Merge tag 'counter-updates-for-6.5a' of...

Merge tag 'counter-updates-for-6.5a' of git://git.kernel.org/pub/scm/linux/kernel/git/wbg/counter into char-misc-next

William writes:

First set of Counter updates for the 6.5 cycle

Biggest changes in this set include the introduction of a new Intel 8254
interface library module and the refactoring of the existing 104-quad-8
modules to migrate it to the regmap API. Some other minor cleanups
touching tools/counter and stm32-timer-cnt are also present.

Changes
* 104-quad-8
  - Remove reference in Kconfig to 25-bit counter value
  - Utilize bitfield access macros
  - Refactor to buffer states for CMR, IOR, and IDR
  - Utilize helper functions to handle PR, FLAG and PSC
  - Migrate to the regmap API
* i8254
  - Introduce the Intel 8254 interface library module
* stm32-timer-cnt
  - Reset TIM_TISEL to its default value in probe
* tools/counter
  - Add .gitignore
  - Remove lingering 'include' directories on make clean

* tag 'counter-updates-for-6.5a' of git://git.kernel.org/pub/scm/linux/kernel/git/wbg/counter:
  counter: i8254: Introduce the Intel 8254 interface library module
  counter: 104-quad-8: Migrate to the regmap API
  counter: 104-quad-8: Utilize helper functions to handle PR, FLAG and PSC
  counter: 104-quad-8: Refactor to buffer states for CMR, IOR, and IDR
  counter: 104-quad-8: Utilize bitfield access macros
  tools/counter: Makefile: Remove lingering 'include' directories on make clean
  tools/counter: Add .gitignore
  counter: stm32-timer-cnt: Reset TIM_TISEL to its default value in probe
  counter: 104-quad-8: Remove reference in Kconfig to 25-bit counter value

Documentation/ABI/testing/sysfs-bus-counter

@@ -90,6 +90,60 @@ Description:
 			counter does not freeze at the boundary points, but
 			counts continuously throughout.
 
+		interrupt on terminal count:
+			The output signal is initially low, and will remain low
+			until the counter reaches zero. The output signal then
+			goes high and remains high until a new preset value is
+			set.
+
+		hardware retriggerable one-shot:
+			The output signal is initially high. The output signal
+			will go low by a trigger input signal, and will remain
+			low until the counter reaches zero. The output will then
+			go high and remain high until the next trigger. A
+			trigger results in loading the counter to the preset
+			value and setting the output signal low, thus starting
+			the one-shot pulse.
+
+		rate generator:
+			The output signal is initially high. When the counter
+			has decremented to 1, the output signal goes low for one
+			clock pulse. The output signal then goes high again, the
+			counter is reloaded to the preset value, and the process
+			repeats in a periodic manner as such.
+
+		square wave mode:
+			The output signal is initially high.
+
+			If the initial count is even, the counter is decremented
+			by two on succeeding clock pulses. When the count
+			expires, the output signal changes value and the
+			counter is reloaded to the preset value. The process
+			repeats in periodic manner as such.
+
+			If the initial count is odd, the initial count minus one
+			(an even number) is loaded and then is decremented by
+			two on succeeding clock pulses. One clock pulse after
+			the count expires, the output signal goes low and the
+			counter is reloaded to the preset value minus one.
+			Succeeding clock pulses decrement the count by two. When
+			the count expires, the output goes high again and the
+			counter is reloaded to the preset value minus one. The
+			process repeats in a periodic manner as such.
+
+		software triggered strobe:
+			The output signal is initially high. When the count
+			expires, the output will go low for one clock pulse and
+			then go high again. The counting sequence is "triggered"
+			by setting the preset value.
+
+		hardware triggered strobe:
+			The output signal is initially high. Counting is started
+			by a trigger input signal. When the count expires, the
+			output signal will go low for one clock pulse and then
+			go high again. A trigger results in loading the counter
+			to the preset value.
+
 What:		/sys/bus/counter/devices/counterX/countY/count_mode_available
 What:		/sys/bus/counter/devices/counterX/countY/error_noise_available
 What:		/sys/bus/counter/devices/counterX/countY/function_available

MAINTAINERS

@@ -10260,6 +10260,13 @@ L:	linux-fbdev@vger.kernel.org
 S:	Maintained
 F:	drivers/video/fbdev/i810/
 
+INTEL 8254 COUNTER DRIVER
+M:	William Breathitt Gray <william.gray@linaro.org>
+L:	linux-iio@vger.kernel.org
+S:	Maintained
+F:	drivers/counter/i8254.c
+F:	include/linux/i8254.h
+
 INTEL 8255 GPIO DRIVER
 M:	William Breathitt Gray <william.gray@linaro.org>
 L:	linux-gpio@vger.kernel.org

drivers/counter/Kconfig

@@ -10,6 +10,21 @@ menuconfig COUNTER
 	  interface. You only need to enable this, if you also want to enable
 	  one or more of the counter device drivers below.
 
+config I8254
+	tristate
+	select COUNTER
+	select REGMAP
+	help
+	  Enables support for the i8254 interface library functions. The i8254
+	  interface library provides functions to facilitate communication with
+	  interfaces compatible with the venerable Intel 8254 Programmable
+	  Interval Timer (PIT). The Intel 825x family of chips was first
+	  released in the early 1980s but compatible interfaces are nowadays
+	  typically found embedded in larger VLSI processing chips and FPGA
+	  components.
+
+	  If built as a module its name will be i8254.
+
 if COUNTER
 
 config 104_QUAD_8
@@ -17,14 +32,15 @@ config 104_QUAD_8
 	depends on (PC104 && X86) || COMPILE_TEST
 	depends on HAS_IOPORT_MAP
 	select ISA_BUS_API
+	select REGMAP_MMIO
 	help
 	  Say yes here to build support for the ACCES 104-QUAD-8 quadrature
 	  encoder counter/interface device family (104-QUAD-8, 104-QUAD-4).
 
