Re: [PATCH v2 3/3] power: wm831x_power: Support USB charger current limit management

From: Peter Chen
Date: Tue Aug 18 2015 - 02:31:25 EST


On Mon, Aug 17, 2015 at 10:26:23AM -0700, Mark Brown wrote:
> On Mon, Aug 17, 2015 at 09:07:08AM +0800, Peter Chen wrote:
> > On Fri, Aug 14, 2015 at 05:47:46PM +0800, Baolin Wang wrote:
>
> > > + 1500,
> > > + 1800,
> > > + 550,
> > > +};
>
> > Why 550 is the last, but not 1800?
>
> You'd have to ask the hardware engineers who designed the chip. I
> suspect it's because 550 was added at a late stage in the design process
> but I'm basically just guessing there.

ok, I just had suspected below function's correctness, after looking
it again, it always set 1800 as charging limit, does it be expected?

+/* In miliamps */
+static unsigned int wm831x_usb_limits[] = {
+ 0,
+ 2,
+ 100,
+ 500,
+ 900,
+ 1500,
+ 1800,
+ 550,
+};
+
+static int wm831x_usb_limit_change(struct notifier_block *nb,
+ unsigned long limit, void *data)
+{
+ struct wm831x_power *wm831x_power = container_of(nb,
+ struct wm831x_power,
+ usb_notify);
+ int i, best;
+
+ /* Find the highest supported limit */
+ best = 0;
+ for (i = 0; i < ARRAY_SIZE(wm831x_usb_limits); i++) {
+ if (limit < wm831x_usb_limits[i] &&
+ wm831x_usb_limits[best] < wm831x_usb_limits[i])
+ best = i;
+ }
+
+ dev_dbg(wm831x_power->wm831x->dev,
+ "Limiting USB current to %dmA", wm831x_usb_limits[best]);
+
+ wm831x_set_bits(wm831x_power->wm831x, WM831X_POWER_STATE,
+ WM831X_USB_ILIM_MASK, best);
+
+ return 0;
+}
+

>
> > > *********************************************************************/
> > > @@ -606,8 +646,31 @@ static int wm831x_power_probe(struct platform_device *pdev)
> > > }
> > > }
>
> > > + if (wm831x_pdata && wm831x_pdata->usb_gadget) {
>
> > Where the wm831x_pdata->usb_gadget is initialized?
>
> It's platform data, it will be initialised by whatever registers the
> platform data.

Get it, I just do not find in this patch set, thanks.

--

Best Regards,
Peter Chen
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