[PATCH] regulator: Add enable_time on probe of WM8994

[PATCH] regulator: Add enable_time on probe of WM8994

[Joonyoung Shim]

WM8994 regulator needs some delay to enable when it is probed too.

Signed-off-by: Joonyoung Shim <jy0922.shim@samsung.com>
---
 drivers/regulator/wm8994-regulator.c |    9 ++++++++-
 1 files changed, 8 insertions(+), 1 deletions(-)

diff --git a/drivers/regulator/wm8994-regulator.c b/drivers/regulator/wm8994-regulator.c
index 1639806..a9f0c89 100644
--- a/drivers/regulator/wm8994-regulator.c
+++ b/drivers/regulator/wm8994-regulator.c
@@ -15,6 +15,7 @@
 #include <linux/moduleparam.h>
 #include <linux/init.h>
 #include <linux/bitops.h>
+#include <linux/delay.h>
 #include <linux/err.h>
 #include <linux/platform_device.h>
 #include <linux/regulator/driver.h>
@@ -206,7 +207,7 @@ static __devinit int wm8994_ldo_probe(struct platform_device *pdev)
 	struct wm8994_pdata *pdata = wm8994->dev->platform_data;
 	int id = pdev->id % ARRAY_SIZE(pdata->ldo);
 	struct wm8994_ldo *ldo;
-	int ret;
+	int ret, delay;
 
 	dev_dbg(&pdev->dev, "Probing LDO%d\n", id + 1);
 
@@ -239,6 +240,12 @@ static __devinit int wm8994_ldo_probe(struct platform_device *pdev)
 				ret);
 			goto err_gpio;
 		}
+
+		delay = wm8994_ldo_enable_time(NULL);
+		if (delay >= 1000)
+			mdelay(delay / 1000);
+		else if (delay)
+			udelay(delay);
 	}
 
 	ldo->regulator = regulator_register(&wm8994_ldo_desc[id], &pdev->dev,
-- 
1.6.3.3

Re: [PATCH] regulator: Add enable_time on probe of WM8994

[Mark Brown]

On Sun, Feb 07, 2010 at 09:41:26AM +0900, Joonyoung Shim wrote:
> WM8994 regulator needs some delay to enable when it is probed too.

What is the problem that's fixed by this change?

The only case I can think of where it would help is if the regulator
constraints are used to enable the regulators and run them at a
non-default voltage.  (which is not a recommended configuration since
this would mean raising the voltage and therefore increasing power
consumption).  For that case this is not quite enough of a change since
the LDO that is being controlled may not be the one that brings the
device out of power on reset.  More extensive rearrangement of the core
regulator code would be required to deal with that, reordering the
application of constraints.

Re: [PATCH] regulator: Add enable_time on probe of WM8994

[Joonyoung Shim]

On 2/8/2010 8:56 AM, Mark Brown wrote:
> On Sun, Feb 07, 2010 at 09:41:26AM +0900, Joonyoung Shim wrote:
>> WM8994 regulator needs some delay to enable when it is probed too.
> 
> What is the problem that's fixed by this change?
> 
> The only case I can think of where it would help is if the regulator
> constraints are used to enable the regulators and run them at a
> non-default voltage.  (which is not a recommended configuration since

You're right. I misunderstanded something. The default voltage already 
is setted at the WM8994 ldo registers, but i made a mistake that set it
again on probe via the regulator constraints.

Thanks.