[PATCH v8 0/2] add support for GPIO or IRQ based event counter

[PATCH v8 0/2] add support for GPIO or IRQ based event counter

[Oleksij Rempel]

changes v8:
- use use enum index instead of enum value for the counter function
- register signal unconditionally and return error is signal revel is
  read 

changes v7:
- make most of structs dynamically allocatable to assign IRQ based
  description to the signal
- assign dev name instead for driver name to the IRQ

changes v6:
- rename it to interrupt-counter
- driver fixes
- device tree fixes

changes v5:
- rename it to event counter, since it support different event sources
- make it work with gpio-only or irq-only configuration
- update yaml binding

changes v4:
- use IRQ_NOAUTOEN to not enable IRQ by default
- rename gpio_ from name pattern and make this driver work any IRQ
  source.

changes v3:
- convert counter to atomic_t

changes v2:
- add commas
- avoid possible unhandled interrupts in the enable path
- do not use of_ specific gpio functions

Add support for GPIO based pulse counter. For now it can only count
pulses. With counter char device support, we will be able to attach
timestamps and measure actual pulse frequency.

Never the less, it is better to mainline this driver now (before chardev
patches go mainline), to provide developers additional use case for the counter
framework with chardev support.

Oleksij Rempel (2):
  dt-bindings: counter: add interrupt-counter binding
  counter: add IRQ or GPIO based counter

 .../bindings/counter/interrupt-counter.yaml   |  62 +++++
 MAINTAINERS                                   |   7 +
 drivers/counter/Kconfig                       |  10 +
 drivers/counter/Makefile                      |   1 +
 drivers/counter/interrupt-cnt.c               | 244 ++++++++++++++++++
 5 files changed, 324 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/counter/interrupt-counter.yaml
 create mode 100644 drivers/counter/interrupt-cnt.c

-- 
2.29.2

[PATCH v8 1/2] dt-bindings: counter: add interrupt-counter binding

[Oleksij Rempel]

Add binding for the interrupt counter node

Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
---
 .../bindings/counter/interrupt-counter.yaml   | 62 +++++++++++++++++++
 1 file changed, 62 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/counter/interrupt-counter.yaml

diff --git a/Documentation/devicetree/bindings/counter/interrupt-counter.yaml b/Documentation/devicetree/bindings/counter/interrupt-counter.yaml
new file mode 100644
index 000000000000..fd075d104631
--- /dev/null
+++ b/Documentation/devicetree/bindings/counter/interrupt-counter.yaml
@@ -0,0 +1,62 @@
+# SPDX-License-Identifier: GPL-2.0
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/counter/interrupt-counter.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Interrupt counter
+
+maintainers:
+  - Oleksij Rempel <o.rempel@pengutronix.de>
+
+description: |
+  A generic interrupt counter to measure interrupt frequency. It was developed
+  and used for agricultural devices to measure rotation speed of wheels or
+  other tools. Since the direction of rotation is not important, only one
+  signal line is needed.
+  Interrupts or gpios are required. If both are defined, the interrupt will
+  take precedence for counting interrupts.
+
+properties:
+  compatible:
+    const: interrupt-counter
+
+  interrupts:
+    maxItems: 1
+
+  gpios:
+    maxItems: 1
+
+required:
+  - compatible
+
+anyOf:
+  - required: [ interrupts-extended ]
+  - required: [ interrupts ]
+  - required: [ gpios ]
+
+additionalProperties: false
+
+examples:
+  - |
+
+    #include <dt-bindings/interrupt-controller/irq.h>
+    #include <dt-bindings/gpio/gpio.h>
+
+    counter-0 {
+        compatible = "interrupt-counter";
+        interrupts-extended = <&gpio 0 IRQ_TYPE_EDGE_RISING>;
+    };
+
+    counter-1 {
+        compatible = "interrupt-counter";
+        gpios = <&gpio 2 GPIO_ACTIVE_HIGH>;
+    };
+
+    counter-2 {
+        compatible = "interrupt-counter";
+        interrupts-extended = <&gpio 2 IRQ_TYPE_EDGE_RISING>;
+        gpios = <&gpio 2 GPIO_ACTIVE_HIGH>;
+    };
+
+...
-- 
2.29.2

[PATCH v8 2/2] counter: add IRQ or GPIO based counter

[Oleksij Rempel]

Add simple IRQ or GPIO base counter. This device is used to measure
rotation speed of some agricultural devices, so no high frequency on the
counter pin is expected.

