthor: Fix an off-by-one in the heap context retrieval logic
drm/panthor: Relax the constraints on the tiler chunk size
drm/panthor: Make sure the tiler initial/max chunks are consistent
drm/panthor: Fix tiler OOM handling to allow incremental rendering
drm: xlnx: zynqmp_dpsub: Fix compilation error
drm: xlnx: zynqmp_dpsub: Fix few function comments
When the system power resumes, the TTL input of IT6505 may experience
some noise before the video signal stabilizes, necessitating a video
reset. This patch is implemented to prevent a loop of video error
interrupts, which can occur when a video reset in the video FIFO error
interrupt triggers another such interrupt. The patch processes the SCDT
and FIFO error interrupts simultaneously and ignores any video FIFO
error interrupts caused by a video reset.
Fixes: b5c84a9edc ("drm/bridge: add it6505 driver")
Signed-off-by: Kuro Chung <kuro.chung@ite.com.tw>
Signed-off-by: Hermes Wu <hermes.wu@ite.com.tw>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Signed-off-by: Robert Foss <rfoss@kernel.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20240522065528.1053439-1-kuro.chung@ite.com.tw
TC9595 datasheet Video Path0 Control (VPCTRL0) Register bit FRMSYNC description
says "This bit should be disabled only in video mode transmission where Host
transmits video timing together with video data and where pixel clock source
is from DSI clock." . This driver always sources pixel clock from external xtal,
therefore the FRMSYNC bit must always be enabled, enable it.
This fixes an actual issue with DSI-to-DPI mode, where the display would
randomly show subtle pixel flickering, or wobble, or shimmering. This is
visible on solid gray color, but the degree of the shimmering differs
between boots, which makes it hard to debug.
There is a caveat to the FRMSYNC and this bridge pixel PLL, which can only
generate pixel clock with limited accuracy, it may therefore be necessary
to reduce the HFP to fit into line length of input pixel data, to avoid any
possible overflows, which make the output video look striped horizontally.
Signed-off-by: Marek Vasut <marex@denx.de>
Reviewed-by: Robert Foss <rfoss@kernel.org>
Signed-off-by: Robert Foss <rfoss@kernel.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20240513021607.129111-1-marex@denx.de
Pull i2c updates from Wolfram Sang:
"i2c core removes an argument from the i2c_mux_add_adapter() call to
further deprecate class based I2C device instantiation. All users are
converted, too.
Other that that, Andi collected a number if I2C host driver patches.
Those merges have their own description"
* tag 'i2c-for-6.10-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux: (72 commits)
power: supply: sbs-manager: Remove class argument from i2c_mux_add_adapter()
i2c: mux: Remove class argument from i2c_mux_add_adapter()
i2c: synquacer: Fix an error handling path in synquacer_i2c_probe()
i2c: acpi: Unbind mux adapters before delete
i2c: designware: Replace MODULE_ALIAS() with MODULE_DEVICE_TABLE()
i2c: pxa: use 'time_left' variable with wait_event_timeout()
i2c: s3c2410: use 'time_left' variable with wait_event_timeout()
i2c: rk3x: use 'time_left' variable with wait_event_timeout()
i2c: qcom-geni: use 'time_left' variable with wait_for_completion_timeout()
i2c: jz4780: use 'time_left' variable with wait_for_completion_timeout()
i2c: synquacer: use 'time_left' variable with wait_for_completion_timeout()
i2c: stm32f7: use 'time_left' variable with wait_for_completion_timeout()
i2c: stm32f4: use 'time_left' variable with wait_for_completion_timeout()
i2c: st: use 'time_left' variable with wait_for_completion_timeout()
i2c: omap: use 'time_left' variable with wait_for_completion_timeout()
i2c: imx-lpi2c: use 'time_left' variable with wait_for_completion_timeout()
i2c: hix5hd2: use 'time_left' variable with wait_for_completion_timeout()
i2c: exynos5: use 'time_left' variable with wait_for_completion_timeout()
i2c: digicolor: use 'time_left' variable with wait_for_completion_timeout()
i2c: amd-mp2-plat: use 'time_left' variable with wait_for_completion_timeout()
...
The connector is created by either this ADV7511 bridge driver or
any DRM device driver/previous bridge driver, so this ADV7511
bridge driver should not let the next bridge driver create connector.
If the next bridge is a HDMI connector, the next bridge driver
would fail to attach bridge from display_connector_attach() without
the DRM_BRIDGE_ATTACH_NO_CONNECTOR flag.
Add that flag to drm_bridge_attach() function call in
adv7511_bridge_attach() to fix the issue.
