sony-laptop: support battery care functions

Allows limiting the maximum battery charge level to a selectable value
(100%, 80% and 50%).

[malattia@linux.it: group function specific variables in a struct, use
kstrtoul. Allow 0 to 100 values into sysfs files rounding to the actual
limit.]

Signed-off-by: Marco Chiappero <marco@absence.it>
Signed-off-by: Mattia Dongili <malattia@linux.it>
Signed-off-by: Matthew Garrett <mjg@redhat.com>

1 files changed, 178 insertions, 0 deletions

diff --git a/drivers/platform/x86/sony-laptop.c b/drivers/platform/x86/sony-laptop.c
index 89e5cf9b1914..0ac186e9abdc 100644
--- a/drivers/platform/x86/sony-laptop.c
+++ b/drivers/platform/x86/sony-laptop.c
@@ -144,6 +144,10 @@ static void sony_nc_kbd_backlight_resume(void);
 static void sony_nc_kbd_backlight_setup(struct platform_device *pd);
 static int sony_nc_kbd_backlight_cleanup(struct platform_device *pd);
 
+static int sony_nc_battery_care_setup(struct platform_device *pd,
+                unsigned int handle);
+static void sony_nc_battery_care_cleanup(struct platform_device *pd);
+
 enum sony_nc_rfkill {
         SONY_WIFI,
         SONY_BLUETOOTH,
@@ -1270,6 +1274,14 @@ static void sony_nc_function_setup(struct acpi_device *device,
                         /* setup hotkeys */
                         sony_call_snc_handle(handle, 0x100, &result);
                         break;
+                case 0x0115:
+                case 0x0136:
+                case 0x013f:
+                        result = sony_nc_battery_care_setup(pf_device, handle);
+                        if (result)
+                                pr_err("couldn't set up battery care function (%d)\n",
+                                                result);
+                        break;
                 case 0x0124:
                 case 0x0135:
                         sony_nc_rfkill_setup(device);
@@ -1306,6 +1318,11 @@ static void sony_nc_function_cleanup(struct platform_device *pd)
                         continue;
 
                 switch (handle) {
+                case 0x0115:
+                case 0x0136:
+                case 0x013f:
+                        sony_nc_battery_care_cleanup(pd);
+                        break;
                 case 0x0124:
                 case 0x0135:
                         sony_nc_rfkill_cleanup();
@@ -1745,6 +1762,167 @@ static void sony_nc_kbd_backlight_resume(void)
                                 &ignore);
 }
 
+struct battery_care_control {
+        struct device_attribute attrs[2];
+        unsigned int handle;
+};
+static struct battery_care_control *bcare_ctl;
+
+static ssize_t sony_nc_battery_care_limit_store(struct device *dev,
+                struct device_attribute *attr,
+                const char *buffer, size_t count)
+{
+        unsigned int result, cmd;
+        unsigned long value;
+
+        if (count > 31)
+                return -EINVAL;
+
+        if (kstrtoul(buffer, 10, &value))
+                return -EINVAL;
+
+        /*  limit values (2 bits):
+         *  00 - none
+         *  01 - 80%
+         *  10 - 50%
+         *  11 - 100%
+         *
+         *  bit 0: 0 disable BCL, 1 enable BCL
+         *  bit 1: 1 tell to store the battery limit (see bits 6,7) too
+         *  bits 2,3: reserved
+         *  bits 4,5: store the limit into the EC
+         *  bits 6,7: store the limit into the battery
+         */
+
+        /*
+         * handle 0x0115 should allow storing on battery too;
+         * handle 0x0136 same as 0x0115 + health status;
+         * handle 0x013f, same as 0x0136 but no storing on the battery
+         *
+         * Store only inside the EC for now, regardless the handle number
+         */
+        if (value == 0)
+                /* disable limits */
+                cmd = 0x0;
+
+        else if (value <= 50)
+                cmd = 0x21;
+
+        else if (value <= 80)
+                cmd = 0x11;
+
+        else if (value <= 100)
+                cmd = 0x31;
+
+        else
+                return -EINVAL;
+
+        if (sony_call_snc_handle(bcare_ctl->handle, (cmd << 0x10) | 0x0100,
+                                &result))
+                return -EIO;
+
+        return count;
+}
+
+static ssize_t sony_nc_battery_care_limit_show(struct device *dev,
+                struct device_attribute *attr, char *buffer)
+{
+        unsigned int result, status;
+
+        if (sony_call_snc_handle(bcare_ctl->handle, 0x0000, &result))
+                return -EIO;
+
+        status = (result & 0x01) ? ((result & 0x30) >> 0x04) : 0;
+        switch (status) {
+        case 1:
+                status = 80;
+                break;
+        case 2:
+                status = 50;
+                break;
+        case 3:
+                status = 100;
+                break;
+        default:
+                status = 0;
+                break;
+        }
+
+        return snprintf(buffer, PAGE_SIZE, "%d\n", status);
+}
+
+static ssize_t sony_nc_battery_care_health_show(struct device *dev,
+                struct device_attribute *attr, char *buffer)
+{
+        ssize_t count = 0;
+        unsigned int health;
+
+        if (sony_call_snc_handle(bcare_ctl->handle, 0x0200, &health))
+                return -EIO;
+
+        count = snprintf(buffer, PAGE_SIZE, "%d\n", health & 0xff);
+
+        return count;
+}
+
+static int sony_nc_battery_care_setup(struct platform_device *pd,
+                unsigned int handle)
+{
+        int ret = 0;
+
+        bcare_ctl = kzalloc(sizeof(struct battery_care_control), GFP_KERNEL);
+        if (!bcare_ctl)
+                return -ENOMEM;
+
+        bcare_ctl->handle = handle;
+
+        sysfs_attr_init(&bcare_ctl->attrs[0].attr);
+        bcare_ctl->attrs[0].attr.name = "battery_care_limiter";
+        bcare_ctl->attrs[0].attr.mode = S_IRUGO | S_IWUSR;
+        bcare_ctl->attrs[0].show = sony_nc_battery_care_limit_show;
+        bcare_ctl->attrs[0].store = sony_nc_battery_care_limit_store;
+
+        ret = device_create_file(&pd->dev, &bcare_ctl->attrs[0]);
+        if (ret)
+                goto outkzalloc;
+
+        /* 0x0115 is for models with no health reporting capability */
+        if (handle == 0x0115)
+                return 0;
+
+        sysfs_attr_init(&bcare_ctl->attrs[1].attr);
+        bcare_ctl->attrs[1].attr.name = "battery_care_health";
+        bcare_ctl->attrs[1].attr.mode = S_IRUGO;
+        bcare_ctl->attrs[1].show = sony_nc_battery_care_health_show;
+
+        ret = device_create_file(&pd->dev, &bcare_ctl->attrs[1]);
+        if (ret)
+                goto outlimiter;
+
+        return 0;
+
+outlimiter:
+        device_remove_file(&pd->dev, &bcare_ctl->attrs[0]);
+
+outkzalloc:
+        kfree(bcare_ctl);
+        bcare_ctl = NULL;
+
+        return ret;
+}
+
+static void sony_nc_battery_care_cleanup(struct platform_device *pd)
+{
+        if (bcare_ctl) {
+                device_remove_file(&pd->dev, &bcare_ctl->attrs[0]);
+                if (bcare_ctl->handle != 0x0115)
+                        device_remove_file(&pd->dev, &bcare_ctl->attrs[1]);
+
+                kfree(bcare_ctl);
+                bcare_ctl = NULL;
+        }
+}
+
 static void sony_nc_backlight_ng_read_limits(int handle,
                 struct sony_backlight_props *props)
 {