// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Copyright (C) 2010, Lars-Peter Clausen <[email protected]>
* Driver for chargers which report their online status through a GPIO pin
*/
#include <linux/device.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/power_supply.h>
#include <linux/slab.h>
#include <linux/of.h>
#include <linux/gpio/consumer.h>
#include <linux/power/gpio-charger.h>
struct gpio_mapping {
u32 limit_ua;
u32 gpiodata;
} __packed;
struct gpio_charger {
struct device *dev;
unsigned int irq;
unsigned int charge_status_irq;
bool wakeup_enabled;
struct power_supply *charger;
struct power_supply_desc charger_desc;
struct gpio_desc *gpiod;
struct gpio_desc *charge_status;
struct gpio_descs *current_limit_gpios;
struct gpio_mapping *current_limit_map;
u32 current_limit_map_size;
u32 charge_current_limit;
};
static irqreturn_t gpio_charger_irq(int irq, void *devid)
{
struct power_supply *charger = devid;
power_supply_changed(charger);
return IRQ_HANDLED;
}
static inline struct gpio_charger *psy_to_gpio_charger(struct power_supply *psy)
{
return power_supply_get_drvdata(psy);
}
static int set_charge_current_limit(struct gpio_charger *gpio_charger, int val)
{
struct gpio_mapping mapping;
int ndescs = gpio_charger->current_limit_gpios->ndescs;
struct gpio_desc **gpios = gpio_charger->current_limit_gpios->desc;
int i;
if (!gpio_charger->current_limit_map_size)
return -EINVAL;
for (i = 0; i < gpio_charger->current_limit_map_size; i++) {
if (gpio_charger->current_limit_map[i].limit_ua <= val)
break;
}
mapping = gpio_charger->current_limit_map[i];
for (i = 0; i < ndescs; i++) {
bool val = (mapping.gpiodata >> i) & 1;
gpiod_set_value_cansleep(gpios[ndescs-i-1], val);
}
gpio_charger->charge_current_limit = mapping.limit_ua;
dev_dbg(gpio_charger->dev, "set charge current limit to %d (requested: %d)\n",
gpio_charger->charge_current_limit, val);
return 0;
}
static int gpio_charger_get_property(struct power_supply *psy,
enum power_supply_property psp, union power_supply_propval *val)
{
struct gpio_charger *gpio_charger = psy_to_gpio_charger(psy);
switch (psp) {
case POWER_SUPPLY_PROP_ONLINE:
val->intval = gpiod_get_value_cansleep(gpio_charger->gpiod);
break;
case POWER_SUPPLY_PROP_STATUS:
if (gpiod_get_value_cansleep(gpio_charger->charge_status))
val->intval = POWER_SUPPLY_STATUS_CHARGING;
else
val->intval = POWER_SUPPLY_STATUS_NOT_CHARGING;
break;
case POWER_SUPPLY_PROP_CONSTANT_CHARGE_CURRENT_MAX:
val->intval = gpio_charger->charge_current_limit;
break;
default:
return -EINVAL;
}
return 0;
}
static int gpio_charger_set_property(struct power_supply *psy,
enum power_supply_property psp, const union power_supply_propval *val)
{
struct gpio_charger *gpio_charger = psy_to_gpio_charger(psy);
switch (psp) {
case POWER_SUPPLY_PROP_CONSTANT_CHARGE_CURRENT_MAX:
return set_charge_current_limit(gpio_charger, val->intval);
default:
return -EINVAL;
}
return 0;
}
static int gpio_charger_property_is_writeable(struct power_supply *psy,
enum power_supply_property psp)
{
switch (psp) {
case POWER_SUPPLY_PROP_CONSTANT_CHARGE_CURRENT_MAX:
return 1;
default:
break;
}
return 0;
}
static enum power_supply_type gpio_charger_get_type(struct device *dev)
{
const char *chargetype;
if (!device_property_read_string(dev, "charger-type", &chargetype)) {
if (!strcmp("unknown", chargetype))
return POWER_SUPPLY_TYPE_UNKNOWN;
if (!strcmp("battery", chargetype))
return POWER_SUPPLY_TYPE_BATTERY;
