linux-kernel - Re: [PATCH v2 6/9] watchdog: st_wdt: Add new driver for ST's LPC Watchdog

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Message-ID: <20150122172100.GF9129@x1>
Date:	Thu, 22 Jan 2015 17:21:00 +0000
From:	Lee Jones <lee.jones@...aro.org>
To:	Guenter Roeck <linux@...ck-us.net>
Cc:	linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
	kernel@...inux.com, rtc-linux@...glegroups.com, wim@...ana.be,
	linux-watchdog@...r.kernel.org, devicetree@...r.kernel.org,
	david.paris@...com
Subject: Re: [PATCH v2 6/9] watchdog: st_wdt: Add new driver for ST's LPC
 Watchdog

On Thu, 22 Jan 2015, Guenter Roeck wrote:

> On 01/22/2015 03:56 AM, Lee Jones wrote:
> >Signed-off-by: David Paris <david.paris@...com>
> >Signed-off-by: Lee Jones <lee.jones@...aro.org>
> >---
> >  drivers/watchdog/Kconfig      |  13 ++
> >  drivers/watchdog/Makefile     |   1 +
> >  drivers/watchdog/st_lpc_wdt.c | 335 ++++++++++++++++++++++++++++++++++++++++++
> >  3 files changed, 349 insertions(+)
> >  create mode 100644 drivers/watchdog/st_lpc_wdt.c

[...]

> >+struct st_wdog_syscfg {
> >+	struct regmap *regmap;
> 
> Hi David & Lee,
> 
> Why did you add the regmap pointer to this structure and not to st_wdog ?
> It is not a configuration value, after all, and it is always dereferenced
> through wt_wdog->syscfg. So all it does is to make the code more complicated.
> 
> Am I missing something ?

I guess it was just to group it all together, as it will all be used
at the same time:

	regmap_update_bits(st_wdog->syscfg->regmap,
			   st_wdog->syscfg->reset_type_reg,
			   st_wdog->syscfg->reset_type_mask,
			   st_wdog->warm_reset);

It really doesn't matter to me either way.

> >+	unsigned int reset_type_reg;
> >+	unsigned int reset_type_mask;
> >+	unsigned int enable_reg;
> >+	unsigned int enable_mask;
> >+};
> >+
> >+struct st_wdog {
> >+	void __iomem *base;
> >+	struct device *dev;
> >+	struct st_wdog_syscfg *syscfg;
> >+	struct clk *clk;
> >+	unsigned long clkrate;
> >+	bool warm_reset;
> >+};

[...]

> >+static int st_wdog_probe(struct platform_device *pdev)
> >+{
> >+	const struct of_device_id *match;
> >+	struct device_node *np = pdev->dev.of_node;
> >+	struct st_wdog *st_wdog;
> >+	struct regmap *regmap;
> >+	struct resource *res;
> >+	struct clk *clk;
> >+	void __iomem *base;
> >+	uint32_t mode;
> >+	int ret;
> >+
> >+	ret = of_property_read_u32(np, "st,lpc-mode", &mode);
> >+	if (ret) {
> >+		dev_err(&pdev->dev, "An LPC mode must be provided\n");
> >+		return -EINVAL;
> >+	}
> >+
> >+	/* LPC can either run in RTC or WDT mode */
> >+	if (mode != ST_LPC_MODE_WDT)
> >+		return -ENODEV;
> >+
> >+	st_wdog = devm_kzalloc(&pdev->dev, sizeof(*st_wdog), GFP_KERNEL);
> >+	if (!st_wdog)
> >+		return -ENOMEM;
> >+
> >+	match = of_match_device(st_wdog_match, &pdev->dev);
> >+	if (!match) {
> >+		dev_err(&pdev->dev, "Couldn't match device\n");
> >+		return -ENODEV;
> >+	}
> >+	st_wdog->syscfg	= (struct st_wdog_syscfg *)match->data;
> >+
> >+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> >+	base = devm_ioremap_resource(&pdev->dev, res);
> >+	if (IS_ERR(base)) {
> >+		dev_err(&pdev->dev, "Failed to ioremap base\n");
> 
> devm_ioremap_resource already displays an error message, do this one is unnecessary.

You're right.  Will fix.

[...]

-- 
Lee Jones
Linaro STMicroelectronics Landing Team Lead
Linaro.org │ Open source software for ARM SoCs
Follow Linaro: Facebook | Twitter | Blog
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