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    Subject[PATCH v5] watchdog: Add MOXA ART watchdog driver
    Date
    Add watchdog driver for MOXA ART SoCs.

    Signed-off-by: Jonas Jensen <jonas.jensen@gmail.com>
    ---

    Notes:
    Changes since v4:

    1. #include <linux/err.h> because IS_ERR comes from there
    2. #include <linux/kernel.h> because UINT_MAX comes from there
    3. #include <linux/moduleparam.h> because module_param() comes from there

    device tree bindings document:
    4. describe compatible variable "Must be" instead of "Should be".
    5. change description so it's from the point of view of the device

    Applies to next-20130729

    .../bindings/watchdog/moxa,moxart-watchdog.txt | 15 ++
    drivers/watchdog/Kconfig | 10 ++
    drivers/watchdog/Makefile | 1 +
    drivers/watchdog/moxart_wdt.c | 169 +++++++++++++++++++++
    4 files changed, 195 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..1169857
    --- /dev/null
    +++ b/Documentation/devicetree/bindings/watchdog/moxa,moxart-watchdog.txt
    @@ -0,0 +1,15 @@
    +MOXA ART Watchdog timer
    +
    +Required properties:
    +
    +- compatible : Must be "moxa,moxart-watchdog"
    +- reg : Should contain registers location and length
    +- clocks : Should contain phandle for the clock that drives the counter
    +
    +Example:
    +
    + watchdog: watchdog@98500000 {
    + compatible = "moxa,moxart-watchdog";
    + reg = <0x98500000 0x10>;
    + clocks = <&coreclk>;
    + };
    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..d79dc9c
    --- /dev/null
    +++ b/drivers/watchdog/moxart_wdt.c
    @@ -0,0 +1,169 @@
    +/*
    + * MOXA ART SoCs watchdog driver.
    + *
    + * Copyright (C) 2013 Jonas Jensen
    + *
    + * Jonas Jensen <jonas.jensen@gmail.com>
    + *
    + * 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/io.h>
    +#include <linux/module.h>
    +#include <linux/err.h>
    +#include <linux/kernel.h>
    +#include <linux/platform_device.h>
    +#include <linux/watchdog.h>
    +#include <linux/moduleparam.h>
    +
    +#define REG_COUNT 0x4
    +#define REG_MODE 0x8
    +#define REG_ENABLE 0xC
    +
    +struct moxart_wdt_dev {
    + struct watchdog_device dev;
    + void __iomem *base;
    + unsigned int clock_frequency;
    +};
    +
    +static int heartbeat;
    +
    +static int moxart_wdt_stop(struct watchdog_device *wdt_dev)
    +{
    + struct moxart_wdt_dev *moxart_wdt = watchdog_get_drvdata(wdt_dev);
    +
    + writel(0, moxart_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);
    +
    + writel(moxart_wdt->clock_frequency * moxart_wdt->dev.timeout,
    + moxart_wdt->base + REG_COUNT);
    + writel(0x5ab9, moxart_wdt->base + REG_MODE);
    + writel(0x03, moxart_wdt->base + REG_ENABLE);
    +
    + return 0;
    +}
    +
    +static int moxart_wdt_set_timeout(struct watchdog_device *wdt_dev,
    + unsigned int timeout)
    +{
    + struct moxart_wdt_dev *moxart_wdt = watchdog_get_drvdata(wdt_dev);
    +
    + dev_dbg(wdt_dev->dev, "%s: timeout=%u\n", __func__, timeout);
    +
    + moxart_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 moxart_wdt_dev *moxart_wdt;
    + struct device *dev = &pdev->dev;
    + struct device_node *node = dev->of_node;
    + struct resource *res;
    + struct clk *clk;
    + int err;
    + unsigned int max_timeout;
    + bool nowayout = WATCHDOG_NOWAYOUT;
    +
    + moxart_wdt = devm_kzalloc(&pdev->dev, sizeof(*moxart_wdt), GFP_KERNEL);
    + if (!moxart_wdt)
    + return -ENOMEM;
    +
    + platform_set_drvdata(pdev, moxart_wdt);
    +
    + res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
    + moxart_wdt->base = devm_ioremap_resource(dev, res);
    + if (IS_ERR(moxart_wdt->base))
    + return PTR_ERR(moxart_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);
    + }
    +
    + moxart_wdt->clock_frequency = clk_get_rate(clk);
    + if (moxart_wdt->clock_frequency == 0) {
    + pr_err("%s: incorrect clock frequency\n", __func__);
    + return -EINVAL;
    + }
    +
    + max_timeout = UINT_MAX / moxart_wdt->clock_frequency;
    +
    + moxart_wdt->dev.info = &moxart_wdt_info;
    + moxart_wdt->dev.ops = &moxart_wdt_ops;
    + moxart_wdt->dev.timeout = max_timeout;
    + moxart_wdt->dev.min_timeout = 1;
    + moxart_wdt->dev.max_timeout = max_timeout;
    + moxart_wdt->dev.parent = &pdev->dev;
    +
    + watchdog_init_timeout(&moxart_wdt->dev, heartbeat, &pdev->dev);
    + watchdog_set_nowayout(&moxart_wdt->dev, nowayout);
    +
    + watchdog_set_drvdata(&moxart_wdt->dev, moxart_wdt);
    +
    + err = watchdog_register_device(&moxart_wdt->dev);
    + if (unlikely(err))
    + return err;
    +
    + dev_dbg(dev, "Watchdog enabled (heartbeat=%d sec, nowayout=%d)\n",
    + moxart_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->dev);
    + watchdog_unregister_device(&moxart_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@gmail.com>");
    --
    1.8.2.1


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