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PPS: pps-gpio PPS ECHO implementation

PATCH Superseded Tom Burkart 1 participant 4 messages Feb 5, 2019

Subsystems (2)
Device tree bindings PPS support

v16 of 18 Superseded Latest is v18 →

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Tom Burkart

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#0 lore raw

v16 cover PPS: pps-gpio PPS ECHO implementation

Hi Andrew,
would you please add this patch set to the kernel tree at the next opportunity? It has been Acked by Rodolfo Giometti, the PPS maintainer.

Tom Burkart

Tom Burkart (3):
pps: descriptor-based gpio
dt-bindings: pps: pps-gpio PPS ECHO implementation
pps: pps-gpio pps-echo implementation

 Documentation/devicetree/bindings/pps/pps-gpio.txt |   7 +
 drivers/pps/clients/pps-gpio.c                     | 153 ++++++++++++++++-----
 include/linux/pps-gpio.h                           |   5 +-
 3 files changed, 125 insertions(+), 40 deletions(-)
Signature · 1 line
2.12.3
author
#1 lore raw

PATCH v16 1/3 pps: descriptor-based gpio

This patch changes the GPIO access for the pps-gpio driver from the integer based API to the descriptor based API.

Acked-by Rodolfo Giometti <[email protected]>
Reviewed-by Philipp Zabel <[email protected]>
Signed-off-by Tom Burkart <[email protected]>
---
 drivers/pps/clients/pps-gpio.c | 67 +++++++++++++++++++-----------------------
 include/linux/pps-gpio.h       |  3 +-
 2 files changed, 32 insertions(+), 38 deletions(-)
drivers/pps/clients/pps-gpio.c +31 -36
index dd5d1103e02b..4e5e9229814b 100644
@@ -31,7 +31,7 @@
 #include <linux/slab.h>
 #include <linux/pps_kernel.h>
 #include <linux/pps-gpio.h>
-#include <linux/gpio.h>
+#include <linux/gpio/consumer.h>
 #include <linux/list.h>
 #include <linux/of_device.h>
 #include <linux/of_gpio.h>

@@ -41,9 +41,9 @@ struct pps_gpio_device_data {
 	int irq;			/* IRQ used as PPS source */
 	struct pps_device *pps;		/* PPS source device */
 	struct pps_source_info info;	/* PPS source information */
+	struct gpio_desc *gpio_pin;	/* GPIO port descriptors */
 	bool assert_falling_edge;
 	bool capture_clear;
-	unsigned int gpio_pin;
 };
 
 /*

@@ -61,18 +61,37 @@ static irqreturn_t pps_gpio_irq_handler(int irq, void *data)
 
 	info = data;
 
-	rising_edge = gpio_get_value(info->gpio_pin);
+	rising_edge = gpiod_get_value(info->gpio_pin);
 	if ((rising_edge && !info->assert_falling_edge) ||
 			(!rising_edge && info->assert_falling_edge))
 		pps_event(info->pps, &ts, PPS_CAPTUREASSERT, NULL);
 	else if (info->capture_clear &&
 			((rising_edge && info->assert_falling_edge) ||
-			 (!rising_edge && !info->assert_falling_edge)))
+			(!rising_edge && !info->assert_falling_edge)))
 		pps_event(info->pps, &ts, PPS_CAPTURECLEAR, NULL);
 
 	return IRQ_HANDLED;
 }
 
+static int pps_gpio_setup(struct platform_device *pdev)
+{
+	struct pps_gpio_device_data *data = platform_get_drvdata(pdev);
+	struct device_node *np = pdev->dev.of_node;
+
+	data->gpio_pin = devm_gpiod_get(&pdev->dev,
+		NULL,	/* request "gpios" */
+		GPIOD_IN);
+	if (IS_ERR(data->gpio_pin)) {
+		dev_err(&pdev->dev,
+			"failed to request PPS GPIO\n");
+		return PTR_ERR(data->gpio_pin);
+	}
+
+	if (of_property_read_bool(np, "assert-falling-edge"))
+		data->assert_falling_edge = true;
+	return 0;
+}
+
 static unsigned long
 get_irqf_trigger_flags(const struct pps_gpio_device_data *data)
 {

@@ -90,53 +109,30 @@ get_irqf_trigger_flags(const struct pps_gpio_device_data *data)
 static int pps_gpio_probe(struct platform_device *pdev)
 {
 	struct pps_gpio_device_data *data;
-	const char *gpio_label;
 	int ret;
 	int pps_default_params;
 	const struct pps_gpio_platform_data *pdata = pdev->dev.platform_data;
-	struct device_node *np = pdev->dev.of_node;
 
