Re: [PATCH 1/2] rtc: pcf2127: move watchdog initialisation to a separate function

From: Bruno Thomsen
Date: Sun Sep 27 2020 - 03:51:15 EST


Den tor. 24. sep. 2020 kl. 12.53 skrev Uwe Kleine-König
<u.kleine-koenig@xxxxxxxxxxxxxx>:
>
> The obvious advantages are:
>
> - The linker can drop the watchdog functions if CONFIG_WATCHDOG is off.
> - All watchdog stuff grouped together with only a single function call
> left in generic code.
> - Watchdog register is only read when it is actually used.
> - Less #ifdefery
>
> Signed-off-by: Uwe Kleine-König <u.kleine-koenig@xxxxxxxxxxxxxx>
> ---
> drivers/rtc/rtc-pcf2127.c | 56 ++++++++++++++++++++++-----------------
> 1 file changed, 31 insertions(+), 25 deletions(-)
>
> diff --git a/drivers/rtc/rtc-pcf2127.c b/drivers/rtc/rtc-pcf2127.c
> index ed6316992cbb..5b1f1949b5e5 100644
> --- a/drivers/rtc/rtc-pcf2127.c
> +++ b/drivers/rtc/rtc-pcf2127.c
> @@ -335,6 +335,36 @@ static const struct watchdog_ops pcf2127_watchdog_ops = {
> .set_timeout = pcf2127_wdt_set_timeout,
> };
>
> +static int pcf2127_watchdog_init(struct device *dev, struct pcf2127 *pcf2127)
> +{
> + u32 wdd_timeout;
> + int ret;
> +
> + if (!IS_ENABLED(CONFIG_WATCHDOG))
> + return 0;
> +
> + pcf2127->wdd.parent = dev;
> + pcf2127->wdd.info = &pcf2127_wdt_info;
> + pcf2127->wdd.ops = &pcf2127_watchdog_ops;
> + pcf2127->wdd.min_timeout = PCF2127_WD_VAL_MIN;
> + pcf2127->wdd.max_timeout = PCF2127_WD_VAL_MAX;
> + pcf2127->wdd.timeout = PCF2127_WD_VAL_DEFAULT;
> + pcf2127->wdd.min_hw_heartbeat_ms = 500;
> + pcf2127->wdd.status = WATCHDOG_NOWAYOUT_INIT_STATUS;
> +
> + watchdog_set_drvdata(&pcf2127->wdd, pcf2127);
> +
> + /* Test if watchdog timer is started by bootloader */
> + ret = regmap_read(pcf2127->regmap, PCF2127_REG_WD_VAL, &wdd_timeout);
> + if (ret)
> + return ret;
> +
> + if (wdd_timeout)
> + set_bit(WDOG_HW_RUNNING, &pcf2127->wdd.status);
> +
> + return devm_watchdog_register_device(dev, &pcf2127->wdd);
> +}
> +
> /* Alarm */
> static int pcf2127_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
> {
> @@ -536,7 +566,6 @@ static int pcf2127_probe(struct device *dev, struct regmap *regmap,
> int alarm_irq, const char *name, bool has_nvmem)
> {
> struct pcf2127 *pcf2127;
> - u32 wdd_timeout;
> int ret = 0;
>
> dev_dbg(dev, "%s\n", __func__);
> @@ -575,17 +604,6 @@ static int pcf2127_probe(struct device *dev, struct regmap *regmap,
> pcf2127->rtc->ops = &pcf2127_rtc_alrm_ops;
> }
>
> - pcf2127->wdd.parent = dev;
> - pcf2127->wdd.info = &pcf2127_wdt_info;
> - pcf2127->wdd.ops = &pcf2127_watchdog_ops;
> - pcf2127->wdd.min_timeout = PCF2127_WD_VAL_MIN;
> - pcf2127->wdd.max_timeout = PCF2127_WD_VAL_MAX;
> - pcf2127->wdd.timeout = PCF2127_WD_VAL_DEFAULT;
> - pcf2127->wdd.min_hw_heartbeat_ms = 500;
> - pcf2127->wdd.status = WATCHDOG_NOWAYOUT_INIT_STATUS;
> -
> - watchdog_set_drvdata(&pcf2127->wdd, pcf2127);
> -
> if (has_nvmem) {
> struct nvmem_config nvmem_cfg = {
> .priv = pcf2127,
> @@ -615,19 +633,7 @@ static int pcf2127_probe(struct device *dev, struct regmap *regmap,
> return ret;
> }
>
> - /* Test if watchdog timer is started by bootloader */
> - ret = regmap_read(pcf2127->regmap, PCF2127_REG_WD_VAL, &wdd_timeout);
> - if (ret)
> - return ret;
> -
> - if (wdd_timeout)
> - set_bit(WDOG_HW_RUNNING, &pcf2127->wdd.status);
> -
> -#ifdef CONFIG_WATCHDOG
> - ret = devm_watchdog_register_device(dev, &pcf2127->wdd);
> - if (ret)
> - return ret;
> -#endif /* CONFIG_WATCHDOG */
> + pcf2127_watchdog_init(dev, pcf2127);

The code refactoring seems like a good idea Uwe, but the new
pcf2127_watchdog_init() is not a void function. If the return
value is not handled, it will change driver behavior. Correct
handling should look like this:

ret = pcf2127_watchdog_init(dev, pcf2127);
if (ret)
return ret;

/Bruno

> /*
> * Disable battery low/switch-over timestamp and interrupts.
> --
> 2.28.0
>