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>

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>

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>

TCB hardware is capable of capturing the timer value to registers RA and
RB. Add these registers as capture extensions.

Signed-off-by: Bence Csókás <csokas.bence@prolan.hu>
Link: https://lore.kernel.org/r/20250306134441.582819-3-csokas.bence@prolan.hu
Signed-off-by: William Breathitt Gray <wbg@kernel.org>

Add interrupt servicing to allow userspace to wait for the following:
* Change-of-state caused by external trigger
* Capture of timer value into RA/RB
* Compare to RC register
* Overflow

Signed-off-by: Bence Csókás <csokas.bence@prolan.hu>
Link: https://lore.kernel.org/r/20250306134441.582819-2-csokas.bence@prolan.hu
Signed-off-by: William Breathitt Gray <wbg@kernel.org>

Hardware initialize of the timer counter channel does not occur on probe
thus leaving the Count in an undefined state until the first
function_write() callback is executed. Fix this by performing the proper
hardware initialization during probe.

Fixes: 106b104137fd ("counter: Add microchip TCB capture counter")
Reported-by: Csókás Bence <csokas.bence@prolan.hu>
Closes: https://lore.kernel.org/all/bfa70e78-3cc3-4295-820b-3925c26135cb@prolan.hu/
Link: https://lore.kernel.org/r/20250305-preset-capture-mode-microchip-tcb-capture-v1-1-632c95c6421e@kernel.org
Signed-off-by: William Breathitt Gray <wbg@kernel.org>

Clean up the existing export namespace code along the same lines of
commit 33def8498fdd ("treewide: Convert macro and uses of __section(foo)
to __section("foo")") and for the same reason, it is not desired for the
namespace argument to be a macro expansion itself.

Scripted using

  git grep -l -e MODULE_IMPORT_NS -e EXPORT_SYMBOL_NS | while read file;
  do
    awk -i inplace '
      /^#define EXPORT_SYMBOL_NS/ {
        gsub(/__stringify\(ns\)/, "ns");
        print;
        next;
      }
      /^#define MODULE_IMPORT_NS/ {
        gsub(/__stringify\(ns\)/, "ns");
        print;
        next;
      }
      /MODULE_IMPORT_NS/ {
        $0 = gensub(/MODULE_IMPORT_NS\(([^)]*)\)/, "MODULE_IMPORT_NS(\"\\1\")", "g");
      }
      /EXPORT_SYMBOL_NS/ {
        if ($0 ~ /(EXPORT_SYMBOL_NS[^(]*)\(([^,]+),/) {
  	if ($0 !~ /(EXPORT_SYMBOL_NS[^(]*)\(([^,]+), ([^)]+)\)/ &&
  	    $0 !~ /(EXPORT_SYMBOL_NS[^(]*)\(\)/ &&
  	    $0 !~ /^my/) {
  	  getline line;
  	  gsub(/[[:space:]]*\\$/, "");
  	  gsub(/[[:space:]]/, "", line);
  	  $0 = $0 " " line;
  	}

  	$0 = gensub(/(EXPORT_SYMBOL_NS[^(]*)\(([^,]+), ([^)]+)\)/,
  		    "\\1(\\2, \"\\3\")", "g");
        }
      }
      { print }' $file;
  done

Requested-by: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://mail.google.com/mail/u/2/#inbox/FMfcgzQXKWgMmjdFwwdsfgxzKpVHWPlc
Acked-by: Greg KH <gregkh@linuxfoundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

William writes:

First set of Counter fixes for 6.6

The counter_get_ext() function would incorrectly refer to the first
element of the extensions array to handle component array extensions
when they are located at a different index; a fix is provided to index
to the correct element in the array for this case. A fix for the
microchip-tcb-capture is provided as well to correct an inverted
internal GCLK logic for clock selection.

* tag 'counter-fixes-for-6.6a' of git://git.kernel.org/pub/scm/linux/kernel/git/wbg/counter:
  counter: microchip-tcb-capture: Fix the use of internal GCLK logic
  counter: chrdev: fix getting array extensions

As per the datasheet, the clock selection Bits 2:0 – TCCLKS[2:0] should
be set to 0 while using the internal GCLK (TIMER_CLOCK1).

Fixes: 106b104137fd ("counter: Add microchip TCB capture counter")
Signed-off-by: Dharma Balasubiramani <dharma.b@microchip.com>
Link: https://lore.kernel.org/r/20230905100835.315024-1-dharma.b@microchip.com
Signed-off-by: William Breathitt Gray <william.gray@linaro.org>