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Subject: Re: [PATCH V2 1/3] watchdog: stm32: add pclk feature for stm32mp1
To:     Ludovic Barre <ludovic.Barre@st.com>,
        Wim Van Sebroeck <wim@linux-watchdog.org>,
        Rob Herring <robh+dt@kernel.org>
Cc:     Maxime Coquelin <mcoquelin.stm32@gmail.com>,
        Alexandre Torgue <alexandre.torgue@st.com>,
        linux-watchdog@vger.kernel.org,
        linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org,
        devicetree@vger.kernel.org
References: <1529481238-15277-1-git-send-email-ludovic.Barre@st.com>
 <1529481238-15277-2-git-send-email-ludovic.Barre@st.com>
From:   Guenter Roeck <linux@roeck-us.net>
Message-ID: <6162d701-2afd-5a22-d38f-7fb9e726cff7@roeck-us.net>
Date:   Wed, 20 Jun 2018 02:19:41 -0700
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On 06/20/2018 12:53 AM, Ludovic Barre wrote:
> From: Ludovic Barre <ludovic.barre@st.com>
> 
> This patch adds config data to manage specific properties by
> compatible. Adds stm32mp1 config which requires pclk clock.
> 
> Signed-off-by: Ludovic Barre <ludovic.barre@st.com>
> ---
>   .../devicetree/bindings/watchdog/st,stm32-iwdg.txt |  21 +++-
>   drivers/watchdog/stm32_iwdg.c                      | 132 ++++++++++++++-------
>   2 files changed, 104 insertions(+), 49 deletions(-)
> 
> diff --git a/Documentation/devicetree/bindings/watchdog/st,stm32-iwdg.txt b/Documentation/devicetree/bindings/watchdog/st,stm32-iwdg.txt
> index cc13b10a..f07f6d89 100644
> --- a/Documentation/devicetree/bindings/watchdog/st,stm32-iwdg.txt
> +++ b/Documentation/devicetree/bindings/watchdog/st,stm32-iwdg.txt
> @@ -2,18 +2,31 @@ STM32 Independent WatchDoG (IWDG)
>   ---------------------------------
>   
>   Required properties:
> -- compatible: "st,stm32-iwdg"
> -- reg: physical base address and length of the registers set for the device
> -- clocks: must contain a single entry describing the clock input
> +- compatible: Should be either "st,stm32-iwdg" or "st,stm32mp1-iwdg"
> +- reg: Physical base address and length of the registers set for the device
> +- clocks: Reference to the clock entry lsi. Additional pclk clock entry
> +  is required only for st,stm32mp1-iwdg.
> +- clock-names: Name of the clocks used.
> +  "lsi" for st,stm32-iwdg
> +  "pclk", "lsi" for st,stm32mp1-iwdg
>   
>   Optional Properties:
>   - timeout-sec: Watchdog timeout value in seconds.
>   
> -Example:
> +Examples:
>   
>   iwdg: watchdog@40003000 {
>   	compatible = "st,stm32-iwdg";
>   	reg = <0x40003000 0x400>;
>   	clocks = <&clk_lsi>;
> +	clock-names = "lsi";
> +	timeout-sec = <32>;
> +};
> +
> +iwdg: iwdg@5a002000 {
> +	compatible = "st,stm32mp1-iwdg";
> +	reg = <0x5a002000 0x400>;
> +	clocks = <&rcc IWDG2>, <&clk_lsi>;
> +	clock-names = "pclk", "lsi";
>   	timeout-sec = <32>;
>   };
> diff --git a/drivers/watchdog/stm32_iwdg.c b/drivers/watchdog/stm32_iwdg.c
> index c97ad56..fc96670 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 +55,17 @@
>   #define TIMEOUT_US	100000
>   #define SLEEP_US	1000
>   
> +struct stm32_iwdg_config {
> +	bool has_pclk;
> +};
> +

This data structure is unnecessary. Just assign the boolean directly to .data
and ...

>   struct stm32_iwdg {
> -	struct watchdog_device	wdd;
> -	void __iomem		*regs;
> -	struct clk		*clk;
> -	unsigned int		rate;
> +	struct watchdog_device		wdd;
> +	void __iomem			*regs;
> +	struct stm32_iwdg_config	*config;

declare bool has_pclk here.

> +	struct clk			*clk_lsi;
> +	struct clk			*clk_pclk;
> +	unsigned int			rate;
>   };
>   
>   static inline u32 reg_read(void __iomem *base, u32 reg)
> @@ -133,6 +140,44 @@ 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");
> +	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->config->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 +192,50 @@ static const struct watchdog_ops stm32_iwdg_ops = {
>   	.set_timeout	= stm32_iwdg_set_timeout,
>   };
>   
> +static const struct stm32_iwdg_config stm32_iwdg_cfg = {
> +	.has_pclk = false,
> +};
> +
> +static const struct stm32_iwdg_config stm32mp1_iwdg_cfg = {
> +	.has_pclk = true,
> +};
> +
> +static const struct of_device_id stm32_iwdg_of_match[] = {
> +	{ .compatible = "st,stm32-iwdg", .data = &stm32_iwdg_cfg },
> +	{ .compatible = "st,stm32mp1-iwdg", .data = &stm32mp1_iwdg_cfg },
> +	{ /* 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 || !match->data)
> +		return -ENODEV;
> +
> +	wdt = devm_kzalloc(&pdev->dev, sizeof(*wdt), GFP_KERNEL);
> +	if (!wdt)
> +		return -ENOMEM;
> +
> +	wdt->config = (struct stm32_iwdg_config *)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 +263,8 @@ 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 +274,18 @@ 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);
>