[PATCH 6/10] watchdog: bcm63xx_wdt: Obtain watchdog clock HZ from "periph" clk

[Simon Arlott <simon@xxxxxxxxxxx>]

Instead of using a fixed clock HZ in the driver, obtain it from the
"periph" clk that the watchdog timer uses.

Signed-off-by: Simon Arlott <simon@xxxxxxxxxxx>
---
 drivers/watchdog/bcm63xx_wdt.c | 36 +++++++++++++++++++++++++++++++-----
 1 file changed, 31 insertions(+), 5 deletions(-)

diff --git a/drivers/watchdog/bcm63xx_wdt.c b/drivers/watchdog/bcm63xx_wdt.c
index 1d2a501..eb5e551 100644
--- a/drivers/watchdog/bcm63xx_wdt.c
+++ b/drivers/watchdog/bcm63xx_wdt.c
@@ -13,6 +13,7 @@
 
 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 
+#include <linux/clk.h>
 #include <linux/errno.h>
 #include <linux/io.h>
 #include <linux/kernel.h>
@@ -32,11 +33,13 @@
 
 #define PFX KBUILD_MODNAME
 
-#define WDT_HZ			50000000		/* Fclk */
+#define WDT_CLK_NAME		"periph"
 
 struct bcm63xx_wdt_hw {
 	raw_spinlock_t lock;
 	void __iomem *regs;
+	struct clk *clk;
+	unsigned long clock_hz;
 	bool running;
 };
 
@@ -51,7 +54,7 @@ static int bcm63xx_wdt_start(struct watchdog_device *wdd)
 	unsigned long flags;
 
 	raw_spin_lock_irqsave(&hw->lock, flags);
-	bcm_writel(wdd->timeout * WDT_HZ, hw->regs + WDT_DEFVAL_REG);
+	bcm_writel(wdd->timeout * hw->clock_hz, hw->regs + WDT_DEFVAL_REG);
 	bcm_writel(WDT_START_1, hw->regs + WDT_CTL_REG);
 	bcm_writel(WDT_START_2, hw->regs + WDT_CTL_REG);
 	hw->running = true;
@@ -116,7 +119,7 @@ static void bcm63xx_wdt_isr(void *data)
 			die(PFX ": watchdog timer expired\n", get_irq_regs());
 		}
 
-		ms = timeleft / (WDT_HZ / 1000);
+		ms = timeleft / (hw->clock_hz / 1000);
 		dev_alert(wdd->dev,
 			"warning timer fired, reboot in %ums\n", ms);
 	}
@@ -160,6 +163,24 @@ static int bcm63xx_wdt_probe(struct platform_device *pdev)
 		return -ENXIO;
 	}
 
+	hw->clk = devm_clk_get(&pdev->dev, WDT_CLK_NAME);
+	if (IS_ERR(hw->clk)) {
+		dev_err(&pdev->dev, "unable to request clock\n");
+		return PTR_ERR(hw->clk);
+	}
+
+	hw->clock_hz = clk_get_rate(hw->clk);
+	if (!hw->clock_hz) {
+		dev_err(&pdev->dev, "unable to fetch clock rate\n");
+		return -EINVAL;
+	}
+
+	ret = clk_prepare_enable(hw->clk);
+	if (ret) {
+		dev_err(&pdev->dev, "unable to enable clock\n");
+		return ret;
+	}
+
 	raw_spin_lock_init(&hw->lock);
 	hw->running = false;
 
@@ -167,7 +188,7 @@ static int bcm63xx_wdt_probe(struct platform_device *pdev)
 	wdd->ops = &bcm63xx_wdt_ops;
 	wdd->info = &bcm63xx_wdt_info;
 	wdd->min_timeout = 1;
-	wdd->max_timeout = 0xffffffff / WDT_HZ;
+	wdd->max_timeout = 0xffffffff / hw->clock_hz;
 	wdd->timeout = min(30U, wdd->max_timeout);
 
 	watchdog_set_drvdata(wdd, hw);
@@ -179,7 +200,7 @@ static int bcm63xx_wdt_probe(struct platform_device *pdev)
 	ret = bcm63xx_timer_register(TIMER_WDT_ID, bcm63xx_wdt_isr, wdd);
 	if (ret < 0) {
 		dev_err(&pdev->dev, "failed to register wdt timer isr\n");
-		return ret;
+		goto disable_clk;
 	}
 
 	ret = watchdog_register_device(wdd);
@@ -197,15 +218,20 @@ static int bcm63xx_wdt_probe(struct platform_device *pdev)
 
 unregister_timer:
 	bcm63xx_timer_unregister(TIMER_WDT_ID);
+
+disable_clk:
+	clk_disable_unprepare(hw->clk);
 	return ret;
 }
 
 static int bcm63xx_wdt_remove(struct platform_device *pdev)
 {
 	struct watchdog_device *wdd = platform_get_drvdata(pdev);
+	struct bcm63xx_wdt_hw *hw = watchdog_get_drvdata(wdd);
 
 	bcm63xx_timer_unregister(TIMER_WDT_ID);
 	watchdog_unregister_device(wdd);
+	clk_disable_unprepare(hw->clk);
 	return 0;
 }
 
-- 
2.1.4

-- 
Simon Arlott