The big motivation for this patch series is mostly described in the patch
("drm/panel: Add a way for other devices to follow panel state"), but to
quickly summarize here: for touchscreens that are connected to a panel we
need the ability to power sequence the two device together. This is not a
new need, but so far we've managed to get by through a combination of
inefficiency, added costs, or perhaps just a little bit of brokenness.
It's time to do better. This patch series allows us to do better.
Assuming that people think this patch series looks OK, we'll have to
figure out the right way to land it. The panel patches and i2c-hid
patches will go through very different trees and so either we'll need
an Ack from one side or the other or someone to create a tag for the
other tree to pull in. This will _probably_ require the true drm-misc
maintainers to get involved, not a lowly committer. ;-)
Version 4 of this series adds a new patch that suspends i2c-hid
devices at remove time even for non panel-followers to make things
consistent. It also attempts to isolate the panel follower code a bit
more as per Benjamin's feedback on v3 and adds an item to the DRM todo
list as per Maxime's request. As per Maxime's response to my v3 cover
letter, I added his Reviewed-by tag to all 10 patches that were part
of v3 (but left it off of the new i2c-hid patch in v4).
Version 3 of this series was a long time coming after v2. Maxime and I
had a very long discussion trying to figure out if there was a beter
way and in the end we didn't find one so he was OK with the series in
general [1]. After that got resolved, I tried to resolve Benjamin's
feedback but got stuck [2]. Eventually I made my best guess. The end
result was a v3 that wasn't that different from v2 but that had a tiny
bit more code split out.
Version 2 of this patch series didn't change too much. At a high level:
* I added all the forgotten "static" to functions.
* I've hopefully made the bindings better.
* I've integrated into fw_devlink.
* I cleaned up a few descriptions / comments.
As far as I can tell, as of v4 everyone is on the same page that this
patch series looks like a reasonable solution to the problem and we
just need to get all the nits fixed and figure out how to land it.
[1] https://lore.kernel.org/r/gkwymmfkdy2p2evz22wmbwgw42ii4wnvmvu64m3bghmj2jhv7x@4mbstjxnagxd
[2] https://lore.kernel.org/r/CAD=FV=VbdeomBGbWhppY+5TOSwt64GWBHga68OXFwsnO4gg4UA@mail.gmail.com
Changes in v4:
- Document further cleanup in the official DRM todo list.
- ("Suspend i2c-hid devices in remove") new for v4.
- Move panel follower alternative checks to wrapper functions.
- Rebase atop ("Suspend i2c-hid devices in remove").
Changes in v3:
- Add is_panel_follower() as a convenience for clients.
- Add "depends on DRM || !DRM" to Kconfig to avoid randconfig error.
- Split more of the panel follower code out of the core.
Changes in v2:
- Move the description to the generic touchscreen.yaml.
- Update the desc to make it clearer it's only for integrated devices.
- Add even more text to the commit message.
- A few comment cleanups.
- ("Add a devlink for panel followers") new for v2.
- i2c_hid_core_initial_power_up() is now static.
- i2c_hid_core_panel_prepared() and ..._unpreparing() are now static.
- ihid_core_panel_prepare_work() is now static.
- Improve documentation for smp_wmb().
Douglas Anderson (11):
dt-bindings: HID: i2c-hid: Add "panel" property to i2c-hid backed
touchscreens
drm/panel: Check for already prepared/enabled in drm_panel
drm/panel: Add a way for other devices to follow panel state
of: property: fw_devlink: Add a devlink for panel followers
HID: i2c-hid: Switch to SYSTEM_SLEEP_PM_OPS()
HID: i2c-hid: Rearrange probe() to power things up later
HID: i2c-hid: Make suspend and resume into helper functions
HID: i2c-hid: Suspend i2c-hid devices in remove
HID: i2c-hid: Support being a panel follower
HID: i2c-hid: Do panel follower work on the system_wq
arm64: dts: qcom: sc7180: Link trogdor touchscreens to the panels
.../bindings/input/elan,ekth6915.yaml | 5 +
.../bindings/input/goodix,gt7375p.yaml | 5 +
.../bindings/input/hid-over-i2c.yaml | 2 +
.../input/touchscreen/touchscreen.yaml | 7 +
Documentation/gpu/todo.rst | 24 ++
.../boot/dts/qcom/sc7180-trogdor-coachz.dtsi | 1 +
.../dts/qcom/sc7180-trogdor-homestar.dtsi | 1 +
.../boot/dts/qcom/sc7180-trogdor-lazor.dtsi | 1 +
.../boot/dts/qcom/sc7180-trogdor-pompom.dtsi | 1 +
.../qcom/sc7180-trogdor-quackingstick.dtsi | 1 +
.../dts/qcom/sc7180-trogdor-wormdingler.dtsi | 1 +
drivers/gpu/drm/drm_panel.c | 218 ++++++++++-
drivers/hid/i2c-hid/Kconfig | 2 +
drivers/hid/i2c-hid/i2c-hid-core.c | 349 +++++++++++++-----
drivers/of/property.c | 2 +
include/drm/drm_panel.h | 94 +++++
16 files changed, 617 insertions(+), 97 deletions(-)
--
2.41.0.487.g6d72f3e995-goog
As talked about in the patch ("drm/panel: Add a way for other devices
to follow panel state"), touchscreens that are connected to panels are
generally expected to be power sequenced together with the panel
they're attached to. Today, nothing provides information allowing you
to find out that a touchscreen is connected to a panel. Let's add a
phandle for this.
The proerty is added to the generic touchscreen bindings and then
enabled in the bindings for the i2c-hid backed devices. This can and
should be added for other touchscreens in the future, but for now
let's start small.
Reviewed-by: Krzysztof Kozlowski <[email protected]>
Reviewed-by: Maxime Ripard <[email protected]>
Signed-off-by: Douglas Anderson <[email protected]>
---
(no changes since v2)
Changes in v2:
- Move the description to the generic touchscreen.yaml.
- Update the desc to make it clearer it's only for integrated devices.
Documentation/devicetree/bindings/input/elan,ekth6915.yaml | 5 +++++
.../devicetree/bindings/input/goodix,gt7375p.yaml | 5 +++++
Documentation/devicetree/bindings/input/hid-over-i2c.yaml | 2 ++
.../devicetree/bindings/input/touchscreen/touchscreen.yaml | 7 +++++++
4 files changed, 19 insertions(+)
diff --git a/Documentation/devicetree/bindings/input/elan,ekth6915.yaml b/Documentation/devicetree/bindings/input/elan,ekth6915.yaml
index 05e6f2df604c..3e2d216c6432 100644
--- a/Documentation/devicetree/bindings/input/elan,ekth6915.yaml
+++ b/Documentation/devicetree/bindings/input/elan,ekth6915.yaml
@@ -13,6 +13,9 @@ description:
Supports the Elan eKTH6915 touchscreen controller.
This touchscreen controller uses the i2c-hid protocol with a reset GPIO.
+allOf:
+ - $ref: /schemas/input/touchscreen/touchscreen.yaml#
+
properties:
compatible:
items:
@@ -24,6 +27,8 @@ properties:
interrupts:
maxItems: 1
+ panel: true
+
reset-gpios:
description: Reset GPIO; not all touchscreens using eKTH6915 hook this up.
diff --git a/Documentation/devicetree/bindings/input/goodix,gt7375p.yaml b/Documentation/devicetree/bindings/input/goodix,gt7375p.yaml
index 1edad1da1196..358cb8275bf1 100644
--- a/Documentation/devicetree/bindings/input/goodix,gt7375p.yaml
+++ b/Documentation/devicetree/bindings/input/goodix,gt7375p.yaml
@@ -14,6 +14,9 @@ description:
This touchscreen uses the i2c-hid protocol but has some non-standard
power sequencing required.
+allOf:
+ - $ref: /schemas/input/touchscreen/touchscreen.yaml#
+
properties:
compatible:
oneOf:
@@ -30,6 +33,8 @@ properties:
interrupts:
maxItems: 1
+ panel: true
+
reset-gpios:
true
diff --git a/Documentation/devicetree/bindings/input/hid-over-i2c.yaml b/Documentation/devicetree/bindings/input/hid-over-i2c.yaml
index 7156b08f7645..138caad96a29 100644
--- a/Documentation/devicetree/bindings/input/hid-over-i2c.yaml
+++ b/Documentation/devicetree/bindings/input/hid-over-i2c.yaml
@@ -44,6 +44,8 @@ properties:
description: HID descriptor address
$ref: /schemas/types.yaml#/definitions/uint32
+ panel: true
+
post-power-on-delay-ms:
description: Time required by the device after enabling its regulators
or powering it on, before it is ready for communication.
diff --git a/Documentation/devicetree/bindings/input/touchscreen/touchscreen.yaml b/Documentation/devicetree/bindings/input/touchscreen/touchscreen.yaml
index 895592da9626..431c13335c40 100644
--- a/Documentation/devicetree/bindings/input/touchscreen/touchscreen.yaml
+++ b/Documentation/devicetree/bindings/input/touchscreen/touchscreen.yaml
@@ -10,6 +10,13 @@ maintainers:
- Dmitry Torokhov <[email protected]>
properties:
+ panel:
+ description: If this touchscreen is integrally connected to a panel, this
+ is a reference to that panel. The presence of this reference indicates
+ that the touchscreen should be power sequenced together with the panel
+ and that they may share power and/or reset signals.
+ $ref: /schemas/types.yaml#/definitions/phandle
+
touchscreen-min-x:
description: minimum x coordinate reported
$ref: /schemas/types.yaml#/definitions/uint32
--
2.41.0.487.g6d72f3e995-goog
In a whole pile of panel drivers, we have code to make the
prepare/unprepare/enable/disable callbacks behave as no-ops if they've
already been called. It's silly to have this code duplicated
everywhere. Add it to the core instead so that we can eventually
delete it from all the drivers. Note: to get some idea of the
duplicated code, try:
git grep 'if.*>prepared' -- drivers/gpu/drm/panel
git grep 'if.*>enabled' -- drivers/gpu/drm/panel
NOTE: arguably, the right thing to do here is actually to skip this
patch and simply remove all the extra checks from the individual
drivers. Perhaps the checks were needed at some point in time in the
past but maybe they no longer are? Certainly as we continue
transitioning over to "panel_bridge" then we expect there to be much
less variety in how these calls are made. When we're called as part of
the bridge chain, things should be pretty simple. In fact, there was
some discussion in the past about these checks [1], including a
discussion about whether the checks were needed and whether the calls
ought to be refcounted. At the time, I decided not to mess with it
because it felt too risky.
Looking closer at it now, I'm fairly certain that nothing in the
existing codebase is expecting these calls to be refcounted. The only
real question is whether someone is already doing something to ensure
prepare()/unprepare() match and enabled()/disable() match. I would say
that, even if there is something else ensuring that things match,
there's enough complexity that adding an extra bool and an extra
double-check here is a good idea. Let's add a drm_warn() to let people
know that it's considered a minor error to take advantage of
drm_panel's double-checking but we'll still make things work fine.
