diff mbox

[1/3] rtc: stmp3xxx: add wdt-accessor function

Message ID 1327347185-620-2-git-send-email-w.sang@pengutronix.de
State Superseded
Headers show

Commit Message

Wolfram Sang Jan. 23, 2012, 7:33 p.m. UTC 
This RTC also includes a watchdog timer. Provide an accessor function
for it to be picked up by a watchdog driver. Also register the
platform_device here to get the boot-time dependencies right.

Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
Cc: Alessandro Zummo <alessandro.zummo@towertech.it>
Cc: Andrew Morton <akpm@linux-foundation.org>
---
 drivers/rtc/rtc-stmp3xxx.c       |   64 ++++++++++++++++++++++++++++++++++++++
 include/linux/stmp3xxx_rtc_wdt.h |   15 +++++++++
 2 files changed, 79 insertions(+), 0 deletions(-)
 create mode 100644 include/linux/stmp3xxx_rtc_wdt.h

Comments

Andrew Morton Jan. 25, 2012, 12:59 a.m. UTC | #1 
On Mon, 23 Jan 2012 20:33:03 +0100
Wolfram Sang <w.sang@pengutronix.de> wrote:

> This RTC also includes a watchdog timer. Provide an accessor function
> for it to be picked up by a watchdog driver. Also register the
> platform_device here to get the boot-time dependencies right.
> 
>
> ...
>
>  struct stmp3xxx_rtc_data {
>  	struct rtc_device *rtc;
>  	void __iomem *io;
>  	int irq_alarm;
>  };
>  
> +#if defined(CONFIG_STMP3XXX_RTC_WATCHDOG) || defined(CONFIG_STMP3XXX_RTC_WATCHDOG_MODULE)

You can use IS_ENABLED() here.

> +/**
> + * stmp3xxx_wdt_set_timeout - configure the watchdog inside the STMP3xxx RTC
> + * @dev: the parent device of the watchdog (= the RTC)
> + * @timeout: the desired value for the timeout register of the watchdog.
> + *           0 disables the watchdog
> + *
> + * The watchdog needs one register and two bits which are in the RTC domain.
> + * To handle the resource conflict, the RTC driver will create another
> + * platform_device for the watchdog driver as a child of the RTC device.
> + * The watchdog driver is passed the below accessor function via platform_data
> + * to configure the watchdog. Locking is not needed because accessing SET/CLR
> + * registers is atomic.
> + */
> +
> +void stmp3xxx_wdt_set_timeout(struct device *dev, u32 timeout)
> +{
> +	struct stmp3xxx_rtc_data *rtc_data = dev_get_drvdata(dev);
> +	void __iomem *base;
> +
> +	if (timeout) {
> +		writel(timeout, rtc_data->io + STMP3XXX_RTC_WATCHDOG);
> +		base = rtc_data->io + MXS_SET_ADDR;
> +	} else {
> +		base = rtc_data->io + MXS_CLR_ADDR;
> +	}
> +	writel(STMP3XXX_RTC_CTRL_WATCHDOGEN, base + STMP3XXX_RTC_CTRL);
> +	writel(STMP3XXX_RTC_PERSISTENT1_FORCE_UPDATER,
> +		base + STMP3XXX_RTC_PERSISTENT1);
> +}

This wants EXPORT_SYMBOL(), surely?

Which points suspicious fingers at your testing ;) Please test all
combinations of y, n and m on both config symbols.

> +static struct stmp3xxx_wdt_pdata wdt_pdata = {
> +	.wdt_set_timeout = stmp3xxx_wdt_set_timeout,
> +};
> +
> +static struct platform_device stmp3xxx_wdt_pdev = {
> +	.name = "stmp3xxx_rtc_wdt",
> +	.dev = {
> +		.platform_data = &wdt_pdata,
> +	},
> +};
> +
> +static void stmp3xxx_wdt_register(struct platform_device *rtc_pdev)
> +{
> +	stmp3xxx_wdt_pdev.dev.parent = &rtc_pdev->dev;
> +	stmp3xxx_wdt_pdev.id = rtc_pdev->id;
> +	platform_device_register(&stmp3xxx_wdt_pdev);
> +}
> +#else
> +static void stmp3xxx_wdt_register(struct device *dev)
> +{
> +}

This stub is unfortunate.  If
!IS_ENABLED(CONFIG_STMP3XXX_RTC_WATCHDOG), the user still must load
this module just to get a silly empty function.  If the
stmp3xxx_wdt_register() stub were made static inline in a header file,
the user won't need to compile or load this module at all.  There may
be other (initialisation?) reasons why the user must still load this
module?
diff mbox

Patch

diff --git a/drivers/rtc/rtc-stmp3xxx.c b/drivers/rtc/rtc-stmp3xxx.c
index 1028786..2cf8858 100644
--- a/drivers/rtc/rtc-stmp3xxx.c
+++ b/drivers/rtc/rtc-stmp3xxx.c
@@ -25,8 +25,10 @@ 
 #include <linux/interrupt.h>
 #include <linux/rtc.h>
 #include <linux/slab.h>
+#include <linux/stmp3xxx_rtc_wdt.h>
 
