linux/drivers/power/ds2782_battery.c
Krzysztof Kozlowski 297d716f62 power_supply: Change ownership from driver to core
Change the ownership of power_supply structure from each driver
implementing the class to the power supply core.

The patch changes power_supply_register() function thus all drivers
implementing power supply class are adjusted.

Each driver provides the implementation of power supply. However it
should not be the owner of power supply class instance because it is
exposed by core to other subsystems with power_supply_get_by_name().
These other subsystems have no knowledge when the driver will unregister
the power supply. This leads to several issues when driver is unbound -
mostly because user of power supply accesses freed memory.

Instead let the core own the instance of struct 'power_supply'.  Other
users of this power supply will still access valid memory because it
will be freed when device reference count reaches 0. Currently this
means "it will leak" but power_supply_put() call in next patches will
solve it.

This solves invalid memory references in following race condition
scenario:

Thread 1: charger manager
Thread 2: power supply driver, used by charger manager

THREAD 1 (charger manager)         THREAD 2 (power supply driver)
==========================         ==============================
psy = power_supply_get_by_name()
                                   Driver unbind, .remove
                                     power_supply_unregister()
                                     Device fully removed
psy->get_property()

The 'get_property' call is executed in invalid context because the driver was
unbound and struct 'power_supply' memory was freed.

This could be observed easily with charger manager driver (here compiled
with max17040 fuel gauge):

$ cat /sys/devices/virtual/power_supply/cm-battery/capacity &
$ echo "1-0036" > /sys/bus/i2c/drivers/max17040/unbind
[   55.725123] Unable to handle kernel NULL pointer dereference at virtual address 00000000
[   55.732584] pgd = d98d4000
[   55.734060] [00000000] *pgd=5afa2831, *pte=00000000, *ppte=00000000
[   55.740318] Internal error: Oops: 80000007 [#1] PREEMPT SMP ARM
[   55.746210] Modules linked in:
[   55.749259] CPU: 1 PID: 2936 Comm: cat Tainted: G        W       3.19.0-rc1-next-20141226-00048-gf79f475f3c44-dirty #1496
[   55.760190] Hardware name: SAMSUNG EXYNOS (Flattened Device Tree)
[   55.766270] task: d9b76f00 ti: daf54000 task.ti: daf54000
[   55.771647] PC is at 0x0
[   55.774182] LR is at charger_get_property+0x2f4/0x36c
