Commit Graph

6 Commits

Author SHA1 Message Date
Stephen Kitt
baf34f3bbe HID: i2c: use simple i2c probe
All these drivers have an i2c probe function which doesn't use the
"struct i2c_device_id *id" parameter, so they can trivially be
converted to the "probe_new" style of probe with a single argument.

This is part of an ongoing transition to single-argument i2c probe
functions. Old-style probe functions involve a call to i2c_match_id:
in drivers/i2c/i2c-core-base.c,

         /*
          * When there are no more users of probe(),
          * rename probe_new to probe.
          */
         if (driver->probe_new)
                 status = driver->probe_new(client);
         else if (driver->probe)
                 status = driver->probe(client,
                                        i2c_match_id(driver->id_table, client));
         else
                 status = -EINVAL;

Drivers which don't need the second parameter can be declared using
probe_new instead, avoiding the call to i2c_match_id. Drivers which do
can still be converted to probe_new-style, calling i2c_match_id
themselves (as is done currently for of_match_id).

This change was done using the following Coccinelle script, and fixed
up for whitespace changes:

@ rule1 @
identifier fn;
identifier client, id;
@@

- static int fn(struct i2c_client *client, const struct i2c_device_id *id)
+ static int fn(struct i2c_client *client)
{
...when != id
}

@ rule2 depends on rule1 @
identifier rule1.fn;
identifier driver;
@@

struct i2c_driver driver = {
-       .probe
+       .probe_new
                =
(
                   fn
|
-                  &fn
+                  fn
)
                ,
};

Signed-off-by: Stephen Kitt <steve@sk2.org>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2022-10-18 16:13:25 +02:00
Daniel Thompson
2787710f73 HID: i2c-hid: goodix: Fix a lockdep splat
I'm was on the receiving end of a lockdep splat from this driver and after
scratching my head I couldn't be entirely sure it was a false positive
given we would also have to think about whether the regulator locking is
safe (since the notifier is called whilst holding regulator locks which
are also needed for regulator_is_enabled() ).

Regardless of whether it is a real bug or not, the mutex isn't needed.
We can use reference counting tricks instead to avoid races with the
notifier calls.

The observed splat follows:

------------------------------------------------------
kworker/u16:3/127 is trying to acquire lock:
ffff00008021fb20 (&ihid_goodix->regulator_mutex){+.+.}-{4:4}, at: ihid_goodix_vdd_notify+0x30/0x94

but task is already holding lock:
ffff0000835c60c0 (&(&rdev->notifier)->rwsem){++++}-{4:4}, at: blocking_notifier_call_chain+0x30/0x70

which lock already depends on the new lock.

the existing dependency chain (in reverse order) is:

-> #1 (&(&rdev->notifier)->rwsem){++++}-{4:4}:
       down_write+0x68/0x8c
       blocking_notifier_chain_register+0x54/0x70
       regulator_register_notifier+0x1c/0x24
       devm_regulator_register_notifier+0x58/0x98
       i2c_hid_of_goodix_probe+0xdc/0x158
       i2c_device_probe+0x25d/0x270
       really_probe+0x174/0x2cc
       __driver_probe_device+0xc0/0xd8
       driver_probe_device+0x50/0xe4
       __device_attach_driver+0xa8/0xc0
       bus_for_each_drv+0x9c/0xc0
       __device_attach_async_helper+0x6c/0xbc
       async_run_entry_fn+0x38/0x100
       process_one_work+0x294/0x438
       worker_thread+0x180/0x258
       kthread+0x120/0x130
       ret_from_fork+0x10/0x20

-> #0 (&ihid_goodix->regulator_mutex){+.+.}-{4:4}:
       __lock_acquire+0xd24/0xfe8
       lock_acquire+0x288/0x2f4
       __mutex_lock+0xa0/0x338
       mutex_lock_nested+0x3c/0x5c
       ihid_goodix_vdd_notify+0x30/0x94
       notifier_call_chain+0x6c/0x8c
       blocking_notifier_call_chain+0x48/0x70
       _notifier_call_chain.isra.0+0x18/0x20
       _regulator_enable+0xc0/0x178
       regulator_enable+0x40/0x7c
       goodix_i2c_hid_power_up+0x18/0x20
       i2c_hid_core_power_up.isra.0+0x1c/0x2c
       i2c_hid_core_probe+0xd8/0x3d4
       i2c_hid_of_goodix_probe+0x14c/0x158
       i2c_device_probe+0x25c/0x270
       really_probe+0x174/0x2cc
       __driver_probe_device+0xc0/0xd8
       driver_probe_device+0x50/0xe4
       __device_attach_driver+0xa8/0xc0
       bus_for_each_drv+0x9c/0xc0
       __device_attach_async_helper+0x6c/0xbc
       async_run_entry_fn+0x38/0x100
       process_one_work+0x294/0x438
       worker_thread+0x180/0x258
       kthread+0x120/0x130
       ret_from_fork+0x10/0x20

other info that might help us debug this:

