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Commit 3b542f08 authored by NeilBrown's avatar NeilBrown Committed by Sebastian Reichel
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twl4030_charger: split uA calculation into a function. 



We will need this calculation in other places, so
create functions to map between register value and uA value.

Acked-by: default avatarPavel Machek <pavel@ucw.cz>
Signed-off-by: default avatarNeilBrown <neil@brown.name>
Signed-off-by: default avatarSebastian Reichel <sre@kernel.org>
parent 6e37ec8c

drivers/power/twl4030_charger.c

+35 −13
Original line number Diff line number Diff line
@@ -177,6 +177,40 @@ static int twl4030_is_battery_present(struct twl4030_bci *bci) 
	return -ENODEV;

}



/*

 * TI provided formulas:

 * CGAIN == 0: ICHG = (BCIICHG * 1.7) / (2^10 - 1) - 0.85

 * CGAIN == 1: ICHG = (BCIICHG * 3.4) / (2^10 - 1) - 1.7

 * Here we use integer approximation of:

 * CGAIN == 0: val * 1.6618 - 0.85 * 1000

 * CGAIN == 1: (val * 1.6618 - 0.85 * 1000) * 2

 */

/*

 * convert twl register value for currents into uA

 */

static int regval2ua(int regval, bool cgain)

{

	if (cgain)

		return (regval * 16618 - 8500 * 1000) / 5;

	else

		return (regval * 16618 - 8500 * 1000) / 10;

}



/*

 * convert uA currents into twl register value

 */

static int ua2regval(int ua, bool cgain)

{

	int ret;

	if (cgain)

		ua /= 2;

	ret = (ua * 10 + 8500 * 1000) / 16618;

	/* rounding problems */

	if (ret < 512)

		ret = 512;

	return ret;

}



/*

 * Enable/Disable USB Charge functionality.

 */
@@ -366,14 +400,6 @@ static int twl4030_bci_usb_ncb(struct notifier_block *nb, unsigned long val, 
	return NOTIFY_OK;

}



/*

 * TI provided formulas:

 * CGAIN == 0: ICHG = (BCIICHG * 1.7) / (2^10 - 1) - 0.85

 * CGAIN == 1: ICHG = (BCIICHG * 3.4) / (2^10 - 1) - 1.7

 * Here we use integer approximation of:

 * CGAIN == 0: val * 1.6618 - 0.85

 * CGAIN == 1: (val * 1.6618 - 0.85) * 2

 */

static int twl4030_charger_get_current(void)

{

	int curr;
@@ -388,11 +414,7 @@ static int twl4030_charger_get_current(void) 
	if (ret)

		return ret;



	ret = (curr * 16618 - 850 * 10000) / 10;

	if (bcictl1 & TWL4030_CGAIN)

		ret *= 2;



	return ret;

	return regval2ua(curr, bcictl1 & TWL4030_CGAIN);

}



/*