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From: Paul Cercueil <paul@crapouillou.net>
To: Rob Herring <robh+dt@kernel.org>,
	Mark Rutland <mark.rutland@arm.com>,
	Thierry Reding <thierry.reding@gmail.com>,
	Daniel Lezcano <daniel.lezcano@linaro.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Wim Van Sebroeck <wim@linux-watchdog.org>,
	Guenter Roeck <linux@roeck-us.net>,
	Ralf Baechle <ralf@linux-mips.org>,
	Paul Burton <paul.burton@mips.com>,
	James Hogan <jhogan@kernel.org>, Jonathan Corbet <corbet@lwn.net>,
	Lee Jones <lee.jones@linaro.org>,
	Mathieu Malaterre <malat@debian.org>,
	Ezequiel Garcia <ezequiel@collabora.co.uk>
Cc: linux-pwm@vger.kernel.org, devicetree@vger.kernel.org,
	linux-kernel@vger.kernel.org, linux-watchdog@vger.kernel.org,
	linux-mips@linux-mips.org, linux-doc@vger.kernel.org,
	linux-clk@vger.kernel.org, Paul Cercueil <paul@crapouillou.net>
Subject: [PATCH v6 08/24] watchdog: jz4740: Use WDT clock provided by TCU driver
Date: Thu,  9 Aug 2018 23:43:58 +0200
Message-ID: <20180809214414.20905-9-paul@crapouillou.net> (raw)
In-Reply-To: <20180809214414.20905-1-paul@crapouillou.net>

Instead of requesting the "ext" clock and handling the watchdog clock
divider and gating in the watchdog driver, we now request and use the
"wdt" clock that is supplied by the ingenic-timer "TCU" driver.

The major benefit is that the watchdog's clock rate and parent can now
be specified from within devicetree, instead of hardcoded in the driver.

Also, this driver won't poke anymore into the TCU registers to
enable/disable the clock, as this is now handled by the TCU driver.

On the bad side, we break the ABI with devicetree - as we now request a
different clock. In this very specific case it is still okay, as every
Ingenic JZ47xx-based board out there compile the devicetree within the
kernel; so it's still time to push breaking changes, in order to get a
clean devicetree that won't break once it musn't.

Signed-off-by: Paul Cercueil <paul@crapouillou.net>
---
 drivers/watchdog/Kconfig      |  2 +
 drivers/watchdog/jz4740_wdt.c | 86 +++++++++++++++++--------------------------
 2 files changed, 36 insertions(+), 52 deletions(-)

 v5: New patch

 v6: - Split regmap change to new patch 09/24
     - The code now sets the WDT clock to the smallest rate possible and
       calculates the maximum timeout from that

diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
index 9af07fd92763..834222abbbdb 100644
--- a/drivers/watchdog/Kconfig
+++ b/drivers/watchdog/Kconfig
@@ -1476,7 +1476,9 @@ config INDYDOG
 config JZ4740_WDT
 	tristate "Ingenic jz4740 SoC hardware watchdog"
 	depends on MACH_JZ4740 || MACH_JZ4780
+	depends on COMMON_CLK
 	select WATCHDOG_CORE
+	select INGENIC_TIMER
 	help
 	  Hardware driver for the built-in watchdog timer on Ingenic jz4740 SoCs.
 
diff --git a/drivers/watchdog/jz4740_wdt.c b/drivers/watchdog/jz4740_wdt.c
index ec4d99a830ba..1d504ecf45e1 100644
--- a/drivers/watchdog/jz4740_wdt.c
+++ b/drivers/watchdog/jz4740_wdt.c
@@ -26,25 +26,9 @@
 #include <linux/err.h>
 #include <linux/of.h>
 
