linux-kernel - Re: [PATCH 3/7] watchdog: npcm: Enable clock if provided

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Date:   Fri, 22 Apr 2022 11:34:17 -0700
From:   Guenter Roeck <linux@...ck-us.net>
To:     Jonathan Neuschäfer <j.neuschaefer@....net>
Cc:     linux-clk@...r.kernel.org, openbmc@...ts.ozlabs.org,
        linux-kernel@...r.kernel.org, linux-watchdog@...r.kernel.org,
        devicetree@...r.kernel.org,
        Michael Turquette <mturquette@...libre.com>,
        Stephen Boyd <sboyd@...nel.org>,
        Rob Herring <robh+dt@...nel.org>,
        Krzysztof Kozlowski <krzk+dt@...nel.org>,
        Avi Fishman <avifishman70@...il.com>,
        Tomer Maimon <tmaimon77@...il.com>,
        Tali Perry <tali.perry1@...il.com>,
        Patrick Venture <venture@...gle.com>,
        Nancy Yuen <yuenn@...gle.com>,
        Benjamin Fair <benjaminfair@...gle.com>,
        Daniel Lezcano <daniel.lezcano@...aro.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        Philipp Zabel <p.zabel@...gutronix.de>,
        Wim Van Sebroeck <wim@...ux-watchdog.org>
Subject: Re: [PATCH 3/7] watchdog: npcm: Enable clock if provided

On Fri, Apr 22, 2022 at 08:30:08PM +0200, Jonathan Neuschäfer wrote:
> On the Nuvoton WPCM450 SoC, with its upcoming clock driver, peripheral
> clocks are individually gated and ungated. Therefore, the watchdog
> driver must be able to ungate the watchdog clock.
> 
> Signed-off-by: Jonathan Neuschäfer <j.neuschaefer@....net>
> ---
>  drivers/watchdog/npcm_wdt.c | 9 +++++++++
>  1 file changed, 9 insertions(+)
> 
> diff --git a/drivers/watchdog/npcm_wdt.c b/drivers/watchdog/npcm_wdt.c
> index 28a24caa2627c..6d27f0e16188e 100644
> --- a/drivers/watchdog/npcm_wdt.c
> +++ b/drivers/watchdog/npcm_wdt.c
> @@ -3,6 +3,7 @@
>  // Copyright (c) 2018 IBM Corp.
> 
>  #include <linux/bitops.h>
> +#include <linux/clk.h>
>  #include <linux/delay.h>
>  #include <linux/interrupt.h>
>  #include <linux/kernel.h>
> @@ -180,6 +181,7 @@ static int npcm_wdt_probe(struct platform_device *pdev)
>  {
>  	struct device *dev = &pdev->dev;
>  	struct npcm_wdt *wdt;
> +	struct clk *clk;
>  	int irq;
>  	int ret;
> 
> @@ -191,6 +193,13 @@ static int npcm_wdt_probe(struct platform_device *pdev)
>  	if (IS_ERR(wdt->reg))
>  		return PTR_ERR(wdt->reg);
> 
> +	clk = devm_clk_get_optional(&pdev->dev, NULL);
> +	if (IS_ERR(clk))
> +		return PTR_ERR(clk);
> +
> +	if (clk)
> +		clk_prepare_enable(clk);
> +

This needs a matching clk_disable_unprepare().

Guenter