pps-gpio: add device-tree binding and support

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>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Rodolfo Giometti <giometti@enneenne.com>
Cc: Grant Likely <grant.likely@linaro.org>
Cc: Rob Herring <rob.herring@calxeda.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/Documentation/devicetree/bindings/pps/pps-gpio.txt b/Documentation/devicetree/bindings/pps/pps-gpio.txt
new file mode 100644 (file)
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 5bd3bf0..eae0eda 100644 (file)
--- 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);
        }
@@ -106,34 +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)
+       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;
+       }
 
        /* 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_to_irq(data->gpio_pin);
+       if (ret < 0) {
+               dev_err(&pdev->dev, "failed to map GPIO to IRQ: %d\n", ret);
                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;
+       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;
@@ -142,28 +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;
 }
@@ -174,16 +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),
        },
 };