The maximal measurement frequency depends on the CPU and system load. On
the idle iMX6S I was able to measure up to 20kHz without count drops.

Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
Reviewed-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
---
 MAINTAINERS                     |   7 +
 drivers/counter/Kconfig         |  10 ++
 drivers/counter/Makefile        |   1 +
 drivers/counter/interrupt-cnt.c | 244 ++++++++++++++++++++++++++++++++
 4 files changed, 262 insertions(+)
 create mode 100644 drivers/counter/interrupt-cnt.c

diff --git a/MAINTAINERS b/MAINTAINERS
index a50a543e3c81..ad0a4455afec 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -9217,6 +9217,13 @@ F:	include/dt-bindings/interconnect/
 F:	include/linux/interconnect-provider.h
 F:	include/linux/interconnect.h
 
+INTERRUPT COUNTER DRIVER
+M:	Oleksij Rempel <o.rempel@pengutronix.de>
+R:	Pengutronix Kernel Team <kernel@pengutronix.de>
+L:	linux-iio@vger.kernel.org
+F:	Documentation/devicetree/bindings/counter/interrupt-counter.yaml
+F:	drivers/counter/interrupt-cnt.c
+
 INVENSENSE ICM-426xx IMU DRIVER
 M:	Jean-Baptiste Maneyrol <jmaneyrol@invensense.com>
 L:	linux-iio@vger.kernel.org
diff --git a/drivers/counter/Kconfig b/drivers/counter/Kconfig
index 2de53ab0dd25..dcad13229134 100644
--- a/drivers/counter/Kconfig
+++ b/drivers/counter/Kconfig
@@ -29,6 +29,16 @@ config 104_QUAD_8
 	  The base port addresses for the devices may be configured via the base
 	  array module parameter.
 
+config INTERRUPT_CNT
+	tristate "Interrupt counter driver"
+	depends on GPIOLIB
+	help
+	  Select this option to enable interrupt counter driver. Any interrupt
+	  source can be used by this driver as the event source.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called interrupt-cnt.
+
 config STM32_TIMER_CNT
 	tristate "STM32 Timer encoder counter driver"
 	depends on MFD_STM32_TIMERS || COMPILE_TEST
diff --git a/drivers/counter/Makefile b/drivers/counter/Makefile
index 0a393f71e481..cb646ed2f039 100644
--- a/drivers/counter/Makefile
+++ b/drivers/counter/Makefile
@@ -6,6 +6,7 @@
 obj-$(CONFIG_COUNTER) += counter.o
 
