Re: [PATCH] power: pcf50633: introduces battery charging current control

[Pavel Machek <pavel@ucw.cz>]

On Wed 2009-10-14 01:59:04, Paul Fertser wrote:
> From: Balaji Rao <balajirrao@openmoko.org>
> 
> Signed-off-by: Balaji Rao <balajirrao@openmoko.org>
> Signed-off-by: Paul Fertser <fercerpav@gmail.com>
> ---
>  drivers/power/pcf50633-charger.c  |   73 ++++++++++++++++++++++++++++++++++---
>  include/linux/mfd/pcf50633/core.h |    2 +
>  2 files changed, 70 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/power/pcf50633-charger.c b/drivers/power/pcf50633-charger.c
> index 48e92c0..13f2839 100644
> --- a/drivers/power/pcf50633-charger.c
> +++ b/drivers/power/pcf50633-charger.c
> @@ -48,16 +48,21 @@ int pcf50633_mbc_usb_curlim_set(struct pcf50633 *pcf, int ma)
>  	u8 bits;
>  	int charging_start = 1;
>  	u8 mbcs2, chgmod;
> +	unsigned int mbcc5;
>  
> -	if (ma >= 1000)
> +	if (ma >= 1000) {
>  		bits = PCF50633_MBCC7_USB_1000mA;
> -	else if (ma >= 500)
> +		ma = 1000;
> +	} else if (ma >= 500) {
>  		bits = PCF50633_MBCC7_USB_500mA;
> -	else if (ma >= 100)
> +		ma = 500;
> +	} else if (ma >= 100) {
>  		bits = PCF50633_MBCC7_USB_100mA;
> -	else {
> +		ma = 100;
> +	} else {
>  		bits = PCF50633_MBCC7_USB_SUSPEND;
>  		charging_start = 0;
> +		ma = 0;
>  	}
>  
>  	ret = pcf50633_reg_set_bit_mask(pcf, PCF50633_REG_MBCC7,
> @@ -67,7 +72,24 @@ int pcf50633_mbc_usb_curlim_set(struct pcf50633 *pcf, int ma)
>  	else
>  		dev_info(pcf->dev, "usb curlim to %d mA\n", ma);
>  
> -	/* Manual charging start */
> +	/*
> +	 * We limit the charging current to be the USB current limit.
> +	 * The reason is that on pcf50633, when it enters PMU Standby mode,
> +	 * which it does when the device goes "off", the USB current limit
> +	 * reverts to the variant default.  In at least one common case, that
> +	 * default is 500mA.  By setting the charging current to be the same
> +	 * as the USB limit we set here before PMU standby, we enforce it only
> +	 * using the correct amount of current even when the USB current limit
> +	 * gets reset to the wrong thing
> +	 */
> +
> +	if (mbc->pcf->pdata->chg_ref_current_ma) {
> +		mbcc5 = (ma << 8) / mbc->pcf->pdata->chg_ref_current_ma;
> +		if (mbcc5 > 255)
> +			mbcc5 = 255;
> +		pcf50633_reg_write(mbc->pcf, PCF50633_REG_MBCC5, mbcc5);
> +	}
> +
>  	mbcs2 = pcf50633_reg_read(pcf, PCF50633_REG_MBCS2);
>  	chgmod = (mbcs2 & PCF50633_MBCS2_MBC_MASK);
>  
> @@ -157,9 +179,50 @@ static ssize_t set_usblim(struct device *dev,
>  
>  static DEVICE_ATTR(usb_curlim, S_IRUGO | S_IWUSR, show_usblim, set_usblim);
>  
> +static ssize_t
> +show_chglim(struct device *dev, struct device_attribute *attr, char *buf)
> +{
> +	struct pcf50633_mbc *mbc = dev_get_drvdata(dev);
> +	u8 mbcc5 = pcf50633_reg_read(mbc->pcf, PCF50633_REG_MBCC5);
> +	unsigned int ma;
> +
> +	if (!mbc->pcf->pdata->chg_ref_current_ma)
> +		return -ENODEV;
> +
> +	ma = (mbc->pcf->pdata->chg_ref_current_ma *  mbcc5) >> 8;
> +
> +	return sprintf(buf, "%u\n", ma);
> +}
> +
> +static ssize_t set_chglim(struct device *dev,
> +		struct device_attribute *attr, const char *buf, size_t count)
> +{
> +	struct pcf50633_mbc *mbc = dev_get_drvdata(dev);
> +	unsigned long ma;
> +	unsigned int mbcc5;
> +	int ret;
> +
> +	if (!mbc->pcf->pdata->chg_ref_current_ma)
> +		return -ENODEV;
> +
> +	ret = strict_strtoul(buf, 10, &ma);
> +	if (ret)
> +		return -EINVAL;
> +
> +	mbcc5 = (ma << 8) / mbc->pcf->pdata->chg_ref_current_ma;
> +	if (mbcc5 > 255)
> +		mbcc5 = 255;
> +	pcf50633_reg_write(mbc->pcf, PCF50633_REG_MBCC5, mbcc5);
> +
> +	return count;
> +}
> +
> +static DEVICE_ATTR(chg_curlim, S_IRUGO | S_IWUSR, show_chglim, set_chglim);
> +
>  static struct attribute *pcf50633_mbc_sysfs_entries[] = {
>  	&dev_attr_chgmode.attr,
>  	&dev_attr_usb_curlim.attr,
> +	&dev_attr_chg_curlim.attr,
>  	NULL,
>  };
>  
> diff --git a/include/linux/mfd/pcf50633/core.h b/include/linux/mfd/pcf50633/core.h
> index 9aba7b7..222dd90 100644
> --- a/include/linux/mfd/pcf50633/core.h
> +++ b/include/linux/mfd/pcf50633/core.h
> @@ -31,6 +31,8 @@ struct pcf50633_platform_data {
>  
>  	int charging_restart_interval;
>  
> +	int chg_ref_current_ma;
> +
>  	/* Callbacks */
>  	void (*probe_done)(struct pcf50633 *);
>  	void (*mbc_event_callback)(struct pcf50633 *, int);

-- 
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