if (!strcmp("ups", chargetype))
return POWER_SUPPLY_TYPE_UPS;
if (!strcmp("mains", chargetype))
return POWER_SUPPLY_TYPE_MAINS;
if (!strcmp("usb-sdp", chargetype))
return POWER_SUPPLY_TYPE_USB;
if (!strcmp("usb-dcp", chargetype))
return POWER_SUPPLY_TYPE_USB;
if (!strcmp("usb-cdp", chargetype))
return POWER_SUPPLY_TYPE_USB;
if (!strcmp("usb-aca", chargetype))
return POWER_SUPPLY_TYPE_USB;
}
dev_warn(dev, "unknown charger type %s\n", chargetype);
return POWER_SUPPLY_TYPE_UNKNOWN;
}
static int gpio_charger_get_irq(struct device *dev, void *dev_id,
struct gpio_desc *gpio)
{
int ret, irq = gpiod_to_irq(gpio);
if (irq > 0) {
ret = devm_request_any_context_irq(dev, irq, gpio_charger_irq,
IRQF_TRIGGER_RISING |
IRQF_TRIGGER_FALLING,
dev_name(dev),
dev_id);
if (ret < 0) {
dev_warn(dev, "Failed to request irq: %d\n", ret);
irq = 0;
}
}
return irq;
}
static int init_charge_current_limit(struct device *dev,
struct gpio_charger *gpio_charger)
{
int i, len;
u32 cur_limit = U32_MAX;
gpio_charger->current_limit_gpios = devm_gpiod_get_array_optional(dev,
"charge-current-limit", GPIOD_OUT_LOW);
if (IS_ERR(gpio_charger->current_limit_gpios)) {
dev_err(dev, "error getting current-limit GPIOs\n");
return PTR_ERR(gpio_charger->current_limit_gpios);
}
if (!gpio_charger->current_limit_gpios)
return 0;
len = device_property_read_u32_array(dev, "charge-current-limit-mapping",
NULL, 0);
if (len < 0)
return len;
if (len == 0 || len % 2) {
dev_err(dev, "invalid charge-current-limit-mapping length\n");
return -EINVAL;
}
gpio_charger->current_limit_map = devm_kmalloc_array(dev,
len / 2, sizeof(*gpio_charger->current_limit_map), GFP_KERNEL);
if (!gpio_charger->current_limit_map)
return -ENOMEM;
gpio_charger->current_limit_map_size = len / 2;
len = device_property_read_u32_array(dev, "charge-current-limit-mapping",
(u32*) gpio_charger->current_limit_map, len);
if (len < 0)
return len;
for (i=0; i < gpio_charger->current_limit_map_size; i++) {
if (gpio_charger->current_limit_map[i].limit_ua > cur_limit) {
dev_err(dev, "charge-current-limit-mapping not sorted by current in descending order\n");
return -EINVAL;
}
cur_limit = gpio_charger->current_limit_map[i].limit_ua;
}
/* default to smallest current limitation for safety reasons */
len = gpio_charger->current_limit_map_size - 1;
set_charge_current_limit(gpio_charger,
gpio_charger->current_limit_map[len].limit_ua);
return 0;
}
/*
* The entries will be overwritten by driver's probe routine depending
* on the available features. This list ensures, that the array is big
* enough for all optional features.
*/
static enum power_supply_property gpio_charger_properties[] = {
POWER_SUPPLY_PROP_ONLINE,
POWER_SUPPLY_PROP_STATUS,
POWER_SUPPLY_PROP_CONSTANT_CHARGE_CURRENT_MAX,
};
static int gpio_charger_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
const struct gpio_charger_platform_data *pdata = dev->platform_data;
struct power_supply_config psy_cfg = {};
struct gpio_charger *gpio_charger;
struct power_supply_desc *charger_desc;
struct gpio_desc *charge_status;
int charge_status_irq;
int ret;
int num_props = 0;
if (!pdata && !dev->of_node) {
dev_err(dev, "No platform data\n");
return -ENOENT;
}
gpio_charger = devm_kzalloc(dev, sizeof(*gpio_charger), GFP_KERNEL);
if (!gpio_charger)
return -ENOMEM;
gpio_charger->dev = dev;
/*
* This will fetch a GPIO descriptor from device tree, ACPI or
* boardfile descriptor tables. It's good to try this first.