 obj-$(CONFIG_104_QUAD_8)	+= 104-quad-8.o
+obj-$(CONFIG_INTERRUPT_CNT)		+= interrupt-cnt.o
 obj-$(CONFIG_STM32_TIMER_CNT)	+= stm32-timer-cnt.o
 obj-$(CONFIG_STM32_LPTIMER_CNT)	+= stm32-lptimer-cnt.o
 obj-$(CONFIG_TI_EQEP)		+= ti-eqep.o
diff --git a/drivers/counter/interrupt-cnt.c b/drivers/counter/interrupt-cnt.c
new file mode 100644
index 000000000000..a99ee7996977
--- /dev/null
+++ b/drivers/counter/interrupt-cnt.c
@@ -0,0 +1,244 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2021 Pengutronix, Oleksij Rempel <kernel@pengutronix.de>
+ */
+
+#include <linux/counter.h>
+#include <linux/gpio/consumer.h>
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/mod_devicetable.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+
+#define INTERRUPT_CNT_NAME "interrupt-cnt"
+
+struct interrupt_cnt_priv {
+	atomic_t count;
+	struct counter_device counter;
+	struct gpio_desc *gpio;
+	int irq;
+	bool enabled;
+	struct counter_signal signals;
+	struct counter_synapse synapses;
+	struct counter_count cnts;
+};
+
+static irqreturn_t interrupt_cnt_isr(int irq, void *dev_id)
+{
+	struct interrupt_cnt_priv *priv = dev_id;
+
+	atomic_inc(&priv->count);
+
+	return IRQ_HANDLED;
+}
+
+static ssize_t interrupt_cnt_enable_read(struct counter_device *counter,
+					 struct counter_count *count,
+					 void *private, char *buf)
+{
+	struct interrupt_cnt_priv *priv = counter->priv;
+
+	return sysfs_emit(buf, "%d\n", priv->enabled);
+}
+
+static ssize_t interrupt_cnt_enable_write(struct counter_device *counter,
+					  struct counter_count *count,
+					  void *private, const char *buf,
+					  size_t len)
+{
+	struct interrupt_cnt_priv *priv = counter->priv;
+	bool enable;
+	ssize_t ret;
+
+	ret = kstrtobool(buf, &enable);
+	if (ret)
+		return ret;
+
+	if (priv->enabled == enable)
+		return len;
+
+	if (enable) {
+		priv->enabled = true;
+		enable_irq(priv->irq);
+	} else {
+		disable_irq(priv->irq);
+		priv->enabled = false;
+	}
+
+	return len;
+}
+
+static const struct counter_count_ext interrupt_cnt_ext[] = {
+	{
+		.name = "enable",
+		.read = interrupt_cnt_enable_read,
+		.write = interrupt_cnt_enable_write,
+	},
+};
+
+static enum counter_synapse_action interrupt_cnt_synapse_actionss[] = {
+	COUNTER_SYNAPSE_ACTION_RISING_EDGE,
+};
+
+static int interrupt_cnt_action_get(struct counter_device *counter,
+				    struct counter_count *count,
+				    struct counter_synapse *synapse,
+				    size_t *action)
+{
+	*action = 0;
+
+	return 0;
+}
+
+static int interrupt_cnt_read(struct counter_device *counter,
+			      struct counter_count *count, unsigned long *val)
+{
+	struct interrupt_cnt_priv *priv = counter->priv;
+
+	*val = atomic_read(&priv->count);
+
+	return 0;
+}
+
+static int interrupt_cnt_write(struct counter_device *counter,
+			       struct counter_count *count,
+			       const unsigned long val)
+{
+	struct interrupt_cnt_priv *priv = counter->priv;
+
+	atomic_set(&priv->count, val);
+
+	return 0;
+}
+
+static enum counter_count_function interrupt_cnt_functions[] = {
+	COUNTER_COUNT_FUNCTION_INCREASE,
+};
+
+static int interrupt_cnt_function_get(struct counter_device *counter,
+				      struct counter_count *count,
+				      size_t *function)
+{
+	*function = 0;
+
+	return 0;
+}
+
+static int interrupt_cnt_signal_read(struct counter_device *counter,