We'll also add an entry to the official DRM todo list to remove the
now pointless check from the panels after this patch lands and,
eventually, fixup anyone who is triggering the new warning.
[1] https://lore.kernel.org/r/20210416153909.v4.27.I502f2a92ddd36c3d28d014dd75e170c2d405a0a5@changeid
Acked-by: Neil Armstrong <[email protected]>
Reviewed-by: Maxime Ripard <[email protected]>
Signed-off-by: Douglas Anderson <[email protected]>
---
This has Neil's Ack and Maxime's review and I could commit it to
drm-misc-next, but for now I'm holding off to land with the rest of
this series since the second drm patch in my series depends on this
one.
Once this lands somewhere, I'll take the action item to post patches
to delete the now pointless checks in the individual panels.
Changes in v4:
- Document further cleanup in the official DRM todo list.
Documentation/gpu/todo.rst | 24 ++++++++++++++++++
drivers/gpu/drm/drm_panel.c | 49 ++++++++++++++++++++++++++++++++-----
include/drm/drm_panel.h | 14 +++++++++++
3 files changed, 81 insertions(+), 6 deletions(-)
diff --git a/Documentation/gpu/todo.rst b/Documentation/gpu/todo.rst
index 68bdafa0284f..e3b272c97758 100644
--- a/Documentation/gpu/todo.rst
+++ b/Documentation/gpu/todo.rst
@@ -452,6 +452,30 @@ Contact: Thomas Zimmermann <[email protected]>
Level: Starter
+Clean up checks for already prepared/enabled in panels
+------------------------------------------------------
+
+In a whole pile of panel drivers, we have code to make the
+prepare/unprepare/enable/disable callbacks behave as no-ops if they've already
+been called. To get some idea of the duplicated code, try:
+ git grep 'if.*>prepared' -- drivers/gpu/drm/panel
+ git grep 'if.*>enabled' -- drivers/gpu/drm/panel
+
+In the patch ("drm/panel: Check for already prepared/enabled in drm_panel")
+we've moved this check to the core. Now we can most definitely remove the
+check from the individual panels and save a pile of code.
+
+In adition to removing the check from the individual panels, it is believed
+that even the core shouldn't need this check and that should be considered
+an error if other code ever relies on this check. The check in the core
+currently prints a warning whenever something is relying on this check with
+dev_warn(). After a little while, we likely want to promote this to a
+WARN(1) to help encourage folks not to rely on this behavior.
+
+Contact: Douglas Anderson <[email protected]>
+
+Level: Starter/Intermediate
+
Core refactorings
=================
diff --git a/drivers/gpu/drm/drm_panel.c b/drivers/gpu/drm/drm_panel.c
index f634371c717a..4e1c4e42575b 100644
--- a/drivers/gpu/drm/drm_panel.c
+++ b/drivers/gpu/drm/drm_panel.c
@@ -105,11 +105,22 @@ EXPORT_SYMBOL(drm_panel_remove);
*/
int drm_panel_prepare(struct drm_panel *panel)
{
+ int ret;
+
if (!panel)
return -EINVAL;
- if (panel->funcs && panel->funcs->prepare)
- return panel->funcs->prepare(panel);
+ if (panel->prepared) {
+ dev_warn(panel->dev, "Skipping prepare of already prepared panel\n");
+ return 0;
+ }
+
+ if (panel->funcs && panel->funcs->prepare) {
+ ret = panel->funcs->prepare(panel);
+ if (ret < 0)
+ return ret;
+ }
+ panel->prepared = true;
return 0;
}
@@ -128,11 +139,22 @@ EXPORT_SYMBOL(drm_panel_prepare);
*/
int drm_panel_unprepare(struct drm_panel *panel)
{
+ int ret;
+
if (!panel)
return -EINVAL;
- if (panel->funcs && panel->funcs->unprepare)
- return panel->funcs->unprepare(panel);
+ if (!panel->prepared) {
+ dev_warn(panel->dev, "Skipping unprepare of already unprepared panel\n");
+ return 0;
+ }
+
+ if (panel->funcs && panel->funcs->unprepare) {
+ ret = panel->funcs->unprepare(panel);
+ if (ret < 0)
+ return ret;
+ }
+ panel->prepared = false;
return 0;
}
@@ -155,11 +177,17 @@ int drm_panel_enable(struct drm_panel *panel)
if (!panel)
return -EINVAL;
+ if (panel->enabled) {
+ dev_warn(panel->dev, "Skipping enable of already enabled panel\n");
+ return 0;
+ }
+
if (panel->funcs && panel->funcs->enable) {
ret = panel->funcs->enable(panel);
if (ret < 0)
return ret;
}
+ panel->enabled = true;
ret = backlight_enable(panel->backlight);
if (ret < 0)
@@ -187,13 +215,22 @@ int drm_panel_disable(struct drm_panel *panel)
if (!panel)
return -EINVAL;
+ if (!panel->enabled) {
+ dev_warn(panel->dev, "Skipping disable of already disabled panel\n");
+ return 0;
+ }
+
ret = backlight_disable(panel->backlight);
if (ret < 0)
DRM_DEV_INFO(panel->dev, "failed to disable backlight: %d\n",
ret);
- if (panel->funcs && panel->funcs->disable)
- return panel->funcs->disable(panel);
+ if (panel->funcs && panel->funcs->disable) {
+ ret = panel->funcs->disable(panel);
+ if (ret < 0)
+ return ret;
+ }
+ panel->enabled = false;
return 0;
}
diff --git a/include/drm/drm_panel.h b/include/drm/drm_panel.h
index 432fab2347eb..c6cf75909389 100644
--- a/include/drm/drm_panel.h
+++ b/include/drm/drm_panel.h
@@ -198,6 +198,20 @@ struct drm_panel {
* the panel is powered up.
*/
bool prepare_prev_first;
+
+ /**
+ * @prepared:
+ *
+ * If true then the panel has been prepared.
+ */
+ bool prepared;
+
+ /**
+ * @enabled:
+ *
+ * If true then the panel has been enabled.
+ */
+ bool enabled;
};
void drm_panel_init(struct drm_panel *panel, struct device *dev,
--
2.41.0.487.g6d72f3e995-goog
Inform fw_devlink of the fact that a panel follower (like a
touchscreen) is effectively a consumer of the panel from the purposes
of fw_devlink.
NOTE: this patch isn't required for correctness but instead optimizes
probe order / helps avoid deferrals.
Acked-by: Rob Herring <[email protected]>
Reviewed-by: Maxime Ripard <[email protected]>
Signed-off-by: Douglas Anderson <[email protected]>
---
Since this is so small, I'd presume it's OK for it to go through a DRM
tree with the proper Ack. That being said, this patch is just an
optimization and thus it could land completely separately from the
rest and they could all meet up in mainline.
(no changes since v2)
Changes in v2:
- ("Add a devlink for panel followers") new for v2.
drivers/of/property.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/drivers/of/property.c b/drivers/of/property.c
index ddc75cd50825..cf8dacf3e3b8 100644
--- a/drivers/of/property.c
+++ b/drivers/of/property.c
@@ -1266,6 +1266,7 @@ DEFINE_SIMPLE_PROP(pwms, "pwms", "#pwm-cells")
DEFINE_SIMPLE_PROP(resets, "resets", "#reset-cells")
DEFINE_SIMPLE_PROP(leds, "leds", NULL)
DEFINE_SIMPLE_PROP(backlight, "backlight", NULL)
+DEFINE_SIMPLE_PROP(panel, "panel", NULL)
DEFINE_SUFFIX_PROP(regulators, "-supply", NULL)
DEFINE_SUFFIX_PROP(gpio, "-gpio", "#gpio-cells")
@@ -1354,6 +1355,7 @@ static const struct supplier_bindings of_supplier_bindings[] = {
{ .parse_prop = parse_resets, },
{ .parse_prop = parse_leds, },
{ .parse_prop = parse_backlight, },
+ { .parse_prop = parse_panel, },
{ .parse_prop = parse_gpio_compat, },
{ .parse_prop = parse_interrupts, },
{ .parse_prop = parse_regulators, },
--
2.41.0.487.g6d72f3e995-goog
In the i2c-hid remove() function we currently try to power off,
depopulate our child device, and free our resources. That's OK, but...
* If the i2c-hid device is on a power rail that can't turn off (either
an always-on or a shared power rail) we won't try to put the device
in a low power state during remove(). This probably doesn't matter
for very many devices but it could be nice in some instances.
* If the i2c-hid device somehow manages to generate an interrupt after
we tried to power off it is conceivable that the interrupt could
arrive during or after the call to hid_destroy_device() but before
the call to free_irq(). That could cause a crash since our IRQ
handler isn't expecting it. One could imagine this happening in
the case where we couldn't turn off (see the previous bullet) or,
possibly, if the interrupt line could glitch shortly after the
device powered off.
Let's call the suspend code during remove to avoid these issues. That
will put the device into a low power state and also disable
interrupts.
Technically, one could consider this a "fix" of commit 4a200c3b9a40
("HID: i2c-hid: introduce HID over i2c specification implementation").
However, since the above bullet points are more theoretical than
problems seen on real systems and since the remove() of an i2c-hid
touchscreen isn't terribly likely to be called in production, it's
probably not worth the bother of trying to backport it.
Signed-off-by: Douglas Anderson <[email protected]>
---
Changes in v4:
- ("Suspend i2c-hid devices in remove") new for v4.
drivers/hid/i2c-hid/i2c-hid-core.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/drivers/hid/i2c-hid/i2c-hid-core.c b/drivers/hid/i2c-hid/i2c-hid-core.c
index fa8a1ca43d7f..46658ed6380f 100644
--- a/drivers/hid/i2c-hid/i2c-hid-core.c
+++ b/drivers/hid/i2c-hid/i2c-hid-core.c
@@ -941,7 +941,7 @@ static void i2c_hid_core_shutdown_tail(struct i2c_hid *ihid)
ihid->ops->shutdown_tail(ihid->ops);
}
-static int i2c_hid_core_suspend(struct i2c_hid *ihid)
+static int i2c_hid_core_suspend(struct i2c_hid *ihid, bool force_poweroff)
{
struct i2c_client *client = ihid->client;
struct hid_device *hid = ihid->hid;
@@ -956,7 +956,7 @@ static int i2c_hid_core_suspend(struct i2c_hid *ihid)
disable_irq(client->irq);
- if (!device_may_wakeup(&client->dev))
+ if (force_poweroff || !device_may_wakeup(&client->dev))
i2c_hid_core_power_down(ihid);
return 0;
@@ -1143,7 +1143,7 @@ void i2c_hid_core_remove(struct i2c_client *client)
struct i2c_hid *ihid = i2c_get_clientdata(client);
struct hid_device *hid;
- i2c_hid_core_power_down(ihid);
+ i2c_hid_core_suspend(ihid, true);
hid = ihid->hid;
hid_destroy_device(hid);
@@ -1171,7 +1171,7 @@ static int i2c_hid_core_pm_suspend(struct device *dev)
struct i2c_client *client = to_i2c_client(dev);
struct i2c_hid *ihid = i2c_get_clientdata(client);
- return i2c_hid_core_suspend(ihid);
+ return i2c_hid_core_suspend(ihid, false);
}
static int i2c_hid_core_pm_resume(struct device *dev)
--
2.41.0.487.g6d72f3e995-goog
As talked about in the patch ("drm/panel: Add a way for other devices
to follow panel state"), we really want to keep the power states of a
touchscreen and the panel it's attached to in sync with each other. In
that spirit, add support to i2c-hid to be a panel follower. This will
let the i2c-hid driver get informed when the panel is powered on and
off. From there we can match the i2c-hid device's power state to that
of the panel.
