On Thu, Jun 30, 2011 at 5:22 PM, Vasily Khoruzhick [off-list ref] wrote:

On Thursday 30 June 2011 10:49:30 MyungJoo Ham wrote:

quoted

This patch allows the Samsung ADC driver to enable VDD regulator at
probe and resume and to disable at exit and suspend.
In a platform where ADC's VDD regulator is not "always-on", this control
is required although this patch does not provide fine-grained power
control (turning on the regulator only when being accessed).

However, if VDD regulator ("vdd" for the adc device) is not provided,
the regulator control will not be activated because there are platforms
that do not provide regulator for ADC device.

arch_initcall has been modified to module_init in order to allow
regulators to be available at probe.

Signed-off-by: MyungJoo Ham <myungjoo.ham@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>

[]

quoted

+ ? ? adc->vdd = regulator_get(dev, "vdd");
+ ? ? if (IS_ERR(adc->vdd)) {
+ ? ? ? ? ? ? dev_err(dev, "operating without regulator \"vdd\" .\n");
+ ? ? ? ? ? ? ret = PTR_ERR(adc->vdd);
+ ? ? ? ? ? ? goto err_alloc;
+ ? ? }
+

NACK. Make it optional, otherwise it breaks s3c24xx.

Ok. Now, I've got the issue I've worried in the previous patch revision.

Anyway, Mark once stated:

--- quote starts ---

On Sun, Jun 19, 2011 at 12:06 AM, Mark Brown
[off-list ref] wrote:

quoted

+     if (IS_ERR_OR_NULL(adc->vdd)) {
+             dev_dbg(dev, "operating without regulator %s.\n", S3C_ADC_REGULATOR_NAME);
+             adc->vdd = NULL; /* Do not control regulator */
+     }
+

No, don't do this.  Just unconditionally assume the regulator is present
if power is essential for use of the device.  The regulator API will
stub out correctly if it's not in use to allow things to proceed and if
vdd is genuinely not hooked up then the driver can't function.

--- quote ends ---

Then, how about unconditionally using ADC VDD for TYPE_ADCV3
(S5PC110/S5PV210/Exynos4210) and forget VDD for older ADC types?


Thanks.

- MyungJoo
-- 
MyungJoo Ham, Ph.D.
Mobile Software Platform Lab,
Digital Media and Communications (DMC) Business
Samsung Electronics
cell: 82-10-6714-2858