diff options
| author | NeilBrown <neil@brown.name> | 2015-07-30 10:11:24 +1000 |
|---|---|---|
| committer | Sebastian Reichel <sre@kernel.org> | 2015-08-05 05:14:43 +0200 |
| commit | 3b542f089dcbdcf1c21a01927fbc6d5116af01f6 (patch) | |
| tree | ac8469ca7f95f1f8c477bd53cdbf79873f6ad939 /drivers/power/twl4030_charger.c | |
| parent | 6e37ec8c77e3e6580cbb844dfeea0fb3970c0a35 (diff) | |
| download | lwn-3b542f089dcbdcf1c21a01927fbc6d5116af01f6.tar.gz lwn-3b542f089dcbdcf1c21a01927fbc6d5116af01f6.zip | |
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: Pavel Machek <pavel@ucw.cz>
Signed-off-by: NeilBrown <neil@brown.name>
Signed-off-by: Sebastian Reichel <sre@kernel.org>
Diffstat (limited to 'drivers/power/twl4030_charger.c')
| -rw-r--r-- | drivers/power/twl4030_charger.c | 48 |
1 files changed, 35 insertions, 13 deletions
diff --git a/drivers/power/twl4030_charger.c b/drivers/power/twl4030_charger.c index a075216d65ed..29984b263a35 100644 --- a/drivers/power/twl4030_charger.c +++ b/drivers/power/twl4030_charger.c @@ -178,6 +178,40 @@ static int twl4030_is_battery_present(struct twl4030_bci *bci) } /* + * 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. */ static int twl4030_charger_enable_usb(struct twl4030_bci *bci, bool enable) @@ -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); } /* |