+				     struct counter_signal *signal,
+				     enum counter_signal_value *val)
+{
+	struct interrupt_cnt_priv *priv = counter->priv;
+	int ret;
+
+	if (!priv->gpio)
+		return -EINVAL;
+
+	ret = gpiod_get_value(priv->gpio);
+	if (ret < 0)
+		return ret;
+
+	*val = ret ? COUNTER_SIGNAL_HIGH : COUNTER_SIGNAL_LOW;
+
+	return 0;
+}
+
+static const struct counter_ops interrupt_cnt_ops = {
+	.action_get = interrupt_cnt_action_get,
+	.count_read = interrupt_cnt_read,
+	.count_write = interrupt_cnt_write,
+	.function_get = interrupt_cnt_function_get,
+	.signal_read  = interrupt_cnt_signal_read,
+};
+
+static int interrupt_cnt_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct interrupt_cnt_priv *priv;
+	int ret;
+
+	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	priv->irq = platform_get_irq_optional(pdev,  0);
+	if (priv->irq == -ENXIO)
+		priv->irq = 0;
+	else if (priv->irq < 0)
+		return dev_err_probe(dev, priv->irq, "failed to get IRQ\n");
+
+	priv->gpio = devm_gpiod_get_optional(dev, NULL, GPIOD_IN);
+	if (IS_ERR(priv->gpio))
+		return dev_err_probe(dev, PTR_ERR(priv->gpio), "failed to get GPIO\n");
+
+	if (!priv->irq && !priv->gpio) {
+		dev_err(dev, "IRQ and GPIO are not found. At least one source should be provided\n");
+		return -ENODEV;
+	}
+
+	if (!priv->irq) {
+		int irq = gpiod_to_irq(priv->gpio);
+
+		if (irq < 0)
+			return dev_err_probe(dev, irq, "failed to get IRQ from GPIO\n");
+
+		priv->irq = irq;
+	}
+
+	priv->signals.name = devm_kasprintf(dev, GFP_KERNEL, "IRQ %d",
+					    priv->irq);
+	if (!priv->signals.name)
+		return -ENOMEM;
+
+	priv->counter.signals = &priv->signals;
+	priv->counter.num_signals = 1;
+
+	priv->synapses.actions_list = interrupt_cnt_synapse_actionss;
+	priv->synapses.num_actions = ARRAY_SIZE(interrupt_cnt_synapse_actionss);
+	priv->synapses.signal = &priv->signals;
+
+	priv->cnts.name = "Channel 0 Count";
+	priv->cnts.functions_list = interrupt_cnt_functions;
+	priv->cnts.num_functions = ARRAY_SIZE(interrupt_cnt_functions);
+	priv->cnts.synapses = &priv->synapses;
+	priv->cnts.num_synapses = 1;
+	priv->cnts.ext = interrupt_cnt_ext;
+	priv->cnts.num_ext = ARRAY_SIZE(interrupt_cnt_ext);
+
+	priv->counter.priv = priv;
+	priv->counter.name = dev_name(dev);
+	priv->counter.parent = dev;
+	priv->counter.ops = &interrupt_cnt_ops;
+	priv->counter.counts = &priv->cnts;
+	priv->counter.num_counts = 1;
+
+	irq_set_status_flags(priv->irq, IRQ_NOAUTOEN);
+	ret = devm_request_irq(dev, priv->irq, interrupt_cnt_isr,
+			       IRQF_TRIGGER_RISING | IRQF_NO_THREAD,
+			       dev_name(dev), priv);
+	if (ret)
+		return ret;
+
+	return devm_counter_register(dev, &priv->counter);
+}
+
+static const struct of_device_id interrupt_cnt_of_match[] = {
+	{ .compatible = "interrupt-counter", },
+	{}
+};
+MODULE_DEVICE_TABLE(of, interrupt_cnt_of_match);
+
+static struct platform_driver interrupt_cnt_driver = {
+	.probe = interrupt_cnt_probe,
+	.driver = {
+		.name = INTERRUPT_CNT_NAME,
+		.of_match_table = interrupt_cnt_of_match,
+	},
+};
+module_platform_driver(interrupt_cnt_driver);
+
+MODULE_ALIAS("platform:interrupt-counter");
+MODULE_AUTHOR("Oleksij Rempel <o.rempel@pengutronix.de>");
+MODULE_DESCRIPTION("Interrupt counter driver");
+MODULE_LICENSE("GPL v2");
-- 
2.29.2

