Re: [PATCH V4 2/4] watchdog: stm32: add pclk feature for stm32mp1

[Ludovic BARRE <ludovic.barre@xxxxxx>]

On 06/21/2018 06:53 PM, Guenter Roeck wrote:
> On Thu, Jun 21, 2018 at 11:02:15AM +0200, Ludovic Barre wrote:
> > From: Ludovic Barre <ludovic.barre@xxxxxx>
> >
> > This patch adds compatible data to manage pclk clock by
> > compatible. Adds stm32mp1 support which requires pclk clock.
> >
> > Signed-off-by: Ludovic Barre <ludovic.barre@xxxxxx>
> > ---
> >   drivers/watchdog/stm32_iwdg.c | 116 +++++++++++++++++++++++++++---------------
> >   1 file changed, 74 insertions(+), 42 deletions(-)
> >
> > diff --git a/drivers/watchdog/stm32_iwdg.c b/drivers/watchdog/stm32_iwdg.c
> > index c97ad56..e00e3b3 100644
> > --- a/drivers/watchdog/stm32_iwdg.c
> > +++ b/drivers/watchdog/stm32_iwdg.c
> > @@ -11,12 +11,13 @@
> >   
> >   #include <linux/clk.h>
> >   #include <linux/delay.h>
> > -#include <linux/kernel.h>
> > -#include <linux/module.h>
> >   #include <linux/interrupt.h>
> >   #include <linux/io.h>
> >   #include <linux/iopoll.h>
> > +#include <linux/kernel.h>
> > +#include <linux/module.h>
> >   #include <linux/of.h>
> > +#include <linux/of_device.h>
> >   #include <linux/platform_device.h>
> >   #include <linux/watchdog.h>
> >   
> > @@ -54,11 +55,15 @@
> >   #define TIMEOUT_US	100000
> >   #define SLEEP_US	1000
> >   
> > +#define HAS_PCLK	true
> > +
> >   struct stm32_iwdg {
> >   	struct watchdog_device	wdd;
> >   	void __iomem		*regs;
> > -	struct clk		*clk;
> > +	struct clk		*clk_lsi;
> > +	struct clk		*clk_pclk;
> >   	unsigned int		rate;
> > +	bool			has_pclk;
> >   };
> >   
> >   static inline u32 reg_read(void __iomem *base, u32 reg)
> > @@ -133,6 +138,44 @@ static int stm32_iwdg_set_timeout(struct watchdog_device *wdd,
> >   	return 0;
> >   }
> >   
> > +static int stm32_iwdg_clk_init(struct platform_device *pdev,
> > +			       struct stm32_iwdg *wdt)
> > +{
> > +	u32 ret;
> > +
> > +	wdt->clk_lsi = devm_clk_get(&pdev->dev, "lsi");
>
> I just noticed a subtle difference: This used to be
> 			devm_clk_get(&pdev->dev, NULL);
> which would always get the first clock, no matter how it is named.
> Can that cause problems with backward compatibility ?

You are right Guenter.

When there are multiple clocks, I prefer to use name interface.
I find it easier to use, and avoid misunderstanding.

Today, only one "dtsi" define the watchdog and it's disabled
(stm32f429.dtsi). I think it's good moment to move to clock named
(before it is used anymore).

But you are right I forgot to change stm32f429.dtsi.
If I add a commit for stm32f429.dtsi, it's Ok for you ?

