ACPI: Revert "ACPI / Battery: Remove battery's proc directory"

commit 3a670cc7 upstream.

The commit 1e2d9cdf and 7d7ee958 remove ACPI Proc Battery
directory and breaks some old userspace tools. This patch
is to revert commit 1e2d9cdf.

Fixes: 1e2d9cdf (ACPI / Battery: Remove battery's proc directory)
Signed-off-by: Lan Tianyu <tianyu.lan@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>

drivers/acpi/battery.c

@@ -36,6 +36,12 @@
 #include <linux/suspend.h>
 #include <asm/unaligned.h>
 
+#ifdef CONFIG_ACPI_PROCFS_POWER
+#include <linux/proc_fs.h>
+#include <linux/seq_file.h>
+#include <asm/uaccess.h>
+#endif
+
 #include <acpi/acpi_bus.h>
 #include <acpi/acpi_drivers.h>
 #include <linux/power_supply.h>
@@ -67,6 +73,19 @@ static unsigned int cache_time = 1000;
 module_param(cache_time, uint, 0644);
 MODULE_PARM_DESC(cache_time, "cache time in milliseconds");
 
+#ifdef CONFIG_ACPI_PROCFS_POWER
+extern struct proc_dir_entry *acpi_lock_battery_dir(void);
+extern void *acpi_unlock_battery_dir(struct proc_dir_entry *acpi_battery_dir);
+
+enum acpi_battery_files {
+	info_tag = 0,
+	state_tag,
+	alarm_tag,
+	ACPI_BATTERY_NUMFILES,
+};
+
+#endif
+
 static const struct acpi_device_id battery_device_ids[] = {
 	{"PNP0C0A", 0},
 	{"", 0},
@@ -302,6 +321,14 @@ static enum power_supply_property energy_battery_props[] = {
 	POWER_SUPPLY_PROP_SERIAL_NUMBER,
 };
 
+#ifdef CONFIG_ACPI_PROCFS_POWER
+inline char *acpi_battery_units(struct acpi_battery *battery)
+{
+	return (battery->power_unit == ACPI_BATTERY_POWER_UNIT_MA) ?
+		"mA" : "mW";
+}
+#endif
+
 /* --------------------------------------------------------------------------
                                Battery Management
    -------------------------------------------------------------------------- */
@@ -719,6 +746,279 @@ static void acpi_battery_refresh(struct acpi_battery *battery)
 	sysfs_add_battery(battery);
 }
 