-#include <asm/mach-jz4740/timer.h>
-
 #define JZ_REG_WDT_TIMER_DATA     0x0
 #define JZ_REG_WDT_COUNTER_ENABLE 0x4
 #define JZ_REG_WDT_TIMER_COUNTER  0x8
-#define JZ_REG_WDT_TIMER_CONTROL  0xC
-
-#define JZ_WDT_CLOCK_PCLK 0x1
-#define JZ_WDT_CLOCK_RTC  0x2
-#define JZ_WDT_CLOCK_EXT  0x4
-
-#define JZ_WDT_CLOCK_DIV_SHIFT   3
-
-#define JZ_WDT_CLOCK_DIV_1    (0 << JZ_WDT_CLOCK_DIV_SHIFT)
-#define JZ_WDT_CLOCK_DIV_4    (1 << JZ_WDT_CLOCK_DIV_SHIFT)
-#define JZ_WDT_CLOCK_DIV_16   (2 << JZ_WDT_CLOCK_DIV_SHIFT)
-#define JZ_WDT_CLOCK_DIV_64   (3 << JZ_WDT_CLOCK_DIV_SHIFT)
-#define JZ_WDT_CLOCK_DIV_256  (4 << JZ_WDT_CLOCK_DIV_SHIFT)
-#define JZ_WDT_CLOCK_DIV_1024 (5 << JZ_WDT_CLOCK_DIV_SHIFT)
 
 #define DEFAULT_HEARTBEAT 5
 #define MAX_HEARTBEAT     2048
@@ -65,7 +49,8 @@ MODULE_PARM_DESC(heartbeat,
 struct jz4740_wdt_drvdata {
 	struct watchdog_device wdt;
 	void __iomem *base;
-	struct clk *rtc_clk;
+	struct clk *clk;
+	unsigned long clk_rate;
 };
 
 static int jz4740_wdt_ping(struct watchdog_device *wdt_dev)
@@ -80,31 +65,12 @@ static int jz4740_wdt_set_timeout(struct watchdog_device *wdt_dev,
 				    unsigned int new_timeout)
 {
 	struct jz4740_wdt_drvdata *drvdata = watchdog_get_drvdata(wdt_dev);
-	unsigned int rtc_clk_rate;
-	unsigned int timeout_value;
-	unsigned short clock_div = JZ_WDT_CLOCK_DIV_1;
-
-	rtc_clk_rate = clk_get_rate(drvdata->rtc_clk);
-
-	timeout_value = rtc_clk_rate * new_timeout;
-	while (timeout_value > 0xffff) {
-		if (clock_div == JZ_WDT_CLOCK_DIV_1024) {
-			/* Requested timeout too high;
-			* use highest possible value. */
-			timeout_value = 0xffff;
-			break;
-		}
-		timeout_value >>= 2;
-		clock_div += (1 << JZ_WDT_CLOCK_DIV_SHIFT);
-	}
+	u16 timeout_value = (u16)(drvdata->clk_rate * new_timeout);
 
 	writeb(0x0, drvdata->base + JZ_REG_WDT_COUNTER_ENABLE);
-	writew(clock_div, drvdata->base + JZ_REG_WDT_TIMER_CONTROL);
 
 	writew((u16)timeout_value, drvdata->base + JZ_REG_WDT_TIMER_DATA);
 	writew(0x0, drvdata->base + JZ_REG_WDT_TIMER_COUNTER);
-	writew(clock_div | JZ_WDT_CLOCK_RTC,
-		drvdata->base + JZ_REG_WDT_TIMER_CONTROL);
 
 	writeb(0x1, drvdata->base + JZ_REG_WDT_COUNTER_ENABLE);
 
