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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>
280 lines
7.3 KiB
C
280 lines
7.3 KiB
C
/*
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* Copyright (C) 2010, Lars-Peter Clausen <lars@metafoo.de>
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* Driver for chargers which report their online status through a GPIO pin
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License as published by the
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* Free Software Foundation; either version 2 of the License, or (at your
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* option) any later version.
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*
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* You should have received a copy of the GNU General Public License along
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* with this program; if not, write to the Free Software Foundation, Inc.,
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* 675 Mass Ave, Cambridge, MA 02139, USA.
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*
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*/
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#include <linux/device.h>
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#include <linux/gpio.h>
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#include <linux/init.h>
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#include <linux/interrupt.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/platform_device.h>
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#include <linux/power_supply.h>
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#include <linux/slab.h>
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#include <linux/of.h>
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#include <linux/of_gpio.h>
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#include <linux/power/gpio-charger.h>
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struct gpio_charger {
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const struct gpio_charger_platform_data *pdata;
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unsigned int irq;
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bool wakeup_enabled;
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struct power_supply *charger;
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struct power_supply_desc charger_desc;
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};
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static irqreturn_t gpio_charger_irq(int irq, void *devid)
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{
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struct power_supply *charger = devid;
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power_supply_changed(charger);
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return IRQ_HANDLED;
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}
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static inline struct gpio_charger *psy_to_gpio_charger(struct power_supply *psy)
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{
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return power_supply_get_drvdata(psy);
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}
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static int gpio_charger_get_property(struct power_supply *psy,
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enum power_supply_property psp, union power_supply_propval *val)
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{
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struct gpio_charger *gpio_charger = psy_to_gpio_charger(psy);
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const struct gpio_charger_platform_data *pdata = gpio_charger->pdata;
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switch (psp) {
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case POWER_SUPPLY_PROP_ONLINE:
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val->intval = !!gpio_get_value_cansleep(pdata->gpio);
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val->intval ^= pdata->gpio_active_low;
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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 enum power_supply_property gpio_charger_properties[] = {
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POWER_SUPPLY_PROP_ONLINE,
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};
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static
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struct gpio_charger_platform_data *gpio_charger_parse_dt(struct device *dev)
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{
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struct device_node *np = dev->of_node;
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struct gpio_charger_platform_data *pdata;
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const char *chargetype;
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enum of_gpio_flags flags;
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int ret;
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if (!np)
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return ERR_PTR(-ENOENT);
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pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);
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if (!pdata)
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return ERR_PTR(-ENOMEM);
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pdata->name = np->name;
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pdata->gpio = of_get_gpio_flags(np, 0, &flags);
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if (pdata->gpio < 0) {
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if (pdata->gpio != -EPROBE_DEFER)
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dev_err(dev, "could not get charger gpio\n");
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return ERR_PTR(pdata->gpio);
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}
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pdata->gpio_active_low = !!(flags & OF_GPIO_ACTIVE_LOW);
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pdata->type = POWER_SUPPLY_TYPE_UNKNOWN;
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ret = of_property_read_string(np, "charger-type", &chargetype);
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if (ret >= 0) {
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if (!strncmp("unknown", chargetype, 7))
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pdata->type = POWER_SUPPLY_TYPE_UNKNOWN;
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else if (!strncmp("battery", chargetype, 7))
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pdata->type = POWER_SUPPLY_TYPE_BATTERY;
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else if (!strncmp("ups", chargetype, 3))
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pdata->type = POWER_SUPPLY_TYPE_UPS;
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else if (!strncmp("mains", chargetype, 5))
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pdata->type = POWER_SUPPLY_TYPE_MAINS;
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else if (!strncmp("usb-sdp", chargetype, 7))
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pdata->type = POWER_SUPPLY_TYPE_USB;
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else if (!strncmp("usb-dcp", chargetype, 7))
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pdata->type = POWER_SUPPLY_TYPE_USB_DCP;
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else if (!strncmp("usb-cdp", chargetype, 7))
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pdata->type = POWER_SUPPLY_TYPE_USB_CDP;
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else if (!strncmp("usb-aca", chargetype, 7))
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pdata->type = POWER_SUPPLY_TYPE_USB_ACA;
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else
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dev_warn(dev, "unknown charger type %s\n", chargetype);
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}
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return pdata;
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}
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static int gpio_charger_probe(struct platform_device *pdev)
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{
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const struct gpio_charger_platform_data *pdata = pdev->dev.platform_data;
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struct power_supply_config psy_cfg = {};
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struct gpio_charger *gpio_charger;
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struct power_supply_desc *charger_desc;
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int ret;
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int irq;
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if (!pdata) {
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pdata = gpio_charger_parse_dt(&pdev->dev);
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if (IS_ERR(pdata)) {
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ret = PTR_ERR(pdata);