+/* --------------------------------------------------------------------------
+                              FS Interface (/proc)
+   -------------------------------------------------------------------------- */
+
+#ifdef CONFIG_ACPI_PROCFS_POWER
+static struct proc_dir_entry *acpi_battery_dir;
+
+static int acpi_battery_print_info(struct seq_file *seq, int result)
+{
+	struct acpi_battery *battery = seq->private;
+
+	if (result)
+		goto end;
+
+	seq_printf(seq, "present:                 %s\n",
+		   acpi_battery_present(battery) ? "yes" : "no");
+	if (!acpi_battery_present(battery))
+		goto end;
+	if (battery->design_capacity == ACPI_BATTERY_VALUE_UNKNOWN)
+		seq_printf(seq, "design capacity:         unknown\n");
+	else
+		seq_printf(seq, "design capacity:         %d %sh\n",
+			   battery->design_capacity,
+			   acpi_battery_units(battery));
+
+	if (battery->full_charge_capacity == ACPI_BATTERY_VALUE_UNKNOWN)
+		seq_printf(seq, "last full capacity:      unknown\n");
+	else
+		seq_printf(seq, "last full capacity:      %d %sh\n",
+			   battery->full_charge_capacity,
+			   acpi_battery_units(battery));
+
+	seq_printf(seq, "battery technology:      %srechargeable\n",
+		   (!battery->technology)?"non-":"");
+
+	if (battery->design_voltage == ACPI_BATTERY_VALUE_UNKNOWN)
+		seq_printf(seq, "design voltage:          unknown\n");
+	else
+		seq_printf(seq, "design voltage:          %d mV\n",
+			   battery->design_voltage);
+	seq_printf(seq, "design capacity warning: %d %sh\n",
+		   battery->design_capacity_warning,
+		   acpi_battery_units(battery));
+	seq_printf(seq, "design capacity low:     %d %sh\n",
+		   battery->design_capacity_low,
+		   acpi_battery_units(battery));
+	seq_printf(seq, "cycle count:		  %i\n", battery->cycle_count);
+	seq_printf(seq, "capacity granularity 1:  %d %sh\n",
+		   battery->capacity_granularity_1,
+		   acpi_battery_units(battery));
+	seq_printf(seq, "capacity granularity 2:  %d %sh\n",
+		   battery->capacity_granularity_2,
+		   acpi_battery_units(battery));
+	seq_printf(seq, "model number:            %s\n", battery->model_number);
+	seq_printf(seq, "serial number:           %s\n", battery->serial_number);
+	seq_printf(seq, "battery type:            %s\n", battery->type);
+	seq_printf(seq, "OEM info:                %s\n", battery->oem_info);
+      end:
+	if (result)
+		seq_printf(seq, "ERROR: Unable to read battery info\n");
+	return result;
+}
+
+static int acpi_battery_print_state(struct seq_file *seq, int result)
+{
+	struct acpi_battery *battery = seq->private;
+
+	if (result)
+		goto end;
+
+	seq_printf(seq, "present:                 %s\n",
+		   acpi_battery_present(battery) ? "yes" : "no");
+	if (!acpi_battery_present(battery))
+		goto end;
+
+	seq_printf(seq, "capacity state:          %s\n",
+			(battery->state & 0x04) ? "critical" : "ok");
+	if ((battery->state & 0x01) && (battery->state & 0x02))
+		seq_printf(seq,
+			   "charging state:          charging/discharging\n");
+	else if (battery->state & 0x01)
+		seq_printf(seq, "charging state:          discharging\n");
+	else if (battery->state & 0x02)
+		seq_printf(seq, "charging state:          charging\n");
+	else
+		seq_printf(seq, "charging state:          charged\n");
+
+	if (battery->rate_now == ACPI_BATTERY_VALUE_UNKNOWN)
+		seq_printf(seq, "present rate:            unknown\n");
+	else
+		seq_printf(seq, "present rate:            %d %s\n",
+			   battery->rate_now, acpi_battery_units(battery));
+
+	if (battery->capacity_now == ACPI_BATTERY_VALUE_UNKNOWN)
+		seq_printf(seq, "remaining capacity:      unknown\n");
+	else
+		seq_printf(seq, "remaining capacity:      %d %sh\n",
+			   battery->capacity_now, acpi_battery_units(battery));
+	if (battery->voltage_now == ACPI_BATTERY_VALUE_UNKNOWN)
+		seq_printf(seq, "present voltage:         unknown\n");
+	else
+		seq_printf(seq, "present voltage:         %d mV\n",
+			   battery->voltage_now);
+      end:
+	if (result)
+		seq_printf(seq, "ERROR: Unable to read battery state\n");
+
+	return result;
+}
+
+static int acpi_battery_print_alarm(struct seq_file *seq, int result)
+{
+	struct acpi_battery *battery = seq->private;
+
+	if (result)
+		goto end;
+
+	if (!acpi_battery_present(battery)) {
+		seq_printf(seq, "present:                 no\n");
+		goto end;
+	}
+	seq_printf(seq, "alarm:                   ");
+	if (!battery->alarm)
+		seq_printf(seq, "unsupported\n");
+	else
+		seq_printf(seq, "%u %sh\n", battery->alarm,
+				acpi_battery_units(battery));
+      end:
+	if (result)
+		seq_printf(seq, "ERROR: Unable to read battery alarm\n");
+	return result;
+}
+
+static ssize_t acpi_battery_write_alarm(struct file *file,
+					const char __user * buffer,
+					size_t count, loff_t * ppos)
+{
+	int result = 0;
+	char alarm_string[12] = { '\0' };
+	struct seq_file *m = file->private_data;
+	struct acpi_battery *battery = m->private;
+
+	if (!battery || (count > sizeof(alarm_string) - 1))
+		return -EINVAL;
+	if (!acpi_battery_present(battery)) {
+		result = -ENODEV;
+		goto end;
+	}
+	if (copy_from_user(alarm_string, buffer, count)) {
+		result = -EFAULT;
+		goto end;
+	}
+	alarm_string[count] = '\0';
+	battery->alarm = simple_strtol(alarm_string, NULL, 0);
+	result = acpi_battery_set_alarm(battery);
+      end:
+	if (!result)
+		return count;
+	return result;
+}
+
+typedef int(*print_func)(struct seq_file *seq, int result);
+
+static print_func acpi_print_funcs[ACPI_BATTERY_NUMFILES] = {
+	acpi_battery_print_info,
+	acpi_battery_print_state,
+	acpi_battery_print_alarm,
+};
+
+static int acpi_battery_read(int fid, struct seq_file *seq)
+{
+	struct acpi_battery *battery = seq->private;
+	int result = acpi_battery_update(battery);
+	return acpi_print_funcs[fid](seq, result);
+}
+
+#define DECLARE_FILE_FUNCTIONS(_name) \
+static int acpi_battery_read_##_name(struct seq_file *seq, void *offset) \
+{ \
+	return acpi_battery_read(_name##_tag, seq); \
+} \
+static int acpi_battery_##_name##_open_fs(struct inode *inode, struct file *file) \
+{ \
+	return single_open(file, acpi_battery_read_##_name, PDE_DATA(inode)); \
+}
+
+DECLARE_FILE_FUNCTIONS(info);
+DECLARE_FILE_FUNCTIONS(state);
+DECLARE_FILE_FUNCTIONS(alarm);
+
+#undef DECLARE_FILE_FUNCTIONS
+
+#define FILE_DESCRIPTION_RO(_name) \
+	{ \
+	.name = __stringify(_name), \
+	.mode = S_IRUGO, \
+	.ops = { \
+		.open = acpi_battery_##_name##_open_fs, \
+		.read = seq_read, \
+		.llseek = seq_lseek, \
+		.release = single_release, \
+		.owner = THIS_MODULE, \
+		}, \
+	}
+
+#define FILE_DESCRIPTION_RW(_name) \
+	{ \
+	.name = __stringify(_name), \
+	.mode = S_IFREG | S_IRUGO | S_IWUSR, \
+	.ops = { \
+		.open = acpi_battery_##_name##_open_fs, \
+		.read = seq_read, \
+		.llseek = seq_lseek, \
+		.write = acpi_battery_write_##_name, \
+		.release = single_release, \
+		.owner = THIS_MODULE, \
+		}, \
+	}
+
+static const struct battery_file {
+	struct file_operations ops;
+	umode_t mode;
+	const char *name;
+} acpi_battery_file[] = {
+	FILE_DESCRIPTION_RO(info),
+	FILE_DESCRIPTION_RO(state),
+	FILE_DESCRIPTION_RW(alarm),
+};
+
+#undef FILE_DESCRIPTION_RO
+#undef FILE_DESCRIPTION_RW
+
+static int acpi_battery_add_fs(struct acpi_device *device)
+{
+	struct proc_dir_entry *entry = NULL;
+	int i;
+
+	printk(KERN_WARNING PREFIX "Deprecated procfs I/F for battery is loaded,"
+			" please retry with CONFIG_ACPI_PROCFS_POWER cleared\n");
+	if (!acpi_device_dir(device)) {
+		acpi_device_dir(device) = proc_mkdir(acpi_device_bid(device),
+						     acpi_battery_dir);
+		if (!acpi_device_dir(device))
+			return -ENODEV;
+	}
+
+	for (i = 0; i < ACPI_BATTERY_NUMFILES; ++i) {
+		entry = proc_create_data(acpi_battery_file[i].name,
+					 acpi_battery_file[i].mode,
+					 acpi_device_dir(device),
+					 &acpi_battery_file[i].ops,
+					 acpi_driver_data(device));
+		if (!entry)
+			return -ENODEV;
+	}
+	return 0;
+}
+
+static void acpi_battery_remove_fs(struct acpi_device *device)
+{
+	int i;
+	if (!acpi_device_dir(device))
+		return;
+	for (i = 0; i < ACPI_BATTERY_NUMFILES; ++i)
+		remove_proc_entry(acpi_battery_file[i].name,
+				  acpi_device_dir(device));
+
+	remove_proc_entry(acpi_device_bid(device), acpi_battery_dir);
+	acpi_device_dir(device) = NULL;
+}
+
+#endif
+
 /* --------------------------------------------------------------------------
                                  Driver Interface
    -------------------------------------------------------------------------- */
@@ -792,6 +1092,15 @@ static int acpi_battery_add(struct acpi_device *device)
 	result = acpi_battery_update(battery);
 	if (result)
 		goto fail;
+#ifdef CONFIG_ACPI_PROCFS_POWER
+	result = acpi_battery_add_fs(device);
+#endif
+	if (result) {
+#ifdef CONFIG_ACPI_PROCFS_POWER
+		acpi_battery_remove_fs(device);
+#endif
+		goto fail;
+	}
 
