[BATTERY] Universal power supply class (was: battery class)

This class is result of "external power" and "battery" classes merge,
as suggested by David Woodhouse. He also implemented uevent support.

Here how userspace seeing it now:

    	# ls /sys/class/power\ supply/
    	ac  main-battery  usb

    	# cat /sys/class/power\ supply/ac/type
    	AC

    	# cat /sys/class/power\ supply/usb/type
    	USB

    	# cat /sys/class/power\ supply/main-battery/type
    	Battery

    	# cat /sys/class/power\ supply/ac/online
    	1

    	# cat /sys/class/power\ supply/usb/online
    	0

    	# cat /sys/class/power\ supply/main-battery/status
    	Charging

    	# cat /sys/class/leds/h5400\:red-left/trigger
    	none h5400-radio timer hwtimer ac-online usb-online
    	main-battery-charging-or-full [main-battery-charging]
    	main-battery-full

Signed-off-by: Anton Vorontsov <cbou@mail.ru>
Signed-off-by: David Woodhouse <dwmw2@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

1 files changed, 299 insertions, 0 deletions

diff --git a/drivers/power/power_supply_sysfs.c b/drivers/power/power_supply_sysfs.c
new file mode 100644
index 00000000000..c07d4258d34
--- /dev/null
+++ b/drivers/power/power_supply_sysfs.c
@@ -0,0 +1,299 @@
+/*
+ *  Sysfs interface for the universal power supply monitor class
+ *
+ *  Copyright © 2007  David Woodhouse <dwmw2@infradead.org>
+ *  Copyright © 2007  Anton Vorontsov <cbou@mail.ru>
+ *  Copyright © 2004  Szabolcs Gyurko
+ *  Copyright © 2003  Ian Molton <spyro@f2s.com>
+ *
+ *  Modified: 2004, Oct     Szabolcs Gyurko
+ *
+ *  You may use this code as per GPL version 2
+ */
+
+#include <linux/ctype.h>
+#include <linux/power_supply.h>
+
+/*
+ * This is because the name "current" breaks the device attr macro.
+ * The "current" word resolves to "(get_current())" so instead of
+ * "current" "(get_current())" appears in the sysfs.
+ *
+ * The source of this definition is the device.h which calls __ATTR
+ * macro in sysfs.h which calls the __stringify macro.
+ *
+ * Only modification that the name is not tried to be resolved
+ * (as a macro let's say).
+ */
+
+#define POWER_SUPPLY_ATTR(_name)					\
+{									\
+	.attr = { .name = #_name, .mode = 0444, .owner = THIS_MODULE },	\
+	.show = power_supply_show_property,				\
+	.store = NULL,							\
+}
+
+static struct device_attribute power_supply_attrs[];
+
+static ssize_t power_supply_show_property(struct device *dev,
+					  struct device_attribute *attr,
+					  char *buf) {
+	static char *status_text[] = {
+		"Unknown", "Charging", "Discharging", "Not charging", "Full"
+	};
+	static char *health_text[] = {
+		"Unknown", "Good", "Overheat", "Dead", "Over voltage",
+		"Unspecified failure"
+	};
+	static char *technology_text[] = {
+		"Unknown", "NiMH", "Li-ion", "Li-poly", "LiFe", "NiCd"
+	};
+	static char *capacity_level_text[] = {
+		"Unknown", "Critical", "Low", "Normal", "High", "Full"
+	};
+	ssize_t ret;
+	struct power_supply *psy = dev_get_drvdata(dev);
+	const ptrdiff_t off = attr - power_supply_attrs;
+	union power_supply_propval value;
+