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&(&rdev->notifier)->rwsem);
                               lock(&ihid_goodix->regulator_mutex);
                               lock(&(&rdev->notifier)->rwsem);
  lock(&ihid_goodix->regulator_mutex);

 *** DEADLOCK ***

Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
Fixes: 18eeef46d3 ("HID: i2c-hid: goodix: Tie the reset line to true state of the regulator")
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2022-02-02 14:47:46 +01:00
Alistair Francis
b60d3c803d HID: i2c-hid-of: Expose the touchscreen-inverted properties
Allow the touchscreen-inverted-x/y device tree properties to control the
HID_QUIRK_X_INVERT/HID_QUIRK_Y_INVERT quirks for the hid-input device.

Signed-off-by: Alistair Francis <alistair@alistair23.me>
Acked-by: Rob Herring <robh@kernel.org>
[bentiss: silence checkpatch warnings]
Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Link: https://lore.kernel.org/r/20211208124045.61815-3-alistair@alistair23.me
2021-12-14 11:38:04 +01:00
Douglas Anderson
25ddd7cfc5 HID: i2c-hid: goodix: Use the devm variant of regulator_register_notifier()
In commit 18eeef46d3 ("HID: i2c-hid: goodix: Tie the reset line to
true state of the regulator") I added a call to
regulator_register_notifier() but no call to unregister. That's a
bug. Let's use the devm variant to handle the unregistering.

Fixes: 18eeef46d3 ("HID: i2c-hid: goodix: Tie the reset line to true state of the regulator")
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2021-07-28 11:48:49 +02:00
Douglas Anderson
18eeef46d3 HID: i2c-hid: goodix: Tie the reset line to true state of the regulator
The regulator for the touchscreen could be:
* A dedicated regulator just for the touchscreen.
* A regulator shared with something else in the system.
* An always-on regulator.

How we want the "reset" line to behave depends a bit on which of those
three cases we're in. Currently the code is written with the
assumption that it has a dedicated regulator, but that's not really
guaranteed to be the case.

The problem we run into is that if we leave the touchscreen powered on
(because someone else is requesting the regulator or it's an always-on
regulator) and we assert reset then we apparently burn an extra 67 mW
of power. That's not great.

Let's instead tie the control of the reset line to the true state of
the regulator as reported by regulator notifiers. If we have an
always-on regulator our notifier will never be called. If we have a
shared regulator then our notifier will be called when the touchscreen
is truly turned on or truly turned off.

Using notifiers like this nicely handles all the cases without
resorting to hacks like pretending that there is no "reset" GPIO if we
have an always-on regulator.

NOTE: if the regulator is on a shared line it's still possible that
things could be a little off. Specifically, this case is not handled
even after this patch:
1. Suspend goodix (send "sleep", goodix stops requesting regulator on)
2. Other regulator user turns off (regulator fully turns off).
3. Goodix driver gets notified and asserts reset.
4. Other regulator user turns on.
5. Goodix driver gets notified and deasserts reset.
6. Nobody resumes goodix.

With that set of steps we'll have reset deasserted but we will have
lost the results of the I2C_HID_PWR_SLEEP from the suspend path. That
means we might be in higher power than we could be even if the goodix
driver thinks things are suspended. Presumably, however, we're still
in better shape than if we were asserting "reset" the whole time. If
somehow the above situation is actually affecting someone and we want
to do better we can deal with it when we have a real use case.

Signed-off-by: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2021-07-15 21:49:32 +02:00
Douglas Anderson
c1ed18c11b HID: i2c-hid: Introduce goodix-i2c-hid using i2c-hid core
Goodix i2c-hid touchscreens are mostly i2c-hid compliant but have some
special power sequencing requirements, including the need to drive a
reset line during the sequencing.

Let's use the new rejiggering of i2c-hid to support this with a thin
wrapper driver to support the first Goodix i2c-hid touchscreen:
GT7375P

Signed-off-by: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
2021-01-18 16:56:22 +01:00