 	printk(KERN_INFO PREFIX "%s Slot [%s] (battery %s)\n",
 		ACPI_BATTERY_DEVICE_NAME, acpi_device_bid(device),
@@ -818,6 +1127,9 @@ static int acpi_battery_remove(struct acpi_device *device)
 		return -EINVAL;
 	battery = acpi_driver_data(device);
 	unregister_pm_notifier(&battery->pm_nb);
+#ifdef CONFIG_ACPI_PROCFS_POWER
+	acpi_battery_remove_fs(device);
+#endif
 	sysfs_remove_battery(battery);
 	mutex_destroy(&battery->lock);
 	mutex_destroy(&battery->sysfs_lock);
@@ -866,7 +1178,19 @@ static void __init acpi_battery_init_async(void *unused, async_cookie_t cookie)
 
 	if (dmi_check_system(bat_dmi_table))
 		battery_bix_broken_package = 1;
-	acpi_bus_register_driver(&acpi_battery_driver);
+	
+#ifdef CONFIG_ACPI_PROCFS_POWER
+	acpi_battery_dir = acpi_lock_battery_dir();
+	if (!acpi_battery_dir)
+		return;
+#endif
+	if (acpi_bus_register_driver(&acpi_battery_driver) < 0) {
+#ifdef CONFIG_ACPI_PROCFS_POWER
+		acpi_unlock_battery_dir(acpi_battery_dir);
+#endif
+		return;
+	}
+	return;
 }
 
 static int __init acpi_battery_init(void)
@@ -878,6 +1202,9 @@ static int __init acpi_battery_init(void)
 static void __exit acpi_battery_exit(void)
 {
 	acpi_bus_unregister_driver(&acpi_battery_driver);
+#ifdef CONFIG_ACPI_PROCFS_POWER
+	acpi_unlock_battery_dir(acpi_battery_dir);
+#endif
 }
 
 module_init(acpi_battery_init);