NOTE: this patch specifically _doesn't_ use pm_runtime to keep track
of / manage the power state of the i2c-hid device, even though my
first instinct said that would be the way to go. Specific problems
with using pm_runtime():
* The initial power up couldn't happen in a runtime resume function
since it create sub-devices and, apparently, that's not good to do
in your resume function.
* Managing our power state with pm_runtime meant fighting to make the
right thing happen at system suspend to prevent the system from
trying to resume us only to suspend us again. While this might be
able to be solved, it added complexity.
Overall the code without pm_runtime() ended up being smaller and
easier to understand.
Reviewed-by: Maxime Ripard <[email protected]>
Signed-off-by: Douglas Anderson <[email protected]>
---
Changes in v4:
- Move panel follower alternative checks to wrapper functions.
- Rebase atop ("Suspend i2c-hid devices in remove").
Changes in v3:
- Add "depends on DRM || !DRM" to Kconfig to avoid randconfig error.
- Split more of the panel follower code out of the core.
Changes in v2:
- i2c_hid_core_panel_prepared() and ..._unpreparing() are now static.
drivers/hid/i2c-hid/Kconfig | 2 +
drivers/hid/i2c-hid/i2c-hid-core.c | 93 +++++++++++++++++++++++++++++-
2 files changed, 92 insertions(+), 3 deletions(-)
diff --git a/drivers/hid/i2c-hid/Kconfig b/drivers/hid/i2c-hid/Kconfig
index 3be17109301a..2bdb55203104 100644
--- a/drivers/hid/i2c-hid/Kconfig
+++ b/drivers/hid/i2c-hid/Kconfig
@@ -70,5 +70,7 @@ config I2C_HID_OF_GOODIX
config I2C_HID_CORE
tristate
+ # We need to call into panel code so if DRM=m, this can't be 'y'
+ depends on DRM || !DRM
endif
diff --git a/drivers/hid/i2c-hid/i2c-hid-core.c b/drivers/hid/i2c-hid/i2c-hid-core.c
index 46658ed6380f..fc3087a983f5 100644
--- a/drivers/hid/i2c-hid/i2c-hid-core.c
+++ b/drivers/hid/i2c-hid/i2c-hid-core.c
@@ -38,6 +38,8 @@
#include <linux/mutex.h>
#include <asm/unaligned.h>
+#include <drm/drm_panel.h>
+
#include "../hid-ids.h"
#include "i2c-hid.h"
@@ -107,6 +109,8 @@ struct i2c_hid {
struct mutex reset_lock;
struct i2chid_ops *ops;
+ struct drm_panel_follower panel_follower;
+ bool is_panel_follower;
};
static const struct i2c_hid_quirks {
@@ -993,7 +997,7 @@ static int i2c_hid_core_resume(struct i2c_hid *ihid)
}
/**
- * i2c_hid_core_initial_power_up() - First time power up of the i2c-hid device.
+ * __do_i2c_hid_core_initial_power_up() - First time power up of the i2c-hid device.
* @ihid: The ihid object created during probe.
*
* This function is called at probe time.
@@ -1004,7 +1008,7 @@ static int i2c_hid_core_resume(struct i2c_hid *ihid)
*
* Return: 0 or error code.
*/
-static int i2c_hid_core_initial_power_up(struct i2c_hid *ihid)
+static int __do_i2c_hid_core_initial_power_up(struct i2c_hid *ihid)
{
struct i2c_client *client = ihid->client;
struct hid_device *hid = ihid->hid;
@@ -1058,6 +1062,83 @@ static int i2c_hid_core_initial_power_up(struct i2c_hid *ihid)
return ret;
}
+static int i2c_hid_core_panel_prepared(struct drm_panel_follower *follower)
+{
+ struct i2c_hid *ihid = container_of(follower, struct i2c_hid, panel_follower);
+ struct hid_device *hid = ihid->hid;
+
+ /*
+ * hid->version is set on the first power up. If it's still zero then
+ * this is the first power on so we should perform initial power up
+ * steps.
+ */
+ if (!hid->version)
+ return __do_i2c_hid_core_initial_power_up(ihid);
+
+ return i2c_hid_core_resume(ihid);
+}
+
+static int i2c_hid_core_panel_unpreparing(struct drm_panel_follower *follower)
+{
+ struct i2c_hid *ihid = container_of(follower, struct i2c_hid, panel_follower);
+
+ return i2c_hid_core_suspend(ihid, true);
+}
+
+static const struct drm_panel_follower_funcs i2c_hid_core_panel_follower_funcs = {
+ .panel_prepared = i2c_hid_core_panel_prepared,
+ .panel_unpreparing = i2c_hid_core_panel_unpreparing,
+};
+
+static int i2c_hid_core_register_panel_follower(struct i2c_hid *ihid)
+{
+ struct device *dev = &ihid->client->dev;
+ int ret;
+
+ ihid->is_panel_follower = true;
+ ihid->panel_follower.funcs = &i2c_hid_core_panel_follower_funcs;
+
+ /*
+ * If we're not in control of our own power up/power down then we can't
+ * do the logic to manage wakeups. Give a warning if a user thought
+ * that was possible then force the capability off.
+ */
+ if (device_can_wakeup(dev)) {
+ dev_warn(dev, "Can't wakeup if following panel\n");
+ device_set_wakeup_capable(dev, false);
+ }
+
+ ret = drm_panel_add_follower(dev, &ihid->panel_follower);
+ if (ret)
+ return ret;
+
+ return 0;
+}
+
+static int i2c_hid_core_initial_power_up(struct i2c_hid *ihid)
+{
+ /*
+ * If we're a panel follower, we'll register and do our initial power
+ * up when the panel turns on; otherwise we do it right away.
+ */
+ if (drm_is_panel_follower(&ihid->client->dev))
+ return i2c_hid_core_register_panel_follower(ihid);
+ else
+ return __do_i2c_hid_core_initial_power_up(ihid);
+}
+
+static void i2c_hid_core_final_power_down(struct i2c_hid *ihid)
+{
+ /*
+ * If we're a follower, the act of unfollowing will cause us to be
+ * powered down. Otherwise we need to manually do it.
+ */
+ if (ihid->is_panel_follower)
+ drm_panel_remove_follower(&ihid->panel_follower);
+ else
+ i2c_hid_core_suspend(ihid, true);
+}
+
int i2c_hid_core_probe(struct i2c_client *client, struct i2chid_ops *ops,
u16 hid_descriptor_address, u32 quirks)
{
@@ -1143,7 +1224,7 @@ void i2c_hid_core_remove(struct i2c_client *client)
struct i2c_hid *ihid = i2c_get_clientdata(client);
struct hid_device *hid;
- i2c_hid_core_suspend(ihid, true);
+ i2c_hid_core_final_power_down(ihid);
hid = ihid->hid;
hid_destroy_device(hid);
@@ -1171,6 +1252,9 @@ static int i2c_hid_core_pm_suspend(struct device *dev)
struct i2c_client *client = to_i2c_client(dev);
struct i2c_hid *ihid = i2c_get_clientdata(client);
+ if (ihid->is_panel_follower)
+ return 0;
+
return i2c_hid_core_suspend(ihid, false);
}
@@ -1179,6 +1263,9 @@ static int i2c_hid_core_pm_resume(struct device *dev)
struct i2c_client *client = to_i2c_client(dev);
struct i2c_hid *ihid = i2c_get_clientdata(client);
+ if (ihid->is_panel_follower)
+ return 0;
+
return i2c_hid_core_resume(ihid);
}
--
2.41.0.487.g6d72f3e995-goog
These days, it's fairly common to see panels that have touchscreens
attached to them. The panel and the touchscreen can somewhat be
thought of as totally separate devices and, historically, this is how
Linux has treated them. However, treating them as separate isn't
necessarily the best way to model the two devices, it was just that
there was no better way. Specifically, there is little practical
reason to have the touchscreen powered on when the panel is turned
off, but if we model the devices separately we have no way to keep the
two devices' power states in sync with each other.
The issue described above makes it sound as if the problem here is
just about efficiency. We're wasting power keeping the touchscreen
powered up when the screen is off. While that's true, the problem can
go deeper. Specifically, hardware designers see that there's no reason
to have the touchscreen on while the screen is off and then build
hardware assuming that software would never turn the touchscreen on
while the screen is off.
In the very simplest case of hardware designs like this, the
touchscreen and the panel share some power rails. In most cases, this
turns out not to be terrible and is, again, just a little less
efficient. Specifically if we tell Linux that the touchscreen and the
panel are using the same rails then Linux will keep the rails on when
_either_ device is turned on. That ends to work OK-ish, but now if you
turn the panel off not only will the touchscreen remain powered, but
the power rails for the panel itself won't be switched off, burning
extra power.
The above two inefficiencies are _extra_ minor when you consider the
fact that laptops rarely spend much time with the screen off. The main
use case would be when an external screen (and presumably a power
supply) is attached.
Unfortunately, it gets worse from here. On sc7180-trogdor-homestar,
for instance, the display's TCON (timing controller) sometimes crashes
if you don't power cycle it whenever you stop and restart the video
stream (like during a modeset). The touchscreen keeping the power
rails on causes real problems. One proposal in the homestar timeframe
was to move the touchscreen to an always-on rail, dedicating the main
power rail to the panel. That caused _different_ problems as talked
about in commit 557e05fa9fdd ("HID: i2c-hid: goodix: Stop tying the
reset line to the regulator"). The end result of all of this was to
add an extra regulator to the board, increasing cost.
Recently, Cong Yang posted a patch [1] where things are even worse.
The panel and touch controller on that system seem even more
intimately tied together and really can't be thought of separately.
To address this issue, let's start allowing devices to register
themselves as "panel followers". These devices will get called after a
panel has been powered on and before a panel is powered off. This
makes the panel the primary device in charge of the power state, which
matches how userspace uses it.
The panel follower API should be fairly straightforward to use. The
current code assumes that panel followers are using device tree and
have a "panel" property pointing to the panel to follow. More
flexibility and non-DT implementations could be added as needed.
Right now, panel followers can follow the prepare/unprepare functions.
There could be arguments made that, instead, they should follow
enable/disable. I've chosen prepare/unprepare for now since those
functions are guaranteed to power up/power down the panel and it seems
better to start the process earlier.
