Hello,
On Friday, July 16, 2010 10:09 AM MyungJoo Ham wrote:
> 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.
>
> Signed-off-by: MyungJoo Ham <myungjoo....@samsung.com>
> Signed-off-by: Kyungmin Park <kyungmin.p...@samsung.com>
Acked-by: Marek Szyprowski <m.szyprow...@samsung.com>
> --
> I've omitted some CC in the previous email, adding them here. Sorry for the
> duplicated submission.
> ---
> drivers/regulator/max8998.c | 30 ++++++++++++++++++++++++++++--
> 1 files changed, 28 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/regulator/max8998.c b/drivers/regulator/max8998.c
> index 1cca8b5..99c5279 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>
> @@ -302,10 +303,13 @@ static int max8998_set_voltage(struct regulator_dev
> *rdev,
> struct max8998_data *max8998 = rdev_get_drvdata(rdev);
> struct i2c_client *i2c = max8998->iodev->i2c;
> 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;
> @@ -317,15 +321,37 @@ 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(i2c, 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(i2c, MAX8998_REG_ONOFF4, &val);
> + if (val & (1 << 4)) {
> + en_ramp = true;
> + previous_vol = max8998_get_voltage(rdev);
> + }
> + }
> +
> + ret = max8998_update_reg(i2c, 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 = {
> --
> 1.6.3.3
Best regards
--
Marek Szyprowski
Samsung Poland R&D Center
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