Re: [PATCH v8 1/2] dt-bindings: counter: add interrupt-counter binding

[William Breathitt Gray]

[-- Attachment #1: Type: text/plain, Size: 2530 bytes --]

On Mon, Mar 01, 2021 at 09:04:00AM +0100, Oleksij Rempel wrote:
> Add binding for the interrupt counter node
> 
> Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
> Reviewed-by: Linus Walleij <linus.walleij@linaro.org>

Acked-by: William Breathitt Gray <vilhelm.gray@gmail.com>

> ---
>  .../bindings/counter/interrupt-counter.yaml   | 62 +++++++++++++++++++
>  1 file changed, 62 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/counter/interrupt-counter.yaml
> 
> diff --git a/Documentation/devicetree/bindings/counter/interrupt-counter.yaml b/Documentation/devicetree/bindings/counter/interrupt-counter.yaml
> new file mode 100644
> index 000000000000..fd075d104631
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/counter/interrupt-counter.yaml
> @@ -0,0 +1,62 @@
> +# SPDX-License-Identifier: GPL-2.0
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/counter/interrupt-counter.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Interrupt counter
> +
> +maintainers:
> +  - Oleksij Rempel <o.rempel@pengutronix.de>
> +
> +description: |
> +  A generic interrupt counter to measure interrupt frequency. It was developed
> +  and used for agricultural devices to measure rotation speed of wheels or
> +  other tools. Since the direction of rotation is not important, only one
> +  signal line is needed.
> +  Interrupts or gpios are required. If both are defined, the interrupt will
> +  take precedence for counting interrupts.
> +
> +properties:
> +  compatible:
> +    const: interrupt-counter
> +
> +  interrupts:
> +    maxItems: 1
> +
> +  gpios:
> +    maxItems: 1
> +
> +required:
> +  - compatible
> +
> +anyOf:
> +  - required: [ interrupts-extended ]
> +  - required: [ interrupts ]
> +  - required: [ gpios ]
> +
> +additionalProperties: false
> +
> +examples:
> +  - |
> +
> +    #include <dt-bindings/interrupt-controller/irq.h>
> +    #include <dt-bindings/gpio/gpio.h>
> +
> +    counter-0 {
> +        compatible = "interrupt-counter";
> +        interrupts-extended = <&gpio 0 IRQ_TYPE_EDGE_RISING>;
> +    };
> +
> +    counter-1 {
> +        compatible = "interrupt-counter";
> +        gpios = <&gpio 2 GPIO_ACTIVE_HIGH>;
> +    };
> +
> +    counter-2 {
> +        compatible = "interrupt-counter";
> +        interrupts-extended = <&gpio 2 IRQ_TYPE_EDGE_RISING>;
> +        gpios = <&gpio 2 GPIO_ACTIVE_HIGH>;
> +    };
> +
> +...
> -- 
> 2.29.2
> 

[-- Attachment #2: signature.asc --]
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Re: [PATCH v8 2/2] counter: add IRQ or GPIO based counter

[William Breathitt Gray]

[-- Attachment #1: Type: text/plain, Size: 10136 bytes --]

On Mon, Mar 01, 2021 at 09:04:01AM +0100, Oleksij Rempel wrote:
> Add simple IRQ or GPIO base counter. This device is used to measure
> rotation speed of some agricultural devices, so no high frequency on the
> counter pin is expected.
> 
> The maximal measurement frequency depends on the CPU and system load. On
> the idle iMX6S I was able to measure up to 20kHz without count drops.
> 
> Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
> Reviewed-by: Ahmad Fatoum <a.fatoum@pengutronix.de>

This version looks acceptable for the Counter subsystem.