BR
Ludo

> Thanks,
> Guenter
>
> > +	if (IS_ERR(wdt->clk_lsi)) {
> > +		dev_err(&pdev->dev, "Unable to get lsi clock\n");
> > +		return PTR_ERR(wdt->clk_lsi);
> > +	}
> > +
> > +	/* optional peripheral clock */
> > +	if (wdt->has_pclk) {
> > +		wdt->clk_pclk = devm_clk_get(&pdev->dev, "pclk");
> > +		if (IS_ERR(wdt->clk_pclk)) {
> > +			dev_err(&pdev->dev, "Unable to get pclk clock\n");
> > +			return PTR_ERR(wdt->clk_pclk);
> > +		}
> > +
> > +		ret = clk_prepare_enable(wdt->clk_pclk);
> > +		if (ret) {
> > +			dev_err(&pdev->dev, "Unable to prepare pclk clock\n");
> > +			return ret;
> > +		}
> > +	}
> > +
> > +	ret = clk_prepare_enable(wdt->clk_lsi);
> > +	if (ret) {
> > +		dev_err(&pdev->dev, "Unable to prepare lsi clock\n");
> > +		clk_disable_unprepare(wdt->clk_pclk);
> > +		return ret;
> > +	}
> > +
> > +	wdt->rate = clk_get_rate(wdt->clk_lsi);
> > +
> > +	return 0;
> > +}
> > +
> >   static const struct watchdog_info stm32_iwdg_info = {
> >   	.options	= WDIOF_SETTIMEOUT |
> >   			  WDIOF_MAGICCLOSE |
> > @@ -147,49 +190,42 @@ static const struct watchdog_ops stm32_iwdg_ops = {
> >   	.set_timeout	= stm32_iwdg_set_timeout,
> >   };
> >   
> > +static const struct of_device_id stm32_iwdg_of_match[] = {
> > +	{ .compatible = "st,stm32-iwdg", .data = (void *)!HAS_PCLK },
> > +	{ .compatible = "st,stm32mp1-iwdg", .data = (void *)HAS_PCLK },
> > +	{ /* end node */ }
> > +};
> > +MODULE_DEVICE_TABLE(of, stm32_iwdg_of_match);
> > +
> >   static int stm32_iwdg_probe(struct platform_device *pdev)
> >   {
> >   	struct watchdog_device *wdd;
> > +	const struct of_device_id *match;
> >   	struct stm32_iwdg *wdt;
> >   	struct resource *res;
> > -	void __iomem *regs;
> > -	struct clk *clk;
> >   	int ret;
> >   
> > +	match = of_match_device(stm32_iwdg_of_match, &pdev->dev);
> > +	if (!match)
> > +		return -ENODEV;
> > +
> > +	wdt = devm_kzalloc(&pdev->dev, sizeof(*wdt), GFP_KERNEL);
> > +	if (!wdt)
> > +		return -ENOMEM;
> > +
> > +	wdt->has_pclk = match->data;
> > +
> >   	/* This is the timer base. */
> >   	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> > -	regs = devm_ioremap_resource(&pdev->dev, res);
> > -	if (IS_ERR(regs)) {
> > +	wdt->regs = devm_ioremap_resource(&pdev->dev, res);
> > +	if (IS_ERR(wdt->regs)) {
> >   		dev_err(&pdev->dev, "Could not get resource\n");
> > -		return PTR_ERR(regs);
> > +		return PTR_ERR(wdt->regs);
> >   	}
> >   
> > -	clk = devm_clk_get(&pdev->dev, NULL);
> > -	if (IS_ERR(clk)) {
> > -		dev_err(&pdev->dev, "Unable to get clock\n");
> > -		return PTR_ERR(clk);
> > -	}
> > -
> > -	ret = clk_prepare_enable(clk);
> > -	if (ret) {
> > -		dev_err(&pdev->dev, "Unable to prepare clock %p\n", clk);
> > +	ret = stm32_iwdg_clk_init(pdev, wdt);
> > +	if (ret)
> >   		return ret;
> > -	}
> > -
> > -	/*
> > -	 * Allocate our watchdog driver data, which has the
> > -	 * struct watchdog_device nested within it.
> > -	 */
> > -	wdt = devm_kzalloc(&pdev->dev, sizeof(*wdt), GFP_KERNEL);
> > -	if (!wdt) {
> > -		ret = -ENOMEM;
> > -		goto err;
> > -	}
> > -
> > -	/* Initialize struct stm32_iwdg. */
> > -	wdt->regs = regs;
> > -	wdt->clk = clk;
> > -	wdt->rate = clk_get_rate(clk);
> >   
> >   	/* Initialize struct watchdog_device. */
> >   	wdd = &wdt->wdd;
> > @@ -217,7 +253,8 @@ static int stm32_iwdg_probe(struct platform_device *pdev)
> >   
> >   	return 0;
> >   err:
> > -	clk_disable_unprepare(clk);
> > +	clk_disable_unprepare(wdt->clk_lsi);
> > +	clk_disable_unprepare(wdt->clk_pclk);
> >   
> >   	return ret;
> >   }
> > @@ -227,23 +264,18 @@ static int stm32_iwdg_remove(struct platform_device *pdev)
> >   	struct stm32_iwdg *wdt = platform_get_drvdata(pdev);
> >   
> >   	watchdog_unregister_device(&wdt->wdd);
> > -	clk_disable_unprepare(wdt->clk);
> > +	clk_disable_unprepare(wdt->clk_lsi);
> > +	clk_disable_unprepare(wdt->clk_pclk);
> >   
> >   	return 0;
> >   }
> >   
> > -static const struct of_device_id stm32_iwdg_of_match[] = {
> > -	{ .compatible = "st,stm32-iwdg" },
> > -	{ /* end node */ }
> > -};
> > -MODULE_DEVICE_TABLE(of, stm32_iwdg_of_match);
> > -
> >   static struct platform_driver stm32_iwdg_driver = {
> >   	.probe		= stm32_iwdg_probe,
> >   	.remove		= stm32_iwdg_remove,
> >   	.driver = {
> >   		.name	= "iwdg",
> > -		.of_match_table = stm32_iwdg_of_match,
> > +		.of_match_table = of_match_ptr(stm32_iwdg_of_match),
> >   	},
> >   };
> >   module_platform_driver(stm32_iwdg_driver);
> > --
> > 2.7.4
> >
> > --
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