On Wed, Jun 24, 2020 at 12:04:24PM +0000, Roy Im wrote:

Hello Uwe,

On Tue, June 23, 2020 11:41 PM, Uwe Kleine-König wrote:

quoted

Hello,

On Mon, Jun 15, 2020 at 08:40:23PM +0900, Roy Im wrote:

quoted

Adds support for the Dialog DA7280 LRA/ERM Haptic Driver with multiple
mode and integrated waveform memory and wideband support.
It communicates via an I2C bus to the device.

Signed-off-by: Roy Im <redacted>

Just some picky comments below.

quoted

+	error = pwm_apply_state(haptics->pwm_dev, &state);
+	if (error)
+		dev_err(haptics->dev,
+			"failed to apply pwm state: %pE\n",
+			ERR_PTR(error));

You can save some horizontal space here by dropping the \n after the first comma. (There are a few more occurences.)

Ok, is this what you want?
	error = pwm_apply_state(haptics->pwm_dev, &state);
	if (error)
		dev_err(haptics->dev, "failed to apply pwm state: %pE\n",
			ERR_PTR(error));

Yes, that's what I meant.

quoted

quoted

+	return error;
+}
+[...]
+
+		/* Sync up PWM state and ensure it is off. */
+		pwm_init_state(haptics->pwm_dev, &state);
+		state.enabled = false;
+		error = pwm_apply_state(haptics->pwm_dev, &state);
+		if (error) {
+			dev_err(dev,
+				"failed to apply initial PWM state: %pE\n",
+				ERR_PTR(error));
+			return error;
+		}
+
+		/* Check PWM Period, it must be in 10k ~ 250kHz */

The unit of a PWM period is in (nano)seconds, to it cannot be in the range [10kHz, 250kHz]. (Is this too picky?)

No, it isn't. The 'Period' should be changed to 'frequency', I will fix this as below.

		/* Check PWM frequency, valid range: 10k ~ 250kHz */

Much better.

quoted

quoted

+		period2freq = 1000000 / state.period;
+		if (period2freq < DA7280_MIN_PWM_FREQ_KHZ ||
+		    period2freq > DA7280_MAX_PWM_FREQ_KHZ) {
+			dev_err(dev, "Not supported PWM frequency(%d)\n",
+				period2freq);

Doesn't the compiler warn here about period2freq being unsigned and %d being for signed int values?

For my (non-native) English ear s/Not supported/Unsupported/ sounds better. Also my eyes would be pleases by a space
before the opening brace.

I didn't see any warning message, but I will change/improve them to proper one and the log as below.

		period2freq = 1000000 / state.period;
		if (period2freq < DA7280_MIN_PWM_FREQ_KHZ ||
		    period2freq > DA7280_MAX_PWM_FREQ_KHZ) {
			dev_err(dev, "Unsupported PWM frequency (%u)\n",
				period2freq);
			return -EINVAL;
		}
If you look ok, let me update this so.

looks fine.

Note that you don't need the division if you check for:

	if (state.period > 100000 || state.period < 4000) {
		...

(maybe the compiler is already clever enough to get rid of the division
for you, but then the check is:

	if (state.period > 100000 || state.period < 3985) {
	
because of rounding errors.)

Best regards
Uwe

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Pengutronix e.K.                           | Uwe Kleine-König            |
Industrial Linux Solutions                 | https://www.pengutronix.de/ |