Hi Guenter,

Thank you for your comments again,
Here are my responses.

Regards,
Steve

On 15 May 2015 03:13, Guenter Roeck 

Subject: Re: [PATCH V2 3/4] watchdog: da9062: DA9062 watchdog driver

[...]

quoted

+static void da9062_apply_window_protection(struct da9062_watchdog

*wdt)

quoted

+{
+	unsigned long delay =

msecs_to_jiffies(DA9062_RESET_PROTECTION_MS);

quoted

+	unsigned long timeout = wdt->j_time_stamp + delay;
+	unsigned long now = jiffies;
+	unsigned int diff_ms;
+
+	/* if time-limit has not elapsed then wait for remainder */
+	if (time_before(now, timeout)) {
+		diff_ms = jiffies_to_msecs(timeout-now);
+		dev_dbg(wdt->hw->dev,
+			"Kicked too quickly. Delaying %u msecs\n", diff_ms);
+		msleep(diff_ms);
+	}
+
+	return;

Unnecessary return statement.

Deleted.

quoted

+static unsigned int da9062_wdt_timeout_to_sel(unsigned int secs)
+{
+	unsigned int i;
+
+	for (i = DA9062_TWDSCALE_MIN; i <= DA9062_TWDSCALE_MAX; i++) {
+		if (wdt_timeout[i] >= secs)
+			return i;
+	}
+
+	return DA9062_TWDSCALE_MAX;
+}
+
+static int da9062_reset_watchdog_timer(struct da9062_watchdog *wdt)
+{
+	int ret;
+
+	da9062_apply_window_protection(wdt);
+
+	ret = regmap_update_bits(wdt->hw->regmap,
+			   DA9062AA_CONTROL_F,
+			   DA9062AA_WATCHDOG_MASK,
+			   DA9062AA_WATCHDOG_MASK);
+
+	da9062_set_window_start(wdt);
+
+	return ret;
+}
+
+static int da9062_wdt_update_timeout_register(struct da9062_watchdog *wdt,
+					      unsigned int regval)
+{
+	struct da9062 *chip = wdt->hw;
+	int ret;
+
+	ret = da9062_reset_watchdog_timer(wdt);
+	if (ret) {
+		dev_err(chip->dev, "Failed to ping the watchdog (err = %d)\n",
+			ret);

I am kind of torn about all this noisiness on error. Personally I would tend to
ask people to let user space handle it, and not be that noisy in the kernel.

Wim, any guidance ?

At the time I thought it would be a really good idea to keep a debug message in. 
But -- this has been questioned several times and so I will remove.

quoted

+		return ret;
+	}
+
+	return regmap_update_bits(chip->regmap,
+				  DA9062AA_CONTROL_D,
+				  DA9062AA_TWDSCALE_MASK,
+				  regval);

... and it is inconsistent - no error message here.

Removed the dev_err() defined previously and therefore this makes this return
without an error message more consistent with the earlier parts of the function.
(no change needed)

 [...]

quoted

+static int da9062_wdt_stop(struct watchdog_device *wdd)
+{
+	struct da9062_watchdog *wdt = watchdog_get_drvdata(wdd);
+	int ret;
+
+	ret = da9062_reset_watchdog_timer(wdt);
+	if (ret) {
+		dev_err(wdt->hw->dev, "Failed to ping the watchdog (err =

%d)\n",

quoted

+			ret);
+		return ret;
+	}
+
+	ret = regmap_update_bits(wdt->hw->regmap,
+				 DA9062AA_CONTROL_D,
+				 DA9062AA_TWDSCALE_MASK,
+				 DA9062_TWDSCALE_DISABLE);
+	if (ret)
+		dev_alert(wdt->hw->dev, "Watchdog failed to stop (err =

%d)\n",

quoted

+			  ret);

.. and now we have an alert. Hmm..

.. I've replaced it with a dev_err()

quoted

+
+	return ret;
+}
+
+static int da9062_wdt_ping(struct watchdog_device *wdd)
+{
+	struct da9062_watchdog *wdt = watchdog_get_drvdata(wdd);
+	int ret;
+
+	dev_dbg(wdt->hw->dev, "watchdog ping\n");
+

Is this really valuable enough to keep in the code ?