This fixes the issue where the HDMI connector bridge fails to attach
to the previous ADV7535 bridge on i.MX8MP EVK platform:
[ 2.216442] [drm:drm_bridge_attach] *ERROR* failed to attach bridge /hdmi-connector to encoder None-37: -22
[ 2.220675] mmc1: SDHCI controller on 30b50000.mmc [30b50000.mmc] using ADMA
[ 2.226262] [drm:drm_bridge_attach] *ERROR* failed to attach bridge /soc@0/bus@30800000/i2c@30a30000/hdmi@3d to encoder None-37: -22
[ 2.245204] [drm:drm_bridge_attach] *ERROR* failed to attach bridge /soc@0/bus@32c00000/dsi@32e60000 to encoder None-37: -22
[ 2.256445] imx-lcdif 32e80000.display-controller: error -EINVAL: Failed to attach bridge for endpoint0
[ 2.265850] imx-lcdif 32e80000.display-controller: error -EINVAL: Cannot connect bridge
[ 2.274009] imx-lcdif 32e80000.display-controller: probe with driver imx-lcdif failed with error -22
Fixes: 14b3cdbd0e ("drm/bridge: adv7511: make it honour next bridge in DT")
Signed-off-by: Liu Ying <victor.liu@nxp.com>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Reviewed-by: Robert Foss <rfoss@kernel.org>
Acked-by: Sui Jingfeng <suijingfeng@bosc.ac.cn>
Reviewed-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240513080243.3952292-1-victor.liu@nxp.com
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
The checks on the existence of bridge->encoder in the implementation of
drm_bridge_funcs::attach() is not necessary, as it has already been checked
in the drm_bridge_attach() function call by previous bridge or KMS driver.
The drm_bridge_attach() will quit with a negative error code returned if
it fails for some reasons, hence, it is guaranteed that the .encoder member
of the drm_bridge instance is not NULL when various bridge attach functions
are called.
Remove the redundant checking codes "if (!bridge->encoder) { ... }".
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Sui Jingfeng <sui.jingfeng@linux.dev>
Signed-off-by: Robert Foss <rfoss@kernel.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20240513153109.46786-13-sui.jingfeng@linux.dev
The checks on the existence of bridge->encoder in the implementation of
drm_bridge_funcs::attach() is not necessary, as it has already been checked
in the drm_bridge_attach() function call by previous bridge or KMS driver.
The drm_bridge_attach() will quit with a negative error code returned if
it fails for some reasons, hence, it is guaranteed that the .encoder member
of the drm_bridge instance is not NULL when various i.MX specific bridge
attach functions are called.
Remove the redundant checking codes "if (!bridge->encoder) { ... }".
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Sui Jingfeng <sui.jingfeng@linux.dev>
Signed-off-by: Robert Foss <rfoss@kernel.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20240513153109.46786-12-sui.jingfeng@linux.dev
In the lt9611uxc_connector_init() function, the check on the existence
of bridge->encoder is not necessary, as it has already been checked in
the drm_bridge_attach() function. And the check on the drm bridge core
happens before check in the implementation. Hence, it is guaranteed that
the .encoder member of the struct drm_bridge is not NULL when
lt9611uxc_connector_init() function get called.
Remove the redundant checking codes "if (!bridge->encoder) { ... }".
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Sui Jingfeng <sui.jingfeng@linux.dev>
Signed-off-by: Robert Foss <rfoss@kernel.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20240513153109.46786-11-sui.jingfeng@linux.dev
In the dw_mipi_dsi_bridge_attach() function, the check on the existence
of bridge->encoder is not necessary, as it has already been checked in
the drm_bridge_attach() function invocked by previous bridge or KMS driver.
The previous drm_bridge_attach() will quit with a negative error code
returned if it fails for some reasons, hence, it is guaranteed that the
.encoder member of the struct drm_bridge is not NULL when
dw_mipi_dsi_bridge_attach() function gets called.
Remove the redundant checking codes "if (!bridge->encoder) { ... }".
Reviewed-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Signed-off-by: Sui Jingfeng <sui.jingfeng@linux.dev>
Signed-off-by: Robert Foss <rfoss@kernel.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20240513153109.46786-10-sui.jingfeng@linux.dev
In the ge_b850v3_lvds_create_connector function, the check on the existence
of bridge->encoder is not necessary, as it has already been checked in the
drm_bridge_attach() function called by upstream bridge or driver. Hence, it
is guaranteed that the .encoder member of the drm_bridge instance is not
NULL when cdns_mhdp_connector_init() function get called.
Remove the redundant checking codes "if (!bridge->encoder) { ... }".
