Hi Andi,

On Fri, Sep 22, 2017 at 01:17:02PM +0900, Andi Shyti wrote:

Hi Dmitry,

thanks for your review!

[...]

quoted

quoted

+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...

[...]

quoted

quoted

+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?

quoted

quoted

+		switch (event_id) {
+
+		case S6SY761_EVENT_ID_COORDINATE:
+			s6sy761_handle_coordinates(sdata, event);
+			break;
+
+		case S6SY761_EVENT_ID_STATUS:
+			break;
+
+		default:
+			break;
+		}
+	}
+}

[...]

quoted

quoted

+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.

quoted

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!

[...]

quoted

quoted

+	sdata->devid = buffer[1] << 8 | buffer[2];

	get_unaligned_be16()?

Thanks!

[...]

quoted

quoted

+	/* 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!

quoted

quoted

+		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!

[...]

quoted

quoted

+static int s6sy761_probe(struct i2c_client *client,
+			const struct i2c_device_id *id)
+{

[...]

quoted

quoted

+	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
--
To unsubscribe from this list: send the line "unsubscribe devicetree" in
the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html