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 50 > /sys/class/leds/(device # here)\:selector\:1/brightness

Only one can be lit at a time. The brightness range is 0 to 127. This patch
also contains short ABI description.

Signed-off-by: Przemo Firszt <przemo@firszt.eu>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

1 files changed, 126 insertions, 0 deletions

diff --git a/drivers/hid/hid-wacom.c b/drivers/hid/hid-wacom.c
index a66e1aa25cac..29372edc31c0 100644
--- a/drivers/hid/hid-wacom.c
+++ b/drivers/hid/hid-wacom.c
@@ -24,6 +24,7 @@
 #include <linux/device.h>
 #include <linux/hid.h>
 #include <linux/module.h>
+#include <linux/leds.h>
 #include <linux/slab.h>
 #include <linux/power_supply.h>
 
@@ -31,6 +32,8 @@
 
 #define PAD_DEVICE_ID   0x0F
 
+#define WAC_CMD_LED_CONTROL     0x20
+
 struct wacom_data {
         __u16 tool;
         __u16 butstate;
@@ -44,6 +47,8 @@ struct wacom_data {
         __u8 ps_connected;
         struct power_supply battery;
         struct power_supply ac;
+        __u8 led_selector;
+        struct led_classdev *leds[4];
 };
 
 /*percent of battery capacity for Graphire
@@ -64,6 +69,117 @@ static enum power_supply_property wacom_ac_props[] = {
         POWER_SUPPLY_PROP_SCOPE,
 };
 
+static void wacom_leds_set_brightness(struct led_classdev *led_dev,
+                                                enum led_brightness value)
+{
+        struct device *dev = led_dev->dev->parent;
+        struct hid_device *hdev;
+        struct wacom_data *wdata;
+        unsigned char *buf;
+        __u8 led = 0;
+        int i;
+
+        hdev = container_of(dev, struct hid_device, dev);
+        wdata = hid_get_drvdata(hdev);
+        for (i = 0; i < 4; ++i) {
+                if (wdata->leds[i] == led_dev)
+                        wdata->led_selector = i;
+        }
+
+        led = wdata->led_selector | 0x04;
+        buf = kzalloc(9, GFP_KERNEL);
+        if (buf) {
+                buf[0] = WAC_CMD_LED_CONTROL;
+                buf[1] = led;
+                buf[2] = value;
+                hdev->hid_output_raw_report(hdev, buf, 9, HID_FEATURE_REPORT);
+                kfree(buf);
+        }
+
+        return;
+}
+
+static enum led_brightness wacom_leds_get_brightness(struct led_classdev *led_dev)
+{
+        struct wacom_data *wdata;
+        struct device *dev = led_dev->dev->parent;
+        int value = 0;
+        int i;
+
+        wdata = hid_get_drvdata(container_of(dev, struct hid_device, dev));
+
+        for (i = 0; i < 4; ++i) {
+                if (wdata->leds[i] == led_dev) {
+                        value = wdata->leds[i]->brightness;
+                        break;
+                }
+        }
+
+        return value;
+}
+
+
+static int wacom_initialize_leds(struct hid_device *hdev)
+{
+        struct wacom_data *wdata = hid_get_drvdata(hdev);
+        struct led_classdev *led;
+        struct device *dev = &hdev->dev;
+        size_t namesz = strlen(dev_name(dev)) + 12;
+        char *name;
+        int i, ret;
+
+        wdata->led_selector = 0;
+
+        for (i = 0; i < 4; i++) {
+                led = kzalloc(sizeof(struct led_classdev) + namesz, GFP_KERNEL);
+                if (!led) {
+                        hid_warn(hdev,
+                                 "can't allocate memory for LED selector\n");
+                        ret = -ENOMEM;
+                        goto err;
+                }
+
+                name = (void *)&led[1];
+                snprintf(name, namesz, "%s:selector:%d", dev_name(dev), i);
+                led->name = name;
+                led->brightness = 0;
+                led->max_brightness = 127;
+                led->brightness_get = wacom_leds_get_brightness;
+                led->brightness_set = wacom_leds_set_brightness;
+
+                wdata->leds[i] = led;
+
+                ret = led_classdev_register(dev, wdata->leds[i]);
+
+                if (ret) {
+                        wdata->leds[i] = NULL;
+                        kfree(led);
+                        hid_warn(hdev, "can't register LED\n");
+                        goto err;
+                }
+        }
+
+err:
+        return ret;
+}
+
+static void wacom_destroy_leds(struct hid_device *hdev)
+{
+        struct wacom_data *wdata = hid_get_drvdata(hdev);
+        struct led_classdev *led;
+        int i;
+
+        for (i = 0; i < 4; ++i) {
+                if (wdata->leds[i]) {
+                        led = wdata->leds[i];
+                        wdata->leds[i] = NULL;
+                        led_classdev_unregister(led);
+                        kfree(led);
+                }
+        }
+
+}
+
 static int wacom_battery_get_property(struct power_supply *psy,
                                 enum power_supply_property psp,
                                 union power_supply_propval *val)
@@ -602,6 +718,12 @@ 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 +766,8 @@ 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;
@@ -652,6 +776,8 @@ err_free:
 static void wacom_remove(struct hid_device *hdev)
 {
         struct wacom_data *wdata = hid_get_drvdata(hdev);
+
+        wacom_destroy_leds(hdev);
         device_remove_file(&hdev->dev, &dev_attr_speed);
         hid_hw_stop(hdev);