Removed also.

quoted

+	ret = da9062_reset_watchdog_timer(wdt);
+	if (ret)
+		dev_err(wdt->hw->dev, "Failed to ping the watchdog (err =

%d)\n",

quoted

+			ret);
+
+	return ret;
+}
+

[...]

quoted

+
+/* E_WDG_WARN interrupt handler */
+static irqreturn_t da9062_wdt_wdg_warn_irq_handler(int irq, void *data)
+{
+	struct da9062_watchdog *wdt = data;
+
+	dev_notice(wdt->hw->dev, "Watchdog timeout warning trigger.\n");
+	return IRQ_HANDLED;
+}
+

[...]

quoted

+static int da9062_wdt_probe(struct platform_device *pdev)
+{
+	int ret;
+	struct da9062 *chip;
+	struct da9062_watchdog *wdt;
+	int irq;
+
+	chip = dev_get_drvdata(pdev->dev.parent);
+	if (!chip)
+		return -EINVAL;
+
+	wdt = devm_kzalloc(&pdev->dev, sizeof(*wdt), GFP_KERNEL);
+	if (!wdt)
+		return -ENOMEM;
+
+	wdt->hw = chip;
+
+	wdt->wdtdev.info = &da9062_watchdog_info;
+	wdt->wdtdev.ops = &da9062_watchdog_ops;
+	wdt->wdtdev.min_timeout = DA9062_WDT_MIN_TIMEOUT;
+	wdt->wdtdev.max_timeout = DA9062_WDT_MAX_TIMEOUT;
+	wdt->wdtdev.timeout = DA9062_WDG_DEFAULT_TIMEOUT;
+	wdt->wdtdev.status = WATCHDOG_NOWAYOUT_INIT_STATUS;
+
+	watchdog_set_drvdata(&wdt->wdtdev, wdt);
+	dev_set_drvdata(&pdev->dev, wdt);
+
+	irq = platform_get_irq_byname(pdev, "WDG_WARN");
+	if (irq < 0) {
+		dev_err(wdt->hw->dev, "Failed to get IRQ.\n");
+		ret = irq;
+		goto error;

Just return; the label does not serve a useful purpose. Same for the other
goto statements below.

Agreed. This is changed now.

Also, is the interrupt mandatory ? All it does is to display a message.
Looks very optional to me.

It is a place holder for something more application specific. 
I could remove it, but I figured it would just get re-added when somebody takes the
driver and modifies it for their needs.

If this is a problem however, it can go.
Please advise ..

quoted

+	}
+
+	ret = devm_request_threaded_irq(&pdev->dev, irq, NULL,
+			   da9062_wdt_wdg_warn_irq_handler,
+			    IRQF_TRIGGER_LOW | IRQF_ONESHOT |

IRQF_SHARED,

quoted

+			   "WDG_WARN", wdt);
+	if (ret) {
+		dev_err(wdt->hw->dev,
+			"Failed to request watchdog device IRQ.\n");
+		goto error;
+	}
+
+	ret = watchdog_register_device(&wdt->wdtdev);
+	if (ret < 0) {
+		dev_err(wdt->hw->dev,
+			"watchdog registration incomplete (%d)\n", ret);

incomplete ? Should that be "failed" ?

Sure. Changed the dev_err()

[...]

quoted

+static struct platform_driver da9062_wdt_driver = {
+	.probe = da9062_wdt_probe,
+	.remove = da9062_wdt_remove,
+	.driver = {
+		.name = "da9062-watchdog",
+	},
+};
+module_platform_driver(da9062_wdt_driver);
+
+MODULE_AUTHOR("S Twiss [off-list ref]");
+MODULE_DESCRIPTION("WDT device driver for Dialog DA9062");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform: da9062-watchdog");

Normally I don't see a space between "platform" and the driver name.
Does this work ?

Removed the space

Regards,
Steve