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| author | MyungJoo Ham <myungjoo.ham@samsung.com> | 2010-07-20 08:07:07 +0200 |
|---|---|---|
| committer | Liam Girdwood <lrg@slimlogic.co.uk> | 2010-08-11 11:38:01 +0100 |
| commit | c5a4655db9e0b5e49a0b17e1bf96462e93e3c326 (patch) | |
| tree | de2afadd98d171248fc0f2a2edb4760f44470b29 /drivers/regulator | |
| parent | c789ca202cae5adfab0208e7e8becbc602e5d079 (diff) | |
| download | kernel_samsung_tuna-c5a4655db9e0b5e49a0b17e1bf96462e93e3c326.zip kernel_samsung_tuna-c5a4655db9e0b5e49a0b17e1bf96462e93e3c326.tar.gz kernel_samsung_tuna-c5a4655db9e0b5e49a0b17e1bf96462e93e3c326.tar.bz2 | |
regulator: MAX8998: set_voltage bugfix. ramp_up delay and min/max voltage
Two issues are addressed for max8998_set_voltage function.
1. Min/Max Voltage.
max8998_set_voltage had been using the voltage value of
min ( voltage[i] >= max_vol , i )
This is corrected to use:
min ( voltage[i] >= min_vol , i )
2. Ramp Up Delay.
max8998_set_voltage should provide delay for BUCK1/2
if ENRAMP is on. It reads RAMP value from ONOFF4 register to determine
RAMP delay length. However, when max8998_set_voltage's new voltage is
lower than the previous, we don't care because it does not deteriorate
the stability.
Changes since v1:
- rebased onto latest regulator-for-next tree
Signed-off-by: MyungJoo Ham <myungjoo.ham@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Acked-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Liam Girdwood <lrg@slimlogic.co.uk>
Diffstat (limited to 'drivers/regulator')
| -rw-r--r-- | drivers/regulator/max8998.c | 29 |
1 files changed, 27 insertions, 2 deletions
diff --git a/drivers/regulator/max8998.c b/drivers/regulator/max8998.c index 174fd19..03e55a1 100644 --- a/drivers/regulator/max8998.c +++ b/drivers/regulator/max8998.c @@ -28,6 +28,7 @@ #include <linux/slab.h> #include <linux/interrupt.h> #include <linux/mutex.h> +#include <linux/delay.h> #include <linux/platform_device.h> #include <linux/regulator/driver.h> #include <linux/mfd/max8998.h> @@ -297,10 +298,13 @@ static int max8998_set_voltage(struct regulator_dev *rdev, { struct max8998_data *max8998 = rdev_get_drvdata(rdev); int min_vol = min_uV / 1000, max_vol = max_uV / 1000; + int previous_vol = 0; const struct voltage_map_desc *desc; int ldo = max8998_get_ldo(rdev); int reg, shift = 0, mask, ret; int i = 0; + u8 val; + bool en_ramp = false; if (ldo > ARRAY_SIZE(ldo_voltage_map)) return -EINVAL; @@ -312,15 +316,36 @@ static int max8998_set_voltage(struct regulator_dev *rdev, if (max_vol < desc->min || min_vol > desc->max) return -EINVAL; - while (desc->min + desc->step*i < max_vol && + while (desc->min + desc->step*i < min_vol && desc->min + desc->step*i < desc->max) i++; + if (desc->min + desc->step*i > max_vol) + return -EINVAL; + ret = max8998_get_voltage_register(rdev, ®, &shift, &mask); if (ret) return ret; - return max8998_update_reg(max8998->iodev, reg, i<<shift, mask<<shift); + /* wait for RAMP_UP_DELAY if rdev is BUCK1/2 and + * ENRAMP is ON */ + if (ldo == MAX8998_BUCK1 || ldo == MAX8998_BUCK2) { + max8998_read_reg(max8998->iodev, MAX8998_REG_ONOFF4, &val); + if (val & (1 << 4)) { + en_ramp = true; + previous_vol = max8998_get_voltage(rdev); + } + } + + ret = max8998_update_reg(max8998->iodev, reg, i<<shift, mask<<shift); + + if (en_ramp == true) { + int difference = desc->min + desc->step*i - previous_vol/1000; + if (difference > 0) + udelay(difference / ((val & 0x0f) + 1)); + } + + return ret; } static struct regulator_ops max8998_ldo_ops = { |