A bit of explaining about why this is a roll-your-own API instead of
using something more standard:
1. In standard APIs in Linux, parent devices are automatically powered
on when a child needs power. Applying that here, it would mean that
we'd force the panel on any time someone was listening to the
touchscreen. That, unfortunately, would have broken homestar's need
(if we hadn't changed the hardware, as per above) where the panel
absolutely needs to be able to power cycle itself. While one could
argue that homestar is broken hardware and we shouldn't have the
API do backflips for it, _officially_ the eDP timing guidelines
agree with homestar's needs and the panel power sequencing diagrams
show power going off. It's nice to be able to support this.
2. We could, conceibably, try to add a new flag to device_link causing
the parent to be in charge of power. Then we could at least use
normal pm_runtime APIs. This sounds great, except that we run into
problems with initial probe. As talked about in the later patch
("HID: i2c-hid: Support being a panel follower") the initial power
on of a panel follower might need to do things (like add
sub-devices) that aren't allowed in a runtime_resume function.
The above complexities explain why this API isn't using common
functions. That being said, this patch is very small and
self-contained, so if someone was later able to adapt it to using more
common APIs while solving the above issues then that could happen in
the future.
[1] https://lore.kernel.org/r/20230519032316.3464732-1-yangcong5@huaqin.corp-partner.google.com
Reviewed-by: Maxime Ripard <[email protected]>
Signed-off-by: Douglas Anderson <[email protected]>
---
(no changes since v3)
Changes in v3:
- Add is_panel_follower() as a convenience for clients.
Changes in v2:
- Add even more text to the commit message.
- A few comment cleanups.
drivers/gpu/drm/drm_panel.c | 173 +++++++++++++++++++++++++++++++++++-
include/drm/drm_panel.h | 80 +++++++++++++++++
2 files changed, 249 insertions(+), 4 deletions(-)
diff --git a/drivers/gpu/drm/drm_panel.c b/drivers/gpu/drm/drm_panel.c
index 4e1c4e42575b..e814020bbcd3 100644
--- a/drivers/gpu/drm/drm_panel.c
+++ b/drivers/gpu/drm/drm_panel.c
@@ -58,6 +58,8 @@ void drm_panel_init(struct drm_panel *panel, struct device *dev,
const struct drm_panel_funcs *funcs, int connector_type)
{
INIT_LIST_HEAD(&panel->list);
+ INIT_LIST_HEAD(&panel->followers);
+ mutex_init(&panel->follower_lock);
panel->dev = dev;
panel->funcs = funcs;
panel->connector_type = connector_type;
@@ -105,6 +107,7 @@ EXPORT_SYMBOL(drm_panel_remove);
*/
int drm_panel_prepare(struct drm_panel *panel)
{
+ struct drm_panel_follower *follower;
int ret;
if (!panel)
@@ -115,14 +118,27 @@ int drm_panel_prepare(struct drm_panel *panel)
return 0;
}
+ mutex_lock(&panel->follower_lock);
+
if (panel->funcs && panel->funcs->prepare) {
ret = panel->funcs->prepare(panel);
if (ret < 0)
- return ret;
+ goto exit;
}
panel->prepared = true;
- return 0;
+ list_for_each_entry(follower, &panel->followers, list) {
+ ret = follower->funcs->panel_prepared(follower);
+ if (ret < 0)
+ dev_info(panel->dev, "%ps failed: %d\n",
+ follower->funcs->panel_prepared, ret);
+ }
+
+ ret = 0;
+exit:
+ mutex_unlock(&panel->follower_lock);
+
+ return ret;
}
EXPORT_SYMBOL(drm_panel_prepare);
@@ -139,6 +155,7 @@ EXPORT_SYMBOL(drm_panel_prepare);
*/
int drm_panel_unprepare(struct drm_panel *panel)
{
+ struct drm_panel_follower *follower;
int ret;
if (!panel)
@@ -149,14 +166,27 @@ int drm_panel_unprepare(struct drm_panel *panel)
return 0;
}
+ mutex_lock(&panel->follower_lock);
+
+ list_for_each_entry(follower, &panel->followers, list) {
+ ret = follower->funcs->panel_unpreparing(follower);
+ if (ret < 0)
+ dev_info(panel->dev, "%ps failed: %d\n",
+ follower->funcs->panel_unpreparing, ret);
+ }
+
if (panel->funcs && panel->funcs->unprepare) {
ret = panel->funcs->unprepare(panel);
if (ret < 0)
- return ret;
+ goto exit;
}
panel->prepared = false;
- return 0;
+ ret = 0;
+exit:
+ mutex_unlock(&panel->follower_lock);
+
+ return ret;
}
EXPORT_SYMBOL(drm_panel_unprepare);
@@ -342,6 +372,141 @@ int of_drm_get_panel_orientation(const struct device_node *np,
EXPORT_SYMBOL(of_drm_get_panel_orientation);
#endif
+/**
+ * drm_is_panel_follower() - Check if the device is a panel follower
+ * @dev: The 'struct device' to check
+ *
+ * This checks to see if a device needs to be power sequenced together with
+ * a panel using the panel follower API.
+ * At the moment panels can only be followed on device tree enabled systems.
+ * The "panel" property of the follower points to the panel to be followed.
+ *
+ * Return: true if we should be power sequenced with a panel; false otherwise.
+ */
+bool drm_is_panel_follower(struct device *dev)
+{
+ /*
+ * The "panel" property is actually a phandle, but for simplicity we
+ * don't bother trying to parse it here. We just need to know if the
+ * property is there.
+ */
+ return of_property_read_bool(dev->of_node, "panel");
+}
+EXPORT_SYMBOL(drm_is_panel_follower);
+
+/**
+ * drm_panel_add_follower() - Register something to follow panel state.
+ * @follower_dev: The 'struct device' for the follower.
+ * @follower: The panel follower descriptor for the follower.
+ *
+ * A panel follower is called right after preparing the panel and right before
+ * unpreparing the panel. It's primary intention is to power on an associated
+ * touchscreen, though it could be used for any similar devices. Multiple
+ * devices are allowed the follow the same panel.
+ *
+ * If a follower is added to a panel that's already been turned on, the
+ * follower's prepare callback is called right away.
+ *
+ * At the moment panels can only be followed on device tree enabled systems.
+ * The "panel" property of the follower points to the panel to be followed.
+ *
+ * Return: 0 or an error code. Note that -ENODEV means that we detected that
+ * follower_dev is not actually following a panel. The caller may
+ * choose to ignore this return value if following a panel is optional.
+ */
+int drm_panel_add_follower(struct device *follower_dev,
+ struct drm_panel_follower *follower)
+{
+ struct device_node *panel_np;
+ struct drm_panel *panel;
+ int ret;
+
+ panel_np = of_parse_phandle(follower_dev->of_node, "panel", 0);
+ if (!panel_np)
+ return -ENODEV;
+
+ panel = of_drm_find_panel(panel_np);
+ of_node_put(panel_np);
+ if (IS_ERR(panel))
+ return PTR_ERR(panel);
+
+ get_device(panel->dev);
+ follower->panel = panel;
+
+ mutex_lock(&panel->follower_lock);
+
+ list_add_tail(&follower->list, &panel->followers);
+ if (panel->prepared) {
+ ret = follower->funcs->panel_prepared(follower);
+ if (ret < 0)
+ dev_info(panel->dev, "%ps failed: %d\n",
+ follower->funcs->panel_prepared, ret);
+ }
+
+ mutex_unlock(&panel->follower_lock);
+
+ return 0;
+}
+EXPORT_SYMBOL(drm_panel_add_follower);
+
+/**
+ * drm_panel_remove_follower() - Reverse drm_panel_add_follower().
+ * @follower: The panel follower descriptor for the follower.
+ *
+ * Undo drm_panel_add_follower(). This includes calling the follower's
+ * unprepare function if we're removed from a panel that's currently prepared.
+ *
+ * Return: 0 or an error code.
+ */
+void drm_panel_remove_follower(struct drm_panel_follower *follower)
+{
+ struct drm_panel *panel = follower->panel;
+ int ret;
+
+ mutex_lock(&panel->follower_lock);
+
+ if (panel->prepared) {
+ ret = follower->funcs->panel_unpreparing(follower);
+ if (ret < 0)
+ dev_info(panel->dev, "%ps failed: %d\n",
+ follower->funcs->panel_unpreparing, ret);
+ }
+ list_del_init(&follower->list);
+
+ mutex_unlock(&panel->follower_lock);
+
+ put_device(panel->dev);
+}
+EXPORT_SYMBOL(drm_panel_remove_follower);
+
+static void drm_panel_remove_follower_void(void *follower)
+{
+ drm_panel_remove_follower(follower);
+}
+
+/**
+ * devm_drm_panel_add_follower() - devm version of drm_panel_add_follower()
+ * @follower_dev: The 'struct device' for the follower.
+ * @follower: The panel follower descriptor for the follower.
+ *
+ * Handles calling drm_panel_remove_follower() using devm on the follower_dev.
+ *
+ * Return: 0 or an error code.
+ */
+int devm_drm_panel_add_follower(struct device *follower_dev,
+ struct drm_panel_follower *follower)
+{
+ int ret;
+
+ ret = drm_panel_add_follower(follower_dev, follower);
+ if (ret)
+ return ret;
+
+ return devm_add_action_or_reset(follower_dev,
+ drm_panel_remove_follower_void, follower);
+}
+EXPORT_SYMBOL(devm_drm_panel_add_follower);
+
#if IS_REACHABLE(CONFIG_BACKLIGHT_CLASS_DEVICE)
/**
* drm_panel_of_backlight - use backlight device node for backlight
diff --git a/include/drm/drm_panel.h b/include/drm/drm_panel.h
index c6cf75909389..5ac67eeb0860 100644
--- a/include/drm/drm_panel.h
+++ b/include/drm/drm_panel.h
@@ -27,12 +27,14 @@
#include <linux/err.h>
#include <linux/errno.h>
#include <linux/list.h>
+#include <linux/mutex.h>
struct backlight_device;
struct dentry;
struct device_node;
struct drm_connector;
struct drm_device;
+struct drm_panel_follower;
struct drm_panel;
struct display_timing;
@@ -144,6 +146,45 @@ struct drm_panel_funcs {
void (*debugfs_init)(struct drm_panel *panel, struct dentry *root);
};
+struct drm_panel_follower_funcs {
+ /**
+ * @panel_prepared:
+ *
+ * Called after the panel has been powered on.
+ */
+ int (*panel_prepared)(struct drm_panel_follower *follower);
+
+ /**
+ * @panel_unpreparing:
+ *
+ * Called before the panel is powered off.
+ */
+ int (*panel_unpreparing)(struct drm_panel_follower *follower);
+};
+
+struct drm_panel_follower {
+ /**
+ * @funcs:
+ *
+ * Dependent device callbacks; should be initted by the caller.
+ */
+ const struct drm_panel_follower_funcs *funcs;
+
+ /**
+ * @list
+ *
+ * Used for linking into panel's list; set by drm_panel_add_follower().
+ */
+ struct list_head list;
+
+ /**
+ * @panel
+ *
+ * The panel we're dependent on; set by drm_panel_add_follower().
