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    Subject[PATCH V3 3/4] watchdog: da9062: DA9062 watchdog driver
    From: S Twiss <stwiss.opensource@diasemi.com>

    Add watchdog driver support for DA9062


    Signed-off-by: Steve Twiss <stwiss.opensource@diasemi.com>

    ---

    Changes in V3:
    - Removed unnecessary return statement in da9062_apply_window_protection()
    - Deleted dev_err() kernel noise in da9062_wdt_update_timeout_register()
    - Changed dev_alert() to be a dev_err() in da9062_wdt_stop()
    - Deleted the "watchdog ping" debug message in da9062_wdt_ping()
    - Refactored the error path inthe probe() to remove redundant error gotos
    - Altered dev_err() string to notify failures more specifically in probe()
    - Removed the space in MODULE_ALIAS string "platform: da9062-watchdog"
    - Ensure request for devm_request_threaded_irq() removal is completed

    Changes in V2:
    - Removed informational dev_info() 'installed watchdog' message
    - Copyright headers GPL v2 (and later) match correct 'GPL' in MODULE_LICENSE
    - Removed the explicit 300 msecs delay from the reset_watchdog_timer()
    function and replaced it with a variable delay (depending on the
    difference since the last ping). A debug message is used to catch the
    multiple pings trying to break the 300 msecs protection barrier.
    - Fix error paths for the functions da9062_wdt_update_timeout_register()
    and da9062_wdt_stop()
    - Add error paths in the probe() and correctly clean-up the registered
    device if there is a problem after registration.

    This patch applies against linux-next and v4.1-rc3



    drivers/watchdog/Kconfig | 9 ++
    drivers/watchdog/Makefile | 1 +
    drivers/watchdog/da9062_wdt.c | 253 ++++++++++++++++++++++++++++++++++++++++++
    3 files changed, 263 insertions(+)
    create mode 100644 drivers/watchdog/da9062_wdt.c

    diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
    index e5e7c55..dfdb6c6 100644
    --- a/drivers/watchdog/Kconfig
    +++ b/drivers/watchdog/Kconfig
    @@ -96,6 +96,15 @@ config DA9063_WATCHDOG

    This driver can be built as a module. The module name is da9063_wdt.

