Hi all,
please find attached the PPS-GPIO PPS ECHO implementation patch. The
driver claims to have echo functionality in the sysfs interface but this
functionality is not present. This patch provides this functionality.
Part 1 of the patch change the original driver from the number
based GPIO API to the descriptor based API.
Parts 2 and 3 then add the PPS ECHO functionality. This is enabled if a
"echo-gpios" entry is found in the devicetree.
Changes in v10:
Changes requested by Philipp Zabel:
Mostly cosmetic changes: PATCH 2/4 now reviewed. Thanks a lot, Philipp!
(Please note that as of v11 PATCH 1 is gone so this has become PATCH 1/3)
Change in v11:
Change requested by Rob Herring:
All changes in regard to the capture-clear DT entry are gone.
Change in v12:
Change requested by Rob Herring:
Deleted superfluous use of invert-pps-echo
Change in v13:
Patch 2/3 (DT bindings) now reviewed. Thanks a lot, Rob!
Changes in v14:
Simplify code enabling PPS ECHO functionality.
On the linuxpps mailing list it was suggested to use a hrtimer for
resetting the GPIO ECHO active state to the inactive state.
Please also comment on whether a hrtimer is necessary/desirable for the
purpose of resetting the echo pin active state. I am happy to implement
it if this is useful/desirable.
Please install, test and comment as it is now a quite major change to
the driver.
Suggestions for improvement are welcome.
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 | 154 ++++++++++++++++-----
include/linux/pps-gpio.h | 5 +-
3 files changed, 126 insertions(+), 40 deletions(-)
--
2.12.3
This patch changes the GPIO access for the pps-gpio driver from the
integer based API to the descriptor based API.
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(-)
diff --git a/drivers/pps/clients/pps-gpio.c b/drivers/pps/clients/pps-gpio.c
index dd5d1103e02b..4e5e9229814b 100644
--- a/drivers/pps/clients/pps-gpio.c
+++ b/drivers/pps/clients/pps-gpio.c
@@ -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");
diff --git a/include/linux/pps-gpio.h b/include/linux/pps-gpio.h
index 56f35dd3d01d..f028d2cda6f5 100644
--- a/include/linux/pps-gpio.h
+++ b/include/linux/pps-gpio.h
@@ -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 */
--
2.12.3
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 was originally written by Lukas Senger as part of a masters
thesis project and modified for inclusion into the linux kernel by Tom
Burkart.
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(+)
diff --git a/Documentation/devicetree/bindings/pps/pps-gpio.txt b/Documentation/devicetree/bindings/pps/pps-gpio.txt
index 3683874832ae..9012a2a02e14 100644
--- a/Documentation/devicetree/bindings/pps/pps-gpio.txt
+++ b/Documentation/devicetree/bindings/pps/pps-gpio.txt
@@ -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";
};
--
2.12.3
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.
Signed-off-by: Lukas Senger <[email protected]>
Signed-off-by: Tom Burkart <[email protected]>
---
drivers/pps/clients/pps-gpio.c | 89 ++++++++++++++++++++++++++++++++++++++++--
include/linux/pps-gpio.h | 2 +
2 files changed, 88 insertions(+), 3 deletions(-)
diff --git a/drivers/pps/clients/pps-gpio.c b/drivers/pps/clients/pps-gpio.c
index 4e5e9229814b..f00f5ca9f9ad 100644
--- a/drivers/pps/clients/pps-gpio.c
+++ b/drivers/pps/clients/pps-gpio.c
@@ -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 +70,57 @@ 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;
}
+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;
+
+ 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 +131,33 @@ 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 +193,11 @@ 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 +221,11 @@ 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 +258,11 @@ 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 +287,4 @@ 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");
diff --git a/include/linux/pps-gpio.h b/include/linux/pps-gpio.h
index f028d2cda6f5..44171e6b7197 100644
--- a/include/linux/pps-gpio.h
+++ b/include/linux/pps-gpio.h
@@ -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 */
--
2.12.3
On 30/12/2018 09:33, Tom Burkart wrote:
> 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 was originally written by Lukas Senger as part of a masters
> thesis project and modified for inclusion into the linux kernel by Tom
> Burkart.
I think this patch it's OK but I'm asking to myself if it should be merged with
next one... logically it describes what patch 3/3 does so why do we keep them
separated?
Ciao,
Rodolfo
--
GNU/Linux Solutions e-mail: [email protected]
Linux Device Driver [email protected]
Embedded Systems phone: +39 349 2432127
UNIX programming skype: rodolfo.giometti
On 30/12/2018 09:33, Tom Burkart wrote:
> 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.
[snip]
> +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;
> +
> + info = data;
Maybe you can write as below and saving two lines and having better readability:
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);
> + }
> +}
I think is better firing the timer if and only if we set the echo GPIO otherwise
it's useless...
Ciao,
Rodolfo
--
GNU/Linux Solutions e-mail: [email protected]
Linux Device Driver [email protected]
Embedded Systems phone: +39 349 2432127
UNIX programming skype: rodolfo.giometti