HID: expose wacom pen tablet battery through power_supply class

This patch exposes wacom pen tablet battery capacity and ac state thru
power_supply class is sysfs.

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

diff --git a/drivers/hid/Kconfig b/drivers/hid/Kconfig
index 71d4c07..8e1b505 100644 (file)
--- a/drivers/hid/Kconfig
+++ b/drivers/hid/Kconfig
@@ -357,6 +357,14 @@ config HID_WACOM
        ---help---
        Support for Wacom Graphire Bluetooth tablet.
 
+config HID_WACOM_POWER_SUPPLY
+       bool "Wacom Bluetooth devices power supply status support"
+       depends on HID_WACOM
+       select POWER_SUPPLY
+       ---help---
+         Say Y here if you want to enable power supply status monitoring for
+         Wacom Bluetooth devices.
+
 config HID_ZEROPLUS
        tristate "Zeroplus based game controller support" if EMBEDDED
        depends on USB_HID

diff --git a/drivers/hid/hid-wacom.c b/drivers/hid/hid-wacom.c
index 8d3b46f..4d2d2a2 100644 (file)
--- a/drivers/hid/hid-wacom.c
+++ b/drivers/hid/hid-wacom.c
@@ -21,14 +21,88 @@
 #include <linux/device.h>
 #include <linux/hid.h>
 #include <linux/module.h>
+#ifdef CONFIG_HID_WACOM_POWER_SUPPLY
+#include <linux/power_supply.h>
+#endif
 
 #include "hid-ids.h"
 
 struct wacom_data {
        __u16 tool;
        unsigned char butstate;
+#ifdef CONFIG_HID_WACOM_POWER_SUPPLY
+       int battery_capacity;
+       struct power_supply battery;
+       struct power_supply ac;
+#endif
 };
 
+#ifdef CONFIG_HID_WACOM_POWER_SUPPLY
+/*percent of battery capacity, 0 means AC online*/
+static unsigned short batcap[8] = { 1, 15, 25, 35, 50, 70, 100, 0 };
+
+static enum power_supply_property wacom_battery_props[] = {
+       POWER_SUPPLY_PROP_PRESENT,
+       POWER_SUPPLY_PROP_CAPACITY
+};
+
+static enum power_supply_property wacom_ac_props[] = {
+       POWER_SUPPLY_PROP_PRESENT,
+       POWER_SUPPLY_PROP_ONLINE
+};
+
+static int wacom_battery_get_property(struct power_supply *psy,
+                               enum power_supply_property psp,
+                               union power_supply_propval *val)
+{
+       struct wacom_data *wdata = container_of(psy,
+                                       struct wacom_data, battery);
+       int power_state = batcap[wdata->battery_capacity];
+       int ret = 0;
+
+       switch (psp) {
+       case POWER_SUPPLY_PROP_PRESENT:
+               val->intval = 1;
+               break;
+       case POWER_SUPPLY_PROP_CAPACITY:
+               /* show 100% battery capacity when charging */
+               if (power_state == 0)
+                       val->intval = 100;
+               else
+                       val->intval = power_state;
+               break;
+       default:
+               ret = -EINVAL;
+               break;
+       }
+       return ret;
+}
+
+static int wacom_ac_get_property(struct power_supply *psy,
+                               enum power_supply_property psp,
+                               union power_supply_propval *val)
+{
+       struct wacom_data *wdata = container_of(psy, struct wacom_data, ac);
+       int power_state = batcap[wdata->battery_capacity];
+       int ret = 0;
+
+       switch (psp) {
+       case POWER_SUPPLY_PROP_PRESENT:
+               /* fall through */
+       case POWER_SUPPLY_PROP_ONLINE:
+               if (power_state == 0)
+                       val->intval = 1;
+               else
+                       val->intval = 0;
+               break;
+       default:
+               ret = -EINVAL;
+               break;
+       }
+       return ret;
+}
+#endif
+
 static int wacom_raw_event(struct hid_device *hdev, struct hid_report *report,
                u8 *raw_data, int size)
 {
@@ -147,6 +221,12 @@ static int wacom_raw_event(struct hid_device *hdev, struct hid_report *report,
                input_sync(input);
        }
 
+#ifdef CONFIG_HID_WACOM_POWER_SUPPLY
+       /* Store current battery capacity */
+       rw = (data[7] >> 2 & 0x07);
+       if (rw != wdata->battery_capacity)
+               wdata->battery_capacity = rw;
+#endif
        return 1;
 }
 
@@ -206,6 +286,45 @@ static int wacom_probe(struct hid_device *hdev,
        if (ret < 0)
                dev_warn(&hdev->dev, "failed to poke device #2, %d\n", ret);
 
+#ifdef CONFIG_HID_WACOM_POWER_SUPPLY
+       wdata->battery.properties = wacom_battery_props;
+       wdata->battery.num_properties = ARRAY_SIZE(wacom_battery_props);
+       wdata->battery.get_property = wacom_battery_get_property;
+       wdata->battery.name = "wacom_battery";
+       wdata->battery.type = POWER_SUPPLY_TYPE_BATTERY;
+       wdata->battery.use_for_apm = 0;
+
+       ret = power_supply_register(&hdev->dev, &wdata->battery);
+       if (ret) {
+               dev_warn(&hdev->dev,
+                       "can't create sysfs battery attribute, err: %d\n", ret);
+               /*
+                * battery attribute is not critical for the tablet, but if it
+                * failed then there is no need to create ac attribute
+                */
+               goto move_on;
+       }
+
+       wdata->ac.properties = wacom_ac_props;
+       wdata->ac.num_properties = ARRAY_SIZE(wacom_ac_props);
+       wdata->ac.get_property = wacom_ac_get_property;
+       wdata->ac.name = "wacom_ac";
+       wdata->ac.type = POWER_SUPPLY_TYPE_MAINS;
+       wdata->ac.use_for_apm = 0;
+
+       ret = power_supply_register(&hdev->dev, &wdata->ac);
+       if (ret) {
+               dev_warn(&hdev->dev,
+                       "can't create ac battery attribute, err: %d\n", ret);
+               /*
+                * ac attribute is not critical for the tablet, but if it
+                * failed then we don't want to battery attribute to exist
+                */
+               power_supply_unregister(&wdata->battery);
+       }
+
+move_on:
+#endif
        hidinput = list_entry(hdev->inputs.next, struct hid_input, list);
        input = hidinput->input;
 
@@ -250,7 +369,15 @@ err_free:
 
 static void wacom_remove(struct hid_device *hdev)
 {
+#ifdef CONFIG_HID_WACOM_POWER_SUPPLY
+       struct wacom_data *wdata = hid_get_drvdata(hdev);
+#endif
        hid_hw_stop(hdev);
+
+#ifdef CONFIG_HID_WACOM_POWER_SUPPLY
+       power_supply_unregister(&wdata->battery);
+       power_supply_unregister(&wdata->ac);
+#endif
        kfree(hid_get_drvdata(hdev));
 }