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regulator: s2mps11: Set default ramp delay for S2MPS11 LDOs

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Driver did not provide default value for ramp delay for LDOs which lead
to warning in dmesg, e.g. on Odroid XU4:

[    1.486076] vdd_ldo9: ramp_delay not set
[    1.506875] vddq_mmc2: ramp_delay not set
[    1.523766] vdd_ldo15: ramp_delay not set
[    1.544702] vdd_sd: ramp_delay not set

The datasheet for all the S2MPS1x family is inconsistent here and does
not specify unambiguously the value of ramp delay for LDO. It mentions
30 mV/us in one timing diagram but then omits it completely in LDO
regulator characteristics table (it is specified for bucks).

However the vendor kernels for Galaxy S5 and Odroid XU3 use values of 12
mV/us or 24 mV/us.

Without the ramp delay value the consumers do not wait for voltage
settle after changing it. Although the proper value of ramp delay for
LDOs is unknown, it seems safer to use at least some value from
reference kernel than to leave it unset.

Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
This commit is contained in:
Krzysztof Kozlowski 2016-04-18 15:33:10 +02:00 committed by Mark Brown
parent 5ab3c49495
commit 94be46b9e5
2 changed files with 4 additions and 0 deletions
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1
drivers/regulator/s2mps11.c
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@ -267,6 +267,7 @@ static struct regulator_ops s2mps11_buck_ops = {
.ops = &s2mps11_ldo_ops, \
.type = REGULATOR_VOLTAGE, \
.owner = THIS_MODULE, \
.ramp_delay = RAMP_DELAY_12_MVUS, \
.min_uV = MIN_800_MV, \
.uV_step = step, \
.n_voltages = S2MPS11_LDO_N_VOLTAGES, \

3
include/linux/mfd/samsung/core.h
View file

@ -30,6 +30,9 @@
#define MIN_600_MV 600000
#define MIN_500_MV 500000
/* Ramp delay in uV/us */
#define RAMP_DELAY_12_MVUS 12000
/* Macros to represent steps for LDO/BUCK */
#define STEP_50_MV 50000
#define STEP_25_MV 25000