 	  A counter's respective error flag may be cleared by performing a write
-	  operation on the respective count value attribute. Although the
-	  104-QUAD-8 counters have a 25-bit range, only the lower 24 bits may be
-	  set, either directly or via the counter's preset attribute.
+	  operation on the respective count value attribute. The 104-QUAD-8
+	  counters may be set either directly or via the counter's preset
+	  attribute.
 
 	  The base port addresses for the devices may be configured via the base
 	  array module parameter. The interrupt line numbers for the devices may

drivers/counter/Makefile

@@ -6,6 +6,7 @@
 obj-$(CONFIG_COUNTER) += counter.o
 counter-y := counter-core.o counter-sysfs.o counter-chrdev.o
 
+obj-$(CONFIG_I8254)		+= i8254.o
 obj-$(CONFIG_104_QUAD_8)	+= 104-quad-8.o
 obj-$(CONFIG_INTERRUPT_CNT)		+= interrupt-cnt.o
 obj-$(CONFIG_RZ_MTU3_CNT)	+= rz-mtu3-cnt.o

drivers/counter/counter-sysfs.c

@@ -88,7 +88,13 @@ static const char *const counter_count_mode_str[] = {
 	[COUNTER_COUNT_MODE_NORMAL] = "normal",
 	[COUNTER_COUNT_MODE_RANGE_LIMIT] = "range limit",
 	[COUNTER_COUNT_MODE_NON_RECYCLE] = "non-recycle",
-	[COUNTER_COUNT_MODE_MODULO_N] = "modulo-n"
+	[COUNTER_COUNT_MODE_MODULO_N] = "modulo-n",
+	[COUNTER_COUNT_MODE_INTERRUPT_ON_TERMINAL_COUNT] = "interrupt on terminal count",
+	[COUNTER_COUNT_MODE_HARDWARE_RETRIGGERABLE_ONESHOT] = "hardware retriggerable one-shot",
+	[COUNTER_COUNT_MODE_RATE_GENERATOR] = "rate generator",
+	[COUNTER_COUNT_MODE_SQUARE_WAVE_MODE] = "square wave mode",
+	[COUNTER_COUNT_MODE_SOFTWARE_TRIGGERED_STROBE] = "software triggered strobe",
+	[COUNTER_COUNT_MODE_HARDWARE_TRIGGERED_STROBE] = "hardware triggered strobe",
 };
 
 static const char *const counter_signal_polarity_str[] = {

drivers/counter/stm32-timer-cnt.c

@@ -342,6 +342,9 @@ static int stm32_timer_cnt_probe(struct platform_device *pdev)
 
 	platform_set_drvdata(pdev, priv);
 
+	/* Reset input selector to its default input */
+	regmap_write(priv->regmap, TIM_TISEL, 0x0);
+
 	/* Register Counter device */
 	ret = devm_counter_add(dev, counter);
 	if (ret < 0)

include/linux/i8254.h

+/* SPDX-License-Identifier: GPL-2.0 */
+/* Copyright (C) William Breathitt Gray */
+#ifndef _I8254_H_
+#define _I8254_H_
+
+struct device;
+struct regmap;
+
+/**
+ * struct i8254_regmap_config - Configuration for the register map of an i8254
+ * @parent:	parent device
+ * @map:	regmap for the i8254
+ */
+struct i8254_regmap_config {
+	struct device *parent;
+	struct regmap *map;
+};
+
+int devm_i8254_regmap_register(struct device *dev, const struct i8254_regmap_config *config);
+
+#endif /* _I8254_H_ */

include/uapi/linux/counter.h

@@ -127,6 +127,12 @@ enum counter_count_mode {
 	COUNTER_COUNT_MODE_RANGE_LIMIT,
 	COUNTER_COUNT_MODE_NON_RECYCLE,
 	COUNTER_COUNT_MODE_MODULO_N,
+	COUNTER_COUNT_MODE_INTERRUPT_ON_TERMINAL_COUNT,
+	COUNTER_COUNT_MODE_HARDWARE_RETRIGGERABLE_ONESHOT,
+	COUNTER_COUNT_MODE_RATE_GENERATOR,
+	COUNTER_COUNT_MODE_SQUARE_WAVE_MODE,
+	COUNTER_COUNT_MODE_SOFTWARE_TRIGGERED_STROBE,
+	COUNTER_COUNT_MODE_HARDWARE_TRIGGERED_STROBE,
 };
 
 /* Count function values */

tools/counter/.gitignore

+/counter_example
+/include/linux/counter.h

tools/counter/Makefile

@@ -40,6 +40,7 @@ $(OUTPUT)counter_example: $(COUNTER_EXAMPLE)
 clean:
 	rm -f $(ALL_PROGRAMS)
 	rm -rf $(OUTPUT)include/linux/counter.h
+	rmdir -p $(OUTPUT)include/linux
 	find $(or $(OUTPUT),.) -name '*.o' -delete -o -name '\.*.d' -delete
 
 install: $(ALL_PROGRAMS)