On Tue, Aug 18, 2015 at 09:12:00AM -0700, Mark Brown wrote:
> On Tue, Aug 18, 2015 at 01:20:12PM +0800, Peter Chen wrote:
>
> > ok, I just had suspected below function's correctness, after looking
> > it again, it always set 1800 as charging limit, does it be expected?
>
> > + /* Find the highest supported limit */
> > + best = 0;
> > + for (i = 0; i < ARRAY_SIZE(wm831x_usb_limits); i++) {
> > + if (limit < wm831x_usb_limits[i] &&
>
+/* 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;
+}
+
> The above check is intended to ensure that we don't go over the limit
> that was passed in in the callback. The goal is to select the highest
> option that is less than the limit passed in.
Please correct me if I was wrong, If there is SDP (PC), the current
limit is 500mA, then when the i = 4, (500 < 900) && (0 < 900) is true,
the best is 4. When the i goes to 5, (500 < 1500) && (900 < 1500) is
true, the best is 5. At last, the best will be 1800, which is not our
expectation.
Below code may be correct for the goal you expressed.
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;
}
--
Best Regards,
Peter Chen
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