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![Krzysztof Kozlowski](/assets/img/avatar_default.png)
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>
305 lines
7.2 KiB
C
305 lines
7.2 KiB
C
/*
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* max17040_battery.c
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* fuel-gauge systems for lithium-ion (Li+) batteries
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*
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* Copyright (C) 2009 Samsung Electronics
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* Minkyu Kang <mk7.kang@samsung.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#include <linux/module.h>
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#include <linux/init.h>
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#include <linux/platform_device.h>
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#include <linux/mutex.h>
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#include <linux/err.h>
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#include <linux/i2c.h>
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#include <linux/delay.h>
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#include <linux/power_supply.h>
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#include <linux/max17040_battery.h>
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#include <linux/slab.h>
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#define MAX17040_VCELL_MSB 0x02
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#define MAX17040_VCELL_LSB 0x03
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#define MAX17040_SOC_MSB 0x04
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#define MAX17040_SOC_LSB 0x05
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#define MAX17040_MODE_MSB 0x06
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#define MAX17040_MODE_LSB 0x07
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#define MAX17040_VER_MSB 0x08
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#define MAX17040_VER_LSB 0x09
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#define MAX17040_RCOMP_MSB 0x0C
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#define MAX17040_RCOMP_LSB 0x0D
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#define MAX17040_CMD_MSB 0xFE
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#define MAX17040_CMD_LSB 0xFF
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#define MAX17040_DELAY 1000
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#define MAX17040_BATTERY_FULL 95
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struct max17040_chip {
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struct i2c_client *client;
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struct delayed_work work;
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struct power_supply *battery;
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struct max17040_platform_data *pdata;
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/* State Of Connect */
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int online;
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/* battery voltage */
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int vcell;
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/* battery capacity */
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int soc;
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/* State Of Charge */
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int status;
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};
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static int max17040_get_property(struct power_supply *psy,
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enum power_supply_property psp,
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union power_supply_propval *val)
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{
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struct max17040_chip *chip = power_supply_get_drvdata(psy);
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switch (psp) {
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case POWER_SUPPLY_PROP_STATUS:
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val->intval = chip->status;
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break;
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case POWER_SUPPLY_PROP_ONLINE:
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val->intval = chip->online;
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break;
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case POWER_SUPPLY_PROP_VOLTAGE_NOW:
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val->intval = chip->vcell;
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break;
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case POWER_SUPPLY_PROP_CAPACITY:
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val->intval = chip->soc;
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break;
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default:
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return -EINVAL;
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}
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return 0;
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}
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static int max17040_write_reg(struct i2c_client *client, int reg, u8 value)
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{
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int ret;
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ret = i2c_smbus_write_byte_data(client, reg, value);
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if (ret < 0)
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dev_err(&client->dev, "%s: err %d\n", __func__, ret);
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return ret;
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}
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static int max17040_read_reg(struct i2c_client *client, int reg)
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{
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int ret;
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ret = i2c_smbus_read_byte_data(client, reg);
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if (ret < 0)
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dev_err(&client->dev, "%s: err %d\n", __func__, ret);
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return ret;
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}
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static void max17040_reset(struct i2c_client *client)
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{
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max17040_write_reg(client, MAX17040_CMD_MSB, 0x54);
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max17040_write_reg(client, MAX17040_CMD_LSB, 0x00);
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}
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static void max17040_get_vcell(struct i2c_client *client)
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{
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struct max17040_chip *chip = i2c_get_clientdata(client);
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u8 msb;
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u8 lsb;
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msb = max17040_read_reg(client, MAX17040_VCELL_MSB);
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lsb = max17040_read_reg(client, MAX17040_VCELL_LSB);
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chip->vcell = (msb << 4) + (lsb >> 4);
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}
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static void max17040_get_soc(struct i2c_client *client)
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{
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struct max17040_chip *chip = i2c_get_clientdata(client);
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u8 msb;
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u8 lsb;
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msb = max17040_read_reg(client, MAX17040_SOC_MSB);
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lsb = max17040_read_reg(client, MAX17040_SOC_LSB);
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chip->soc = msb;
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}
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static void max17040_get_version(struct i2c_client *client)
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{
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u8 msb;
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u8 lsb;
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msb = max17040_read_reg(client, MAX17040_VER_MSB);
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lsb = max17040_read_reg(client, MAX17040_VER_LSB);
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dev_info(&client->dev, "MAX17040 Fuel-Gauge Ver %d%d\n", msb, lsb);
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}
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static void max17040_get_online(struct i2c_client *client)
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{
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struct max17040_chip *chip = i2c_get_clientdata(client);
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if (chip->pdata && chip->pdata->battery_online)
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chip->online = chip->pdata->battery_online();
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else
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chip->online = 1;
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}