+ */
+ struct drm_panel *panel;
+};
+
/**
* struct drm_panel - DRM panel object
*/
@@ -189,6 +230,20 @@ struct drm_panel {
*/
struct list_head list;
+ /**
+ * @followers:
+ *
+ * A list of struct drm_panel_follower dependent on this panel.
+ */
+ struct list_head followers;
+
+ /**
+ * @followers_lock:
+ *
+ * Lock for followers list.
+ */
+ struct mutex follower_lock;
+
/**
* @prepare_prev_first:
*
@@ -246,6 +301,31 @@ static inline int of_drm_get_panel_orientation(const struct device_node *np,
}
#endif
+#if defined(CONFIG_DRM_PANEL)
+bool drm_is_panel_follower(struct device *dev);
+int drm_panel_add_follower(struct device *follower_dev,
+ struct drm_panel_follower *follower);
+void drm_panel_remove_follower(struct drm_panel_follower *follower);
+int devm_drm_panel_add_follower(struct device *follower_dev,
+ struct drm_panel_follower *follower);
+#else
+static inline bool drm_is_panel_follower(struct device *dev)
+{
+ return false;
+}
+static inline int drm_panel_add_follower(struct device *follower_dev,
+ struct drm_panel_follower *follower)
+{
+ return -ENODEV;
+}
+static inline void drm_panel_remove_follower(struct drm_panel_follower *follower) { }
+static inline int devm_drm_panel_add_follower(struct device *follower_dev,
+ struct drm_panel_follower *follower)
+{
+ return -ENODEV;
+}
+#endif
+
#if IS_ENABLED(CONFIG_DRM_PANEL) && (IS_BUILTIN(CONFIG_BACKLIGHT_CLASS_DEVICE) || \
(IS_MODULE(CONFIG_DRM) && IS_MODULE(CONFIG_BACKLIGHT_CLASS_DEVICE)))
int drm_panel_of_backlight(struct drm_panel *panel);
--
2.41.0.487.g6d72f3e995-goog
In a future patch we'd like to be able to call the current i2c-hid
suspend and resume functions from times other than system
suspend. Move the functions higher up in the file and have them take a
"struct i2c_hid" to make this simpler. We'll then add tiny wrappers of
the functions for use with system suspend.
This change is expected to have no functional effect.
Reviewed-by: Maxime Ripard <[email protected]>
Signed-off-by: Douglas Anderson <[email protected]>
---
(no changes since v1)
drivers/hid/i2c-hid/i2c-hid-core.c | 98 +++++++++++++++++-------------
1 file changed, 56 insertions(+), 42 deletions(-)
diff --git a/drivers/hid/i2c-hid/i2c-hid-core.c b/drivers/hid/i2c-hid/i2c-hid-core.c
index d29e6421ecba..fa8a1ca43d7f 100644
--- a/drivers/hid/i2c-hid/i2c-hid-core.c
+++ b/drivers/hid/i2c-hid/i2c-hid-core.c
@@ -941,6 +941,57 @@ static void i2c_hid_core_shutdown_tail(struct i2c_hid *ihid)
ihid->ops->shutdown_tail(ihid->ops);
}
+static int i2c_hid_core_suspend(struct i2c_hid *ihid)
+{
+ struct i2c_client *client = ihid->client;
+ struct hid_device *hid = ihid->hid;
+ int ret;
+
+ ret = hid_driver_suspend(hid, PMSG_SUSPEND);
+ if (ret < 0)
+ return ret;
+
+ /* Save some power */
+ i2c_hid_set_power(ihid, I2C_HID_PWR_SLEEP);
+
+ disable_irq(client->irq);
+
+ if (!device_may_wakeup(&client->dev))
+ i2c_hid_core_power_down(ihid);
+
+ return 0;
+}
+
+static int i2c_hid_core_resume(struct i2c_hid *ihid)
+{
+ struct i2c_client *client = ihid->client;
+ struct hid_device *hid = ihid->hid;
+ int ret;
+
+ if (!device_may_wakeup(&client->dev))
+ i2c_hid_core_power_up(ihid);
+
+ enable_irq(client->irq);
+
+ /* Instead of resetting device, simply powers the device on. This
+ * solves "incomplete reports" on Raydium devices 2386:3118 and
+ * 2386:4B33 and fixes various SIS touchscreens no longer sending
+ * data after a suspend/resume.
+ *
+ * However some ALPS touchpads generate IRQ storm without reset, so
+ * let's still reset them here.
+ */
+ if (ihid->quirks & I2C_HID_QUIRK_RESET_ON_RESUME)
+ ret = i2c_hid_hwreset(ihid);
+ else
+ ret = i2c_hid_set_power(ihid, I2C_HID_PWR_ON);
+
+ if (ret)
+ return ret;
+
+ return hid_driver_reset_resume(hid);
+}
+
/**
* i2c_hid_core_initial_power_up() - First time power up of the i2c-hid device.
* @ihid: The ihid object created during probe.
@@ -1115,61 +1166,24 @@ void i2c_hid_core_shutdown(struct i2c_client *client)
}
EXPORT_SYMBOL_GPL(i2c_hid_core_shutdown);
-static int i2c_hid_core_suspend(struct device *dev)
+static int i2c_hid_core_pm_suspend(struct device *dev)
{
struct i2c_client *client = to_i2c_client(dev);
struct i2c_hid *ihid = i2c_get_clientdata(client);
- struct hid_device *hid = ihid->hid;
- int ret;
-
- ret = hid_driver_suspend(hid, PMSG_SUSPEND);
- if (ret < 0)
- return ret;
- /* Save some power */
- i2c_hid_set_power(ihid, I2C_HID_PWR_SLEEP);
-
- disable_irq(client->irq);
-
- if (!device_may_wakeup(&client->dev))
- i2c_hid_core_power_down(ihid);
-
- return 0;
+ return i2c_hid_core_suspend(ihid);
}
-static int i2c_hid_core_resume(struct device *dev)
+static int i2c_hid_core_pm_resume(struct device *dev)
{
- int ret;
struct i2c_client *client = to_i2c_client(dev);
struct i2c_hid *ihid = i2c_get_clientdata(client);
- struct hid_device *hid = ihid->hid;
- if (!device_may_wakeup(&client->dev))
- i2c_hid_core_power_up(ihid);
-
- enable_irq(client->irq);
-
- /* Instead of resetting device, simply powers the device on. This
- * solves "incomplete reports" on Raydium devices 2386:3118 and
- * 2386:4B33 and fixes various SIS touchscreens no longer sending
- * data after a suspend/resume.
- *
- * However some ALPS touchpads generate IRQ storm without reset, so
- * let's still reset them here.
- */
- if (ihid->quirks & I2C_HID_QUIRK_RESET_ON_RESUME)
- ret = i2c_hid_hwreset(ihid);
- else
- ret = i2c_hid_set_power(ihid, I2C_HID_PWR_ON);
-
- if (ret)
- return ret;
-
- return hid_driver_reset_resume(hid);
+ return i2c_hid_core_resume(ihid);
}
const struct dev_pm_ops i2c_hid_core_pm = {
- SYSTEM_SLEEP_PM_OPS(i2c_hid_core_suspend, i2c_hid_core_resume)
+ SYSTEM_SLEEP_PM_OPS(i2c_hid_core_pm_suspend, i2c_hid_core_pm_resume)
};
EXPORT_SYMBOL_GPL(i2c_hid_core_pm);
--
2.41.0.487.g6d72f3e995-goog
In a future patch, we want to change i2c-hid not to necessarily power
up the touchscreen during probe. In preparation for that, rearrange
the probe function so that we put as much stuff _before_ powering up
the device as possible.
This change is expected to have no functional effect.
Reviewed-by: Maxime Ripard <[email protected]>
Signed-off-by: Douglas Anderson <[email protected]>
---
(no changes since v2)
Changes in v2:
- i2c_hid_core_initial_power_up() is now static.
drivers/hid/i2c-hid/i2c-hid-core.c | 124 ++++++++++++++++++-----------
1 file changed, 77 insertions(+), 47 deletions(-)
diff --git a/drivers/hid/i2c-hid/i2c-hid-core.c b/drivers/hid/i2c-hid/i2c-hid-core.c
index 19d985c20a5c..d29e6421ecba 100644
--- a/drivers/hid/i2c-hid/i2c-hid-core.c
+++ b/drivers/hid/i2c-hid/i2c-hid-core.c
@@ -855,7 +855,8 @@ static int i2c_hid_init_irq(struct i2c_client *client)
irqflags = IRQF_TRIGGER_LOW;
ret = request_threaded_irq(client->irq, NULL, i2c_hid_irq,
- irqflags | IRQF_ONESHOT, client->name, ihid);
+ irqflags | IRQF_ONESHOT | IRQF_NO_AUTOEN,
+ client->name, ihid);
if (ret < 0) {
dev_warn(&client->dev,
"Could not register for %s interrupt, irq = %d,"
@@ -940,6 +941,72 @@ static void i2c_hid_core_shutdown_tail(struct i2c_hid *ihid)
ihid->ops->shutdown_tail(ihid->ops);
}
+/**
+ * i2c_hid_core_initial_power_up() - First time power up of the i2c-hid device.
+ * @ihid: The ihid object created during probe.
+ *
+ * This function is called at probe time.
+ *
+ * The initial power on is where we do some basic validation that the device
+ * exists, where we fetch the HID descriptor, and where we create the actual
+ * HID devices.
+ *
+ * Return: 0 or error code.
