samsung-laptop: add battery life extender 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>

diff --git a/Documentation/ABI/testing/sysfs-driver-samsung-laptop b/Documentation/ABI/testing/sysfs-driver-samsung-laptop
index 0a81023..a6a56e1 100644 (file)
--- a/Documentation/ABI/testing/sysfs-driver-samsung-laptop
+++ b/Documentation/ABI/testing/sysfs-driver-samsung-laptop
@@ -17,3 +17,13 @@ Description: Some Samsung laptops have different "performance levels"
                Specifically, not all support the "overclock" option,
                and it's still unknown if this value even changes
                anything, other than making the user feel a bit better.
+
+What:          /sys/devices/platform/samsung/battery_life_extender
+Date:          December 1, 2011
+KernelVersion: 3.3
+Contact:       Corentin Chary <corentin.chary@gmail.com>
+Description:   Max battery charge level can be modified, battery cycle
+               life can be extended by reducing the max battery charge
+               level.
+               0 means normal battery mode (100% charge)
+               1 means battery life extender mode (80% charge)

diff --git a/drivers/platform/x86/samsung-laptop.c b/drivers/platform/x86/samsung-laptop.c
index b39fa53..918fa35 100644 (file)
--- a/drivers/platform/x86/samsung-laptop.c
+++ b/drivers/platform/x86/samsung-laptop.c
@@ -104,6 +104,10 @@ struct sabi_commands {
        u16 get_performance_level;
        u16 set_performance_level;
 
+       /* 0x80 is off, 0x81 is on */
+       u16 get_battery_life_extender;
+       u16 set_battery_life_extender;
+
        /*
         * Tell the BIOS that Linux is running on this machine.
         * 81 is on, 80 is off
@@ -157,6 +161,9 @@ static const struct sabi_config sabi_configs[] = {
                        .get_performance_level = 0x08,
                        .set_performance_level = 0x09,
 
+                       .get_battery_life_extender = 0xFFFF,
+                       .set_battery_life_extender = 0xFFFF,
+
                        .set_linux = 0x0a,
                },
 
@@ -204,6 +211,9 @@ static const struct sabi_config sabi_configs[] = {
                        .get_performance_level = 0x31,
                        .set_performance_level = 0x32,
 
+                       .get_battery_life_extender = 0x65,
+                       .set_battery_life_extender = 0x66,
+
                        .set_linux = 0xff,
                },
 
@@ -543,8 +553,78 @@ static ssize_t set_performance_level(struct device *dev,
 static DEVICE_ATTR(performance_level, S_IWUSR | S_IRUGO,
                   get_performance_level, set_performance_level);
 
+static int read_battery_life_extender(struct samsung_laptop *samsung)
+{
+       const struct sabi_commands *commands = &samsung->config->commands;
+       struct sabi_data data;
+       int retval;
+
+       if (commands->get_battery_life_extender == 0xFFFF)
+               return -ENODEV;
+
+       memset(&data, 0, sizeof(data));
+       data.data[0] = 0x80;
+       retval = sabi_command(samsung, commands->get_battery_life_extender,
+                             &data, &data);
+
+       if (retval)
+               return retval;
+
+       if (data.data[0] != 0 && data.data[0] != 1)
+               return -ENODEV;
+
+       return data.data[0];
+}
+
+static int write_battery_life_extender(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_battery_life_extender,
+                           &data, NULL);
+}
+
+static ssize_t get_battery_life_extender(struct device *dev,
+                                        struct device_attribute *attr,
+                                        char *buf)
+{
+       struct samsung_laptop *samsung = dev_get_drvdata(dev);
+       int ret;
+
+       ret = read_battery_life_extender(samsung);
+       if (ret < 0)
+               return ret;
+
+       return sprintf(buf, "%d\n", ret);
+}
+
+static ssize_t set_battery_life_extender(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_battery_life_extender(samsung, !!value);
+       if (ret < 0)
+               return ret;
+
+       return count;
+}
+
+static DEVICE_ATTR(battery_life_extender, S_IWUSR | S_IRUGO,
+                  get_battery_life_extender, set_battery_life_extender);
+
 static struct attribute *platform_attributes[] = {
        &dev_attr_performance_level.attr,
+       &dev_attr_battery_life_extender.attr,
        NULL
 };
 
@@ -643,6 +723,8 @@ static mode_t samsung_sysfs_is_visible(struct kobject *kobj,
 
        if (attr == &dev_attr_performance_level.attr)
                ok = !!samsung->config->performance_levels[0].name;
+       if (attr == &dev_attr_battery_life_extender.attr)
+               ok = !!(read_battery_life_extender(samsung) >= 0);
 
        return ok ? attr->mode : 0;
 }