Thanks,

Reviewed-by: William Breathitt Gray <vilhelm.gray@gmail.com>

> ---
>  MAINTAINERS                     |   7 +
>  drivers/counter/Kconfig         |  10 ++
>  drivers/counter/Makefile        |   1 +
>  drivers/counter/interrupt-cnt.c | 244 ++++++++++++++++++++++++++++++++
>  4 files changed, 262 insertions(+)
>  create mode 100644 drivers/counter/interrupt-cnt.c
> 
> diff --git a/MAINTAINERS b/MAINTAINERS
> index a50a543e3c81..ad0a4455afec 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -9217,6 +9217,13 @@ F:	include/dt-bindings/interconnect/
>  F:	include/linux/interconnect-provider.h
>  F:	include/linux/interconnect.h
>  
> +INTERRUPT COUNTER DRIVER
> +M:	Oleksij Rempel <o.rempel@pengutronix.de>
> +R:	Pengutronix Kernel Team <kernel@pengutronix.de>
> +L:	linux-iio@vger.kernel.org
> +F:	Documentation/devicetree/bindings/counter/interrupt-counter.yaml
> +F:	drivers/counter/interrupt-cnt.c
> +
>  INVENSENSE ICM-426xx IMU DRIVER
>  M:	Jean-Baptiste Maneyrol <jmaneyrol@invensense.com>
>  L:	linux-iio@vger.kernel.org
> diff --git a/drivers/counter/Kconfig b/drivers/counter/Kconfig
> index 2de53ab0dd25..dcad13229134 100644
> --- a/drivers/counter/Kconfig
> +++ b/drivers/counter/Kconfig
> @@ -29,6 +29,16 @@ config 104_QUAD_8
>  	  The base port addresses for the devices may be configured via the base
>  	  array module parameter.
>  
> +config INTERRUPT_CNT
> +	tristate "Interrupt counter driver"
> +	depends on GPIOLIB
> +	help
> +	  Select this option to enable interrupt counter driver. Any interrupt
> +	  source can be used by this driver as the event source.
> +
> +	  To compile this driver as a module, choose M here: the
> +	  module will be called interrupt-cnt.
> +
>  config STM32_TIMER_CNT
>  	tristate "STM32 Timer encoder counter driver"
>  	depends on MFD_STM32_TIMERS || COMPILE_TEST
> diff --git a/drivers/counter/Makefile b/drivers/counter/Makefile
> index 0a393f71e481..cb646ed2f039 100644
> --- a/drivers/counter/Makefile
> +++ b/drivers/counter/Makefile
> @@ -6,6 +6,7 @@
>  obj-$(CONFIG_COUNTER) += counter.o
>  
>  obj-$(CONFIG_104_QUAD_8)	+= 104-quad-8.o
> +obj-$(CONFIG_INTERRUPT_CNT)		+= interrupt-cnt.o
>  obj-$(CONFIG_STM32_TIMER_CNT)	+= stm32-timer-cnt.o
>  obj-$(CONFIG_STM32_LPTIMER_CNT)	+= stm32-lptimer-cnt.o
>  obj-$(CONFIG_TI_EQEP)		+= ti-eqep.o
> diff --git a/drivers/counter/interrupt-cnt.c b/drivers/counter/interrupt-cnt.c
> new file mode 100644
> index 000000000000..a99ee7996977
> --- /dev/null
> +++ b/drivers/counter/interrupt-cnt.c
> @@ -0,0 +1,244 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright (c) 2021 Pengutronix, Oleksij Rempel <kernel@pengutronix.de>
> + */
> +
> +#include <linux/counter.h>
> +#include <linux/gpio/consumer.h>
> +#include <linux/interrupt.h>
> +#include <linux/irq.h>
> +#include <linux/mod_devicetable.h>
> +#include <linux/module.h>
> +#include <linux/platform_device.h>
> +
> +#define INTERRUPT_CNT_NAME "interrupt-cnt"
> +
> +struct interrupt_cnt_priv {
> +	atomic_t count;
> +	struct counter_device counter;
> +	struct gpio_desc *gpio;
> +	int irq;
> +	bool enabled;
> +	struct counter_signal signals;
> +	struct counter_synapse synapses;
> +	struct counter_count cnts;
> +};
> +
> +static irqreturn_t interrupt_cnt_isr(int irq, void *dev_id)
> +{
> +	struct interrupt_cnt_priv *priv = dev_id;
> +
> +	atomic_inc(&priv->count);
> +
> +	return IRQ_HANDLED;
> +}
> +
> +static ssize_t interrupt_cnt_enable_read(struct counter_device *counter,
> +					 struct counter_count *count,
> +					 void *private, char *buf)
> +{
> +	struct interrupt_cnt_priv *priv = counter->priv;
> +
> +	return sysfs_emit(buf, "%d\n", priv->enabled);
> +}
> +
> +static ssize_t interrupt_cnt_enable_write(struct counter_device *counter,
> +					  struct counter_count *count,
> +					  void *private, const char *buf,
> +					  size_t len)
> +{
> +	struct interrupt_cnt_priv *priv = counter->priv;
> +	bool enable;
> +	ssize_t ret;
> +
> +	ret = kstrtobool(buf, &enable);
> +	if (ret)
> +		return ret;
> +
> +	if (priv->enabled == enable)
> +		return len;
> +
> +	if (enable) {
> +		priv->enabled = true;
> +		enable_irq(priv->irq);
> +	} else {
> +		disable_irq(priv->irq);
> +		priv->enabled = false;
> +	}
> +
> +	return len;
> +}
> +
> +static const struct counter_count_ext interrupt_cnt_ext[] = {
> +	{
> +		.name = "enable",
> +		.read = interrupt_cnt_enable_read,
> +		.write = interrupt_cnt_enable_write,
> +	},
> +};
> +
> +static enum counter_synapse_action interrupt_cnt_synapse_actionss[] = {
> +	COUNTER_SYNAPSE_ACTION_RISING_EDGE,
> +};
> +
> +static int interrupt_cnt_action_get(struct counter_device *counter,