 	/* allocate space for device info */
-	data = devm_kzalloc(&pdev->dev, sizeof(struct pps_gpio_device_data),
-			GFP_KERNEL);
+	data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
 	if (!data)
 		return -ENOMEM;
+	platform_set_drvdata(pdev, data);
 
+	/* GPIO setup */
 	if (pdata) {
 		data->gpio_pin = pdata->gpio_pin;
-		gpio_label = pdata->gpio_label;
 
 		data->assert_falling_edge = pdata->assert_falling_edge;
 		data->capture_clear = pdata->capture_clear;
 	} else {
-		ret = of_get_gpio(np, 0);
-		if (ret < 0) {
-			dev_err(&pdev->dev, "failed to get GPIO from device tree\n");
-			return ret;
-		}
-		data->gpio_pin = ret;
-		gpio_label = PPS_GPIO_NAME;
-
-		if (of_get_property(np, "assert-falling-edge", NULL))
-			data->assert_falling_edge = true;
-	}
-
-	/* GPIO setup */
-	ret = devm_gpio_request(&pdev->dev, data->gpio_pin, gpio_label);
-	if (ret) {
-		dev_err(&pdev->dev, "failed to request GPIO %u\n",
-			data->gpio_pin);
-		return ret;
-	}
-
-	ret = gpio_direction_input(data->gpio_pin);
-	if (ret) {
-		dev_err(&pdev->dev, "failed to set pin direction\n");
-		return -EINVAL;
+		ret = pps_gpio_setup(pdev);
+		if (ret)
+			return -EINVAL;
 	}
 
 	/* IRQ setup */
-	ret = gpio_to_irq(data->gpio_pin);
+	ret = gpiod_to_irq(data->gpio_pin);
 	if (ret < 0) {
 		dev_err(&pdev->dev, "failed to map GPIO to IRQ: %d\n", ret);
 		return -EINVAL;

@@ -173,7 +169,6 @@ static int pps_gpio_probe(struct platform_device *pdev)
 		return -EINVAL;
 	}
 
-	platform_set_drvdata(pdev, data);
 	dev_info(data->pps->dev, "Registered IRQ %d as PPS source\n",
 		 data->irq);
 

@@ -209,4 +204,4 @@ MODULE_AUTHOR("Ricardo Martins <[email protected]>");
 MODULE_AUTHOR("James Nuss <[email protected]>");
 MODULE_DESCRIPTION("Use GPIO pin as PPS source");
 MODULE_LICENSE("GPL");
-MODULE_VERSION("1.0.0");
+MODULE_VERSION("1.1.0");
include/linux/pps-gpio.h +1 -2
index 56f35dd3d01d..f028d2cda6f5 100644
@@ -23,10 +23,9 @@
 #define _PPS_GPIO_H
 
 struct pps_gpio_platform_data {
+	struct gpio_desc *gpio_pin;
 	bool assert_falling_edge;
 	bool capture_clear;
-	unsigned int gpio_pin;
-	const char *gpio_label;
 };
 
 #endif /* _PPS_GPIO_H */
Signature · 1 line
2.12.3
author
#2 lore raw

PATCH v16 2/3 dt-bindings: pps: pps-gpio PPS ECHO implementation

This patch implements the device tree binding changes required for the pps echo functionality for pps-gpio, that sysfs claims is available already.
This patch is provided separated from the rest of the patch per Documentation/devicetree/bindings/submitting-patches.txt.

This patch was originally written by Lukas Senger as part of a masters thesis project and modified for inclusion into the linux kernel by Tom Burkart.

Acked-by Rodolfo Giometti <[email protected]>
Reviewed-by Rob Herring <[email protected]>
Signed-off-by Lukas Senger <[email protected]>
Signed-off-by Tom Burkart <[email protected]>
---
 Documentation/devicetree/bindings/pps/pps-gpio.txt | 7 +++++++
 1 file changed, 7 insertions(+)
Documentation/devicetree/bindings/pps/pps-gpio.txt +7 -0
index 3683874832ae..9012a2a02e14 100644
@@ -7,6 +7,10 @@ Required properties:
 - compatible: should be "pps-gpio"
 - gpios: one PPS GPIO in the format described by ../gpio/gpio.txt
 