[   55.779201] pc : [<00000000>]    lr : [<c034b0b4>]    psr: 60000013
[   55.779201] sp : daf55e90  ip : 00000003  fp : 00000000
[   55.790657] r10: 00000000  r9 : c06e2878  r8 : d9b26c68
[   55.795865] r7 : dad81610  r6 : daec7410  r5 : daf55ebc  r4 : 00000000
[   55.802367] r3 : 00000000  r2 : daf55ebc  r1 : 0000002a  r0 : d9b26c68
[   55.808879] Flags: nZCv  IRQs on  FIQs on  Mode SVC_32  ISA ARM  Segment user
[   55.815994] Control: 10c5387d  Table: 598d406a  DAC: 00000015
[   55.821723] Process cat (pid: 2936, stack limit = 0xdaf54210)
[   55.827451] Stack: (0xdaf55e90 to 0xdaf56000)
[   55.831795] 5e80:                                     60000013 c01459c4 0000002a c06f8ef8
[   55.839956] 5ea0: db651000 c06f8ef8 daebac00 c04cb668 daebac08 c0346864 00000000 c01459c4
[   55.848115] 5ec0: d99eaa80 c06f8ef8 00000fff 00001000 db651000 c027f25c c027f240 d99eaa80
[   55.856274] 5ee0: d9a06c00 c0146218 daf55f18 00001000 d99eaa80 db4c18c0 00000001 00000001
[   55.864468] 5f00: daf55f80 c0144c78 c0144c54 c0107f90 00015000 d99eaab0 00000000 00000000
[   55.872603] 5f20: 000051c7 00000000 db4c18c0 c04a9370 00015000 00001000 daf55f80 00001000
[   55.880763] 5f40: daf54000 00015000 00000000 c00e53dc db4c18c0 c00e548c 0000000d 00008124
[   55.888937] 5f60: 00000001 00000000 00000000 db4c18c0 db4c18c0 00001000 00015000 c00e5550
[   55.897099] 5f80: 00000000 00000000 00001000 00001000 00015000 00000003 00000003 c000f364
[   55.905239] 5fa0: 00000000 c000f1a0 00001000 00015000 00000003 00015000 00001000 0001333c
[   55.913399] 5fc0: 00001000 00015000 00000003 00000003 00000002 00000000 00000000 00000000
[   55.921560] 5fe0: 7fffe000 be999850 0000a225 b6f3c19c 60000010 00000003 00000000 00000000
[   55.929744] [<c034b0b4>] (charger_get_property) from [<c0346864>] (power_supply_show_property+0x48/0x20c)
[   55.939286] [<c0346864>] (power_supply_show_property) from [<c027f25c>] (dev_attr_show+0x1c/0x48)
[   55.948130] [<c027f25c>] (dev_attr_show) from [<c0146218>] (sysfs_kf_seq_show+0x84/0x104)
[   55.956298] [<c0146218>] (sysfs_kf_seq_show) from [<c0144c78>] (kernfs_seq_show+0x24/0x28)
[   55.964536] [<c0144c78>] (kernfs_seq_show) from [<c0107f90>] (seq_read+0x1b0/0x484)
[   55.972172] [<c0107f90>] (seq_read) from [<c00e53dc>] (__vfs_read+0x18/0x4c)
[   55.979188] [<c00e53dc>] (__vfs_read) from [<c00e548c>] (vfs_read+0x7c/0x100)
[   55.986304] [<c00e548c>] (vfs_read) from [<c00e5550>] (SyS_read+0x40/0x8c)
[   55.993164] [<c00e5550>] (SyS_read) from [<c000f1a0>] (ret_fast_syscall+0x0/0x48)
[   56.000626] Code: bad PC value
[   56.011652] ---[ end trace 7b64343fbdae8ef1 ]---

Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Reviewed-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>

[for the nvec part]
Reviewed-by: Marc Dietrich <marvin24@gmx.de>

[for compal-laptop.c]
Acked-by: Darren Hart <dvhart@linux.intel.com>

[for the mfd part]
Acked-by: Lee Jones <lee.jones@linaro.org>

[for the hid part]
Acked-by: Jiri Kosina <jkosina@suse.cz>

[for the acpi part]
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Signed-off-by: Sebastian Reichel <sre@kernel.org>
2015-03-13 23:15:51 +01:00

476 lines
11 KiB
C

/*
* I2C client/driver for the Maxim/Dallas DS2782 Stand-Alone Fuel Gauge IC
*
* Copyright (C) 2009 Bluewater Systems Ltd
*
* Author: Ryan Mallon
*
* DS2786 added by Yulia Vilensky <vilensky@compulab.co.il>
*
* UEvent sending added by Evgeny Romanov <romanov@neurosoft.ru>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/types.h>
#include <linux/errno.h>
#include <linux/swab.h>
#include <linux/i2c.h>
#include <linux/delay.h>
#include <linux/idr.h>
#include <linux/power_supply.h>
#include <linux/slab.h>
#include <linux/ds2782_battery.h>
#define DS2782_REG_RARC 0x06 /* Remaining active relative capacity */
#define DS278x_REG_VOLT_MSB 0x0c
#define DS278x_REG_TEMP_MSB 0x0a
#define DS278x_REG_CURRENT_MSB 0x0e
/* EEPROM Block */
#define DS2782_REG_RSNSP 0x69 /* Sense resistor value */
/* Current unit measurement in uA for a 1 milli-ohm sense resistor */
#define DS2782_CURRENT_UNITS 1563
#define DS2786_REG_RARC 0x02 /* Remaining active relative capacity */
#define DS2786_CURRENT_UNITS 25
#define DS278x_DELAY 1000
struct ds278x_info;
struct ds278x_battery_ops {
int (*get_battery_current)(struct ds278x_info *info, int *current_uA);
int (*get_battery_voltage)(struct ds278x_info *info, int *voltage_uV);
int (*get_battery_capacity)(struct ds278x_info *info, int *capacity);
};
#define to_ds278x_info(x) power_supply_get_drvdata(x)
struct ds278x_info {
struct i2c_client *client;
struct power_supply *battery;
struct power_supply_desc battery_desc;
struct ds278x_battery_ops *ops;
struct delayed_work bat_work;
int id;
int rsns;
int capacity;
int status; /* State Of Charge */
};
static DEFINE_IDR(battery_id);
static DEFINE_MUTEX(battery_lock);
static inline int ds278x_read_reg(struct ds278x_info *info, int reg, u8 *val)
{
int ret;
ret = i2c_smbus_read_byte_data(info->client, reg);
if (ret < 0) {
dev_err(&info->client->dev, "register read failed\n");
return ret;
}
*val = ret;
return 0;
}
static inline int ds278x_read_reg16(struct ds278x_info *info, int reg_msb,
s16 *val)
{
int ret;
ret = i2c_smbus_read_word_data(info->client, reg_msb);
if (ret < 0) {
dev_err(&info->client->dev, "register read failed\n");
return ret;
}
*val = swab16(ret);
return 0;
}
static int ds278x_get_temp(struct ds278x_info *info, int *temp)
{
s16 raw;
int err;
/*
* Temperature is measured in units of 0.125 degrees celcius, the
* power_supply class measures temperature in tenths of degrees
* celsius. The temperature value is stored as a 10 bit number, plus
* sign in the upper bits of a 16 bit register.
*/
err = ds278x_read_reg16(info, DS278x_REG_TEMP_MSB, &raw);
if (err)
return err;
*temp = ((raw / 32) * 125) / 100;
return 0;
}
static int ds2782_get_current(struct ds278x_info *info, int *current_uA)
{
int sense_res;
int err;
u8 sense_res_raw;
s16 raw;
/*
* The units of measurement for current are dependent on the value of
* the sense resistor.
*/
err = ds278x_read_reg(info, DS2782_REG_RSNSP, &sense_res_raw);
if (err)
return err;
if (sense_res_raw == 0) {
dev_err(&info->client->dev, "sense resistor value is 0\n");
return -ENXIO;
}
sense_res = 1000 / sense_res_raw;
dev_dbg(&info->client->dev, "sense resistor = %d milli-ohms\n",