*/
gpio_charger->gpiod = devm_gpiod_get_optional(dev, NULL, GPIOD_IN);
if (IS_ERR(gpio_charger->gpiod)) {
/* Just try again if this happens */
return dev_err_probe(dev, PTR_ERR(gpio_charger->gpiod),
"error getting GPIO descriptor\n");
}
if (gpio_charger->gpiod) {
gpio_charger_properties[num_props] = POWER_SUPPLY_PROP_ONLINE;
num_props++;
}
charge_status = devm_gpiod_get_optional(dev, "charge-status", GPIOD_IN);
if (IS_ERR(charge_status))
return PTR_ERR(charge_status);
if (charge_status) {
gpio_charger->charge_status = charge_status;
gpio_charger_properties[num_props] = POWER_SUPPLY_PROP_STATUS;
num_props++;
}
ret = init_charge_current_limit(dev, gpio_charger);
if (ret < 0)
return ret;
if (gpio_charger->current_limit_map) {
gpio_charger_properties[num_props] =
POWER_SUPPLY_PROP_CONSTANT_CHARGE_CURRENT_MAX;
num_props++;
}
charger_desc = &gpio_charger->charger_desc;
charger_desc->properties = gpio_charger_properties;
charger_desc->num_properties = num_props;
charger_desc->get_property = gpio_charger_get_property;
charger_desc->set_property = gpio_charger_set_property;
charger_desc->property_is_writeable =
gpio_charger_property_is_writeable;
psy_cfg.of_node = dev->of_node;
psy_cfg.drv_data = gpio_charger;
if (pdata) {
charger_desc->name = pdata->name;
charger_desc->type = pdata->type;
psy_cfg.supplied_to = pdata->supplied_to;
psy_cfg.num_supplicants = pdata->num_supplicants;
} else {
charger_desc->name = dev->of_node->name;
charger_desc->type = gpio_charger_get_type(dev);
}
if (!charger_desc->name)
charger_desc->name = pdev->name;
gpio_charger->charger = devm_power_supply_register(dev, charger_desc,
&psy_cfg);
if (IS_ERR(gpio_charger->charger)) {
ret = PTR_ERR(gpio_charger->charger);
dev_err(dev, "Failed to register power supply: %d\n", ret);
return ret;
}
gpio_charger->irq = gpio_charger_get_irq(dev, gpio_charger->charger,
gpio_charger->gpiod);
charge_status_irq = gpio_charger_get_irq(dev, gpio_charger->charger,
gpio_charger->charge_status);
gpio_charger->charge_status_irq = charge_status_irq;
platform_set_drvdata(pdev, gpio_charger);
device_init_wakeup(dev, 1);
return 0;
}
#ifdef CONFIG_PM_SLEEP
static int gpio_charger_suspend(struct device *dev)
{
struct gpio_charger *gpio_charger = dev_get_drvdata(dev);
if (device_may_wakeup(dev))
gpio_charger->wakeup_enabled =
!enable_irq_wake(gpio_charger->irq);
return 0;
}
static int gpio_charger_resume(struct device *dev)
{
struct gpio_charger *gpio_charger = dev_get_drvdata(dev);
if (device_may_wakeup(dev) && gpio_charger->wakeup_enabled)
disable_irq_wake(gpio_charger->irq);
power_supply_changed(gpio_charger->charger);
return 0;
}
#endif
static SIMPLE_DEV_PM_OPS(gpio_charger_pm_ops,
gpio_charger_suspend, gpio_charger_resume);
static const struct of_device_id gpio_charger_match[] = {
{ .compatible = "gpio-charger" },
{ }
};
MODULE_DEVICE_TABLE(of, gpio_charger_match);
static struct platform_driver gpio_charger_driver = {
.probe = gpio_charger_probe,
.driver = {
.name = "gpio-charger",
.pm = &gpio_charger_pm_ops,
.of_match_table = gpio_charger_match,
},
};
module_platform_driver(gpio_charger_driver);
MODULE_AUTHOR("Lars-Peter Clausen <[email protected]>");
MODULE_DESCRIPTION("Driver for chargers only communicating via GPIO(s)");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:gpio-charger");
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