Date:	Mon,  7 May 2012 13:53:38 +0100
From:	Przemo Firszt <przemo@...szt.eu>
To:	pinglinux@...il.com, jkosina@...e.cz
Cc:	linux-kernel@...r.kernel.org, linux-input@...r.kernel.org,
	linuxwacom-devel@...ts.sourceforge.net,
	Przemo Firszt <przemo@...szt.eu>
Subject: [PATCH] HID: wacom: Add LED selector control for Wacom Intuos4 WL

Add sysfs attribute to control LED selector on Wacom Intuos4. There are 4
different LEDs on the tablet and they can be turned on by something like:

echo 1 > /sys/class/bluetooth/hci0:1/(dev no here)/wacom_led/status_led0_select

The status_led0_select range is 0 to 3. The brightness of the LED selector can
be controlled as well, but this patch uses a fixed value (0x0F) and the
selector is also permanently switched on. The naming of the attribute
(wacom_led/status_led0_select) is the same is in USB driver for Intuos4 Wl.

Signed-off-by: Przemo Firszt <przemo@...szt.eu>
---
 drivers/hid/hid-wacom.c |   93 +++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 93 insertions(+)

diff --git a/drivers/hid/hid-wacom.c b/drivers/hid/hid-wacom.c
index a66e1aa..c5c6ec6 100644
--- a/drivers/hid/hid-wacom.c
+++ b/drivers/hid/hid-wacom.c
@@ -31,6 +31,8 @@
 
 #define PAD_DEVICE_ID	0x0F
 
+#define WAC_CMD_LED_CONTROL     0x20
+
 struct wacom_data {
 	__u16 tool;
 	__u16 butstate;
@@ -44,6 +46,7 @@ struct wacom_data {
 	__u8 ps_connected;
 	struct power_supply battery;
 	struct power_supply ac;
+	__u8 led_selector;
 };
 
 /*percent of battery capacity for Graphire
@@ -64,6 +67,88 @@ static enum power_supply_property wacom_ac_props[] = {
 	POWER_SUPPLY_PROP_SCOPE,
 };
 
+static void wacom_led_control(struct hid_device *hdev)
+{
+	struct wacom_data *wdata = hid_get_drvdata(hdev);
+	unsigned char *buf;
+		__u8 led = 0;
+
+	buf = kzalloc(9, GFP_KERNEL);
+	if (buf) {
+		led =  wdata->led_selector | 0x4;
+
+		buf[0] = WAC_CMD_LED_CONTROL;
+		buf[1] = led;
+		buf[2] = 0x0F;
+		hdev->hid_output_raw_report(hdev, buf, 9, HID_FEATURE_REPORT);
+
+		kfree(buf);
+	}
+
+	return;
+}
+
+static ssize_t wacom_led0_select_store(struct device *dev,
+	struct device_attribute *attr, const char *buf, size_t count)
+{
+	struct hid_device *hdev = container_of(dev, struct hid_device, dev);
+	struct wacom_data *wdata = hid_get_drvdata(hdev);
+	int new_led;
+
+	if (sscanf(buf, "%1d", &new_led) != 1)
+		return -EINVAL;
+
+	wdata->led_selector = new_led & 0x03;
+
+	wacom_led_control(hdev);
+	return strnlen(buf, PAGE_SIZE);
+}
+
+static ssize_t wacom_led0_select_show(struct device *dev,
+	struct device_attribute *attr, char *buf)
+{
+	struct hid_device *hdev = container_of(dev, struct hid_device, dev);
+	struct wacom_data *wdata = hid_get_drvdata(hdev);
+
+	return snprintf(buf, 2, "%d\n", wdata->led_selector);
+}
+
+static DEVICE_ATTR(status_led0_select, S_IWUSR | S_IRUSR,
+		    wacom_led0_select_show, wacom_led0_select_store);
+
+static struct attribute *intuos4_led_attrs[] = {
+	&dev_attr_status_led0_select.attr,
+	NULL
+};
+
+static struct attribute_group intuos4_led_attr_group = {
+	.name = "wacom_led",
+	.attrs = intuos4_led_attrs,
+};
+
+static int wacom_initialize_leds(struct hid_device *hdev)
+{
+	struct wacom_data *wdata = hid_get_drvdata(hdev);
+	int ret;
+
+	wdata->led_selector = 0;
+	ret = sysfs_create_group(&hdev->dev.kobj, &intuos4_led_attr_group);
+
+	if (ret) {
+		dev_err(&hdev->dev,
+			"cannot create sysfs group err: %d\n", ret);
+		return ret;
+	}
+	wacom_led_control(hdev);
+
+	return 0;
+}
+
+static void wacom_destroy_leds(struct hid_device *hdev)
+{
+	sysfs_remove_group(&hdev->dev.kobj, &intuos4_led_attr_group);
+}
+
 static int wacom_battery_get_property(struct power_supply *psy,
 				enum power_supply_property psp,
 				union power_supply_propval *val)
@@ -602,6 +687,12 @@ static int wacom_probe(struct hid_device *hdev,
 		sprintf(hdev->name, "%s", "Wacom Intuos4 WL");
 		wdata->features = 0;
 		wacom_set_features(hdev);
+		ret = wacom_initialize_leds(hdev);
+		if (ret) {
+			hid_warn(hdev,
+				 "can't create led attribute, err: %d\n", ret);
+			goto destroy_leds;
+		}
 		break;
 	}
 
@@ -644,6 +735,8 @@ err_ac:
 err_battery:
 	device_remove_file(&hdev->dev, &dev_attr_speed);
 	hid_hw_stop(hdev);
+destroy_leds:
+	wacom_destroy_leds(hdev);
 err_free:
 	kfree(wdata);
 	return ret;
-- 
1.7.10

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