On Wed, Jul 17, 2013 at 11:24:51AM +0200, Jonas Jensen wrote:
> Add watchdog driver for MOXA ART SoCs.
>
> Signed-off-by: Jonas Jensen <jonas.jensen@xxxxxxxxx>
> ---
>
> Notes:
> Changes since v2:
>
> 1. add devicetree bindings document
>
> Applies to next-20130716
>
> .../bindings/watchdog/moxa,moxart-watchdog.txt | 15 ++
> drivers/watchdog/Kconfig | 10 ++
> drivers/watchdog/Makefile | 1 +
> drivers/watchdog/moxart_wdt.c | 171 +++++++++++++++++++++
> 4 files changed, 197 insertions(+)
> create mode 100644 Documentation/devicetree/bindings/watchdog/moxa,moxart-watchdog.txt
> create mode 100644 drivers/watchdog/moxart_wdt.c
>
> diff --git a/Documentation/devicetree/bindings/watchdog/moxa,moxart-watchdog.txt b/Documentation/devicetree/bindings/watchdog/moxa,moxart-watchdog.txt
> new file mode 100644
> index 0000000..fb99e50
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/watchdog/moxa,moxart-watchdog.txt
> @@ -0,0 +1,15 @@
> +MOXA ART Watchdog timer
> +
> +Required properties:
> +
> +- compatible : Should be "moxa,moxart-watchdog"
> +- reg : Should contain registers location and length
> +- clocks : Should contain phandle for APB clock "clkapb"
> +
> +Example:
> +
> + watchdog: watchdog@98500000 {
> + compatible = "moxa,moxart-watchdog";
> + reg = <0x98500000 0x10>;
> + clocks = <&clkapb>;
> + };
> diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
> index 362085d..6883aab 100644
> --- a/drivers/watchdog/Kconfig
> +++ b/drivers/watchdog/Kconfig
> @@ -382,6 +382,16 @@ config RETU_WATCHDOG
> To compile this driver as a module, choose M here: the
> module will be called retu_wdt.
>
> +config MOXART_WDT
> + tristate "MOXART watchdog"
> + depends on ARCH_MOXART
> + help
> + Say Y here to include Watchdog timer support for the watchdog
> + existing on the MOXA ART SoC series platforms.
> +
> + To compile this driver as a module, choose M here: the
> + module will be called moxart_wdt.
> +
> # AVR32 Architecture
>
> config AT32AP700X_WDT
> diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
> index 2f26a0b..7cab53a 100644
> --- a/drivers/watchdog/Makefile
> +++ b/drivers/watchdog/Makefile
> @@ -54,6 +54,7 @@ obj-$(CONFIG_IMX2_WDT) += imx2_wdt.o
> obj-$(CONFIG_UX500_WATCHDOG) += ux500_wdt.o
> obj-$(CONFIG_RETU_WATCHDOG) += retu_wdt.o
> obj-$(CONFIG_BCM2835_WDT) += bcm2835_wdt.o
> +obj-$(CONFIG_MOXART_WDT) += moxart_wdt.o
>
> # AVR32 Architecture
> obj-$(CONFIG_AT32AP700X_WDT) += at32ap700x_wdt.o
> diff --git a/drivers/watchdog/moxart_wdt.c b/drivers/watchdog/moxart_wdt.c
> new file mode 100644
> index 0000000..966855d
> --- /dev/null
> +++ b/drivers/watchdog/moxart_wdt.c
> @@ -0,0 +1,171 @@
> +/*
> + * MOXA ART SoCs watchdog driver.
> + *
> + * Copyright (C) 2013 Jonas Jensen
> + *
> + * Jonas Jensen <jonas.jensen@xxxxxxxxx>
> + *
> + * This file is licensed under the terms of the GNU General Public
> + * License version 2. This program is licensed "as is" without any
> + * warranty of any kind, whether express or implied.
> + */
> +
> +#include <linux/clk.h>
> +#include <linux/err.h>
> +#include <linux/init.h>
> +#include <linux/io.h>
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/moduleparam.h>
> +#include <linux/of.h>
> +#include <linux/of_address.h>
Do you need the above two includes ?
> +#include <linux/platform_device.h>
> +#include <linux/types.h>
> +#include <linux/watchdog.h>
> +
> +#include <asm/system_misc.h>
> +
> +#define REG_COUNT 0x4
> +#define REG_MODE 0x8
> +#define REG_ENABLE 0xC
> +
> +struct moxart_wdt_dev {
> + struct watchdog_device wdt_dev;
> + void __iomem *wdt_base;
> +};
> +
> +static struct moxart_wdt_dev *moxart_wdt;
I don't think this variable is really needed as static variable;
you should be able to use platform_get_drvdata() to get it whereever needed.
In fact, you sometimes use the static variable and sometimes a local variable
with the same name. I find this confusing.
> +static bool nowayout = WATCHDOG_NOWAYOUT;
Only used in probe function and should be declared there.
> +static int heartbeat;
> +static unsigned int clock_frequency;
Curious - why did you declare this variable as static variable, but wdt_base is
part of moxart_wdt_dev.
> +static unsigned int max_timeout;
This variable is only used in the probe function and should thus be declared
there.
