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twl4030_charger: allow max_current to be managed via sysfs. 

'max_current' sysfs attributes are created which allow the
max to be set.
Whenever a current source changes, the default is restored.
This will be followed by a uevent, so user-space can decide to
update again.

Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: NeilBrown <neil@brown.name>
Signed-off-by: Sebastian Reichel <sre@kernel.org>
This commit is contained in:
NeilBrown 2015-07-30 10:11:24 +10:00 committed by Sebastian Reichel
parent e4ae537e04
commit aca3c35463
2 changed files with 87 additions and 0 deletions
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15
Documentation/ABI/testing/sysfs-class-power-twl4030 Normal file
View File

@ -0,0 +1,15 @@
What: /sys/class/power_supply/twl4030_ac/max_current
/sys/class/power_supply/twl4030_usb/max_current
Description:
Read/Write limit on current which may
be drawn from the ac (Accessory Charger) or
USB port.
Value is in micro-Amps.
Value is set automatically to an appropriate
value when a cable is plugged or unplugged.
Value can the set by writing to the attribute.
The change will only persist until the next
plug event. These event are reported via udev.

72
drivers/power/twl4030_charger.c
View File

@ -482,6 +482,8 @@ static irqreturn_t twl4030_charger_interrupt(int irq, void *arg)
struct twl4030_bci *bci = arg;
dev_dbg(bci->dev, "CHG_PRES irq\n");
/* reset current on each 'plug' event */
bci->ac_cur = 500000;
twl4030_charger_update_current(bci);
power_supply_changed(bci->ac);
power_supply_changed(bci->usb);
@ -536,6 +538,63 @@ static irqreturn_t twl4030_bci_interrupt(int irq, void *arg)
return IRQ_HANDLED;
}
/*
* Provide "max_current" attribute in sysfs.
*/
static ssize_t
twl4030_bci_max_current_store(struct device *dev, struct device_attribute *attr,
const char *buf, size_t n)
{
struct twl4030_bci *bci = dev_get_drvdata(dev->parent);
int cur = 0;
int status = 0;
status = kstrtoint(buf, 10, &cur);
if (status)
return status;
if (cur < 0)
return -EINVAL;
if (dev == &bci->ac->dev)
bci->ac_cur = cur;
else
bci->usb_cur = cur;
twl4030_charger_update_current(bci);
return n;
}
/*
* sysfs max_current show
*/
static ssize_t twl4030_bci_max_current_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
int status = 0;
int cur = -1;
u8 bcictl1;
struct twl4030_bci *bci = dev_get_drvdata(dev->parent);
if (dev == &bci->ac->dev) {
if (!bci->ac_is_active)
cur = bci->ac_cur;
} else {
if (bci->ac_is_active)
cur = bci->usb_cur;
}
if (cur < 0) {
cur = twl4030bci_read_adc_val(TWL4030_BCIIREF1);
if (cur < 0)
return cur;
status = twl4030_bci_read(TWL4030_BCICTL1, &bcictl1);
if (status < 0)
return status;
cur = regval2ua(cur, bcictl1 & TWL4030_CGAIN);
}
return scnprintf(buf, PAGE_SIZE, "%u\n", cur);
}
static DEVICE_ATTR(max_current, 0644, twl4030_bci_max_current_show,
twl4030_bci_max_current_store);
static void twl4030_bci_usb_work(struct work_struct *data)
{
struct twl4030_bci *bci = container_of(data, struct twl4030_bci, work);
@ -558,6 +617,12 @@ static int twl4030_bci_usb_ncb(struct notifier_block *nb, unsigned long val,
dev_dbg(bci->dev, "OTG notify %lu\n", val);
/* reset current on each 'plug' event */
if (allow_usb)
bci->usb_cur = 500000;
else
bci->usb_cur = 100000;
bci->event = val;
schedule_work(&bci->work);
@ -831,6 +896,11 @@ static int twl4030_bci_probe(struct platform_device *pdev)
dev_warn(&pdev->dev, "failed to unmask interrupts: %d\n", ret);
twl4030_charger_update_current(bci);
if (device_create_file(&bci->usb->dev, &dev_attr_max_current))
dev_warn(&pdev->dev, "could not create sysfs file\n");
if (device_create_file(&bci->ac->dev, &dev_attr_max_current))
dev_warn(&pdev->dev, "could not create sysfs file\n");
twl4030_charger_enable_ac(true);
if (!IS_ERR_OR_NULL(bci->transceiver))
twl4030_bci_usb_ncb(&bci->usb_nb,
@ -855,6 +925,8 @@ static int __exit twl4030_bci_remove(struct platform_device *pdev)
twl4030_charger_enable_usb(bci, false);
twl4030_charger_enable_backup(0, 0);
device_remove_file(&bci->usb->dev, &dev_attr_max_current);
device_remove_file(&bci->ac->dev, &dev_attr_max_current);
/* mask interrupts */
twl_i2c_write_u8(TWL4030_MODULE_INTERRUPTS, 0xff,
TWL4030_INTERRUPTS_BCIIMR1A);