@@ -114,7 +80,13 @@ static int jz4740_wdt_set_timeout(struct watchdog_device *wdt_dev,
 
 static int jz4740_wdt_start(struct watchdog_device *wdt_dev)
 {
-	jz4740_timer_enable_watchdog();
+	struct jz4740_wdt_drvdata *drvdata = watchdog_get_drvdata(wdt_dev);
+	int ret;
+
+	ret = clk_prepare_enable(drvdata->clk);
+	if (ret)
+		return ret;
+
 	jz4740_wdt_set_timeout(wdt_dev, wdt_dev->timeout);
 
 	return 0;
@@ -125,7 +97,7 @@ static int jz4740_wdt_stop(struct watchdog_device *wdt_dev)
 	struct jz4740_wdt_drvdata *drvdata = watchdog_get_drvdata(wdt_dev);
 
 	writeb(0x0, drvdata->base + JZ_REG_WDT_COUNTER_ENABLE);
-	jz4740_timer_disable_watchdog();
+	clk_disable_unprepare(drvdata->clk);
 
 	return 0;
 }
@@ -163,26 +135,42 @@ MODULE_DEVICE_TABLE(of, jz4740_wdt_of_matches);
 
 static int jz4740_wdt_probe(struct platform_device *pdev)
 {
+	struct device *dev = &pdev->dev;
 	struct jz4740_wdt_drvdata *drvdata;
 	struct watchdog_device *jz4740_wdt;
 	struct resource	*res;
+	long rate;
 	int ret;
 
-	drvdata = devm_kzalloc(&pdev->dev, sizeof(struct jz4740_wdt_drvdata),
-			       GFP_KERNEL);
+	drvdata = devm_kzalloc(dev, sizeof(*drvdata), GFP_KERNEL);
 	if (!drvdata)
 		return -ENOMEM;
 
-	if (heartbeat < 1 || heartbeat > MAX_HEARTBEAT)
-		heartbeat = DEFAULT_HEARTBEAT;
+	drvdata->clk = devm_clk_get(&pdev->dev, "wdt");
+	if (IS_ERR(drvdata->clk)) {
+		dev_err(&pdev->dev, "cannot find WDT clock\n");
+		return PTR_ERR(drvdata->clk);
+	}
+
+	/* Set smallest clock possible */
+	rate = clk_round_rate(drvdata->clk, 1);
+	if (rate < 0)
+		return rate;
 
+	ret = clk_set_rate(drvdata->clk, rate);
+	if (ret)
+		return ret;
+
+	drvdata->clk_rate = rate;
 	jz4740_wdt = &drvdata->wdt;
 	jz4740_wdt->info = &jz4740_wdt_info;
 	jz4740_wdt->ops = &jz4740_wdt_ops;
-	jz4740_wdt->timeout = heartbeat;
 	jz4740_wdt->min_timeout = 1;
-	jz4740_wdt->max_timeout = MAX_HEARTBEAT;
-	jz4740_wdt->parent = &pdev->dev;
+	jz4740_wdt->max_timeout = 0xffff / rate;
+	jz4740_wdt->timeout = clamp(heartbeat,
+				    jz4740_wdt->min_timeout,
+				    jz4740_wdt->max_timeout);
+	jz4740_wdt->parent = dev;
 	watchdog_set_nowayout(jz4740_wdt, nowayout);
 	watchdog_set_drvdata(jz4740_wdt, drvdata);
 
@@ -191,12 +179,6 @@ static int jz4740_wdt_probe(struct platform_device *pdev)
 	if (IS_ERR(drvdata->base))
 		return PTR_ERR(drvdata->base);
 
-	drvdata->rtc_clk = devm_clk_get(&pdev->dev, "rtc");
-	if (IS_ERR(drvdata->rtc_clk)) {
-		dev_err(&pdev->dev, "cannot find RTC clock\n");
-		return PTR_ERR(drvdata->rtc_clk);
-	}
-
 	ret = devm_watchdog_register_device(&pdev->dev, &drvdata->wdt);
 	if (ret < 0)
 		return ret;
-- 
2.11.0


