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([2001:861:44c0:66c0:3c4f:78be:dc90:14f9]) by smtp.gmail.com with ESMTPSA id c8-20020a7bc848000000b0039c457cea21sm22409891wml.34.2022.07.05.07.39.59 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 05 Jul 2022 07:40:00 -0700 (PDT) Message-ID: Date: Tue, 5 Jul 2022 16:39:59 +0200 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.8.1 Subject: Re: [PATCH v1] watchdog: meson: keep running if already active Content-Language: en-US To: Philippe Boos , Wim Van Sebroeck , Guenter Roeck Cc: Kevin Hilman , Jerome Brunet , Martin Blumenstingl , linux-watchdog@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-amlogic@lists.infradead.org, linux-kernel@vger.kernel.org References: <20220705142444.17063-1-pboos@baylibre.com> From: Neil Armstrong Organization: Baylibre In-Reply-To: <20220705142444.17063-1-pboos@baylibre.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, On 05/07/2022 16:24, Philippe Boos wrote: > If the watchdog is already running (e.g.: started by bootloader) then > the kernel driver should keep the watchdog active but the amlogic driver > turns it off. > > Let the driver fix the clock rate then restart the watchdog if it was > previously active. > > Reviewed-by: Jerome Brunet Please drop this review tag since it was done off-list > Signed-off-by: Philippe Boos > --- > drivers/watchdog/meson_gxbb_wdt.c | 10 ++++++++++ > 1 file changed, 10 insertions(+) > > diff --git a/drivers/watchdog/meson_gxbb_wdt.c b/drivers/watchdog/meson_gxbb_wdt.c > index 5a9ca10fbcfa..8c2c6f7f3bb5 100644 > --- a/drivers/watchdog/meson_gxbb_wdt.c > +++ b/drivers/watchdog/meson_gxbb_wdt.c > @@ -146,6 +146,7 @@ static int meson_gxbb_wdt_probe(struct platform_device *pdev) > struct device *dev = &pdev->dev; > struct meson_gxbb_wdt *data; > int ret; > + u32 regval; > > data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL); > if (!data) > @@ -177,6 +178,8 @@ static int meson_gxbb_wdt_probe(struct platform_device *pdev) > data->wdt_dev.timeout = DEFAULT_TIMEOUT; > watchdog_set_drvdata(&data->wdt_dev, data); > > + regval = readl(data->reg_base + GXBB_WDT_CTRL_REG); > + > /* Setup with 1ms timebase */ > writel(((clk_get_rate(data->clk) / 1000) & GXBB_WDT_CTRL_DIV_MASK) | > GXBB_WDT_CTRL_EE_RESET | > @@ -186,6 +189,13 @@ static int meson_gxbb_wdt_probe(struct platform_device *pdev) > > meson_gxbb_wdt_set_timeout(&data->wdt_dev, data->wdt_dev.timeout); > > + if ((regval & GXBB_WDT_CTRL_EN) != 0) { > + ret = meson_gxbb_wdt_start(&data->wdt_dev); > + if (ret) > + return ret; > + set_bit(WDOG_HW_RUNNING, &data->wdt_dev.status); > + } > + > watchdog_stop_on_reboot(&data->wdt_dev); > return devm_watchdog_register_device(dev, &data->wdt_dev); > } I think it would be much claner to leave the watchdog enabled, and get the parameters from the registers and update the wdt_dev accordingly. Neil