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Subject[PATCH/RFC] regulator: Reverse the disable sequence in regulator_bulk_disable()
Often there is a need for disabling a set of regulators in order opposite
to the enable order. Currently the function regulator_bulk_disable() walks
list of regulators in same order as regulator_bulk_enable(). This may cause
trouble, especially for devices with mixed analogue and digital circuits.
So reverse the disabling sequence of regulator_bulk_disable().
While at it, also correct the comment.

Cc: Jaroslav Kysela <perex@perex.cz>
Cc: Takashi Iwai <tiwai@suse.de>
Cc: Samuel Ortiz <sameo@linux.intel.com>
Cc: Steve Glendinning <steve.glendinning@smsc.com>
Cc: Richard Purdie <rpurdie@rpsys.net>
Cc: Timur Tabi <timur@freescale.com>
Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
---
The alternatives to directly modifying regulator_bulk_disable() could be:

- re-implement it in modules that need the order reversed; it is not
really helpful in practice since such code would have to be repeated
in multiple modules;

- create new function, e.g. regulator_bulk_disable_reversed() with the
order reversed - not sure if it is not an overkill though;
---
drivers/regulator/core.c | 8 ++++----
1 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c
index e9a83f8..67db4a6 100644
--- a/drivers/regulator/core.c
+++ b/drivers/regulator/core.c
@@ -2463,8 +2463,8 @@ EXPORT_SYMBOL_GPL(regulator_bulk_enable);
* @return 0 on success, an errno on failure
*
* This convenience API allows consumers to disable multiple regulator
- * clients in a single API call. If any consumers cannot be enabled
- * then any others that were disabled will be disabled again prior to
+ * clients in a single API call. If any consumers cannot be disabled
+ * then any others that were disabled will be enabled again prior to
* return.
*/
int regulator_bulk_disable(int num_consumers,
@@ -2473,7 +2473,7 @@ int regulator_bulk_disable(int num_consumers,
int i;
int ret;

- for (i = 0; i < num_consumers; i++) {
+ for (i = num_consumers - 1; i >= 0; --i) {
ret = regulator_disable(consumers[i].consumer);
if (ret != 0)
goto err;
@@ -2483,7 +2483,7 @@ int regulator_bulk_disable(int num_consumers,

err:
pr_err("Failed to disable %s: %d\n", consumers[i].supply, ret);
- for (--i; i >= 0; --i)
+ for (++i; i < num_consumers; ++i)
regulator_enable(consumers[i].consumer);

return ret;
--
1.7.8.3


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