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Subject[PATCH v2] pps-gpio: add device-tree binding and support
Date
Instead of allocating a struct pps_gpio_platform_data in the DT case, store
the necessary information in struct pps_gpio_device_data itself. This avoids
an additional allocation and the ifdef. It also gets rid of some indirection.

Also use dev_err instead of pr_err in the changed code.

Signed-off-by: Jan Luebbe <jlu@pengutronix.de>

---
This patch depends on my two recent pps-gpio patches, which are currently
in Andrew Morton's mmotm. So it should probably also go via Andrew if it
is acceptable.

Changes since v1:
- Do not allocate a pdata struct, store info in pps_gpio_device_data.
Also fold the two calls from pps_gpio_setup into the probe function.
(suggested by Arnd Bergmann)

Documentation/devicetree/bindings/pps/pps-gpio.txt | 20 +++
drivers/pps/clients/pps-gpio.c | 128 +++++++++++---------
2 files changed, 93 insertions(+), 55 deletions(-)
create mode 100644 Documentation/devicetree/bindings/pps/pps-gpio.txt

diff --git a/Documentation/devicetree/bindings/pps/pps-gpio.txt b/Documentation/devicetree/bindings/pps/pps-gpio.txt
new file mode 100644
index 0000000..40bf9c3
--- /dev/null
+++ b/Documentation/devicetree/bindings/pps/pps-gpio.txt
@@ -0,0 +1,20 @@
+Device-Tree Bindings for a PPS Signal on GPIO
+
+These properties describe a PPS (pulse-per-second) signal connected to
+a GPIO pin.
+
+Required properties:
+- compatible: should be "pps-gpio"
+- gpios: one PPS GPIO in the format described by ../gpio/gpio.txt
+
+Optional properties:
+- assert-falling-edge: when present, assert is indicated by a falling edge
+ (instead of by a rising edge)
+
+Example:
+ pps {
+ compatible = "pps-gpio";
+ gpios = <&gpio2 6 0>;
+
+ assert-falling-edge;
+ };
diff --git a/drivers/pps/clients/pps-gpio.c b/drivers/pps/clients/pps-gpio.c
index 6768f95..eae0eda 100644
--- a/drivers/pps/clients/pps-gpio.c
+++ b/drivers/pps/clients/pps-gpio.c
@@ -33,13 +33,17 @@
#include <linux/pps-gpio.h>
#include <linux/gpio.h>
#include <linux/list.h>
+#include <linux/of_device.h>
+#include <linux/of_gpio.h>

/* Info for each registered platform device */
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 */
- const struct pps_gpio_platform_data *pdata;
+ bool assert_falling_edge;
+ bool capture_clear;
+ unsigned int gpio_pin;
};

/*
@@ -57,45 +61,25 @@ static irqreturn_t pps_gpio_irq_handler(int irq, void *data)

info = data;

- rising_edge = gpio_get_value(info->pdata->gpio_pin);
- if ((rising_edge && !info->pdata->assert_falling_edge) ||
- (!rising_edge && info->pdata->assert_falling_edge))
+ rising_edge = gpio_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->pdata->capture_clear &&
- ((rising_edge && info->pdata->assert_falling_edge) ||
- (!rising_edge && !info->pdata->assert_falling_edge)))
+ 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);

return IRQ_HANDLED;
}

-static int pps_gpio_setup(struct platform_device *pdev)
-{
- int ret;
- const struct pps_gpio_platform_data *pdata = pdev->dev.platform_data;
-
- ret = devm_gpio_request(&pdev->dev, pdata->gpio_pin, pdata->gpio_label);
- if (ret) {
- pr_warning("failed to request GPIO %u\n", pdata->gpio_pin);
- return -EINVAL;
- }
-
- ret = gpio_direction_input(pdata->gpio_pin);
- if (ret) {
- pr_warning("failed to set pin direction\n");
- return -EINVAL;
- }
-
- return 0;
-}
-
static unsigned long
-get_irqf_trigger_flags(const struct pps_gpio_platform_data *pdata)
+get_irqf_trigger_flags(const struct pps_gpio_device_data *data)
{
- unsigned long flags = pdata->assert_falling_edge ?
+ unsigned long flags = data->assert_falling_edge ?
IRQF_TRIGGER_FALLING : IRQF_TRIGGER_RISING;