> +				    struct counter_count *count,
> +				    struct counter_synapse *synapse,
> +				    size_t *action)
> +{
> +	*action = 0;
> +
> +	return 0;
> +}
> +
> +static int interrupt_cnt_read(struct counter_device *counter,
> +			      struct counter_count *count, unsigned long *val)
> +{
> +	struct interrupt_cnt_priv *priv = counter->priv;
> +
> +	*val = atomic_read(&priv->count);
> +
> +	return 0;
> +}
> +
> +static int interrupt_cnt_write(struct counter_device *counter,
> +			       struct counter_count *count,
> +			       const unsigned long val)
> +{
> +	struct interrupt_cnt_priv *priv = counter->priv;
> +
> +	atomic_set(&priv->count, val);
> +
> +	return 0;
> +}
> +
> +static enum counter_count_function interrupt_cnt_functions[] = {
> +	COUNTER_COUNT_FUNCTION_INCREASE,
> +};
> +
> +static int interrupt_cnt_function_get(struct counter_device *counter,
> +				      struct counter_count *count,
> +				      size_t *function)
> +{
> +	*function = 0;
> +
> +	return 0;
> +}
> +
> +static int interrupt_cnt_signal_read(struct counter_device *counter,
> +				     struct counter_signal *signal,
> +				     enum counter_signal_value *val)
> +{
> +	struct interrupt_cnt_priv *priv = counter->priv;
> +	int ret;
> +
> +	if (!priv->gpio)
> +		return -EINVAL;
> +
> +	ret = gpiod_get_value(priv->gpio);
> +	if (ret < 0)
> +		return ret;
> +
> +	*val = ret ? COUNTER_SIGNAL_HIGH : COUNTER_SIGNAL_LOW;
> +
> +	return 0;
> +}
> +
> +static const struct counter_ops interrupt_cnt_ops = {
> +	.action_get = interrupt_cnt_action_get,
> +	.count_read = interrupt_cnt_read,
> +	.count_write = interrupt_cnt_write,
> +	.function_get = interrupt_cnt_function_get,
> +	.signal_read  = interrupt_cnt_signal_read,
> +};
> +
> +static int interrupt_cnt_probe(struct platform_device *pdev)
> +{
> +	struct device *dev = &pdev->dev;
> +	struct interrupt_cnt_priv *priv;
> +	int ret;
> +
> +	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
> +	if (!priv)
> +		return -ENOMEM;
> +
> +	priv->irq = platform_get_irq_optional(pdev,  0);
> +	if (priv->irq == -ENXIO)
> +		priv->irq = 0;
> +	else if (priv->irq < 0)
> +		return dev_err_probe(dev, priv->irq, "failed to get IRQ\n");
> +
> +	priv->gpio = devm_gpiod_get_optional(dev, NULL, GPIOD_IN);
> +	if (IS_ERR(priv->gpio))
> +		return dev_err_probe(dev, PTR_ERR(priv->gpio), "failed to get GPIO\n");
> +
> +	if (!priv->irq && !priv->gpio) {
> +		dev_err(dev, "IRQ and GPIO are not found. At least one source should be provided\n");
> +		return -ENODEV;
> +	}
> +
> +	if (!priv->irq) {
> +		int irq = gpiod_to_irq(priv->gpio);
> +
> +		if (irq < 0)
> +			return dev_err_probe(dev, irq, "failed to get IRQ from GPIO\n");
> +
> +		priv->irq = irq;
> +	}
> +
> +	priv->signals.name = devm_kasprintf(dev, GFP_KERNEL, "IRQ %d",
> +					    priv->irq);
> +	if (!priv->signals.name)
> +		return -ENOMEM;
> +
> +	priv->counter.signals = &priv->signals;
> +	priv->counter.num_signals = 1;
> +
> +	priv->synapses.actions_list = interrupt_cnt_synapse_actionss;
> +	priv->synapses.num_actions = ARRAY_SIZE(interrupt_cnt_synapse_actionss);
> +	priv->synapses.signal = &priv->signals;
> +
> +	priv->cnts.name = "Channel 0 Count";
> +	priv->cnts.functions_list = interrupt_cnt_functions;
> +	priv->cnts.num_functions = ARRAY_SIZE(interrupt_cnt_functions);
> +	priv->cnts.synapses = &priv->synapses;
> +	priv->cnts.num_synapses = 1;
> +	priv->cnts.ext = interrupt_cnt_ext;
> +	priv->cnts.num_ext = ARRAY_SIZE(interrupt_cnt_ext);
> +
> +	priv->counter.priv = priv;
> +	priv->counter.name = dev_name(dev);
> +	priv->counter.parent = dev;
> +	priv->counter.ops = &interrupt_cnt_ops;
> +	priv->counter.counts = &priv->cnts;
> +	priv->counter.num_counts = 1;
> +
> +	irq_set_status_flags(priv->irq, IRQ_NOAUTOEN);
> +	ret = devm_request_irq(dev, priv->irq, interrupt_cnt_isr,
> +			       IRQF_TRIGGER_RISING | IRQF_NO_THREAD,
> +			       dev_name(dev), priv);
> +	if (ret)
> +		return ret;
> +
> +	return devm_counter_register(dev, &priv->counter);
> +}
> +
> +static const struct of_device_id interrupt_cnt_of_match[] = {
> +	{ .compatible = "interrupt-counter", },
> +	{}
> +};
> +MODULE_DEVICE_TABLE(of, interrupt_cnt_of_match);
> +
> +static struct platform_driver interrupt_cnt_driver = {
> +	.probe = interrupt_cnt_probe,
> +	.driver = {
> +		.name = INTERRUPT_CNT_NAME,
> +		.of_match_table = interrupt_cnt_of_match,
> +	},
> +};
> +module_platform_driver(interrupt_cnt_driver);
> +
> +MODULE_ALIAS("platform:interrupt-counter");
> +MODULE_AUTHOR("Oleksij Rempel <o.rempel@pengutronix.de>");
> +MODULE_DESCRIPTION("Interrupt counter driver");
> +MODULE_LICENSE("GPL v2");
> -- 
> 2.29.2
> 

