linux-kernel - Re: [PATCH 1/2] power: reset: at91: add sama5d3 reset function

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Date:	Fri, 10 Jul 2015 08:54:40 +0200
From:	Maxime Ripard <maxime.ripard@...e-electrons.com>
To:	Josh Wu <josh.wu@...el.com>
Cc:	Nicolas Ferre <nicolas.ferre@...el.com>,
	linux-arm-kernel@...ts.infradead.org,
	Guenter Roeck <linux@...ck-us.net>,
	Wei Yongjun <yongjun_wei@...ndmicro.com.cn>,
	Alexandre Belloni <alexandre.belloni@...e-electrons.com>,
	Ben Dooks <ben.dooks@...ethink.co.uk>,
	linux-kernel@...r.kernel.org,
	Krzysztof Kozlowski <k.kozlowski.k@...il.com>,
	Sebastian Reichel <sre@...nel.org>,
	Dmitry Eremin-Solenikov <dbaryshkov@...il.com>,
	David Woodhouse <dwmw2@...radead.org>,
	Fabian Frederick <fabf@...net.be>, linux-pm@...r.kernel.org
Subject: Re: [PATCH 1/2] power: reset: at91: add sama5d3 reset function

On Fri, Jul 10, 2015 at 11:06:52AM +0800, Josh Wu wrote:
> Hi, Maxime
> 
> On 7/9/2015 8:03 PM, Maxime Ripard wrote:
> >Hi,
> >
> >On Thu, Jul 09, 2015 at 06:15:46PM +0800, Josh Wu wrote:
> >>As since sama5d3, to reset the chip, we don't need to shutdown the ddr
> >>controller.
> >>
> >>So add a new compatible string and new restart function for sama5d3 and
> >>later chips. As we don't use sama5d3 ddr controller, so remove it as
> >>well.
> >>
> >>Signed-off-by: Josh Wu <josh.wu@...el.com>
> >>Acked-by: Nicolas Ferre <nicolas.ferre@...el.com>
> >>---
> >>
> >>  drivers/power/reset/at91-reset.c | 30 +++++++++++++++++++++---------
> >>  1 file changed, 21 insertions(+), 9 deletions(-)
> >>
> >>diff --git a/drivers/power/reset/at91-reset.c b/drivers/power/reset/at91-reset.c
> >>index 36dc52f..8944b63 100644
> >>--- a/drivers/power/reset/at91-reset.c
> >>+++ b/drivers/power/reset/at91-reset.c
> >>@@ -123,6 +123,14 @@ static int at91sam9g45_restart(struct notifier_block *this, unsigned long mode,
> >>  	return NOTIFY_DONE;
> >>  }
> >>+static int sama5d3_restart(struct notifier_block *this, unsigned long mode,
> >>+			void *cmd)
> >>+{
> >>+	writel(cpu_to_le32(AT91_RSTC_KEY | AT91_RSTC_PERRST | AT91_RSTC_PROCRST),
> >>+				at91_rstc_base);
> >>+	return NOTIFY_DONE;
> >>+}
> >>+
> >>  static void __init at91_reset_status(struct platform_device *pdev)
> >>  {
> >>  	u32 reg = readl(at91_rstc_base + AT91_RSTC_SR);
> >>@@ -155,13 +163,13 @@ static void __init at91_reset_status(struct platform_device *pdev)
> >>  static const struct of_device_id at91_ramc_of_match[] = {
> >>  	{ .compatible = "atmel,at91sam9260-sdramc", },
> >>  	{ .compatible = "atmel,at91sam9g45-ddramc", },
> >>-	{ .compatible = "atmel,sama5d3-ddramc", },
> >>  	{ /* sentinel */ }
> >>  };
> >>  static const struct of_device_id at91_reset_of_match[] = {
> >>  	{ .compatible = "atmel,at91sam9260-rstc", .data = at91sam9260_restart },
> >>  	{ .compatible = "atmel,at91sam9g45-rstc", .data = at91sam9g45_restart },
> >>+	{ .compatible = "atmel,sama5d3-rstc", .data = sama5d3_restart },
> >>  	{ /* sentinel */ }
> >>  };
> >>@@ -181,17 +189,21 @@ static int at91_reset_of_probe(struct platform_device *pdev)
> >>  		return -ENODEV;
> >>  	}
> >>-	for_each_matching_node(np, at91_ramc_of_match) {
> >>-		at91_ramc_base[idx] = of_iomap(np, 0);
> >>-		if (!at91_ramc_base[idx]) {
> >>-			dev_err(&pdev->dev, "Could not map ram controller address\n");
> >>-			return -ENODEV;
> >>+	match = of_match_node(at91_reset_of_match, pdev->dev.of_node);
> >>+	at91_restart_nb.notifier_call = match->data;
> >>+
> >>+	if (match->data != sama5d3_restart) {
> >Using of_device_is_compatible seems more appropriate.
> >
> >Also, why are you changing the order of this loop and the notifier
> >registration?
> 
> I moved this order because I use the match->data to compare whether is
> sama5d3_restart. So I need to move this function (of_match_node) up.

Ah right, my bad.

Still, testing against the kernel pointer is not that great.

It would be great to use something explicit instead, like
of_device_is_compatible.

Maxime

-- 
Maxime Ripard, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com

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