+Additional required properties for the PPS ECHO functionality:
+- echo-gpios: one PPS ECHO GPIO in the format described by ../gpio/gpio.txt
+- echo-active-ms: duration in ms of the active portion of the echo pulse
+
 Optional properties:
 - assert-falling-edge: when present, assert is indicated by a falling edge
                        (instead of by a rising edge)

@@ -19,5 +23,8 @@ Example:
 		gpios = <&gpio1 26 GPIO_ACTIVE_HIGH>;
 		assert-falling-edge;
 
+		echo-gpios = <&gpio1 27 GPIO_ACTIVE_HIGH>;
+		echo-active-ms = <100>;
+
 		compatible = "pps-gpio";
 	};
Signature · 1 line
2.12.3
author
#3 lore raw

PATCH v16 3/3 pps: pps-gpio pps-echo implementation

This patch implements the pps echo functionality for pps-gpio, that sysfs claims is available already.

Configuration is done via device tree bindings.

This patch was originally written by Lukas Senger as part of a masters thesis project and modified for inclusion into the linux kernel by Tom Burkart.

Acked-by Rodolfo Giometti <[email protected]>
Signed-off-by Lukas Senger <[email protected]>
Signed-off-by Tom Burkart <[email protected]>
---
 drivers/pps/clients/pps-gpio.c | 88 ++++++++++++++++++++++++++++++++++++++++--
 include/linux/pps-gpio.h       |  2 +
 2 files changed, 87 insertions(+), 3 deletions(-)
drivers/pps/clients/pps-gpio.c +85 -3
index 4e5e9229814b..4b6418039387 100644
@@ -35,6 +35,8 @@
 #include <linux/list.h>
 #include <linux/of_device.h>
 #include <linux/of_gpio.h>
+#include <linux/timer.h>
+#include <linux/jiffies.h>
 
 /* Info for each registered platform device */
 struct pps_gpio_device_data {

@@ -42,8 +44,12 @@ struct pps_gpio_device_data {
 	struct pps_device *pps;		/* PPS source device */
 	struct pps_source_info info;	/* PPS source information */
 	struct gpio_desc *gpio_pin;	/* GPIO port descriptors */
+	struct gpio_desc *echo_pin;
+	struct timer_list echo_timer;	/* timer to reset echo active state */
 	bool assert_falling_edge;
 	bool capture_clear;
+	unsigned int echo_active_ms;	/* PPS echo active duration */
+	unsigned long echo_timeout;	/* timer timeout value in jiffies */
 };
 
 /*

@@ -64,19 +70,56 @@ static irqreturn_t pps_gpio_irq_handler(int irq, void *data)
 	rising_edge = gpiod_get_value(info->gpio_pin);
 	if ((rising_edge && !info->assert_falling_edge) ||
 			(!rising_edge && info->assert_falling_edge))
-		pps_event(info->pps, &ts, PPS_CAPTUREASSERT, NULL);
+		pps_event(info->pps, &ts, PPS_CAPTUREASSERT, data);
 	else if (info->capture_clear &&
 			((rising_edge && info->assert_falling_edge) ||
 			(!rising_edge && !info->assert_falling_edge)))
-		pps_event(info->pps, &ts, PPS_CAPTURECLEAR, NULL);
+		pps_event(info->pps, &ts, PPS_CAPTURECLEAR, data);
 
 	return IRQ_HANDLED;
 }
 
+/* This function will only be called when an ECHO GPIO is defined */
+static void pps_gpio_echo(struct pps_device *pps, int event, void *data)
+{
+	/* add_timer() needs to write into info->echo_timer */
+	struct pps_gpio_device_data *info = data;
+
+	switch (event) {
+	case PPS_CAPTUREASSERT:
+		if (pps->params.mode & PPS_ECHOASSERT)
+			gpiod_set_value(info->echo_pin, 1);
+		break;
+
+	case PPS_CAPTURECLEAR:
+		if (pps->params.mode & PPS_ECHOCLEAR)
+			gpiod_set_value(info->echo_pin, 1);
+		break;
+	}
+
+	/* fire the timer */
+	if (info->pps->params.mode & (PPS_ECHOASSERT | PPS_ECHOCLEAR)) {
+		info->echo_timer.expires = jiffies + info->echo_timeout;
+		add_timer(&info->echo_timer);
+	}
+}
+
+/* Timer callback to reset the echo pin to the inactive state */
+static void pps_gpio_echo_timer_callback(struct timer_list *t)
+{
+	const struct pps_gpio_device_data *info;
+
+	info = from_timer(info, t, echo_timer);
+
+	gpiod_set_value(info->echo_pin, 0);
+}
+
 static int pps_gpio_setup(struct platform_device *pdev)
 {
 	struct pps_gpio_device_data *data = platform_get_drvdata(pdev);
 	struct device_node *np = pdev->dev.of_node;
+	int ret;
+	u32 value;
 
