Re: [PATCH v4 2/2] watchdog: Add Renesas RZ/N1 Watchdog driver

From: Jean-Jacques Hiblot
Date: Fri Apr 01 2022 - 09:04:04 EST



On 31/03/2022 08:08, Tzung-Bi Shih wrote:
On Wed, Mar 30, 2022 at 12:08:29PM +0200, Jean-Jacques Hiblot wrote:
diff --git a/drivers/watchdog/rzn1_wdt.c b/drivers/watchdog/rzn1_wdt.c
[...]
+/*
+ * Renesas RZ/N1 Watchdog timer.
+ * This is a 12-bit timer driver from a (62.5/16384) MHz clock. It can't even
+ * cope with 2 seconds.
+ *
+ * Copyright 2018 Renesas Electronics Europe Ltd.
s/2018/2022/ ?
This driver wasn't written by me originally. So I'd rather not change this line.

+#define RZN1_WDT_RETRIGGER 0x0
+#define RZN1_WDT_RETRIGGER_RELOAD_VAL 0
+#define RZN1_WDT_RETRIGGER_RELOAD_VAL_MASK 0xfff
+#define RZN1_WDT_RETRIGGER_PRESCALE BIT(12)
+#define RZN1_WDT_RETRIGGER_ENABLE BIT(13)
+#define RZN1_WDT_RETRIGGER_WDSI (0x2 << 14)
Do RZN1_WDT_RETRIGGER_RELOAD_VAL and RZN1_WDT_RETRIGGER_WDSI get 1 more tab
indent intentionally?

+static const struct watchdog_device rzn1_wdt = {
+ .info = &rzn1_wdt_info,
+ .ops = &rzn1_wdt_ops,
+ .status = WATCHDOG_NOWAYOUT_INIT_STATUS,
+};
[...]
+static int rzn1_wdt_probe(struct platform_device *pdev)
+{
[...]
+ wdt->wdt = rzn1_wdt;
Does it really need to copy the memory? For example,

1. Use the memory in `wdt` directly and fill the `wdd`.

struct watchdog_device *wdd = &wdt->wdt;
wdd->info = &rzn1_wdt_info;
wdd->ops = &rzn1_wdt_ops;
...

2. Use drvdata instead of container_of().

Use watchdog_set_drvdata() in _probe and watchdog_get_drvdata() in the
watchdog ops to get struct rzn1_watchdog.
I'll rework this. Thanks for the review
+static const struct of_device_id rzn1_wdt_match[] = {
+ { .compatible = "renesas,rzn1-wdt" },
+ {},
+};
+MODULE_DEVICE_TABLE(of, rzn1_wdt_match);
Doesn't it need to guard by CONFIG_OF?

I don't think it has to.


+static struct platform_driver rzn1_wdt_driver = {
+ .probe = rzn1_wdt_probe,
+ .driver = {
+ .name = KBUILD_MODNAME,
+ .of_match_table = rzn1_wdt_match,
Does it makes more sense to use of_match_ptr()?

+ },
+};
+
+module_platform_driver(rzn1_wdt_driver);
To make it look like a whole thing, I prefer to remove the extra blank line
in between struct platform_driver and module_platform_driver().