From 819eb8196422f5fbe19690c903093ccc37519227 Mon Sep 17 00:00:00 2001 From: Balaji Rao Date: Mon, 29 Dec 2008 12:11:33 +0000 Subject: Manually restart charger periodically This avoids excessive discharges seen in case of Li-ion batteries even when charger is connected. Signed-off-by: Balaji Rao --- drivers/power/pcf50633-charger.c | 42 ++++++++++++++++++++++++++++++++++++++++ 1 file changed, 42 insertions(+) (limited to 'drivers/power') diff --git a/drivers/power/pcf50633-charger.c b/drivers/power/pcf50633-charger.c index 5cfdb274f89..b06a2ed4ddf 100644 --- a/drivers/power/pcf50633-charger.c +++ b/drivers/power/pcf50633-charger.c @@ -143,6 +143,42 @@ static struct attribute_group mbc_attr_group = { .attrs = mbc_sysfs_entries, }; +/* MBC state machine switches into charging mode when the battery voltage + * falls below 96% of a battery float voltage. But the voltage drop in Li-ion + * batteries is marginal(1~2 %) till about 80% of its capacity - which means, + * after a BATFULL, charging won't be restarted until 80%. + * + * This work_struct function restarts charging every + * CHARGING_RESTART_TIMEOUT seconds and makes sure we don't discharge too much + */ + +#define CHARGING_RESTART_TIMEOUT (900 * HZ) /* 15 minutes */ + +static void pcf50633_mbc_charging_restart(struct work_struct *work) +{ + struct pcf50633_mbc *mbc; + struct pcf50633 *pcf; + u8 mbcs2, chgmod; + + mbc = container_of(work, struct pcf50633_mbc, + charging_restart_work.work); + pcf = container_of(mbc, struct pcf50633, mbc); + + mbcs2 = pcf50633_reg_read(pcf, PCF50633_REG_MBCS2); + chgmod = (mbcs2 & PCF50633_MBCS2_MBC_MASK); + + if (chgmod != PCF50633_MBCS2_MBC_BAT_FULL) + return; + + /* Restart charging */ + pcf50633_reg_set_bit_mask(pcf, PCF50633_REG_MBCC1, PCF50633_MBCC1_RESUME, + PCF50633_MBCC1_RESUME); + mbc->usb_active = 1; + power_supply_changed(&mbc->usb); + + dev_info(pcf->dev, "Charging restarted..\n"); +} + static void pcf50633_mbc_irq_handler(struct pcf50633 *pcf, int irq, void *data) { struct pcf50633_mbc *mbc; @@ -156,6 +192,7 @@ static void pcf50633_mbc_irq_handler(struct pcf50633 *pcf, int irq, void *data) mbc->usb_online = 0; mbc->usb_active = 0; pcf50633_mbc_usb_curlim_set(pcf, 0); + cancel_delayed_work_sync(&mbc->charging_restart_work); } /* Adapter */ @@ -170,6 +207,8 @@ static void pcf50633_mbc_irq_handler(struct pcf50633 *pcf, int irq, void *data) if (irq == PCF50633_IRQ_BATFULL) { mbc->usb_active = 0; mbc->adapter_active = 0; + schedule_delayed_work(&mbc->charging_restart_work, + CHARGING_RESTART_TIMEOUT); } else if (irq == PCF50633_IRQ_USBLIMON) mbc->usb_active = 0; else if (irq == PCF50633_IRQ_USBLIMOFF) @@ -310,6 +349,9 @@ int __init pcf50633_mbc_probe(struct platform_device *pdev) mbc->ac.supplied_to = pcf->pdata->batteries; mbc->ac.num_supplicants = pcf->pdata->num_batteries; + INIT_DELAYED_WORK(&mbc->charging_restart_work, + pcf50633_mbc_charging_restart); + ret = power_supply_register(&pdev->dev, &mbc->adapter); if (ret) dev_err(pcf->dev, "failed to register adapter\n"); -- cgit v1.2.3