a7y18lte-ubports/android_kernel_samsung_universal7885
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regulator: Add soft start support

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Some regulators support a "soft start" feature where the voltage
ramps up slowly when the regulator is enabled. Add an op
(set_soft_start) and a DT property + constraint to support this.

Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Mark Brown <broonie@kernel.org>
This commit is contained in:
Stephen Boyd 2015-06-11 17:37:05 -07:00 committed by Mark Brown
parent 23c779b9f9
commit 57f66b7886
5 changed files with 15 additions and 0 deletions
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1
Documentation/devicetree/bindings/regulator/regulator.txt
View File

@ -19,6 +19,7 @@ Optional properties:
design requires. This property describes the total system ramp time design requires. This property describes the total system ramp time
required due to the combination of internal ramping of the regulator itself, required due to the combination of internal ramping of the regulator itself,
and board design issues such as trace capacitance and load on the supply. and board design issues such as trace capacitance and load on the supply.
- regulator-soft-start: Enable soft start so that voltage ramps slowly
- regulator-state-mem sub-root node for Suspend-to-RAM mode - regulator-state-mem sub-root node for Suspend-to-RAM mode
: suspend to memory, the device goes to sleep, but all data stored in memory, : suspend to memory, the device goes to sleep, but all data stored in memory,
only some external interrupt can wake the device. only some external interrupt can wake the device.

8
drivers/regulator/core.c
View File

@ -1059,6 +1059,14 @@ static int set_machine_constraints(struct regulator_dev *rdev,
} }
} }
if (rdev->constraints->soft_start && ops->set_soft_start) {
ret = ops->set_soft_start(rdev);
if (ret < 0) {
rdev_err(rdev, "failed to set soft start\n");
goto out;
}
}
print_constraints(rdev); print_constraints(rdev);
return 0; return 0;
out: out:

3
drivers/regulator/of_regulator.c
View File

@ -84,6 +84,9 @@ static void of_get_regulation_constraints(struct device_node *np,
if (!ret) if (!ret)
constraints->enable_time = pval; constraints->enable_time = pval;
constraints->soft_start = of_property_read_bool(np,
"regulator-soft-start");
if (!of_property_read_u32(np, "regulator-initial-mode", &pval)) { if (!of_property_read_u32(np, "regulator-initial-mode", &pval)) {
if (desc && desc->of_map_mode) { if (desc && desc->of_map_mode) {
ret = desc->of_map_mode(pval); ret = desc->of_map_mode(pval);

2
include/linux/regulator/driver.h
View File

@ -161,6 +161,8 @@ struct regulator_ops {
unsigned int old_selector, unsigned int old_selector,
unsigned int new_selector); unsigned int new_selector);
int (*set_soft_start) (struct regulator_dev *);
/* report regulator status ... most other accessors report /* report regulator status ... most other accessors report
* control inputs, this reports results of combining inputs * control inputs, this reports results of combining inputs
* from Linux (and other sources) with the actual load. * from Linux (and other sources) with the actual load.

1
include/linux/regulator/machine.h
View File

@ -142,6 +142,7 @@ struct regulation_constraints {
unsigned boot_on:1; /* bootloader/firmware enabled regulator */ unsigned boot_on:1; /* bootloader/firmware enabled regulator */
unsigned apply_uV:1; /* apply uV constraint if min == max */ unsigned apply_uV:1; /* apply uV constraint if min == max */
unsigned ramp_disable:1; /* disable ramp delay */ unsigned ramp_disable:1; /* disable ramp delay */
unsigned soft_start:1; /* ramp voltage slowly */
unsigned pull_down:1; /* pull down resistor when regulator off */ unsigned pull_down:1; /* pull down resistor when regulator off */
}; };