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Sui Jingfeng <sui.jingfeng@linux.dev>
Signed-off-by: Robert Foss <rfoss@kernel.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20240513153109.46786-9-sui.jingfeng@linux.dev
In the cdns_mhdp_connector_init() function, the check on the existence
of bridge->encoder is not necessary, as it has already been checked in
the drm_bridge_attach() function. As the cdns_mhdp_connector_init() is
only called by cdns_mhdp_attach(), it is guaranteed that the .encoder
member of the struct drm_bridge is not NULL when cdns_mhdp_attach() gets
called.
Remove the redundant checking codes "if (!bridge->encoder) { ... }".
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Sui Jingfeng <sui.jingfeng@linux.dev>
Signed-off-by: Robert Foss <rfoss@kernel.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20240513153109.46786-8-sui.jingfeng@linux.dev
In the adv7511_connector_init() function, the check on the existence of
bridge->encoder is not necessary. As it has already been checked in the
drm_bridge_attach() which happens prior to the adv7511_bridge_attach()
get called. Also note that the adv7511_connector_init() is only called by
adv7511_bridge_attach(). Hence, it is guaranteed that the .encoder member
of the drm_bridge instance is not NULL when adv7511_connector_init() get
called.
Remove the redundant checking codes "if (!bridge->encoder) { ... }".
Reviewed-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Signed-off-by: Sui Jingfeng <sui.jingfeng@linux.dev>
Signed-off-by: Robert Foss <rfoss@kernel.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20240513153109.46786-7-sui.jingfeng@linux.dev
In it6505_bridge_attach(), the check on the existence of 'bridge->encoder'
is not necessary, as it has already been checked in the drm_bridge_attach()
which happens prior to it6505_bridge_attach() get called. Note that the
it6505_bridge_attach() will only be called by .attach() of the previous
bridge or KMS driver. The previous drm_bridge_attach() will quit with a
negative error code returned if it fails for some reasons. Hence, it is
guaranteed that the .encoder member of the drm_bridge instance is not NULL
when it6505_bridge_attach() function get called.
Remove the redundant checking codes "if (!bridge->encoder) { ... }".
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Sui Jingfeng <sui.jingfeng@linux.dev>
Signed-off-by: Robert Foss <rfoss@kernel.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20240513153109.46786-6-sui.jingfeng@linux.dev
Because the existence of 'bridge->encoder' has already been checked before
the panel_bridge_attach() function get called, and the drm_bridge_attach()
will quit with a negative error code returned if it fails for some reasons.
Hence, it is guaranteed that the .encoder member of the drm_bridge instance
is not NULL when panel_bridge_attach() function get called.
Remove the redundant checking codes "if (!bridge->encoder) { ... }".
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Sui Jingfeng <sui.jingfeng@linux.dev>
Signed-off-by: Robert Foss <rfoss@kernel.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20240513153109.46786-5-sui.jingfeng@linux.dev
Because the existence of 'bridge->encoder' has already been checked before
the ptn3460_bridge_attach() function get called, and drm_bridge_attach()
will quit with a negative error code returned if it fails for some reasons.
Hence, it is guaranteed that the .encoder member of the drm_bridge instance
is not NULL when the ptn3460_bridge_attach() function get called.
Remove the redundant checking codes "if (!bridge->encoder) { ... }".
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Sui Jingfeng <sui.jingfeng@linux.dev>
Signed-off-by: Robert Foss <rfoss@kernel.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20240513153109.46786-4-sui.jingfeng@linux.dev
Because the existence of bridge->encoder has already been checked before
the simple_bridge_attach() function get called, And drm_bridge_attach()
will quit with a negative error code returned if it fails for some reasons.
Hence, it is guaranteed that the .encoder member of the drm_bridge instance
is not NULL when the tfp410_attach() function get called.
Remove the redundant checking codes "if (!bridge->encoder) { ... }".
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Sui Jingfeng <sui.jingfeng@linux.dev>
Signed-off-by: Robert Foss <rfoss@kernel.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20240513153109.46786-3-sui.jingfeng@linux.dev
Because the existence of 'bridge->encoder' has already been checked before
the simple_bridge_attach() function get called, and drm_bridge_attach()
will quit with a negative error code returned if it fails for some reasons.
Hence, it is guaranteed that the .encoder member of the drm_bridge instance
is not NULL when the simple_bridge_attach() get called.
Remove the redundant checking codes "if (!bridge->encoder) { ... }".
