From: Guenter Roeck <linux@roeck-us.net>
To: Paul Cercueil <paul@crapouillou.net>
Cc: Wim Van Sebroeck <wim@linux-watchdog.org>,
od@zcrc.me, linux-watchdog@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/4] watchdog: jz4740: Avoid starting watchdog in set_timeout
Date: Tue, 28 May 2019 12:27:02 -0700 [thread overview]
Message-ID: <20190528192702.GB24853@roeck-us.net> (raw)
In-Reply-To: <20190521155313.19326-2-paul@crapouillou.net>
On Tue, May 21, 2019 at 05:53:11PM +0200, Paul Cercueil wrote:
> Previously the jz4740_wdt_set_timeout() function was starting the timer
> unconditionally, even if it was stopped when that function was entered.
>
> Now, the timer will be restarted only if it was already running before
> this function is called.
>
> Signed-off-by: Paul Cercueil <paul@crapouillou.net>
Comment inline, but not worth a respin (and I don't have a good idea how to
improve it).
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
> ---
> drivers/watchdog/jz4740_wdt.c | 7 ++++++-
> 1 file changed, 6 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/watchdog/jz4740_wdt.c b/drivers/watchdog/jz4740_wdt.c
> index 51be321c775a..f970a7a53084 100644
> --- a/drivers/watchdog/jz4740_wdt.c
> +++ b/drivers/watchdog/jz4740_wdt.c
> @@ -77,6 +77,7 @@ static int jz4740_wdt_set_timeout(struct watchdog_device *wdt_dev,
> unsigned int rtc_clk_rate;
> unsigned int timeout_value;
> unsigned short clock_div = JZ_WDT_CLOCK_DIV_1;
> + u8 tcer;
>
> rtc_clk_rate = clk_get_rate(drvdata->rtc_clk);
>
> @@ -92,6 +93,7 @@ static int jz4740_wdt_set_timeout(struct watchdog_device *wdt_dev,
> clock_div += (1 << TCU_TCSR_PRESCALE_LSB);
> }
>
> + tcer = readb(drvdata->base + TCU_REG_WDT_TCER);
> writeb(0x0, drvdata->base + TCU_REG_WDT_TCER);
> writew(clock_div, drvdata->base + TCU_REG_WDT_TCSR);
>
> @@ -99,7 +101,7 @@ static int jz4740_wdt_set_timeout(struct watchdog_device *wdt_dev,
> writew(0x0, drvdata->base + TCU_REG_WDT_TCNT);
> writew(clock_div | JZ_WDT_CLOCK_RTC, drvdata->base + TCU_REG_WDT_TCSR);
>
> - writeb(0x1, drvdata->base + TCU_REG_WDT_TCER);
> + writeb(tcer & TCU_WDT_TCER_TCEN, drvdata->base + TCU_REG_WDT_TCER);
This unnecessarily writes 0 if the timer is not running.
>
> wdt_dev->timeout = new_timeout;
> return 0;
> @@ -107,8 +109,11 @@ static int jz4740_wdt_set_timeout(struct watchdog_device *wdt_dev,
>
> static int jz4740_wdt_start(struct watchdog_device *wdt_dev)
> {
> + struct jz4740_wdt_drvdata *drvdata = watchdog_get_drvdata(wdt_dev);
> +
> jz4740_timer_enable_watchdog();
> jz4740_wdt_set_timeout(wdt_dev, wdt_dev->timeout);
> + writeb(TCU_WDT_TCER_TCEN, drvdata->base + TCU_REG_WDT_TCER);
This unnecessarily enables the timer even if it is already enabled (that should not
happen, but does if the watchdog is already running at boot).
>
> return 0;
> }
> --
> 2.21.0.593.g511ec345e18
>
next prev parent reply other threads:[~2019-05-28 19:27 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-05-21 15:53 [PATCH 1/4] watchdog: jz4740: Use register names from <linux/mfd/ingenic-tcu.h> Paul Cercueil
2019-05-21 15:53 ` [PATCH 2/4] watchdog: jz4740: Avoid starting watchdog in set_timeout Paul Cercueil
2019-05-28 19:27 ` Guenter Roeck [this message]
2019-05-21 15:53 ` [PATCH 3/4] watchdog: jz4740: Drop dependency on MACH_JZ47xx Paul Cercueil
2019-05-28 19:36 ` Guenter Roeck
2019-05-21 15:53 ` [PATCH 4/4] watchdog: jz4740: Switch to SPDX license identifier Paul Cercueil
2019-05-28 19:37 ` Guenter Roeck
2019-05-28 18:11 ` [PATCH 1/4] watchdog: jz4740: Use register names from <linux/mfd/ingenic-tcu.h> Guenter Roeck
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