Mark the interrupt as IRQF_SHARED to permit multiple counter channels to
share the same TCB IRQ line.

Each Timer/Counter Block (TCB) instance shares a single IRQ line among its
three internal channels. When multiple counter channels (e.g., counter@0
and counter@1) within the same TCB are enabled, the second call to
devm_request_irq() fails because the IRQ line is already requested by the
first channel.

Cc: stable@vger.kernel.org
Fixes: e5d581396821 ("counter: microchip-tcb-capture: Add IRQ handling")
Signed-off-by: Dharma Balasubiramani <dharma.b@microchip.com>
Reviewed-by: Kamel Bouhara <kamel.bouhara@bootlin.com>
Reviewed-by: Bence Csókás <bence98@sch.bme.hu>
Link: https://lore.kernel.org/r/20251006-microchip-tcb-v1-1-09c19181bb4a@microchip.com
Signed-off-by: William Breathitt Gray <wbg@kernel.org>

There is no need to register a manual `devm` action for
`pm_runtime_disable()` when `devm_pm_runtime_enable()` exists. It does
the same thing (but also calls `pm_runtime_dont_use_autosuspend()`,
which should be fine here).

Moreover, when `devm_add_action_or_reset()` fails, it is due to a failed
memory allocation and will thus return `-ENOMEM`. `dev_err_probe()`
doesn't do anything when error is `-ENOMEM`. Therefore, the call to
`dev_err_probe()` is useless. Note that `devm_pm_runtime_enable()` has a
tail call to `devm_add_action_or_reset()` and thus returns that value.
Therefore, replace `dev_err_probe()` with the returning value.

Signed-off-by: Waqar Hameed <waqar.hameed@axis.com>
Acked-by: Andrew Davis <afd@ti.com>
Link: https://lore.kernel.org/r/pnda54bjmij.a.out@axis.com
Signed-off-by: William Breathitt Gray <wbg@kernel.org>

William writes:

Second set of Counter updates for 6.16

Adds compatible for STM32MP25 SoC and enables respective encoder
capability for stm32-timer-cnt. Implements watch_validate callback for
microchip-tcb-capture.

* tag 'counter-updates-for-6.16b' of ssh://gitolite.kernel.org/pub/scm/linux/kernel/git/wbg/counter:
  counter: microchip-tcb-capture: Add watch validation support
  counter: stm32-timer-cnt: add support for stm32mp25

The Timer Counter Block (TCB) exposes several kinds of events to the
Counter framework, but not every event is meaningful on every hardware
channel. Add a `watch_validate()` callback so userspace may register only
the combinations actually supported:

* Channel 0 (COUNTER_MCHP_EVCHN_CV, COUNTER_MCHP_EVCHN_RA)
   - COUNTER_EVENT_CAPTURE
   - COUNTER_EVENT_CHANGE_OF_STATE
   - COUNTER_EVENT_OVERFLOW

* Channel 1 (COUNTER_MCHP_EVCHN_RB)
   - COUNTER_EVENT_CAPTURE

* Channel 2 (COUNTER_MCHP_EVCHN_RC)
   - COUNTER_EVENT_THRESHOLD

Any other request is rejected with `-EINVAL`.

Signed-off-by: Dharma Balasubiramani <dharma.b@microchip.com>
Link: https://lore.kernel.org/r/20250520-counter-tcb-v3-1-4631e2aff7ed@microchip.com
Signed-off-by: William Breathitt Gray <wbg@kernel.org>

William writes:

Counter updates for 6.16

An update to allow for larger count values in interrupt-cnt.

* tag 'counter-updates-for-6.16' of ssh://gitolite.kernel.org/pub/scm/linux/kernel/git/wbg/counter:
  counter: interrupt-cnt: Convert atomic_t -> atomic_long_t

Add support for STM32MP25 SoC. There are new counter modes that may be
implemented in later. Still, use newly introduced compatible to handle
this new HW variant and avoid being blocked with existing compatible
in SoC dtsi file. Modes supported currently still remains compatible.
New timer 20 has encoder capability, add it to the list.

Signed-off-by: Fabrice Gasnier <fabrice.gasnier@foss.st.com>
Link: https://lore.kernel.org/r/20250110091922.980627-4-fabrice.gasnier@foss.st.com
Signed-off-by: William Breathitt Gray <wbg@kernel.org>

Enable/disable seems to be racy on SMP, consider the following scenario:

CPU0					CPU1

interrupt_cnt_enable_write(true)
{
	if (priv->enabled == enable)
		return 0;

	if (enable) {
		priv->enabled = true;
					interrupt_cnt_enable_write(false)
					{
						if (priv->enabled == enable)
							return 0;

						if (enable) {
							priv->enabled = true;
							enable_irq(priv->irq);
						} else {
							disable_irq(priv->irq)
							priv->enabled = false;
						}
		enable_irq(priv->irq);
	} else {
		disable_irq(priv->irq);
		priv->enabled = false;
	}

The above would result in priv->enabled == false, but IRQ left enabled.
Protect both write (above race) and read (to propagate the value on SMP)
callbacks with a mutex.

Signed-off-by: Alexander Sverdlin <alexander.sverdlin@siemens.com>
Fixes: a55ebd47f21f ("counter: add IRQ or GPIO based counter")
Acked-by: Oleksij Rempel <o.rempel@pengutronix.de>
Link: https://lore.kernel.org/r/20250331163642.2382651-1-alexander.sverdlin@siemens.com
Signed-off-by: William Breathitt Gray <wbg@kernel.org>

Convert the internal counter type to atomic_long_t, which:
- doesn't change much for existing in-tree users as they are 32-bit anyway
  (stm32/i.MX6)
- doesn't introduce performace penalty on 32-bit platforms
- provides 64-bit resolution on 64-bit platforms with virtually no
  preformance penalty

Signed-off-by: Alexander Sverdlin <alexander.sverdlin@siemens.com>
Acked-by: Oleksij Rempel <o.rempel@pengutronix.de>
Link: https://lore.kernel.org/r/20250331152222.2263776-1-alexander.sverdlin@siemens.com
Signed-off-by: William Breathitt Gray <wbg@kernel.org>

Pull char/misc fixes from Greg KH:
 "Here are two counter driver fixes that I realized I never sent to you
  for 6.14-final.

  They have been in my for weeks, as well as linux-next, my fault for
  not sending them earlier. They are:

   - bugfix for stm32-lptimer-cnt counter driver

   - bugfix for microchip-tcb-capture counter driver

  Again, these have been in linux-next for weeks with no reported
  issues"

* tag 'char-misc-6.15-rc1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc:
  counter: microchip-tcb-capture: Fix undefined counter channel state on probe
  counter: stm32-lptimer-cnt: fix error handling when enabling

In Capture mode, the RC register serves as a compare register for the
Timer Counter Channel. When a the Counter Value reaches the RC value, a
RC Compare event occurs (COUNTER_EVENT_THRESHOLD). This patch exposes
the RC register to userspace as the 'compare' Count extension, thus
allowing users to configure the threshold condition for these events.

Acked-by: Bence Csókás <csokas.bence@prolan.hu>
Link: https://lore.kernel.org/r/20250306-introduce-compare-component-v1-2-93993b3dca9c@kernel.org
Signed-off-by: William Breathitt Gray <wbg@kernel.org>