sense_res);
err = ds278x_read_reg16(info, DS278x_REG_CURRENT_MSB, &raw);
if (err)
return err;
*current_uA = raw * (DS2782_CURRENT_UNITS / sense_res);
return 0;
}
static int ds2782_get_voltage(struct ds278x_info *info, int *voltage_uV)
{
s16 raw;
int err;
/*
* Voltage is measured in units of 4.88mV. The voltage is stored as
* a 10-bit number plus sign, in the upper bits of a 16-bit register
*/
err = ds278x_read_reg16(info, DS278x_REG_VOLT_MSB, &raw);
if (err)
return err;
*voltage_uV = (raw / 32) * 4800;
return 0;
}
static int ds2782_get_capacity(struct ds278x_info *info, int *capacity)
{
int err;
u8 raw;
err = ds278x_read_reg(info, DS2782_REG_RARC, &raw);
if (err)
return err;
*capacity = raw;
return 0;
}
static int ds2786_get_current(struct ds278x_info *info, int *current_uA)
{
int err;
s16 raw;
err = ds278x_read_reg16(info, DS278x_REG_CURRENT_MSB, &raw);
if (err)
return err;
*current_uA = (raw / 16) * (DS2786_CURRENT_UNITS / info->rsns);
return 0;
}
static int ds2786_get_voltage(struct ds278x_info *info, int *voltage_uV)
{
s16 raw;
int err;
/*
* Voltage is measured in units of 1.22mV. The voltage is stored as
* a 12-bit number plus sign, in the upper bits of a 16-bit register
*/
err = ds278x_read_reg16(info, DS278x_REG_VOLT_MSB, &raw);
if (err)
return err;
*voltage_uV = (raw / 8) * 1220;
return 0;
}
static int ds2786_get_capacity(struct ds278x_info *info, int *capacity)
{
int err;
u8 raw;
err = ds278x_read_reg(info, DS2786_REG_RARC, &raw);
if (err)
return err;
/* Relative capacity is displayed with resolution 0.5 % */
*capacity = raw/2 ;
return 0;
}
static int ds278x_get_status(struct ds278x_info *info, int *status)
{
int err;
int current_uA;
int capacity;
err = info->ops->get_battery_current(info, &current_uA);
if (err)
return err;
err = info->ops->get_battery_capacity(info, &capacity);
if (err)
return err;
info->capacity = capacity;
if (capacity == 100)
*status = POWER_SUPPLY_STATUS_FULL;
else if (current_uA == 0)
*status = POWER_SUPPLY_STATUS_NOT_CHARGING;
else if (current_uA < 0)
*status = POWER_SUPPLY_STATUS_DISCHARGING;
else
*status = POWER_SUPPLY_STATUS_CHARGING;
return 0;
}
static int ds278x_battery_get_property(struct power_supply *psy,
enum power_supply_property prop,
union power_supply_propval *val)
{
struct ds278x_info *info = to_ds278x_info(psy);
int ret;
switch (prop) {
case POWER_SUPPLY_PROP_STATUS:
ret = ds278x_get_status(info, &val->intval);
break;
case POWER_SUPPLY_PROP_CAPACITY:
ret = info->ops->get_battery_capacity(info, &val->intval);
break;
case POWER_SUPPLY_PROP_VOLTAGE_NOW:
ret = info->ops->get_battery_voltage(info, &val->intval);
break;
case POWER_SUPPLY_PROP_CURRENT_NOW:
ret = info->ops->get_battery_current(info, &val->intval);
break;
case POWER_SUPPLY_PROP_TEMP:
ret = ds278x_get_temp(info, &val->intval);
break;
default:
ret = -EINVAL;
}
return ret;
}
static void ds278x_bat_update(struct ds278x_info *info)
{
int old_status = info->status;
int old_capacity = info->capacity;
ds278x_get_status(info, &info->status);
if ((old_status != info->status) || (old_capacity != info->capacity))
power_supply_changed(info->battery);
}
static void ds278x_bat_work(struct work_struct *work)
{
struct ds278x_info *info;
info = container_of(work, struct ds278x_info, bat_work.work);
ds278x_bat_update(info);
schedule_delayed_work(&info->bat_work, DS278x_DELAY);
}
static enum power_supply_property ds278x_battery_props[] = {
POWER_SUPPLY_PROP_STATUS,
POWER_SUPPLY_PROP_CAPACITY,
POWER_SUPPLY_PROP_VOLTAGE_NOW,
POWER_SUPPLY_PROP_CURRENT_NOW,
POWER_SUPPLY_PROP_TEMP,
};
static void ds278x_power_supply_init(struct power_supply_desc *battery)
{
battery->type = POWER_SUPPLY_TYPE_BATTERY;