+	ret = psy->get_property(psy, off, &value);
+
+	if (ret < 0) {
+		if (ret != -ENODEV)
+			dev_err(dev, "driver failed to report `%s' property\n",
+				attr->attr.name);
+		return ret;
+	}
+
+	if (off == POWER_SUPPLY_PROP_STATUS)
+		return sprintf(buf, "%s\n", status_text[value.intval]);
+	else if (off == POWER_SUPPLY_PROP_HEALTH)
+		return sprintf(buf, "%s\n", health_text[value.intval]);
+	else if (off == POWER_SUPPLY_PROP_TECHNOLOGY)
+		return sprintf(buf, "%s\n", technology_text[value.intval]);
+	else if (off == POWER_SUPPLY_PROP_CAPACITY_LEVEL)
+		return sprintf(buf, "%s\n",
+			       capacity_level_text[value.intval]);
+	else if (off >= POWER_SUPPLY_PROP_MODEL_NAME)
+		return sprintf(buf, "%s\n", value.strval);
+
+	return sprintf(buf, "%d\n", value.intval);
+}
+
+/* Must be in the same order as POWER_SUPPLY_PROP_* */
+static struct device_attribute power_supply_attrs[] = {
+	/* Properties of type `int' */
+	POWER_SUPPLY_ATTR(status),
+	POWER_SUPPLY_ATTR(health),
+	POWER_SUPPLY_ATTR(present),
+	POWER_SUPPLY_ATTR(online),
+	POWER_SUPPLY_ATTR(technology),
+	POWER_SUPPLY_ATTR(voltage_max_design),
+	POWER_SUPPLY_ATTR(voltage_min_design),
+	POWER_SUPPLY_ATTR(voltage_now),
+	POWER_SUPPLY_ATTR(voltage_avg),
+	POWER_SUPPLY_ATTR(current_now),
+	POWER_SUPPLY_ATTR(current_avg),
+	POWER_SUPPLY_ATTR(charge_full_design),
+	POWER_SUPPLY_ATTR(charge_empty_design),
+	POWER_SUPPLY_ATTR(charge_full),
+	POWER_SUPPLY_ATTR(charge_empty),
+	POWER_SUPPLY_ATTR(charge_now),
+	POWER_SUPPLY_ATTR(charge_avg),
+	POWER_SUPPLY_ATTR(energy_full_design),
+	POWER_SUPPLY_ATTR(energy_empty_design),
+	POWER_SUPPLY_ATTR(energy_full),
+	POWER_SUPPLY_ATTR(energy_empty),
+	POWER_SUPPLY_ATTR(energy_now),
+	POWER_SUPPLY_ATTR(energy_avg),
+	POWER_SUPPLY_ATTR(capacity),
+	POWER_SUPPLY_ATTR(capacity_level),
+	POWER_SUPPLY_ATTR(temp),
+	POWER_SUPPLY_ATTR(temp_ambient),
+	POWER_SUPPLY_ATTR(time_to_empty_now),
+	POWER_SUPPLY_ATTR(time_to_empty_avg),
+	POWER_SUPPLY_ATTR(time_to_full_now),
+	POWER_SUPPLY_ATTR(time_to_full_avg),
+	/* Properties of type `const char *' */
+	POWER_SUPPLY_ATTR(model_name),
+	POWER_SUPPLY_ATTR(manufacturer),
+};
+
+static ssize_t power_supply_show_static_attrs(struct device *dev,
+					      struct device_attribute *attr,
+					      char *buf) {
+	static char *type_text[] = { "Battery", "UPS", "Mains", "USB" };
+	struct power_supply *psy = dev_get_drvdata(dev);
+
+	return sprintf(buf, "%s\n", type_text[psy->type]);
+}
+
+static struct device_attribute power_supply_static_attrs[] = {
+	__ATTR(type, 0444, power_supply_show_static_attrs, NULL),
+};
+
+int power_supply_create_attrs(struct power_supply *psy)
+{
+	int rc = 0;
+	int i, j;
+
+	for (i = 0; i < ARRAY_SIZE(power_supply_static_attrs); i++) {
+		rc = device_create_file(psy->dev,
+			    &power_supply_static_attrs[i]);
+		if (rc)
+			goto statics_failed;
+	}
+
+	for (j = 0; j < psy->num_properties; j++) {
+		rc = device_create_file(psy->dev,
+			    &power_supply_attrs[psy->properties[j]]);
+		if (rc)
+			goto dynamics_failed;
+	}
+
+	goto succeed;
+
+dynamics_failed:
+	while (j--)
+		device_remove_file(psy->dev,
