diff mbox

[RFC,1/1] Input: gpio-keys: export gpio key information through sysfs

Message ID 937a56e01181bef04c6661dc61032c1d08269cfa.1256298993.git.ext-mika.1.westerberg@nokia.com
State New, archived
Headers show

Commit Message

Mika Westerberg Oct. 23, 2009, 12:15 p.m. UTC
None
diff mbox

Patch

diff --git a/drivers/input/keyboard/gpio_keys.c b/drivers/input/keyboard/gpio_keys.c
index a88aff3..76e7c5c 100644
--- a/drivers/input/keyboard/gpio_keys.c
+++ b/drivers/input/keyboard/gpio_keys.c
@@ -31,6 +31,8 @@  struct gpio_button_data {
 	struct input_dev *input;
 	struct timer_list timer;
 	struct work_struct work;
+	struct device *dev;	/* device used to export button to sysfs */
+	bool disable;		/* is this gpio button disabled */
 };
 
 struct gpio_keys_drvdata {
@@ -38,6 +40,159 @@  struct gpio_keys_drvdata {
 	struct gpio_button_data data[0];
 };
 
+/*
+ * gpio-keys sysfs interface
+ *
+ * Following interface is export to userspace through
+ * sysfs.  This interface can be used to enable/disable
+ * single GPIO lines from generating events.
+ *
+ * /sys/class/input/gpio-keys/input/input0/gpio-key.N/
+ * 	/code	 ... input event code (ro)
+ *	/type	 ... input event type (ro)
+ *	/desc	 ... description of the button (ro)
+ *	/disable ... enable/disable gpio line from
+ *	             generating events (rw)
+ *
+ * Userspace program can enumerate these keys and based
+ * on {code,type,desc} tuple disable or enable the line
+ * depending on the system state.
+ */
+
+static ssize_t gpio_keys_code_show(struct device *dev,
+	struct device_attribute *attr, char *buf)
+{
+	const struct gpio_button_data *bdata = dev_get_drvdata(dev);
+
+	return snprintf(buf, PAGE_SIZE, "%d\n", bdata->button->code);
+}
+
+static DEVICE_ATTR(code, S_IRUGO, gpio_keys_code_show, NULL);
+
+static ssize_t gpio_keys_type_show(struct device *dev,
+	struct device_attribute *attr, char *buf)
+{
+	const struct gpio_button_data *bdata = dev_get_drvdata(dev);
+
+	return snprintf(buf, PAGE_SIZE, "%d\n", bdata->button->type);
+}
+
+static DEVICE_ATTR(type, S_IRUGO, gpio_keys_type_show, NULL);
+
+static ssize_t gpio_keys_desc_show(struct device *dev,
+	struct device_attribute *attr, char *buf)
+{
+	const struct gpio_button_data *bdata = dev_get_drvdata(dev);
+
+	return snprintf(buf, PAGE_SIZE, "%s\n", bdata->button->desc);
+}
+
+static DEVICE_ATTR(desc, S_IRUGO, gpio_keys_desc_show, NULL);
+
+static ssize_t gpio_keys_disable_show(struct device *dev,
+	struct device_attribute *attr, char *buf)
+{
+	const struct gpio_button_data *bdata = dev_get_drvdata(dev);
+
+	return snprintf(buf, PAGE_SIZE, "%d\n", (int)bdata->disable);
+}
+
+static ssize_t gpio_keys_disable_store(struct device *dev,
+	struct device_attribute *attr, const char *buf, size_t size)
+{
+	struct gpio_button_data *bdata = dev_get_drvdata(dev);
+	int val;
+
+	if (sscanf(buf, "%d", &val) != 1)
+		return -EINVAL;
+
+	val = !!val;
+	if (bdata->disable == val)
+		return size;
+
+	if (val) {
+		disable_irq(gpio_to_irq(bdata->button->gpio));
+	} else {
+		enable_irq(gpio_to_irq(bdata->button->gpio));
+	}
+
+	bdata->disable = val;
+	return size;
+}
+
+static DEVICE_ATTR(disable, S_IWUSR | S_IRUGO,
+	gpio_keys_disable_show, gpio_keys_disable_store);
+
+static struct attribute *gpio_keys_attrs[] = {
+	&dev_attr_code.attr,
+	&dev_attr_type.attr,
+	&dev_attr_desc.attr,
+	&dev_attr_disable.attr,
+	NULL,
+};
+
+static const struct attribute_group gpio_keys_attr_group = {
+	.attrs = gpio_keys_attrs,
+};
+
+static void gpio_keys_unexport(struct platform_device *pdev)
+{
+	struct gpio_keys_platform_data *pdata = pdev->dev.platform_data;
+	struct gpio_keys_drvdata *ddata = platform_get_drvdata(pdev);
+	int i;
+
+	for (i = 0; i < pdata->nbuttons; i++) {
+		struct gpio_button_data *bdata = &ddata->data[i];
+
+		if (bdata->dev != NULL) {
+			sysfs_remove_group(&bdata->dev->kobj,
+				&gpio_keys_attr_group);
+			device_unregister(bdata->dev);
+			bdata->dev = NULL;
+		}
+	}
+}
+
+static int gpio_keys_export(struct platform_device *pdev)
+{
+	struct gpio_keys_platform_data *pdata = pdev->dev.platform_data;
+	struct gpio_keys_drvdata *ddata = platform_get_drvdata(pdev);
+	struct input_dev *input = ddata->input;
+	int i, error = 0;
+
+	for (i = 0; i < pdata->nbuttons; i++) {
+		struct gpio_button_data *bdata = &ddata->data[i];
+		struct device *dev;
+
+		/*
+		 * We create one "device" per gpio line that is used
+		 * as input gpio key device.
+		 */
+		dev = device_create(input->dev.class, &input->dev,
+			MKDEV(0, 0), bdata, "gpio-key.%d", i);
+		if (dev == NULL) {
+			error = -ENOMEM;
+			break;
+		}
+
+		error = sysfs_create_group(&dev->kobj, &gpio_keys_attr_group);
+		if (error != 0) {
+			device_unregister(dev);
+			break;
+		}
+
+		bdata->disable = false;
+		bdata->dev = dev;
+	}
+
+	if (error != 0) {
+		/* something failed, clean up all entries */
+		gpio_keys_unexport(pdev);
+	}
+
+	return error;
+}
+
 static void gpio_keys_report_event(struct work_struct *work)
 {
 	struct gpio_button_data *bdata =
@@ -170,6 +325,12 @@  static int __devinit gpio_keys_probe(struct platform_device *pdev)
 		goto fail2;
 	}
 
+	error = gpio_keys_export(pdev);
+	if (error) {
+		pr_warning("gpio-keys: Unable to export gpio-keys to sysfs, "
+			" error %d", error);
+	}
+
 	device_init_wakeup(&pdev->dev, wakeup);
 
 	return 0;
@@ -199,6 +360,7 @@  static int __devexit gpio_keys_remove(struct platform_device *pdev)
 	int i;
 
 	device_init_wakeup(&pdev->dev, 0);
+	gpio_keys_unexport(pdev);
 
 	for (i = 0; i < pdata->nbuttons; i++) {
 		int irq = gpio_to_irq(pdata->buttons[i].gpio);