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From:   Ludovic Barre <ludovic.Barre@st.com>
To:     Wim Van Sebroeck <wim@linux-watchdog.org>,
        Guenter Roeck <linux@roeck-us.net>,
        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>,
        Ludovic Barre <ludovic.barre@st.com>
Subject: [PATCH V3 1/3] watchdog: stm32: add pclk feature for stm32mp1
Date:   Wed, 20 Jun 2018 15:51:36 +0200
Message-ID: <1529502698-13263-2-git-send-email-ludovic.Barre@st.com>
In-Reply-To: <1529502698-13263-1-git-send-email-ludovic.Barre@st.com>
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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                      | 116 +++++++++++++--------
 2 files changed, 91 insertions(+), 46 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..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");
+	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