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static void max17040_get_status(struct i2c_client *client)
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{
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struct max17040_chip *chip = i2c_get_clientdata(client);
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if (!chip->pdata || !chip->pdata->charger_online
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|| !chip->pdata->charger_enable) {
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chip->status = POWER_SUPPLY_STATUS_UNKNOWN;
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return;
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}
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if (chip->pdata->charger_online()) {
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if (chip->pdata->charger_enable())
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chip->status = POWER_SUPPLY_STATUS_CHARGING;
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else
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chip->status = POWER_SUPPLY_STATUS_NOT_CHARGING;
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} else {
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chip->status = POWER_SUPPLY_STATUS_DISCHARGING;
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}
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if (chip->soc > MAX17040_BATTERY_FULL)
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chip->status = POWER_SUPPLY_STATUS_FULL;
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}
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static void max17040_work(struct work_struct *work)
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{
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struct max17040_chip *chip;
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chip = container_of(work, struct max17040_chip, work.work);
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max17040_get_vcell(chip->client);
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max17040_get_soc(chip->client);
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max17040_get_online(chip->client);
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max17040_get_status(chip->client);
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queue_delayed_work(system_power_efficient_wq, &chip->work,
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MAX17040_DELAY);
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}
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static enum power_supply_property max17040_battery_props[] = {
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POWER_SUPPLY_PROP_STATUS,
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POWER_SUPPLY_PROP_ONLINE,
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POWER_SUPPLY_PROP_VOLTAGE_NOW,
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POWER_SUPPLY_PROP_CAPACITY,
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};
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static const struct power_supply_desc max17040_battery_desc = {
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.name = "battery",
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.type = POWER_SUPPLY_TYPE_BATTERY,
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.get_property = max17040_get_property,
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.properties = max17040_battery_props,
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.num_properties = ARRAY_SIZE(max17040_battery_props),
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};
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static int max17040_probe(struct i2c_client *client,
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const struct i2c_device_id *id)
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{
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struct i2c_adapter *adapter = to_i2c_adapter(client->dev.parent);
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struct power_supply_config psy_cfg = {};
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struct max17040_chip *chip;
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if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE))
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return -EIO;
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chip = devm_kzalloc(&client->dev, sizeof(*chip), GFP_KERNEL);
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if (!chip)
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return -ENOMEM;
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chip->client = client;
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chip->pdata = client->dev.platform_data;
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i2c_set_clientdata(client, chip);
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psy_cfg.drv_data = chip;
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chip->battery = power_supply_register(&client->dev,
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&max17040_battery_desc, &psy_cfg);
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if (IS_ERR(chip->battery)) {
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dev_err(&client->dev, "failed: power supply register\n");
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return PTR_ERR(chip->battery);
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}
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max17040_reset(client);
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max17040_get_version(client);
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INIT_DEFERRABLE_WORK(&chip->work, max17040_work);
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queue_delayed_work(system_power_efficient_wq, &chip->work,
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MAX17040_DELAY);
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return 0;
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}
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static int max17040_remove(struct i2c_client *client)
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{
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struct max17040_chip *chip = i2c_get_clientdata(client);
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power_supply_unregister(chip->battery);
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cancel_delayed_work(&chip->work);
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return 0;
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}
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#ifdef CONFIG_PM_SLEEP
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static int max17040_suspend(struct device *dev)
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{
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struct i2c_client *client = to_i2c_client(dev);
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struct max17040_chip *chip = i2c_get_clientdata(client);
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cancel_delayed_work(&chip->work);
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return 0;
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}
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static int max17040_resume(struct device *dev)
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{
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struct i2c_client *client = to_i2c_client(dev);
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struct max17040_chip *chip = i2c_get_clientdata(client);
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queue_delayed_work(system_power_efficient_wq, &chip->work,
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MAX17040_DELAY);
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return 0;
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}
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static SIMPLE_DEV_PM_OPS(max17040_pm_ops, max17040_suspend, max17040_resume);
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#define MAX17040_PM_OPS (&max17040_pm_ops)
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#else
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#define MAX17040_PM_OPS NULL
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#endif /* CONFIG_PM_SLEEP */
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static const struct i2c_device_id max17040_id[] = {
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{ "max17040" },
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{ "max77836-battery" },
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{ }
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};
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MODULE_DEVICE_TABLE(i2c, max17040_id);
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static struct i2c_driver max17040_i2c_driver = {
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.driver = {
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.name = "max17040",
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.pm = MAX17040_PM_OPS,
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},
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.probe = max17040_probe,
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.remove = max17040_remove,
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.id_table = max17040_id,
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};
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module_i2c_driver(max17040_i2c_driver);
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MODULE_AUTHOR("Minkyu Kang <mk7.kang@samsung.com>");
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MODULE_DESCRIPTION("MAX17040 Fuel Gauge");
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MODULE_LICENSE("GPL");
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