  parent reply index

Thread overview: 32+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-08-09 21:43 [PATCH v6 00/24] Ingenic TCU patchset v6 Paul Cercueil
2018-08-09 21:43 ` [PATCH v6 01/24] mfd: Add ingenic-tcu.h header Paul Cercueil
2018-08-09 21:43 ` [PATCH v6 02/24] dt-bindings: ingenic: Add DT bindings for TCU clocks Paul Cercueil
2018-08-09 21:43 ` [PATCH v6 03/24] doc: Add doc for the Ingenic TCU hardware Paul Cercueil
2018-08-09 21:43 ` [PATCH v6 04/24] dt-bindings: Add doc for the Ingenic TCU drivers Paul Cercueil
2018-08-13 15:24   ` Rob Herring
2018-08-09 21:43 ` [PATCH v6 05/24] clocksource: Add a new timer-ingenic driver Paul Cercueil
2018-08-09 21:43 ` [PATCH v6 06/24] clocksource: Add driver for the Ingenic JZ47xx OST Paul Cercueil
2018-08-14  9:42   ` Mathieu Malaterre
2018-08-16 16:07     ` Paul Cercueil
2018-08-09 21:43 ` [PATCH v6 07/24] MAINTAINERS: Add myself as maintainer for Ingenic TCU drivers Paul Cercueil
2018-08-09 21:43 ` Paul Cercueil [this message]
2018-08-10 13:36   ` [PATCH v6 08/24] watchdog: jz4740: Use WDT clock provided by TCU driver Guenter Roeck
2018-08-09 21:43 ` [PATCH v6 09/24] watchdog: jz4740: Use regmap " Paul Cercueil
2018-08-10 13:37   ` Guenter Roeck
2018-08-09 21:44 ` [PATCH v6 10/24] watchdog: jz4740: Avoid starting watchdog in set_timeout Paul Cercueil
2018-08-10 13:37   ` Guenter Roeck
2018-08-09 21:44 ` [PATCH v6 11/24] watchdog: jz4740: Drop dependency on MACH_JZ47xx, use COMPILE_TEST Paul Cercueil
2018-08-10 13:38   ` Guenter Roeck
2018-08-09 21:44 ` [PATCH v6 12/24] pwm: jz4740: Use regmap and clocks from TCU driver Paul Cercueil
2018-08-09 21:44 ` [PATCH v6 13/24] pwm: jz4740: Allow selection of PWM channels 0 and 1 Paul Cercueil
2018-08-09 21:44 ` [PATCH v6 14/24] pwm: jz4740: Drop dependency on MACH_INGENIC, use COMPILE_TEST Paul Cercueil
2018-08-09 21:44 ` [PATCH v6 15/24] pwm: jz4740: Remove unused devicetree compatible strings Paul Cercueil
2018-08-09 21:44 ` [PATCH v6 16/24] pwm: jz4740: Add support for the JZ4725B Paul Cercueil
2018-08-09 21:44 ` [PATCH v6 17/24] clk: jz4740: Add TCU clock Paul Cercueil
2018-08-09 21:44 ` [PATCH v6 18/24] MIPS: Kconfig: Select TCU timer driver when MACH_INGENIC is set Paul Cercueil
2018-08-09 21:44 ` [PATCH v6 19/24] MIPS: jz4740: Add DTS nodes for the TCU drivers Paul Cercueil
2018-08-09 21:44 ` [PATCH v6 20/24] MIPS: qi_lb60: Move PWM devices to devicetree Paul Cercueil
2018-08-09 21:46 ` [PATCH v6 21/24] MIPS: qi_lb60: Reduce system timer and clocksource to 750 kHz Paul Cercueil
2018-08-09 21:46 ` [PATCH v6 22/24] MIPS: CI20: Reduce system timer and clocksource to 3 MHz Paul Cercueil
2018-08-09 21:47 ` [PATCH v6 23/24] MIPS: CI20: defconfig: enable OST driver Paul Cercueil
2018-08-09 21:48 ` [PATCH v6 24/24] MIPS: jz4740: Drop obsolete code Paul Cercueil

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