+ */
+static int i2c_hid_core_initial_power_up(struct i2c_hid *ihid)
+{
+ struct i2c_client *client = ihid->client;
+ struct hid_device *hid = ihid->hid;
+ int ret;
+
+ ret = i2c_hid_core_power_up(ihid);
+ if (ret)
+ return ret;
+
+ /* Make sure there is something at this address */
+ ret = i2c_smbus_read_byte(client);
+ if (ret < 0) {
+ i2c_hid_dbg(ihid, "nothing at this address: %d\n", ret);
+ ret = -ENXIO;
+ goto err;
+ }
+
+ ret = i2c_hid_fetch_hid_descriptor(ihid);
+ if (ret < 0) {
+ dev_err(&client->dev,
+ "Failed to fetch the HID Descriptor\n");
+ goto err;
+ }
+
+ enable_irq(client->irq);
+
+ hid->version = le16_to_cpu(ihid->hdesc.bcdVersion);
+ hid->vendor = le16_to_cpu(ihid->hdesc.wVendorID);
+ hid->product = le16_to_cpu(ihid->hdesc.wProductID);
+
+ hid->initial_quirks |= i2c_hid_get_dmi_quirks(hid->vendor,
+ hid->product);
+
+ snprintf(hid->name, sizeof(hid->name), "%s %04X:%04X",
+ client->name, (u16)hid->vendor, (u16)hid->product);
+ strscpy(hid->phys, dev_name(&client->dev), sizeof(hid->phys));
+
+ ihid->quirks = i2c_hid_lookup_quirk(hid->vendor, hid->product);
+
+ ret = hid_add_device(hid);
+ if (ret) {
+ if (ret != -ENODEV)
+ hid_err(client, "can't add hid device: %d\n", ret);
+ goto err;
+ }
+
+ return 0;
+
+err:
+ i2c_hid_core_power_down(ihid);
+ return ret;
+}
+
int i2c_hid_core_probe(struct i2c_client *client, struct i2chid_ops *ops,
u16 hid_descriptor_address, u32 quirks)
{
@@ -966,16 +1033,10 @@ int i2c_hid_core_probe(struct i2c_client *client, struct i2chid_ops *ops,
if (!ihid)
return -ENOMEM;
- ihid->ops = ops;
-
- ret = i2c_hid_core_power_up(ihid);
- if (ret)
- return ret;
-
i2c_set_clientdata(client, ihid);
+ ihid->ops = ops;
ihid->client = client;
-
ihid->wHIDDescRegister = cpu_to_le16(hid_descriptor_address);
init_waitqueue_head(&ihid->wait);
@@ -986,28 +1047,12 @@ int i2c_hid_core_probe(struct i2c_client *client, struct i2chid_ops *ops,
* real computation later. */
ret = i2c_hid_alloc_buffers(ihid, HID_MIN_BUFFER_SIZE);
if (ret < 0)
- goto err_powered;
-
+ return ret;
device_enable_async_suspend(&client->dev);
- /* Make sure there is something at this address */
- ret = i2c_smbus_read_byte(client);
- if (ret < 0) {
- i2c_hid_dbg(ihid, "nothing at this address: %d\n", ret);
- ret = -ENXIO;
- goto err_powered;
- }
-
- ret = i2c_hid_fetch_hid_descriptor(ihid);
- if (ret < 0) {
- dev_err(&client->dev,
- "Failed to fetch the HID Descriptor\n");
- goto err_powered;
- }
-
ret = i2c_hid_init_irq(client);
if (ret < 0)
- goto err_powered;
+ goto err_buffers_allocated;
hid = hid_allocate_device();
if (IS_ERR(hid)) {
@@ -1021,26 +1066,11 @@ int i2c_hid_core_probe(struct i2c_client *client, struct i2chid_ops *ops,
hid->ll_driver = &i2c_hid_ll_driver;
hid->dev.parent = &client->dev;
hid->bus = BUS_I2C;
- hid->version = le16_to_cpu(ihid->hdesc.bcdVersion);
- hid->vendor = le16_to_cpu(ihid->hdesc.wVendorID);
- hid->product = le16_to_cpu(ihid->hdesc.wProductID);
-
hid->initial_quirks = quirks;
- hid->initial_quirks |= i2c_hid_get_dmi_quirks(hid->vendor,
- hid->product);
-
- snprintf(hid->name, sizeof(hid->name), "%s %04X:%04X",
- client->name, (u16)hid->vendor, (u16)hid->product);
- strscpy(hid->phys, dev_name(&client->dev), sizeof(hid->phys));
-
- ihid->quirks = i2c_hid_lookup_quirk(hid->vendor, hid->product);
- ret = hid_add_device(hid);
- if (ret) {
- if (ret != -ENODEV)
- hid_err(client, "can't add hid device: %d\n", ret);
+ ret = i2c_hid_core_initial_power_up(ihid);
+ if (ret)
goto err_mem_free;
- }
return 0;
@@ -1050,9 +1080,9 @@ int i2c_hid_core_probe(struct i2c_client *client, struct i2chid_ops *ops,
err_irq:
free_irq(client->irq, ihid);
-err_powered:
- i2c_hid_core_power_down(ihid);
+err_buffers_allocated:
i2c_hid_free_buffers(ihid);
+
return ret;
}
EXPORT_SYMBOL_GPL(i2c_hid_core_probe);
@@ -1062,6 +1092,8 @@ void i2c_hid_core_remove(struct i2c_client *client)
struct i2c_hid *ihid = i2c_get_clientdata(client);
struct hid_device *hid;
+ i2c_hid_core_power_down(ihid);
+
hid = ihid->hid;
hid_destroy_device(hid);
@@ -1069,8 +1101,6 @@ void i2c_hid_core_remove(struct i2c_client *client)
if (ihid->bufsize)
i2c_hid_free_buffers(ihid);
-
- i2c_hid_core_power_down(ihid);
}
EXPORT_SYMBOL_GPL(i2c_hid_core_remove);
--
2.41.0.487.g6d72f3e995-goog
The SYSTEM_SLEEP_PM_OPS() allows us to get rid of '#ifdef
CONFIG_PM_SLEEP', as talked about in commit 1a3c7bb08826 ("PM: core:
Add new *_PM_OPS macros, deprecate old ones").
This change is expected to have no functional effect.
Reviewed-by: Maxime Ripard <[email protected]>
Signed-off-by: Douglas Anderson <[email protected]>
---
(no changes since v1)
drivers/hid/i2c-hid/i2c-hid-core.c | 4 +---
1 file changed, 1 insertion(+), 3 deletions(-)
diff --git a/drivers/hid/i2c-hid/i2c-hid-core.c b/drivers/hid/i2c-hid/i2c-hid-core.c
index efbba0465eef..19d985c20a5c 100644
--- a/drivers/hid/i2c-hid/i2c-hid-core.c
+++ b/drivers/hid/i2c-hid/i2c-hid-core.c
@@ -1085,7 +1085,6 @@ void i2c_hid_core_shutdown(struct i2c_client *client)
}
EXPORT_SYMBOL_GPL(i2c_hid_core_shutdown);
-#ifdef CONFIG_PM_SLEEP
static int i2c_hid_core_suspend(struct device *dev)
{
struct i2c_client *client = to_i2c_client(dev);
@@ -1138,10 +1137,9 @@ static int i2c_hid_core_resume(struct device *dev)
return hid_driver_reset_resume(hid);
}
-#endif
const struct dev_pm_ops i2c_hid_core_pm = {
- SET_SYSTEM_SLEEP_PM_OPS(i2c_hid_core_suspend, i2c_hid_core_resume)
+ SYSTEM_SLEEP_PM_OPS(i2c_hid_core_suspend, i2c_hid_core_resume)
};
EXPORT_SYMBOL_GPL(i2c_hid_core_pm);
--
2.41.0.487.g6d72f3e995-goog
Let's provide the proper link from the touchscreen to the panel on
trogdor devices where the touchscreen support it. This allows the OS
to power sequence the touchscreen more properly.
For the most part, this is just expected to marginally improve power
consumption while the screen is off. However, in at least one trogdor
model (wormdingler) it's suspected that this will fix some behavorial
corner cases when the panel power cycles (like for a modeset) without
the touchscreen power cycling.
NOTE: some trogdor variants use touchscreens that don't (yet) support
linking the touchscreen and the panel. Those variants are left alone.
Reviewed-by: Maxime Ripard <[email protected]>
Signed-off-by: Douglas Anderson <[email protected]>
---
(no changes since v1)
arch/arm64/boot/dts/qcom/sc7180-trogdor-coachz.dtsi | 1 +
arch/arm64/boot/dts/qcom/sc7180-trogdor-homestar.dtsi | 1 +
arch/arm64/boot/dts/qcom/sc7180-trogdor-lazor.dtsi | 1 +
arch/arm64/boot/dts/qcom/sc7180-trogdor-pompom.dtsi | 1 +
arch/arm64/boot/dts/qcom/sc7180-trogdor-quackingstick.dtsi | 1 +
arch/arm64/boot/dts/qcom/sc7180-trogdor-wormdingler.dtsi | 1 +
6 files changed, 6 insertions(+)
diff --git a/arch/arm64/boot/dts/qcom/sc7180-trogdor-coachz.dtsi b/arch/arm64/boot/dts/qcom/sc7180-trogdor-coachz.dtsi
index 8b8ea8af165d..b4f328d3e1f6 100644
--- a/arch/arm64/boot/dts/qcom/sc7180-trogdor-coachz.dtsi
+++ b/arch/arm64/boot/dts/qcom/sc7180-trogdor-coachz.dtsi
@@ -104,6 +104,7 @@ ap_ts: touchscreen@5d {
interrupt-parent = <&tlmm>;
interrupts = <9 IRQ_TYPE_LEVEL_LOW>;
+ panel = <&panel>;
reset-gpios = <&tlmm 8 GPIO_ACTIVE_LOW>;
vdd-supply = <&pp3300_ts>;
diff --git a/arch/arm64/boot/dts/qcom/sc7180-trogdor-homestar.dtsi b/arch/arm64/boot/dts/qcom/sc7180-trogdor-homestar.dtsi
index b3ba23a88a0b..88aeb415bd5b 100644
--- a/arch/arm64/boot/dts/qcom/sc7180-trogdor-homestar.dtsi
+++ b/arch/arm64/boot/dts/qcom/sc7180-trogdor-homestar.dtsi
@@ -116,6 +116,7 @@ ap_ts: touchscreen@14 {
interrupt-parent = <&tlmm>;
interrupts = <9 IRQ_TYPE_LEVEL_LOW>;
+ panel = <&panel>;
reset-gpios = <&tlmm 8 GPIO_ACTIVE_LOW>;
vdd-supply = <&pp3300_touch>;
diff --git a/arch/arm64/boot/dts/qcom/sc7180-trogdor-lazor.dtsi b/arch/arm64/boot/dts/qcom/sc7180-trogdor-lazor.dtsi
index 269007d73162..c65f18ea3e5c 100644
--- a/arch/arm64/boot/dts/qcom/sc7180-trogdor-lazor.dtsi
+++ b/arch/arm64/boot/dts/qcom/sc7180-trogdor-lazor.dtsi
@@ -43,6 +43,7 @@ ap_ts: touchscreen@10 {
interrupt-parent = <&tlmm>;
interrupts = <9 IRQ_TYPE_LEVEL_LOW>;
+ panel = <&panel>;
post-power-on-delay-ms = <20>;
hid-descr-addr = <0x0001>;
diff --git a/arch/arm64/boot/dts/qcom/sc7180-trogdor-pompom.dtsi b/arch/arm64/boot/dts/qcom/sc7180-trogdor-pompom.dtsi
index 6c5287bd27d6..d2aafd1ea672 100644
--- a/arch/arm64/boot/dts/qcom/sc7180-trogdor-pompom.dtsi
+++ b/arch/arm64/boot/dts/qcom/sc7180-trogdor-pompom.dtsi
@@ -102,6 +102,7 @@ ap_ts: touchscreen@10 {
interrupt-parent = <&tlmm>;
interrupts = <9 IRQ_TYPE_LEVEL_LOW>;
+ panel = <&panel>;
post-power-on-delay-ms = <20>;
hid-descr-addr = <0x0001>;
diff --git a/arch/arm64/boot/dts/qcom/sc7180-trogdor-quackingstick.dtsi b/arch/arm64/boot/dts/qcom/sc7180-trogdor-quackingstick.dtsi
index 62ab6427dd65..e5d6a7898f8c 100644
--- a/arch/arm64/boot/dts/qcom/sc7180-trogdor-quackingstick.dtsi
+++ b/arch/arm64/boot/dts/qcom/sc7180-trogdor-quackingstick.dtsi
@@ -69,6 +69,7 @@ ap_ts: touchscreen@10 {
interrupt-parent = <&tlmm>;
interrupts = <9 IRQ_TYPE_LEVEL_LOW>;
+ panel = <&panel>;
post-power-on-delay-ms = <20>;
hid-descr-addr = <0x0001>;
diff --git a/arch/arm64/boot/dts/qcom/sc7180-trogdor-wormdingler.dtsi b/arch/arm64/boot/dts/qcom/sc7180-trogdor-wormdingler.dtsi
index 2efa8a4bcda6..0e2b4d06b490 100644
--- a/arch/arm64/boot/dts/qcom/sc7180-trogdor-wormdingler.dtsi
+++ b/arch/arm64/boot/dts/qcom/sc7180-trogdor-wormdingler.dtsi
@@ -123,6 +123,7 @@ ap_ts: touchscreen@1 {
interrupt-parent = <&tlmm>;
interrupts = <9 IRQ_TYPE_EDGE_FALLING>;
+ panel = <&panel>;
post-power-on-delay-ms = <70>;
hid-descr-addr = <0x0001>;
--
2.41.0.487.g6d72f3e995-goog
Turning on an i2c-hid device can be a slow process. This is why
i2c-hid devices use PROBE_PREFER_ASYNCHRONOUS. Unfortunately, when
we're a panel follower the i2c-hid power up sequence now blocks the
power on of the panel. Let's fix that by scheduling the work on the
system_wq.