battery->properties = ds278x_battery_props;
battery->num_properties = ARRAY_SIZE(ds278x_battery_props);
battery->get_property = ds278x_battery_get_property;
battery->external_power_changed = NULL;
}
static int ds278x_battery_remove(struct i2c_client *client)
{
struct ds278x_info *info = i2c_get_clientdata(client);
power_supply_unregister(info->battery);
kfree(info->battery_desc.name);
mutex_lock(&battery_lock);
idr_remove(&battery_id, info->id);
mutex_unlock(&battery_lock);
cancel_delayed_work(&info->bat_work);
kfree(info);
return 0;
}
#ifdef CONFIG_PM_SLEEP
static int ds278x_suspend(struct device *dev)
{
struct i2c_client *client = to_i2c_client(dev);
struct ds278x_info *info = i2c_get_clientdata(client);
cancel_delayed_work(&info->bat_work);
return 0;
}
static int ds278x_resume(struct device *dev)
{
struct i2c_client *client = to_i2c_client(dev);
struct ds278x_info *info = i2c_get_clientdata(client);
schedule_delayed_work(&info->bat_work, DS278x_DELAY);
return 0;
}
#endif /* CONFIG_PM_SLEEP */
static SIMPLE_DEV_PM_OPS(ds278x_battery_pm_ops, ds278x_suspend, ds278x_resume);
enum ds278x_num_id {
DS2782 = 0,
DS2786,
};
static struct ds278x_battery_ops ds278x_ops[] = {
[DS2782] = {
.get_battery_current = ds2782_get_current,
.get_battery_voltage = ds2782_get_voltage,
.get_battery_capacity = ds2782_get_capacity,
},
[DS2786] = {
.get_battery_current = ds2786_get_current,
.get_battery_voltage = ds2786_get_voltage,
.get_battery_capacity = ds2786_get_capacity,
}
};
static int ds278x_battery_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
struct ds278x_platform_data *pdata = client->dev.platform_data;
struct power_supply_config psy_cfg = {};
struct ds278x_info *info;
int ret;
int num;
/*
* ds2786 should have the sense resistor value set
* in the platform data
*/
if (id->driver_data == DS2786 && !pdata) {
dev_err(&client->dev, "missing platform data for ds2786\n");
return -EINVAL;
}
/* Get an ID for this battery */
mutex_lock(&battery_lock);
ret = idr_alloc(&battery_id, client, 0, 0, GFP_KERNEL);
mutex_unlock(&battery_lock);
if (ret < 0)
goto fail_id;
num = ret;
info = kzalloc(sizeof(*info), GFP_KERNEL);
if (!info) {
ret = -ENOMEM;
goto fail_info;
}
info->battery_desc.name = kasprintf(GFP_KERNEL, "%s-%d",
client->name, num);
if (!info->battery_desc.name) {
ret = -ENOMEM;
goto fail_name;
}
if (id->driver_data == DS2786)
info->rsns = pdata->rsns;
i2c_set_clientdata(client, info);
info->client = client;
info->id = num;
info->ops = &ds278x_ops[id->driver_data];
ds278x_power_supply_init(&info->battery_desc);
psy_cfg.drv_data = info;
info->capacity = 100;
info->status = POWER_SUPPLY_STATUS_FULL;
INIT_DELAYED_WORK(&info->bat_work, ds278x_bat_work);
info->battery = power_supply_register(&client->dev,
&info->battery_desc, &psy_cfg);
if (IS_ERR(info->battery)) {
dev_err(&client->dev, "failed to register battery\n");
ret = PTR_ERR(info->battery);
goto fail_register;
} else {
schedule_delayed_work(&info->bat_work, DS278x_DELAY);
}
return 0;
fail_register:
kfree(info->battery_desc.name);
fail_name:
kfree(info);
fail_info:
mutex_lock(&battery_lock);
idr_remove(&battery_id, num);
mutex_unlock(&battery_lock);
fail_id:
return ret;
}
static const struct i2c_device_id ds278x_id[] = {
{"ds2782", DS2782},
{"ds2786", DS2786},
{},
};
MODULE_DEVICE_TABLE(i2c, ds278x_id);
static struct i2c_driver ds278x_battery_driver = {
.driver = {
.name = "ds2782-battery",
.pm = &ds278x_battery_pm_ops,
},
.probe = ds278x_battery_probe,
.remove = ds278x_battery_remove,
.id_table = ds278x_id,
};
module_i2c_driver(ds278x_battery_driver);
MODULE_AUTHOR("Ryan Mallon");
MODULE_DESCRIPTION("Maxim/Dallas DS2782 Stand-Alone Fuel Gauage IC driver");
MODULE_LICENSE("GPL");