 	data->gpio_pin = devm_gpiod_get(&pdev->dev,
 		NULL,	/* request "gpios" */

@@ -87,6 +130,33 @@ static int pps_gpio_setup(struct platform_device *pdev)
 		return PTR_ERR(data->gpio_pin);
 	}
 
+	data->echo_pin = devm_gpiod_get_optional(&pdev->dev,
+			"echo",
+			GPIOD_OUT_LOW);
+	if (data->echo_pin) {
+		if (IS_ERR(data->echo_pin)) {
+			dev_err(&pdev->dev, "failed to request ECHO GPIO\n");
+			return PTR_ERR(data->echo_pin);
+		}
+
+		ret = of_property_read_u32(np,
+			"echo-active-ms",
+			&value);
+		if (ret) {
+			dev_err(&pdev->dev,
+				"failed to get echo-active-ms from OF\n");
+			return ret;
+		}
+		data->echo_active_ms = value;
+		/* sanity check on echo_active_ms */
+		if (!data->echo_active_ms || data->echo_active_ms > 999) {
+			dev_err(&pdev->dev,
+				"echo-active-ms: %u - bad value from OF\n",
+				data->echo_active_ms);
+			return -EINVAL;
+		}
+	}
+
 	if (of_property_read_bool(np, "assert-falling-edge"))
 		data->assert_falling_edge = true;
 	return 0;

@@ -122,9 +192,11 @@ static int pps_gpio_probe(struct platform_device *pdev)
 	/* GPIO setup */
 	if (pdata) {
 		data->gpio_pin = pdata->gpio_pin;
+		data->echo_pin = pdata->echo_pin;
 
 		data->assert_falling_edge = pdata->assert_falling_edge;
 		data->capture_clear = pdata->capture_clear;
+		data->echo_active_ms = pdata->echo_active_ms;
 	} else {
 		ret = pps_gpio_setup(pdev);
 		if (ret)

@@ -148,6 +220,11 @@ static int pps_gpio_probe(struct platform_device *pdev)
 	data->info.owner = THIS_MODULE;
 	snprintf(data->info.name, PPS_MAX_NAME_LEN - 1, "%s.%d",
 		 pdev->name, pdev->id);
+	if (data->echo_pin) {
+		data->info.echo = pps_gpio_echo;
+		data->echo_timeout = msecs_to_jiffies(data->echo_active_ms);
+		timer_setup(&data->echo_timer, pps_gpio_echo_timer_callback, 0);
+	}
 
 	/* register PPS source */
 	pps_default_params = PPS_CAPTUREASSERT | PPS_OFFSETASSERT;

@@ -180,6 +257,11 @@ static int pps_gpio_remove(struct platform_device *pdev)
 	struct pps_gpio_device_data *data = platform_get_drvdata(pdev);
 
 	pps_unregister_source(data->pps);
+	if (data->echo_pin) {
+		del_timer_sync(&data->echo_timer);
+		/* reset echo pin in any case */
+		gpiod_set_value(data->echo_pin, 0);
+	}
 	dev_info(&pdev->dev, "removed IRQ %d as PPS source\n", data->irq);
 	return 0;
 }

@@ -204,4 +286,4 @@ MODULE_AUTHOR("Ricardo Martins <[email protected]>");
 MODULE_AUTHOR("James Nuss <[email protected]>");
 MODULE_DESCRIPTION("Use GPIO pin as PPS source");
 MODULE_LICENSE("GPL");
-MODULE_VERSION("1.1.0");
+MODULE_VERSION("1.2.0");
include/linux/pps-gpio.h +2 -0
index f028d2cda6f5..44171e6b7197 100644
@@ -24,8 +24,10 @@
 
 struct pps_gpio_platform_data {
 	struct gpio_desc *gpio_pin;
+	struct gpio_desc *echo_pin;
 	bool assert_falling_edge;
 	bool capture_clear;
+	unsigned int echo_active_ms;
 };
 
 #endif /* _PPS_GPIO_H */
Signature · 1 line
2.12.3