Reviewed-by: Maxime Ripard <[email protected]>
Signed-off-by: Douglas Anderson <[email protected]>
---
(no changes since v2)
Changes in v2:
- ihid_core_panel_prepare_work() is now static.
- Improve documentation for smp_wmb().
drivers/hid/i2c-hid/i2c-hid-core.c | 50 +++++++++++++++++++++++++++---
1 file changed, 46 insertions(+), 4 deletions(-)
diff --git a/drivers/hid/i2c-hid/i2c-hid-core.c b/drivers/hid/i2c-hid/i2c-hid-core.c
index fc3087a983f5..9601c0605fd9 100644
--- a/drivers/hid/i2c-hid/i2c-hid-core.c
+++ b/drivers/hid/i2c-hid/i2c-hid-core.c
@@ -110,7 +110,9 @@ struct i2c_hid {
struct i2chid_ops *ops;
struct drm_panel_follower panel_follower;
+ struct work_struct panel_follower_prepare_work;
bool is_panel_follower;
+ bool prepare_work_finished;
};
static const struct i2c_hid_quirks {
@@ -1062,10 +1064,12 @@ static int __do_i2c_hid_core_initial_power_up(struct i2c_hid *ihid)
return ret;
}
-static int i2c_hid_core_panel_prepared(struct drm_panel_follower *follower)
+static void ihid_core_panel_prepare_work(struct work_struct *work)
{
- struct i2c_hid *ihid = container_of(follower, struct i2c_hid, panel_follower);
+ struct i2c_hid *ihid = container_of(work, struct i2c_hid,
+ panel_follower_prepare_work);
struct hid_device *hid = ihid->hid;
+ int ret;
/*
* hid->version is set on the first power up. If it's still zero then
@@ -1073,15 +1077,52 @@ static int i2c_hid_core_panel_prepared(struct drm_panel_follower *follower)
* steps.
*/
if (!hid->version)
- return __do_i2c_hid_core_initial_power_up(ihid);
+ ret = __do_i2c_hid_core_initial_power_up(ihid);
+ else
+ ret = i2c_hid_core_resume(ihid);
- return i2c_hid_core_resume(ihid);
+ if (ret)
+ dev_warn(&ihid->client->dev, "Power on failed: %d\n", ret);
+ else
+ WRITE_ONCE(ihid->prepare_work_finished, true);
+
+ /*
+ * The work APIs provide a number of memory ordering guarantees
+ * including one that says that memory writes before schedule_work()
+ * are always visible to the work function, but they don't appear to
+ * guarantee that a write that happened in the work is visible after
+ * cancel_work_sync(). We'll add a write memory barrier here to match
+ * with i2c_hid_core_panel_unpreparing() to ensure that our write to
+ * prepare_work_finished is visible there.
+ */
+ smp_wmb();
+}
+
+static int i2c_hid_core_panel_prepared(struct drm_panel_follower *follower)
+{
+ struct i2c_hid *ihid = container_of(follower, struct i2c_hid, panel_follower);
+
+ /*
+ * Powering on a touchscreen can be a slow process. Queue the work to
+ * the system workqueue so we don't block the panel's power up.
+ */
+ WRITE_ONCE(ihid->prepare_work_finished, false);
+ schedule_work(&ihid->panel_follower_prepare_work);
+
+ return 0;
}
static int i2c_hid_core_panel_unpreparing(struct drm_panel_follower *follower)
{
struct i2c_hid *ihid = container_of(follower, struct i2c_hid, panel_follower);
+ cancel_work_sync(&ihid->panel_follower_prepare_work);
+
+ /* Match with ihid_core_panel_prepare_work() */
+ smp_rmb();
+ if (!READ_ONCE(ihid->prepare_work_finished))
+ return 0;
+
return i2c_hid_core_suspend(ihid, true);
}
@@ -1173,6 +1214,7 @@ int i2c_hid_core_probe(struct i2c_client *client, struct i2chid_ops *ops,
init_waitqueue_head(&ihid->wait);
mutex_init(&ihid->reset_lock);
+ INIT_WORK(&ihid->panel_follower_prepare_work, ihid_core_panel_prepare_work);
/* we need to allocate the command buffer without knowing the maximum
* size of the reports. Let's use HID_MIN_BUFFER_SIZE, then we do the
--
2.41.0.487.g6d72f3e995-goog
On Jul 27 2023, Douglas Anderson wrote:
>
> The big motivation for this patch series is mostly described in the patch
> ("drm/panel: Add a way for other devices to follow panel state"), but to
> quickly summarize here: for touchscreens that are connected to a panel we
> need the ability to power sequence the two device together. This is not a
> new need, but so far we've managed to get by through a combination of
> inefficiency, added costs, or perhaps just a little bit of brokenness.
> It's time to do better. This patch series allows us to do better.
>
> Assuming that people think this patch series looks OK, we'll have to
> figure out the right way to land it. The panel patches and i2c-hid
> patches will go through very different trees and so either we'll need
> an Ack from one side or the other or someone to create a tag for the
> other tree to pull in. This will _probably_ require the true drm-misc
> maintainers to get involved, not a lowly committer. ;-)
>
> Version 4 of this series adds a new patch that suspends i2c-hid
> devices at remove time even for non panel-followers to make things
> consistent. It also attempts to isolate the panel follower code a bit
> more as per Benjamin's feedback on v3 and adds an item to the DRM todo
> list as per Maxime's request. As per Maxime's response to my v3 cover
> letter, I added his Reviewed-by tag to all 10 patches that were part
> of v3 (but left it off of the new i2c-hid patch in v4).
>
> Version 3 of this series was a long time coming after v2. Maxime and I
> had a very long discussion trying to figure out if there was a beter
> way and in the end we didn't find one so he was OK with the series in
> general [1]. After that got resolved, I tried to resolve Benjamin's
> feedback but got stuck [2]. Eventually I made my best guess. The end
> result was a v3 that wasn't that different from v2 but that had a tiny
> bit more code split out.
>
> Version 2 of this patch series didn't change too much. At a high level:
> * I added all the forgotten "static" to functions.
> * I've hopefully made the bindings better.
> * I've integrated into fw_devlink.
> * I cleaned up a few descriptions / comments.
>
> As far as I can tell, as of v4 everyone is on the same page that this
> patch series looks like a reasonable solution to the problem and we
> just need to get all the nits fixed and figure out how to land it.
Thanks a lot for the new version. I like it much more on the HID side:
for the HID part:
Reviewed-by: Benjamin Tissoires <[email protected]>
I wouldn't mind having this series taken from the drm tree if that is
easier. i2c-hid is a low patch rate driver, so having it updated through
DRM should not be an issue.
In that case:
Acked-by: Benjamin Tissoires <[email protected]>
Cheers,
Benjamin
>
> [1] https://lore.kernel.org/r/gkwymmfkdy2p2evz22wmbwgw42ii4wnvmvu64m3bghmj2jhv7x@4mbstjxnagxd
> [2] https://lore.kernel.org/r/CAD=FV=VbdeomBGbWhppY+5TOSwt64GWBHga68OXFwsnO4gg4UA@mail.gmail.com
>
> Changes in v4:
> - Document further cleanup in the official DRM todo list.
> - ("Suspend i2c-hid devices in remove") new for v4.
> - Move panel follower alternative checks to wrapper functions.
> - Rebase atop ("Suspend i2c-hid devices in remove").
>
> Changes in v3:
> - Add is_panel_follower() as a convenience for clients.
> - Add "depends on DRM || !DRM" to Kconfig to avoid randconfig error.
> - Split more of the panel follower code out of the core.
>
> Changes in v2:
> - Move the description to the generic touchscreen.yaml.
> - Update the desc to make it clearer it's only for integrated devices.
> - Add even more text to the commit message.
> - A few comment cleanups.
> - ("Add a devlink for panel followers") new for v2.
> - i2c_hid_core_initial_power_up() is now static.
> - i2c_hid_core_panel_prepared() and ..._unpreparing() are now static.
> - ihid_core_panel_prepare_work() is now static.
> - Improve documentation for smp_wmb().
>
> Douglas Anderson (11):
> dt-bindings: HID: i2c-hid: Add "panel" property to i2c-hid backed
> touchscreens
> drm/panel: Check for already prepared/enabled in drm_panel
> drm/panel: Add a way for other devices to follow panel state
> of: property: fw_devlink: Add a devlink for panel followers
> HID: i2c-hid: Switch to SYSTEM_SLEEP_PM_OPS()
> HID: i2c-hid: Rearrange probe() to power things up later
> HID: i2c-hid: Make suspend and resume into helper functions
> HID: i2c-hid: Suspend i2c-hid devices in remove
> HID: i2c-hid: Support being a panel follower
> HID: i2c-hid: Do panel follower work on the system_wq
> arm64: dts: qcom: sc7180: Link trogdor touchscreens to the panels
>
> .../bindings/input/elan,ekth6915.yaml | 5 +
> .../bindings/input/goodix,gt7375p.yaml | 5 +
> .../bindings/input/hid-over-i2c.yaml | 2 +
> .../input/touchscreen/touchscreen.yaml | 7 +
> Documentation/gpu/todo.rst | 24 ++
> .../boot/dts/qcom/sc7180-trogdor-coachz.dtsi | 1 +
> .../dts/qcom/sc7180-trogdor-homestar.dtsi | 1 +
> .../boot/dts/qcom/sc7180-trogdor-lazor.dtsi | 1 +
> .../boot/dts/qcom/sc7180-trogdor-pompom.dtsi | 1 +
> .../qcom/sc7180-trogdor-quackingstick.dtsi | 1 +
> .../dts/qcom/sc7180-trogdor-wormdingler.dtsi | 1 +
> drivers/gpu/drm/drm_panel.c | 218 ++++++++++-
> drivers/hid/i2c-hid/Kconfig | 2 +
> drivers/hid/i2c-hid/i2c-hid-core.c | 349 +++++++++++++-----
> drivers/of/property.c | 2 +
> include/drm/drm_panel.h | 94 +++++
> 16 files changed, 617 insertions(+), 97 deletions(-)
>
> --
> 2.41.0.487.g6d72f3e995-goog
>
Hi,
On Fri, Jul 28, 2023 at 8:31 AM Benjamin Tissoires <[email protected]> wrote:
>
> On Jul 27 2023, Douglas Anderson wrote:
> >
> > The big motivation for this patch series is mostly described in the patch
> > ("drm/panel: Add a way for other devices to follow panel state"), but to
> > quickly summarize here: for touchscreens that are connected to a panel we
> > need the ability to power sequence the two device together. This is not a
> > new need, but so far we've managed to get by through a combination of
> > inefficiency, added costs, or perhaps just a little bit of brokenness.