- if (pdata->capture_clear) {
+ if (data->capture_clear) {
flags |= ((flags & IRQF_TRIGGER_RISING) ?
IRQF_TRIGGER_FALLING : IRQF_TRIGGER_RISING);
}
@@ -106,35 +90,63 @@ get_irqf_trigger_flags(const struct pps_gpio_platform_data *pdata)
static int pps_gpio_probe(struct platform_device *pdev)
{
struct pps_gpio_device_data *data;
- int irq;
+ 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);
+ if (!data)
+ return -ENOMEM;
+
+ 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 = pps_gpio_setup(pdev);
- if (ret)
- return -EINVAL;
+ 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;
+ }

- /* IRQ setup */
- irq = gpio_to_irq(pdata->gpio_pin);
- if (irq < 0) {
- pr_err("failed to map GPIO to IRQ: %d\n", irq);
+ ret = gpio_direction_input(data->gpio_pin);
+ if (ret) {
+ dev_err(&pdev->dev, "failed to set pin direction\n");
return -EINVAL;
}

- /* allocate space for device info */
- data = devm_kzalloc(&pdev->dev, sizeof(struct pps_gpio_device_data),
- GFP_KERNEL);
- if (data == NULL) {
- return -ENOMEM;
+ /* IRQ setup */
+ ret = gpio_to_irq(data->gpio_pin);
+ if (ret < 0) {
+ dev_err(&pdev->dev, "failed to map GPIO to IRQ: %d\n", ret);
+ return -EINVAL;
}
+ data->irq = ret;

/* initialize PPS specific parts of the bookkeeping data structure. */
data->info.mode = PPS_CAPTUREASSERT | PPS_OFFSETASSERT |
PPS_ECHOASSERT | PPS_CANWAIT | PPS_TSFMT_TSPEC;
- if (pdata->capture_clear)
+ if (data->capture_clear)
data->info.mode |= PPS_CAPTURECLEAR | PPS_OFFSETCLEAR |
PPS_ECHOCLEAR;
data->info.owner = THIS_MODULE;
@@ -143,28 +155,27 @@ static int pps_gpio_probe(struct platform_device *pdev)

/* register PPS source */
pps_default_params = PPS_CAPTUREASSERT | PPS_OFFSETASSERT;
- if (pdata->capture_clear)
+ if (data->capture_clear)
pps_default_params |= PPS_CAPTURECLEAR | PPS_OFFSETCLEAR;
data->pps = pps_register_source(&data->info, pps_default_params);
if (data->pps == NULL) {
- pr_err("failed to register IRQ %d as PPS source\n", irq);
+ dev_err(&pdev->dev, "failed to register IRQ %d as PPS source\n",
+ data->irq);
return -EINVAL;
}

- data->irq = irq;
- data->pdata = pdata;
-
/* register IRQ interrupt handler */
- ret = devm_request_irq(&pdev->dev, irq, pps_gpio_irq_handler,
- get_irqf_trigger_flags(pdata), data->info.name, data);
+ ret = devm_request_irq(&pdev->dev, data->irq, pps_gpio_irq_handler,
+ get_irqf_trigger_flags(data), data->info.name, data);
if (ret) {
pps_unregister_source(data->pps);
- pr_err("failed to acquire IRQ %d\n", irq);
+ dev_err(&pdev->dev, "failed to acquire IRQ %d\n", data->irq);
return -EINVAL;
}

platform_set_drvdata(pdev, data);
- dev_info(data->pps->dev, "Registered IRQ %d as PPS source\n", irq);
+ dev_info(data->pps->dev, "Registered IRQ %d as PPS source\n",
+ data->irq);

return 0;
}
@@ -175,16 +186,23 @@ static int pps_gpio_remove(struct platform_device *pdev)

platform_set_drvdata(pdev, NULL);
pps_unregister_source(data->pps);
- pr_info("removed IRQ %d as PPS source\n", data->irq);
+ dev_info(&pdev->dev, "removed IRQ %d as PPS source\n", data->irq);
return 0;
}

+static const struct of_device_id pps_gpio_dt_ids[] = {
+ { .compatible = "pps-gpio", },
+ { /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, pps_gpio_dt_ids);
+
static struct platform_driver pps_gpio_driver = {
.probe = pps_gpio_probe,
.remove = pps_gpio_remove,
.driver = {
.name = PPS_GPIO_NAME,
- .owner = THIS_MODULE
+ .owner = THIS_MODULE,
+ .of_match_table = of_match_ptr(pps_gpio_dt_ids),
},
};

--
1.7.10.4


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