+			   &power_supply_attrs[psy->properties[j]]);
+statics_failed:
+	while (i--)
+		device_remove_file(psy->dev,
+			   &power_supply_static_attrs[psy->properties[i]]);
+succeed:
+	return rc;
+}
+
+void power_supply_remove_attrs(struct power_supply *psy)
+{
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(power_supply_static_attrs); i++)
+		device_remove_file(psy->dev,
+			    &power_supply_static_attrs[i]);
+
+	for (i = 0; i < psy->num_properties; i++)
+		device_remove_file(psy->dev,
+			    &power_supply_attrs[psy->properties[i]]);
+
+	return;
+}
+
+static char *kstruprdup(const char *str, gfp_t gfp)
+{
+	char *ret, *ustr;
+
+	ustr = ret = kmalloc(strlen(str) + 1, gfp);
+
+	if (!ret)
+		return NULL;
+
+	while (*str)
+		*ustr++ = toupper(*str++);
+
+	*ustr = 0;
+
+	return ret;
+}
+
+int power_supply_uevent(struct device *dev, char **envp, int num_envp,
+			char *buffer, int buffer_size)
+{
+	struct power_supply *psy = dev_get_drvdata(dev);
+	int i = 0, length = 0, ret = 0, j;
+	char *prop_buf;
+	char *attrname;
+
+	dev_dbg(dev, "uevent\n");
+
+	if (!psy) {
+		dev_dbg(dev, "No power supply yet\n");
+		return ret;
+	}
+
+	dev_dbg(dev, "POWER_SUPPLY_NAME=%s\n", psy->name);
+
+	ret = add_uevent_var(envp, num_envp, &i, buffer, buffer_size,
+			     &length, "POWER_SUPPLY_NAME=%s", psy->name);
+	if (ret)
+		return ret;
+
+	prop_buf = (char *)get_zeroed_page(GFP_KERNEL);
+	if (!prop_buf)
+		return -ENOMEM;
+
+	for (j = 0; j < ARRAY_SIZE(power_supply_static_attrs); j++) {
+		struct device_attribute *attr;
+		char *line;
+
+		attr = &power_supply_static_attrs[j];
+
+		ret = power_supply_show_static_attrs(dev, attr, prop_buf);
+		if (ret < 0)
+			goto out;
+
+		line = strchr(prop_buf, '\n');
+		if (line)
+			*line = 0;
+
+		attrname = kstruprdup(attr->attr.name, GFP_KERNEL);
+		if (!attrname) {
+			ret = -ENOMEM;
+			goto out;
+		}
+
+		dev_dbg(dev, "Static prop %s=%s\n", attrname, prop_buf);
+
+		ret = add_uevent_var(envp, num_envp, &i, buffer, buffer_size,
+				     &length, "POWER_SUPPLY_%s=%s",
+				     attrname, prop_buf);
+		kfree(attrname);
+		if (ret)
+			goto out;
+	}
+
+	dev_dbg(dev, "%zd dynamic props\n", psy->num_properties);
+
+	for (j = 0; j < psy->num_properties; j++) {
+		struct device_attribute *attr;
+		char *line;
+
+		attr = &power_supply_attrs[psy->properties[j]];
+
+		ret = power_supply_show_property(dev, attr, prop_buf);
+		if (ret == -ENODEV) {
+			/* When a battery is absent, we expect -ENODEV. Don't abort;
+			   send the uevent with at least the the PRESENT=0 property */
+			ret = 0;
+			continue;
+		}
+
+		if (ret < 0)
+			goto out;
+
+		line = strchr(prop_buf, '\n');
+		if (line)
+			*line = 0;
+
+		attrname = kstruprdup(attr->attr.name, GFP_KERNEL);
+		if (!attrname) {
+			ret = -ENOMEM;
+			goto out;
+		}
+
+		dev_dbg(dev, "prop %s=%s\n", attrname, prop_buf);
+
+		ret = add_uevent_var(envp, num_envp, &i, buffer, buffer_size,
+				     &length, "POWER_SUPPLY_%s=%s",
+				     attrname, prop_buf);
+		kfree(attrname);
+		if (ret)
+			goto out;
+	}
+
+out:
+	free_page((unsigned long)prop_buf);
+
+	return ret;
+}