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Sui Jingfeng <sui.jingfeng@linux.dev>
Signed-off-by: Robert Foss <rfoss@kernel.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20240513153109.46786-2-sui.jingfeng@linux.dev
99a741aa7a2d ("i2c: mux: gpio: remove support for class-based device
instantiation") removed the last call to i2c_mux_add_adapter() with a
non-null class argument. Therefore the class argument can be removed.
Note: Class-based device instantiation is a legacy mechanism which
shouldn't be used in new code, so we can rule out that this argument
may be needed again in the future.
Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Reviewed-by: Thomas Zimmermann <tzimmermann@suse.de>
Acked-by: Peter Rosin <peda@axentia.se>
Reviewed-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Acked-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Acked-by: Rob Herring (Arm) <robh@kernel.org>
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
This reverts commit 8a91b29f1f.
The regulator_disable() added by the original commit solves one kind of
regulator imbalance but adds another one as it allows the regulator to be
disabled one more time than it is enabled in the following scenario:
1. Start video pipeline -> sn65dsi83_atomic_pre_enable -> regulator_enable
2. PLL lock fails -> regulator_disable
3. Stop video pipeline -> sn65dsi83_atomic_disable -> regulator_disable
The reason is clear from the code flow, which looks like this (after
removing unrelated code):
static void sn65dsi83_atomic_pre_enable()
{
regulator_enable(ctx->vcc);
if (PLL failed locking) {
regulator_disable(ctx->vcc); <---- added by patch being reverted
return;
}
}
static void sn65dsi83_atomic_disable()
{
regulator_disable(ctx->vcc);
}
The use case for introducing the additional regulator_disable() was
removing the module for debugging (see link below for the discussion). If
the module is removed after a .atomic_pre_enable, i.e. with an active
pipeline from the DRM point of view, .atomic_disable is not called and thus
the regulator would not be disabled.
According to the discussion however there is no actual use case for
removing the module with an active pipeline, except for
debugging/development.
On the other hand, the occurrence of a PLL lock failure is possible due to
any physical reason (e.g. a temporary hardware failure for electrical
reasons) so handling it gracefully should be supported. As there is no way
for .atomic[_pre]_enable to report an error to the core, the only clean way
to support it is calling regulator_disabled() only in .atomic_disable,
unconditionally, as it was before.
Link: https://lore.kernel.org/all/15244220.uLZWGnKmhe@steina-w/
Fixes: 8a91b29f1f ("drm/bridge: ti-sn65dsi83: Fix enable error path")
Reviewed-by: Alexander Stein <alexander.stein@ew.tq-group.com>
Signed-off-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
Signed-off-by: Robert Foss <rfoss@kernel.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20240426122259.46808-1-luca.ceresoli@bootlin.com
(cherry picked from commit 2940ee03b2)
Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
This reverts commit 8a91b29f1f.
The regulator_disable() added by the original commit solves one kind of
regulator imbalance but adds another one as it allows the regulator to be
disabled one more time than it is enabled in the following scenario:
1. Start video pipeline -> sn65dsi83_atomic_pre_enable -> regulator_enable
2. PLL lock fails -> regulator_disable
3. Stop video pipeline -> sn65dsi83_atomic_disable -> regulator_disable
The reason is clear from the code flow, which looks like this (after
removing unrelated code):
static void sn65dsi83_atomic_pre_enable()
{
regulator_enable(ctx->vcc);
if (PLL failed locking) {
regulator_disable(ctx->vcc); <---- added by patch being reverted
return;
}
}
static void sn65dsi83_atomic_disable()
{
regulator_disable(ctx->vcc);
}
The use case for introducing the additional regulator_disable() was
removing the module for debugging (see link below for the discussion). If
the module is removed after a .atomic_pre_enable, i.e. with an active
pipeline from the DRM point of view, .atomic_disable is not called and thus
the regulator would not be disabled.
According to the discussion however there is no actual use case for
removing the module with an active pipeline, except for
debugging/development.
On the other hand, the occurrence of a PLL lock failure is possible due to
any physical reason (e.g. a temporary hardware failure for electrical
reasons) so handling it gracefully should be supported. As there is no way
for .atomic[_pre]_enable to report an error to the core, the only clean way
to support it is calling regulator_disabled() only in .atomic_disable,
unconditionally, as it was before.
Link: https://lore.kernel.org/all/15244220.uLZWGnKmhe@steina-w/
Fixes: 8a91b29f1f ("drm/bridge: ti-sn65dsi83: Fix enable error path")
Reviewed-by: Alexander Stein <alexander.stein@ew.tq-group.com>
Signed-off-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
Signed-off-by: Robert Foss <rfoss@kernel.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20240426122259.46808-1-luca.ceresoli@bootlin.com