> > It's time to do better. This patch series allows us to do better.
> >
> > Assuming that people think this patch series looks OK, we'll have to
> > figure out the right way to land it. The panel patches and i2c-hid
> > patches will go through very different trees and so either we'll need
> > an Ack from one side or the other or someone to create a tag for the
> > other tree to pull in. This will _probably_ require the true drm-misc
> > maintainers to get involved, not a lowly committer. ;-)
> >
> > Version 4 of this series adds a new patch that suspends i2c-hid
> > devices at remove time even for non panel-followers to make things
> > consistent. It also attempts to isolate the panel follower code a bit
> > more as per Benjamin's feedback on v3 and adds an item to the DRM todo
> > list as per Maxime's request. As per Maxime's response to my v3 cover
> > letter, I added his Reviewed-by tag to all 10 patches that were part
> > of v3 (but left it off of the new i2c-hid patch in v4).
> >
> > Version 3 of this series was a long time coming after v2. Maxime and I
> > had a very long discussion trying to figure out if there was a beter
> > way and in the end we didn't find one so he was OK with the series in
> > general [1]. After that got resolved, I tried to resolve Benjamin's
> > feedback but got stuck [2]. Eventually I made my best guess. The end
> > result was a v3 that wasn't that different from v2 but that had a tiny
> > bit more code split out.
> >
> > Version 2 of this patch series didn't change too much. At a high level:
> > * I added all the forgotten "static" to functions.
> > * I've hopefully made the bindings better.
> > * I've integrated into fw_devlink.
> > * I cleaned up a few descriptions / comments.
> >
> > As far as I can tell, as of v4 everyone is on the same page that this
> > patch series looks like a reasonable solution to the problem and we
> > just need to get all the nits fixed and figure out how to land it.
>
> Thanks a lot for the new version. I like it much more on the HID side:
>
> for the HID part:
> Reviewed-by: Benjamin Tissoires <[email protected]>
>
> I wouldn't mind having this series taken from the drm tree if that is
> easier. i2c-hid is a low patch rate driver, so having it updated through
> DRM should not be an issue.
>
> In that case:
> Acked-by: Benjamin Tissoires <[email protected]>
Thanks for your reviews and your help getting this whipped into shape.
Lading through drm makes sense to me. I'm a drm committer, so with
your Ack I believe it should be fine for me to land the series (minus
the dts) in drm-misc-next. This series has been around for a while,
has been reviewed by relevant folks, and the last few changes haven't
fundamentally changed anything about the design, so I'm not going to
twiddle my thumbs too long. That being said, I'll still plan to wait
until early next week (Tuesday?) before landing to allow for any last
minute shouts.
Given how drm-misc works [1] and the fact that mainline is currently
at v6.5-rc3 (it will be -rc4 when I land it), I'd expect that these
commits will find their way into v6.6.
[1] https://drm.pages.freedesktop.org/maintainer-tools/drm-misc.html
Hi,
On Fri, Jul 28, 2023 at 10:24 AM Doug Anderson <[email protected]> wrote:
>
> Hi,
>
> On Fri, Jul 28, 2023 at 8:31 AM Benjamin Tissoires <[email protected]> wrote:
> >
> > On Jul 27 2023, Douglas Anderson wrote:
> > >
> > > The big motivation for this patch series is mostly described in the patch
> > > ("drm/panel: Add a way for other devices to follow panel state"), but to
> > > quickly summarize here: for touchscreens that are connected to a panel we
> > > need the ability to power sequence the two device together. This is not a
> > > new need, but so far we've managed to get by through a combination of
> > > inefficiency, added costs, or perhaps just a little bit of brokenness.
> > > It's time to do better. This patch series allows us to do better.
> > >
> > > Assuming that people think this patch series looks OK, we'll have to
> > > figure out the right way to land it. The panel patches and i2c-hid
> > > patches will go through very different trees and so either we'll need
> > > an Ack from one side or the other or someone to create a tag for the
> > > other tree to pull in. This will _probably_ require the true drm-misc
> > > maintainers to get involved, not a lowly committer. ;-)
> > >
> > > Version 4 of this series adds a new patch that suspends i2c-hid
> > > devices at remove time even for non panel-followers to make things
> > > consistent. It also attempts to isolate the panel follower code a bit
> > > more as per Benjamin's feedback on v3 and adds an item to the DRM todo
> > > list as per Maxime's request. As per Maxime's response to my v3 cover
> > > letter, I added his Reviewed-by tag to all 10 patches that were part
> > > of v3 (but left it off of the new i2c-hid patch in v4).
> > >
> > > Version 3 of this series was a long time coming after v2. Maxime and I
> > > had a very long discussion trying to figure out if there was a beter
> > > way and in the end we didn't find one so he was OK with the series in
> > > general [1]. After that got resolved, I tried to resolve Benjamin's
> > > feedback but got stuck [2]. Eventually I made my best guess. The end
> > > result was a v3 that wasn't that different from v2 but that had a tiny
> > > bit more code split out.
> > >
> > > Version 2 of this patch series didn't change too much. At a high level:
> > > * I added all the forgotten "static" to functions.
> > > * I've hopefully made the bindings better.
> > > * I've integrated into fw_devlink.
> > > * I cleaned up a few descriptions / comments.
> > >
> > > As far as I can tell, as of v4 everyone is on the same page that this
> > > patch series looks like a reasonable solution to the problem and we
> > > just need to get all the nits fixed and figure out how to land it.
> >
> > Thanks a lot for the new version. I like it much more on the HID side:
> >
> > for the HID part:
> > Reviewed-by: Benjamin Tissoires <[email protected]>
> >
> > I wouldn't mind having this series taken from the drm tree if that is
> > easier. i2c-hid is a low patch rate driver, so having it updated through
> > DRM should not be an issue.
> >
> > In that case:
> > Acked-by: Benjamin Tissoires <[email protected]>
>
> Thanks for your reviews and your help getting this whipped into shape.
>
> Lading through drm makes sense to me. I'm a drm committer, so with
> your Ack I believe it should be fine for me to land the series (minus
> the dts) in drm-misc-next. This series has been around for a while,
> has been reviewed by relevant folks, and the last few changes haven't
> fundamentally changed anything about the design, so I'm not going to
> twiddle my thumbs too long. That being said, I'll still plan to wait
> until early next week (Tuesday?) before landing to allow for any last
> minute shouts.
>
> Given how drm-misc works [1] and the fact that mainline is currently
> at v6.5-rc3 (it will be -rc4 when I land it), I'd expect that these
> commits will find their way into v6.6.
>
> [1] https://drm.pages.freedesktop.org/maintainer-tools/drm-misc.html
Pushed the first 10 patches to drm-misc-next. Bjorn: whenever it's
convenient you could land patch #11 (the device tree change) into the
Qualcomm tree.
76edfcf430cc HID: i2c-hid: Do panel follower work on the system_wq
96a37bfd232a HID: i2c-hid: Support being a panel follower
5f8838e9405d HID: i2c-hid: Suspend i2c-hid devices in remove
d93d28477222 HID: i2c-hid: Make suspend and resume into helper functions
675cd877c952 HID: i2c-hid: Rearrange probe() to power things up later
a889ee12d53d HID: i2c-hid: Switch to SYSTEM_SLEEP_PM_OPS()
fbf0ea2da3c7 of: property: fw_devlink: Add a devlink for panel followers
de0874165b83 drm/panel: Add a way for other devices to follow panel state
d2aacaf07395 drm/panel: Check for already prepared/enabled in drm_panel
2ca376ef18f6 dt-bindings: HID: i2c-hid: Add "panel" property to
i2c-hid backed touchscreens
-Doug
Hi,
On Thu, Jul 27, 2023 at 10:19 AM Douglas Anderson <[email protected]> wrote:
>
> Let's provide the proper link from the touchscreen to the panel on
> trogdor devices where the touchscreen support it. This allows the OS
> to power sequence the touchscreen more properly.
>
> For the most part, this is just expected to marginally improve power
> consumption while the screen is off. However, in at least one trogdor
> model (wormdingler) it's suspected that this will fix some behavorial
> corner cases when the panel power cycles (like for a modeset) without
> the touchscreen power cycling.
>
> NOTE: some trogdor variants use touchscreens that don't (yet) support
> linking the touchscreen and the panel. Those variants are left alone.
>
> Reviewed-by: Maxime Ripard <[email protected]>
> Signed-off-by: Douglas Anderson <[email protected]>
> ---
>
> (no changes since v1)
>
> arch/arm64/boot/dts/qcom/sc7180-trogdor-coachz.dtsi | 1 +
> arch/arm64/boot/dts/qcom/sc7180-trogdor-homestar.dtsi | 1 +
> arch/arm64/boot/dts/qcom/sc7180-trogdor-lazor.dtsi | 1 +
> arch/arm64/boot/dts/qcom/sc7180-trogdor-pompom.dtsi | 1 +
> arch/arm64/boot/dts/qcom/sc7180-trogdor-quackingstick.dtsi | 1 +
> arch/arm64/boot/dts/qcom/sc7180-trogdor-wormdingler.dtsi | 1 +
> 6 files changed, 6 insertions(+)
FWIW, this old patch could land any time. All the earlier patches in
the series have landed.
-Doug
On Thu, 27 Jul 2023 10:16:27 -0700, Douglas Anderson wrote:
> The big motivation for this patch series is mostly described in the patch
> ("drm/panel: Add a way for other devices to follow panel state"), but to
> quickly summarize here: for touchscreens that are connected to a panel we
> need the ability to power sequence the two device together. This is not a
> new need, but so far we've managed to get by through a combination of
> inefficiency, added costs, or perhaps just a little bit of brokenness.
> It's time to do better. This patch series allows us to do better.
>
> [...]
Applied, thanks!
[11/11] arm64: dts: qcom: sc7180: Link trogdor touchscreens to the panels
commit: 989aac9dea7fcfc33b5eedc4ae44abbf71460a4d
Best regards,
--
Bjorn Andersson <[email protected]>