regulator: Add soft start support

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>

2 files changed, 3 insertions, 0 deletions

diff --git a/include/linux/regulator/driver.h b/include/linux/regulator/driver.h
index 76144a337ff7..e0635d0894aa 100644
--- a/include/linux/regulator/driver.h
+++ b/include/linux/regulator/driver.h
@@ -161,6 +161,8 @@ struct regulator_ops {
                                      unsigned int old_selector,
                                      unsigned int new_selector);
 
+        int (*set_soft_start) (struct regulator_dev *);
+
         /* report regulator status ... most other accessors report
          * control inputs, this reports results of combining inputs
          * from Linux (and other sources) with the actual load.
diff --git a/include/linux/regulator/machine.h b/include/linux/regulator/machine.h
index 8ffb0619a03c..7f7d0a3fe1e1 100644
--- a/include/linux/regulator/machine.h
+++ b/include/linux/regulator/machine.h
@@ -142,6 +142,7 @@ struct regulation_constraints {
         unsigned boot_on:1;     /* bootloader/firmware enabled regulator */
         unsigned apply_uV:1;    /* apply uV constraint if min == max */
         unsigned ramp_disable:1; /* disable ramp delay */
+        unsigned soft_start:1;  /* ramp voltage slowly */
         unsigned pull_down:1;   /* pull down resistor when regulator off */
 };