Hi Andi,
On Fri, Sep 22, 2017 at 01:17:02PM +0900, Andi Shyti wrote:
> Hi Dmitry,
>
> thanks for your review!
>
> [...]
>
> > > +static void s6sy761_report_coordinates(struct s6sy761_data *sdata, u8 *event)
> > > +{
> > > + u8 tid = ((event[0] & S6SY761_MASK_TID) >> 2) - 1;
> >
> > Should we make sure that event[0] & S6SY761_MASK_TID is not 0?
>
> I check event[0] already in s6sy761_handle_events (called by the
> irq handler), if we get here event[0] is for sure positive...
>
> [...]
>
> > > +static void s6sy761_handle_events(struct s6sy761_data *sdata, u8 left_event)
> > > +{
> > > + int i;
> > > +
> > > + for (i = 0; i < left_event; i++) {
> > > + u8 *event = &sdata->data[i * S6SY761_EVENT_SIZE];
> > > + u8 event_id = event[0] & S6SY761_MASK_EID;
> > > +
> > > + if (!event[0])
> > > + return;
> ^^^^^^^^
> ... exactly here.
>
> '!event[0]' means also to me that there is nothing left,
> therefore I can discard whatever is next (given that there is
> something left).
What happens if you get event[0] == S6SY761_EVENT_ID_COORDINATE? I.e.
the value is non-zero, but tid component is 0?
>
> > > + switch (event_id) {
> > > +
> > > + case S6SY761_EVENT_ID_COORDINATE:
> > > + s6sy761_handle_coordinates(sdata, event);
> > > + break;
> > > +
> > > + case S6SY761_EVENT_ID_STATUS:
> > > + break;
> > > +
> > > + default:
> > > + break;
> > > + }
> > > + }
> > > +}
>
> [...]
>
> > > +static ssize_t s6sy761_sysfs_low_power_store(struct device *dev,
> > > + struct device_attribute *attr,
> > > + const char *buf, size_t len)
> > > +{
> > > + struct s6sy761_data *sdata = dev_get_drvdata(dev);
> > > + unsigned long value;
> > > + s32 ret;
> > > + u8 new_status;
> > > +
> > > + if (kstrtoul(buf, 0, &value))
> > > + return -EINVAL;
> > > +
> > > + /*
> > > + * The device does not respond to read/write in low power,
> > > + * it will enable only in case of external events (e.g. touch).
> > > + * The i2c read will fail as expected if no external events occur
> > > + */
> >
> > I am not quite sure how to parse this. Are you saying that the device in
> > low power mode will wake up when touched? Then your runtime PM
> > implementation seems incomplete.
>
> I was startled as well when I saw this working. It cannot be in
> the PM runtime because the device would freeze (unless is
> touched). I don't know if it's a bug in the firmware or this is
> how it meant to be.
>
> > In any case, I'd rather we did not expose this state as a custom
> > attribute.
>
> I can remove it completely, indeed I don't see much use of it.
Great!
>
> [...]
>
> > > + sdata->devid = buffer[1] << 8 | buffer[2];
> >
> > get_unaligned_be16()?
>
> Thanks!
>
> [...]
>
> > > + /* check if both max_x and max_y have a value */
> > > + if (unlikely(!sdata->prop.max_x || !sdata->prop.max_y))
> >
> > This is not in hot path, we do not need unlikely() here.
>
> OK, Thanks!
>
> > > + return -EINVAL;
> > > +
> > > + /* if no tx channels defined, at least keep one */
> > > + sdata->tx_channel = !buffer[8] ? 1 : buffer[8];
> >
> > sdata->tx_channel = max(buffer[8], 1);
>
> Thanks!
>
> [...]
>
> > > +static int s6sy761_probe(struct i2c_client *client,
> > > + const struct i2c_device_id *id)
> > > +{
>
> [...]
>
> > > + err = devm_request_threaded_irq(&client->dev, client->irq, NULL,
> > > + s6sy761_irq_handler,
> > > + IRQF_TRIGGER_LOW | IRQF_ONESHOT,
> > > + "s6sy761_irq", sdata);
> > > + if (err)
> > > + return err;
> > > +
> > > + disable_irq(client->irq);
> >
> > Can you request IRQ after allocating and setting up the input device?
> > Then you do not need to check for its presence in the interrupt handler.
>
> The reason I do it here is because the x and y are embedded in
> the device itself. This means that I first need to enable the
> device, read x and y and then register the input device.
>
> At power up I might expect an interrupt coming, thus I need to
> check if 'input' is not 'NULL'.
But you do not need interrupts to read x and y, right? So you can power
device, create input device, set it up as needed, and then request irq,
or am I missing something?
Thanks.
--
Dmitry
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