samsung-laptop: add usb charge support

Signed-off-by: Corentin Chary <corentincj@iksaif.net>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Matthew Garrett <mjg@redhat.com>

2 files changed, 90 insertions, 0 deletions

diff --git a/Documentation/ABI/testing/sysfs-driver-samsung-laptop b/Documentation/ABI/testing/sysfs-driver-samsung-laptop
index a6a56e11ebaf..f05b897805e5 100644
--- a/Documentation/ABI/testing/sysfs-driver-samsung-laptop
+++ b/Documentation/ABI/testing/sysfs-driver-samsung-laptop
@@ -27,3 +27,11 @@ Description:	Max battery charge level can be modified, battery cycle
                 level.
                 0 means normal battery mode (100% charge)
                 1 means battery life extender mode (80% charge)
+
+What:           /sys/devices/platform/samsung/usb_charge
+Date:           December 1, 2011
+KernelVersion:  3.3
+Contact:        Corentin Chary <corentin.chary@gmail.com>
+Description:    Use your USB ports to charge devices, even
+                when your laptop is powered off.
+                1 means enabled, 0 means disabled.
diff --git a/drivers/platform/x86/samsung-laptop.c b/drivers/platform/x86/samsung-laptop.c
index 918fa358c11e..b8d2145981e0 100644
--- a/drivers/platform/x86/samsung-laptop.c
+++ b/drivers/platform/x86/samsung-laptop.c
@@ -108,6 +108,10 @@ struct sabi_commands {
         u16 get_battery_life_extender;
         u16 set_battery_life_extender;
 
+        /* 0x80 is off, 0x81 is on */
+        u16 get_usb_charge;
+        u16 set_usb_charge;
+
         /*
          * Tell the BIOS that Linux is running on this machine.
          * 81 is on, 80 is off
@@ -164,6 +168,9 @@ static const struct sabi_config sabi_configs[] = {
                         .get_battery_life_extender = 0xFFFF,
                         .set_battery_life_extender = 0xFFFF,
 
+                        .get_usb_charge = 0xFFFF,
+                        .set_usb_charge = 0xFFFF,
+
                         .set_linux = 0x0a,
                 },
 
@@ -214,6 +221,9 @@ static const struct sabi_config sabi_configs[] = {
                         .get_battery_life_extender = 0x65,
                         .set_battery_life_extender = 0x66,
 
+                        .get_usb_charge = 0x67,
+                        .set_usb_charge = 0x68,
+
                         .set_linux = 0xff,
                 },
 
@@ -622,9 +632,79 @@ static ssize_t set_battery_life_extender(struct device *dev,
 static DEVICE_ATTR(battery_life_extender, S_IWUSR | S_IRUGO,
                    get_battery_life_extender, set_battery_life_extender);
 
+static int read_usb_charge(struct samsung_laptop *samsung)
+{
+        const struct sabi_commands *commands = &samsung->config->commands;
+        struct sabi_data data;
+        int retval;
+
+        if (commands->get_usb_charge == 0xFFFF)
+                return -ENODEV;
+
+        memset(&data, 0, sizeof(data));
+        data.data[0] = 0x80;
+        retval = sabi_command(samsung, commands->get_usb_charge,
+                              &data, &data);
+
+        if (retval)
+                return retval;
+
+        if (data.data[0] != 0 && data.data[0] != 1)
+                return -ENODEV;
+
+        return data.data[0];
+}
+
+static int write_usb_charge(struct samsung_laptop *samsung,
+                            int enabled)
+{
+        const struct sabi_commands *commands = &samsung->config->commands;
+        struct sabi_data data;
+
+        memset(&data, 0, sizeof(data));
+        data.data[0] = 0x80 | enabled;
+        return sabi_command(samsung, commands->set_usb_charge,
+                            &data, NULL);
+}
+
+static ssize_t get_usb_charge(struct device *dev,
+                              struct device_attribute *attr,
+                              char *buf)
+{
+        struct samsung_laptop *samsung = dev_get_drvdata(dev);
+        int ret;
+
+        ret = read_usb_charge(samsung);
+        if (ret < 0)
+                return ret;
+
+        return sprintf(buf, "%d\n", ret);
+}
+
+static ssize_t set_usb_charge(struct device *dev,
+                              struct device_attribute *attr,
+                              const char *buf, size_t count)
+{
+        struct samsung_laptop *samsung = dev_get_drvdata(dev);
+        int ret, value;
+
+        if (!count || sscanf(buf, "%i", &value) != 1)
+                return -EINVAL;
+
+        ret = write_usb_charge(samsung, !!value);
+        if (ret < 0)
+                return ret;
+
+        return count;
+}
+
+static DEVICE_ATTR(usb_charge, S_IWUSR | S_IRUGO,
+                   get_usb_charge, set_usb_charge);
+
 static struct attribute *platform_attributes[] = {
         &dev_attr_performance_level.attr,
         &dev_attr_battery_life_extender.attr,
+        &dev_attr_usb_charge.attr,
         NULL
 };
 
@@ -725,6 +805,8 @@ static mode_t samsung_sysfs_is_visible(struct kobject *kobj,
                 ok = !!samsung->config->performance_levels[0].name;
         if (attr == &dev_attr_battery_life_extender.attr)
                 ok = !!(read_battery_life_extender(samsung) >= 0);
+        if (attr == &dev_attr_usb_charge.attr)
+                ok = !!(read_usb_charge(samsung) >= 0);
 
         return ok ? attr->mode : 0;
 }