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if (ret != -EPROBE_DEFER)
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dev_err(&pdev->dev, "No platform data\n");
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return ret;
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}
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}
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if (!gpio_is_valid(pdata->gpio)) {
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dev_err(&pdev->dev, "Invalid gpio pin\n");
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return -EINVAL;
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}
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gpio_charger = devm_kzalloc(&pdev->dev, sizeof(*gpio_charger),
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GFP_KERNEL);
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if (!gpio_charger) {
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dev_err(&pdev->dev, "Failed to alloc driver structure\n");
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return -ENOMEM;
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}
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charger_desc = &gpio_charger->charger_desc;
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charger_desc->name = pdata->name ? pdata->name : "gpio-charger";
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charger_desc->type = pdata->type;
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charger_desc->properties = gpio_charger_properties;
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charger_desc->num_properties = ARRAY_SIZE(gpio_charger_properties);
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charger_desc->get_property = gpio_charger_get_property;
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psy_cfg.supplied_to = pdata->supplied_to;
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psy_cfg.num_supplicants = pdata->num_supplicants;
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psy_cfg.of_node = pdev->dev.of_node;
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psy_cfg.drv_data = gpio_charger;
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ret = gpio_request(pdata->gpio, dev_name(&pdev->dev));
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if (ret) {
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dev_err(&pdev->dev, "Failed to request gpio pin: %d\n", ret);
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goto err_free;
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}
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ret = gpio_direction_input(pdata->gpio);
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if (ret) {
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dev_err(&pdev->dev, "Failed to set gpio to input: %d\n", ret);
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goto err_gpio_free;
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}
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gpio_charger->pdata = pdata;
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gpio_charger->charger = power_supply_register(&pdev->dev,
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charger_desc, &psy_cfg);
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if (IS_ERR(gpio_charger->charger)) {
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ret = PTR_ERR(gpio_charger->charger);
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dev_err(&pdev->dev, "Failed to register power supply: %d\n",
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ret);
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goto err_gpio_free;
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}
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irq = gpio_to_irq(pdata->gpio);
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if (irq > 0) {
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ret = request_any_context_irq(irq, gpio_charger_irq,
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IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING,
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dev_name(&pdev->dev), gpio_charger->charger);
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if (ret < 0)
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dev_warn(&pdev->dev, "Failed to request irq: %d\n", ret);
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else
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gpio_charger->irq = irq;
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}
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platform_set_drvdata(pdev, gpio_charger);
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device_init_wakeup(&pdev->dev, 1);
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return 0;
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err_gpio_free:
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gpio_free(pdata->gpio);
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err_free:
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return ret;
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}
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static int gpio_charger_remove(struct platform_device *pdev)
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{
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struct gpio_charger *gpio_charger = platform_get_drvdata(pdev);
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if (gpio_charger->irq)
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free_irq(gpio_charger->irq, gpio_charger->charger);
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power_supply_unregister(gpio_charger->charger);
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gpio_free(gpio_charger->pdata->gpio);
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return 0;
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}
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#ifdef CONFIG_PM_SLEEP
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static int gpio_charger_suspend(struct device *dev)
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{
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struct gpio_charger *gpio_charger = dev_get_drvdata(dev);
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if (device_may_wakeup(dev))
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gpio_charger->wakeup_enabled =
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!enable_irq_wake(gpio_charger->irq);
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return 0;
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}
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static int gpio_charger_resume(struct device *dev)
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{
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struct platform_device *pdev = to_platform_device(dev);
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struct gpio_charger *gpio_charger = platform_get_drvdata(pdev);
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if (device_may_wakeup(dev) && gpio_charger->wakeup_enabled)
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disable_irq_wake(gpio_charger->irq);
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power_supply_changed(gpio_charger->charger);
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return 0;
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}
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#endif
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static SIMPLE_DEV_PM_OPS(gpio_charger_pm_ops,
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gpio_charger_suspend, gpio_charger_resume);
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static const struct of_device_id gpio_charger_match[] = {
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{ .compatible = "gpio-charger" },
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{ }
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};
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MODULE_DEVICE_TABLE(of, gpio_charger_match);
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static struct platform_driver gpio_charger_driver = {
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.probe = gpio_charger_probe,
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.remove = gpio_charger_remove,
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.driver = {
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.name = "gpio-charger",
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.pm = &gpio_charger_pm_ops,
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.of_match_table = gpio_charger_match,
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},
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};
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module_platform_driver(gpio_charger_driver);
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MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
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MODULE_DESCRIPTION("Driver for chargers which report their online status through a GPIO");
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MODULE_LICENSE("GPL");
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MODULE_ALIAS("platform:gpio-charger");
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