> +static int moxart_wdt_stop(struct watchdog_device *wdt_dev)
> +{
> + struct moxart_wdt_dev *moxart_wdt = watchdog_get_drvdata(wdt_dev);
> + void __iomem *wdt_base = moxart_wdt->wdt_base;
> +
> + writel(0, wdt_base + REG_ENABLE);
> +
> + return 0;
> +}
> +
> +static int moxart_wdt_start(struct watchdog_device *wdt_dev)
> +{
> + struct moxart_wdt_dev *moxart_wdt = watchdog_get_drvdata(wdt_dev);
> + void __iomem *wdt_base = moxart_wdt->wdt_base;
> +
> + writel(clock_frequency * moxart_wdt->wdt_dev.timeout,
> + wdt_base + REG_COUNT);
> + writel(0x5ab9, wdt_base + REG_MODE);
> + writel(0x03, wdt_base + REG_ENABLE);
> +
> + return 0;
> +}
> +
> +static int moxart_wdt_set_timeout(struct watchdog_device *wdt_dev,
> + unsigned int timeout)
> +{
> + dev_dbg(wdt_dev->dev, "%s: timeout=%u\n", __func__, timeout);
> +
> + moxart_wdt->wdt_dev.timeout = timeout;
> +
> + return 0;
> +}
> +
> +static const struct watchdog_info moxart_wdt_info = {
> + .identity = "moxart-wdt",
> + .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING |
> + WDIOF_MAGICCLOSE,
> +};
> +
> +static const struct watchdog_ops moxart_wdt_ops = {
> + .owner = THIS_MODULE,
> + .start = moxart_wdt_start,
> + .stop = moxart_wdt_stop,
> + .set_timeout = moxart_wdt_set_timeout,
> +};
> +
> +static int moxart_wdt_probe(struct platform_device *pdev)
> +{
> + struct device *dev = &pdev->dev;
> + struct device_node *node = dev->of_node;
> + struct resource *res;
> + struct clk *clk;
> + int err;
> +
> + moxart_wdt = devm_kzalloc(&pdev->dev, sizeof(*moxart_wdt), GFP_KERNEL);
> + if (!moxart_wdt)
> + return -EINVAL;
> +
> + platform_set_drvdata(pdev, moxart_wdt);
> +
> + res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> + moxart_wdt->wdt_base = devm_ioremap_resource(dev, res);
> + if (IS_ERR(moxart_wdt->wdt_base))
> + return PTR_ERR(moxart_wdt->wdt_base);
> +
> + clk = of_clk_get(node, 0);
> + if (IS_ERR(clk)) {
> + pr_err("%s: of_clk_get failed\n", __func__);
> + return PTR_ERR(clk);
> + }
> +
> + clock_frequency = clk_get_rate(clk);
Other callers of this function check the return value. Maybe the error can not
happen here, but I am a bit concerned that the function may return 0, in which
case you would have a problem with division by zero below. Is it guaranteed
that this can never happen ?
> +
> + max_timeout = UINT_MAX / clock_frequency;
> +
> + moxart_wdt->wdt_dev.info = &moxart_wdt_info;
> + moxart_wdt->wdt_dev.ops = &moxart_wdt_ops;
> + moxart_wdt->wdt_dev.timeout = max_timeout;
> + moxart_wdt->wdt_dev.min_timeout = 1;
> + moxart_wdt->wdt_dev.max_timeout = max_timeout;
> + moxart_wdt->wdt_dev.parent = &pdev->dev;
> +
> + watchdog_init_timeout(&moxart_wdt->wdt_dev, heartbeat, &pdev->dev);
> + watchdog_set_nowayout(&moxart_wdt->wdt_dev, nowayout);
> +
> + watchdog_set_drvdata(&moxart_wdt->wdt_dev, moxart_wdt);
> +
> + err = watchdog_register_device(&moxart_wdt->wdt_dev);
> + if (unlikely(err))
> + return err;
> +
> + dev_dbg(dev, "Watchdog enabled (heartbeat=%d sec, nowayout=%d)\n",
> + moxart_wdt->wdt_dev.timeout, nowayout);
> +
> + return 0;
> +}
> +
> +static int moxart_wdt_remove(struct platform_device *pdev)
> +{
> + struct moxart_wdt_dev *moxart_wdt = platform_get_drvdata(pdev);
> +
> + moxart_wdt_stop(&moxart_wdt->wdt_dev);
> + watchdog_unregister_device(&moxart_wdt->wdt_dev);
> +
> + return 0;
> +}
> +
> +static const struct of_device_id moxart_watchdog_match[] = {
> + { .compatible = "moxa,moxart-watchdog" },
> + { },
> +};
> +
> +static struct platform_driver moxart_wdt_driver = {
> + .probe = moxart_wdt_probe,
> + .remove = moxart_wdt_remove,
> + .driver = {
> + .name = "moxart-watchdog",
> + .owner = THIS_MODULE,
> + .of_match_table = moxart_watchdog_match,
> + },
> +};
> +module_platform_driver(moxart_wdt_driver);
> +
> +module_param(heartbeat, int, 0);
> +MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat in seconds");
> +
> +MODULE_DESCRIPTION("MOXART watchdog driver");
> +MODULE_LICENSE("GPL");
> +MODULE_AUTHOR("Jonas Jensen <jonas.jensen@xxxxxxxxx>");
> --
> 1.8.2.1
>
>
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