Hi Priit and Olliver,
On Tue, Dec 11, 2018 at 5:42 AM Priit Laes <plaes@xxxxxxxxx> wrote:
>
> From: Olliver Schinagl <oliver@xxxxxxxxxxx>
>
> The AXP209 supports ramping up voltages on several regulators such as
> DCDC2 and LDO3.
>
> This patch adds preliminary support for the regulator-ramp-delay property
> for these 2 regulators. Note that the voltage ramp only works when
> regulator is already enabled. E.g. when going from say 0.7 V to 3.6 V.
>
> When turning on the regulator, no voltage ramp is performed in hardware.
>
> What this means, is that if the bootloader brings up the voltage at 0.7 V,
> the ramp delay property is properly applied. If however, the bootloader
> leaves the power off, no ramp delay is applied when the power is
> enabled by the regulator framework.
>
> Signed-off-by: Olliver Schinagl <oliver@xxxxxxxxxxx>
> Signed-off-by: Priit Laes <plaes@xxxxxxxxx>
> ---
> drivers/regulator/axp20x-regulator.c | 85 +++++++++++++++++++++++++++++-
> 1 file changed, 85 insertions(+)
>
> diff --git a/drivers/regulator/axp20x-regulator.c b/drivers/regulator/axp20x-regulator.c
> index 9a2db28..1d9fa62 100644
> --- a/drivers/regulator/axp20x-regulator.c
> +++ b/drivers/regulator/axp20x-regulator.c
> @@ -346,6 +357,79 @@
> .ops = &axp20x_ops_range, \
> }
>
> +static const int axp209_dcdc2_ldo3_slew_rates[] = {
> + 1600,
> + 800,
> +};
> +
> +static int axp20x_set_ramp_delay(struct regulator_dev *rdev, int ramp)
> +{
> + struct axp20x_dev *axp20x = rdev_get_drvdata(rdev);
> + const struct regulator_desc *desc = rdev->desc;
> + u8 reg, mask, enable, cfg = 0xff;
> + const int *slew_rates;
> + int rate_count = 0;
> +
> + if (!rdev)
> + return -EINVAL;
> +
> + switch (axp20x->variant) {
> + case AXP209_ID:
> + if (desc->id == AXP20X_DCDC2) {
Is slew_rates supposed to be set here?
> + rate_count = ARRAY_SIZE(axp209_dcdc2_ldo3_slew_rates);
> + reg = AXP20X_DCDC2_LDO3_V_RAMP;
> + mask = AXP20X_DCDC2_LDO3_V_RAMP_DCDC2_RATE_MASK |
> + AXP20X_DCDC2_LDO3_V_RAMP_DCDC2_EN_MASK;
> + enable = (ramp > 0) ?
> + AXP20X_DCDC2_LDO3_V_RAMP_DCDC2_EN :
> + !AXP20X_DCDC2_LDO3_V_RAMP_DCDC2_EN;
> + break;
> + }
> +
> + if (desc->id == AXP20X_LDO3) {
> + slew_rates = axp209_dcdc2_ldo3_slew_rates;
> + rate_count = ARRAY_SIZE(axp209_dcdc2_ldo3_slew_rates);
> + reg = AXP20X_DCDC2_LDO3_V_RAMP;
> + mask = AXP20X_DCDC2_LDO3_V_RAMP_LDO3_RATE_MASK |
> + AXP20X_DCDC2_LDO3_V_RAMP_LDO3_EN_MASK;
> + enable = (ramp > 0) ?
> + AXP20X_DCDC2_LDO3_V_RAMP_LDO3_EN :
> + !AXP20X_DCDC2_LDO3_V_RAMP_LDO3_EN;
> + break;
> + }
> +
> + if (rate_count > 0)
> + break;
You could save one to two tests by combining the above three if statements, i.e.
if (DCDC2) {
// set DCDC2 stuff
break;
} else if (LDO3) {
// set LDO3 stuff
break;
}
As written, the rate_count > 0 test will never be true as every block
that sets rate_count breaks out of the switch block.
You could then calculate rate_count below the switch block.
> +
> + /* fall through */
> + default:
> + /* Not supported for this regulator */
> + return -ENOTSUPP;
> + }
> +
> + if (ramp == 0) {
> + cfg = enable;
> + } else {
> + int i;
> +
> + for (i = 0; i < rate_count; i++) {
> + if (ramp <= slew_rates[i])
> + cfg = AXP20X_DCDC2_LDO3_V_RAMP_LDO3_RATE(i);
> + else
> + break;
> + }
> +
> + if (cfg == 0xff) {
> + dev_err(axp20x->dev, "unsupported ramp value %d", ramp);
> + return -EINVAL;
> + }
> +
> + cfg |= enable;
> + }
> +
> + return regmap_update_bits(axp20x->regmap, reg, mask, cfg);
> +}
> +
--
Julian Calaby
Email: julian.calaby@xxxxxxxxx
Profile: http://www.google.com/profiles/julian.calaby/