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Re: [PATCH v8 1/2] dt-bindings: counter: add interrupt-counter binding

[Rob Herring]

On Mon, 01 Mar 2021 09:04:00 +0100, Oleksij Rempel wrote:
> Add binding for the interrupt counter node
> 
> Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
> Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
> ---
>  .../bindings/counter/interrupt-counter.yaml   | 62 +++++++++++++++++++
>  1 file changed, 62 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/counter/interrupt-counter.yaml
> 

Reviewed-by: Rob Herring <robh@kernel.org>

Re: [PATCH v8 0/2] add support for GPIO or IRQ based event counter

[Jonathan Cameron]

On Mon,  1 Mar 2021 09:03:59 +0100
Oleksij Rempel <o.rempel@pengutronix.de> wrote:

> changes v8:
> - use use enum index instead of enum value for the counter function
> - register signal unconditionally and return error is signal revel is
>   read 
> 
> changes v7:
> - make most of structs dynamically allocatable to assign IRQ based
>   description to the signal
> - assign dev name instead for driver name to the IRQ
> 
> changes v6:
> - rename it to interrupt-counter
> - driver fixes
> - device tree fixes
> 
> changes v5:
> - rename it to event counter, since it support different event sources
> - make it work with gpio-only or irq-only configuration
> - update yaml binding
> 
> changes v4:
> - use IRQ_NOAUTOEN to not enable IRQ by default
> - rename gpio_ from name pattern and make this driver work any IRQ
>   source.
> 
> changes v3:
> - convert counter to atomic_t
> 
> changes v2:
> - add commas
> - avoid possible unhandled interrupts in the enable path
> - do not use of_ specific gpio functions
> 
> Add support for GPIO based pulse counter. For now it can only count
> pulses. With counter char device support, we will be able to attach
> timestamps and measure actual pulse frequency.
> 
> Never the less, it is better to mainline this driver now (before chardev
> patches go mainline), to provide developers additional use case for the counter
> framework with chardev support.
> 
> Oleksij Rempel (2):
>   dt-bindings: counter: add interrupt-counter binding
>   counter: add IRQ or GPIO based counter

Series applied to the togreg branch of iio.git and pushed out as testing.

thanks,

Jonathan

> 
>  .../bindings/counter/interrupt-counter.yaml   |  62 +++++
>  MAINTAINERS                                   |   7 +
>  drivers/counter/Kconfig                       |  10 +
>  drivers/counter/Makefile                      |   1 +
>  drivers/counter/interrupt-cnt.c               | 244 ++++++++++++++++++
>  5 files changed, 324 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/counter/interrupt-counter.yaml
>  create mode 100644 drivers/counter/interrupt-cnt.c
>