 #include <mach/common.h>
+#include <mach/mxs.h>
 
 #define STMP3XXX_RTC_CTRL			0x0
 #define STMP3XXX_RTC_CTRL_SET			0x4
@@ -34,6 +36,7 @@ 
 #define STMP3XXX_RTC_CTRL_ALARM_IRQ_EN		0x00000001
 #define STMP3XXX_RTC_CTRL_ONEMSEC_IRQ_EN	0x00000002
 #define STMP3XXX_RTC_CTRL_ALARM_IRQ		0x00000004
+#define STMP3XXX_RTC_CTRL_WATCHDOGEN		0x00000010
 
 #define STMP3XXX_RTC_STAT			0x10
 #define STMP3XXX_RTC_STAT_STALE_SHIFT		16
@@ -43,6 +46,8 @@ 
 
 #define STMP3XXX_RTC_ALARM			0x40
 
+#define STMP3XXX_RTC_WATCHDOG			0x50
+
 #define STMP3XXX_RTC_PERSISTENT0		0x60
 #define STMP3XXX_RTC_PERSISTENT0_SET		0x64
 #define STMP3XXX_RTC_PERSISTENT0_CLR		0x68
@@ -50,12 +55,70 @@ 
 #define STMP3XXX_RTC_PERSISTENT0_ALARM_EN	0x00000004
 #define STMP3XXX_RTC_PERSISTENT0_ALARM_WAKE	0x00000080
 
+#define STMP3XXX_RTC_PERSISTENT1		0x70
+/* missing bitmask in headers */
+#define STMP3XXX_RTC_PERSISTENT1_FORCE_UPDATER	0x80000000
+
 struct stmp3xxx_rtc_data {
 	struct rtc_device *rtc;
 	void __iomem *io;
 	int irq_alarm;
 };
 
+#if defined(CONFIG_STMP3XXX_RTC_WATCHDOG) || defined(CONFIG_STMP3XXX_RTC_WATCHDOG_MODULE)
+/**
+ * stmp3xxx_wdt_set_timeout - configure the watchdog inside the STMP3xxx RTC
+ * @dev: the parent device of the watchdog (= the RTC)
+ * @timeout: the desired value for the timeout register of the watchdog.
+ *           0 disables the watchdog
+ *
+ * The watchdog needs one register and two bits which are in the RTC domain.
+ * To handle the resource conflict, the RTC driver will create another
+ * platform_device for the watchdog driver as a child of the RTC device.
+ * The watchdog driver is passed the below accessor function via platform_data
+ * to configure the watchdog. Locking is not needed because accessing SET/CLR
+ * registers is atomic.
+ */
+
+void stmp3xxx_wdt_set_timeout(struct device *dev, u32 timeout)
+{
+	struct stmp3xxx_rtc_data *rtc_data = dev_get_drvdata(dev);
+	void __iomem *base;
+
+	if (timeout) {
+		writel(timeout, rtc_data->io + STMP3XXX_RTC_WATCHDOG);
+		base = rtc_data->io + MXS_SET_ADDR;
+	} else {
+		base = rtc_data->io + MXS_CLR_ADDR;
+	}
+	writel(STMP3XXX_RTC_CTRL_WATCHDOGEN, base + STMP3XXX_RTC_CTRL);
+	writel(STMP3XXX_RTC_PERSISTENT1_FORCE_UPDATER,
+		base + STMP3XXX_RTC_PERSISTENT1);
+}
+
+static struct stmp3xxx_wdt_pdata wdt_pdata = {
+	.wdt_set_timeout = stmp3xxx_wdt_set_timeout,
+};
+
+static struct platform_device stmp3xxx_wdt_pdev = {
+	.name = "stmp3xxx_rtc_wdt",
+	.dev = {
+		.platform_data = &wdt_pdata,
+	},
+};
+
+static void stmp3xxx_wdt_register(struct platform_device *rtc_pdev)
+{
+	stmp3xxx_wdt_pdev.dev.parent = &rtc_pdev->dev;
+	stmp3xxx_wdt_pdev.id = rtc_pdev->id;
+	platform_device_register(&stmp3xxx_wdt_pdev);
+}
+#else
+static void stmp3xxx_wdt_register(struct device *dev)
+{
+}
+#endif /* CONFIG_STMP3XXX_RTC_WATCHDOG */
+
 static void stmp3xxx_wait_time(struct stmp3xxx_rtc_data *rtc_data)
 {
 	/*
@@ -231,6 +294,7 @@  static int stmp3xxx_rtc_probe(struct platform_device *pdev)
 		goto out_irq_alarm;
 	}
 
+	stmp3xxx_wdt_register(pdev);
 	return 0;
 
 out_irq_alarm:
diff --git a/include/linux/stmp3xxx_rtc_wdt.h b/include/linux/stmp3xxx_rtc_wdt.h
new file mode 100644
index 0000000..1dd12c9
--- /dev/null
+++ b/include/linux/stmp3xxx_rtc_wdt.h
@@ -0,0 +1,15 @@ 
+/*
+ * stmp3xxx_rtc_wdt.h
+ *
+ * Copyright (C) 2011 Wolfram Sang, Pengutronix e.K.
+ *
+ * This file is released under the GPLv2.
+ */
+#ifndef __LINUX_STMP3XXX_RTC_WDT_H
+#define __LINUX_STMP3XXX_RTC_WDT_H
+
+struct stmp3xxx_wdt_pdata {
+	void (*wdt_set_timeout)(struct device *dev, u32 timeout);
+};
+
+#endif /* __LINUX_STMP3XXX_RTC_WDT_H */