Re: [PATCH v4 1/2] drivers: watchdog: add a driver to support SAMA5D4 watchdog timer

From: Guenter Roeck
Date: Thu Aug 06 2015 - 04:05:55 EST


On 08/05/2015 09:59 PM, Wenyou Yang wrote:
From SAMA5D4, the watchdog timer is upgrated with a new feature,
which is describled as in the datasheet, "WDT_MR can be written
until a LOCKMR command is issued in WDT_CR".
That is to say, as long as the bootstrap and u-boot don't issue
a LOCKMR command, WDT_MR can be written more than once in the driver.

So the SAMA5D4 watchdog driver's implementation is different from
the at91sam9260 watchdog driver implemented in file at91sam9_wdt.c.
The user application open the device file to enable the watchdog timer
hardware, and close to disable it, and set the watchdog timer timeout
by seting WDV and WDD fields of WDT_MR register, and ping the watchdog
by issuing WDRSTT command to WDT_CR register with hard-coded key.

Signed-off-by: Wenyou Yang <wenyou.yang@xxxxxxxxx>
---
[ ... ]
+
+/* minimum and maximum watchdog timeout, in seconds */
+#define MIN_WDT_TIMEOUT 1
+#define MAX_WDT_TIMEOUT 16
+#define WDT_DEFAULT_TIMEOUT MAX_WDT_TIMEOUT
+
+#define WDT_SEC2TICKS(s) ((s) ? (((s) << 8) - 1) : 0)
+

Why did you replace the spaces after #define with tabs ?
I understand this is done in the at91.h file, but that is bad enough,
it doesn't add any value, and I don't see a reason to do it here.

+
+ if ((wdt->config & AT91_WDT_WDFIEN) && irq) {
+ ret = devm_request_irq(&pdev->dev, irq, sama5d4_wdt_irq_handler,
+ 0, pdev->name, pdev);

I just realized - this interrupt is registered with flags set to 0,
while in the at91sam driver the flags are "IRQF_SHARED | IRQF_IRQPOLL |
IRQF_NO_SUSPEND". Is this different with the new SOC ?

Thanks,
Guenter

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