    +config DA9062_WATCHDOG
    + tristate "Dialog DA9062 Watchdog"
    + depends on MFD_DA9062
    + select WATCHDOG_CORE
    + help
    + Support for the watchdog in the DA9062 PMIC.
    +
    + This driver can be built as a module. The module name is da9062_wdt.
    +
    config GPIO_WATCHDOG
    tristate "Watchdog device controlled through GPIO-line"
    depends on OF_GPIO
    diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
    index 5c19294..57ba815 100644
    --- a/drivers/watchdog/Makefile
    +++ b/drivers/watchdog/Makefile
    @@ -179,6 +179,7 @@ obj-$(CONFIG_XEN_WDT) += xen_wdt.o
    # Architecture Independent
    obj-$(CONFIG_DA9052_WATCHDOG) += da9052_wdt.o
    obj-$(CONFIG_DA9055_WATCHDOG) += da9055_wdt.o
    +obj-$(CONFIG_DA9062_WATCHDOG) += da9062_wdt.o
    obj-$(CONFIG_DA9063_WATCHDOG) += da9063_wdt.o
    obj-$(CONFIG_GPIO_WATCHDOG) += gpio_wdt.o
    obj-$(CONFIG_WM831X_WATCHDOG) += wm831x_wdt.o
    diff --git a/drivers/watchdog/da9062_wdt.c b/drivers/watchdog/da9062_wdt.c
    new file mode 100644
    index 0000000..b3a870c
    --- /dev/null
    +++ b/drivers/watchdog/da9062_wdt.c
    @@ -0,0 +1,253 @@
    +/*
    + * da9062_wdt.c - WDT device driver for DA9062
    + * Copyright (C) 2015 Dialog Semiconductor Ltd.
    + *
    + * This program is free software; you can redistribute it and/or
    + * modify it under the terms of the GNU General Public License
    + * as published by the Free Software Foundation; either version 2
    + * of the License, or (at your option) any later version.
    + *
    + * This program is distributed in the hope that it will be useful,
    + * but WITHOUT ANY WARRANTY; without even the implied warranty of
    + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
    + * GNU General Public License for more details.
    + */
    +
    +#include <linux/kernel.h>
    +#include <linux/module.h>
    +#include <linux/watchdog.h>
    +#include <linux/platform_device.h>
    +#include <linux/uaccess.h>
    +#include <linux/slab.h>
    +#include <linux/delay.h>
    +#include <linux/jiffies.h>
    +#include <linux/mfd/da9062/registers.h>
    +#include <linux/mfd/da9062/core.h>
    +#include <linux/regmap.h>
    +#include <linux/of.h>
    +
    +static const unsigned int wdt_timeout[] = { 0, 2, 4, 8, 16, 32, 65, 131 };
    +#define DA9062_TWDSCALE_DISABLE 0
    +#define DA9062_TWDSCALE_MIN 1
    +#define DA9062_TWDSCALE_MAX (ARRAY_SIZE(wdt_timeout) - 1)
    +#define DA9062_WDT_MIN_TIMEOUT wdt_timeout[DA9062_TWDSCALE_MIN]
    +#define DA9062_WDT_MAX_TIMEOUT wdt_timeout[DA9062_TWDSCALE_MAX]
    +#define DA9062_WDG_DEFAULT_TIMEOUT wdt_timeout[DA9062_TWDSCALE_MAX-1]
    +#define DA9062_RESET_PROTECTION_MS 300
    +
    +struct da9062_watchdog {
    + struct da9062 *hw;
    + struct watchdog_device wdtdev;
    + unsigned long j_time_stamp;
    +};
    +
    +static void da9062_set_window_start(struct da9062_watchdog *wdt)
    +{
    + wdt->j_time_stamp = jiffies;
    +}
    +
    +static void da9062_apply_window_protection(struct da9062_watchdog *wdt)
    +{
    + unsigned long delay = msecs_to_jiffies(DA9062_RESET_PROTECTION_MS);
    + unsigned long timeout = wdt->j_time_stamp + delay;
    + unsigned long now = jiffies;
    + unsigned int diff_ms;
    +
    + /* if time-limit has not elapsed then wait for remainder */
    + if (time_before(now, timeout)) {
    + diff_ms = jiffies_to_msecs(timeout-now);
    + dev_dbg(wdt->hw->dev,
    + "Kicked too quickly. Delaying %u msecs\n", diff_ms);
    + msleep(diff_ms);
    + }
    +}
    +
    +static unsigned int da9062_wdt_timeout_to_sel(unsigned int secs)
    +{
    + unsigned int i;
    +
    + for (i = DA9062_TWDSCALE_MIN; i <= DA9062_TWDSCALE_MAX; i++) {
    + if (wdt_timeout[i] >= secs)
    + return i;
    + }
    +
    + return DA9062_TWDSCALE_MAX;
    +}
    +
    +static int da9062_reset_watchdog_timer(struct da9062_watchdog *wdt)
    +{
    + int ret;
    +
    + da9062_apply_window_protection(wdt);
    +
    + ret = regmap_update_bits(wdt->hw->regmap,
    + DA9062AA_CONTROL_F,
    + DA9062AA_WATCHDOG_MASK,
    + DA9062AA_WATCHDOG_MASK);
    +
    + da9062_set_window_start(wdt);
    +
    + return ret;
    +}
    +
    +static int da9062_wdt_update_timeout_register(struct da9062_watchdog *wdt,
    + unsigned int regval)
    +{
    + struct da9062 *chip = wdt->hw;
    + int ret;
    +
    + ret = da9062_reset_watchdog_timer(wdt);
    + if (ret)
    + return ret;
    +
    + return regmap_update_bits(chip->regmap,
    + DA9062AA_CONTROL_D,
    + DA9062AA_TWDSCALE_MASK,
    + regval);
    +}
    +
    +static int da9062_wdt_start(struct watchdog_device *wdd)
    +{
    + struct da9062_watchdog *wdt = watchdog_get_drvdata(wdd);
    + unsigned int selector;
    + int ret;
    +
    + selector = da9062_wdt_timeout_to_sel(wdt->wdtdev.timeout);
    + ret = da9062_wdt_update_timeout_register(wdt, selector);
    + if (ret)
    + dev_err(wdt->hw->dev, "Watchdog failed to start (err = %d)\n",
    + ret);
    +
    + return ret;
    +}
    +
    +static int da9062_wdt_stop(struct watchdog_device *wdd)
    +{
    + struct da9062_watchdog *wdt = watchdog_get_drvdata(wdd);
    + int ret;
    +
    + ret = da9062_reset_watchdog_timer(wdt);
    + if (ret) {
    + dev_err(wdt->hw->dev, "Failed to ping the watchdog (err = %d)\n",
    + ret);
    + return ret;
    + }
    +
    + ret = regmap_update_bits(wdt->hw->regmap,
    + DA9062AA_CONTROL_D,
    + DA9062AA_TWDSCALE_MASK,
    + DA9062_TWDSCALE_DISABLE);
    + if (ret)
    + dev_err(wdt->hw->dev, "Watchdog failed to stop (err = %d)\n",
    + ret);
    +
    + return ret;
    +}
    +
    +static int da9062_wdt_ping(struct watchdog_device *wdd)
    +{
    + struct da9062_watchdog *wdt = watchdog_get_drvdata(wdd);
    + int ret;
    +
    + ret = da9062_reset_watchdog_timer(wdt);
    + if (ret)
    + dev_err(wdt->hw->dev, "Failed to ping the watchdog (err = %d)\n",
    + ret);
    +
    + return ret;
    +}
    +
    +static int da9062_wdt_set_timeout(struct watchdog_device *wdd,
    + unsigned int timeout)
    +{
    + struct da9062_watchdog *wdt = watchdog_get_drvdata(wdd);
    + unsigned int selector;
    + int ret;
    +
    + selector = da9062_wdt_timeout_to_sel(timeout);
    + ret = da9062_wdt_update_timeout_register(wdt, selector);
    + if (ret)
    + dev_err(wdt->hw->dev, "Failed to set watchdog timeout (err = %d)\n",
    + ret);
    + else
    + wdd->timeout = wdt_timeout[selector];
    +
    + return ret;
    +}
    +
    +static const struct watchdog_info da9062_watchdog_info = {
    + .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
    + .identity = "DA9062 WDT",
    +};
    +
    +static const struct watchdog_ops da9062_watchdog_ops = {
    + .owner = THIS_MODULE,
    + .start = da9062_wdt_start,
    + .stop = da9062_wdt_stop,
    + .ping = da9062_wdt_ping,
    + .set_timeout = da9062_wdt_set_timeout,
    +};
    +
    +static int da9062_wdt_probe(struct platform_device *pdev)
    +{
    + int ret;
    + struct da9062 *chip;
    + struct da9062_watchdog *wdt;
    +
    + chip = dev_get_drvdata(pdev->dev.parent);
    + if (!chip)
    + return -EINVAL;
    +
    + wdt = devm_kzalloc(&pdev->dev, sizeof(*wdt), GFP_KERNEL);
    + if (!wdt)
    + return -ENOMEM;
    +
    + wdt->hw = chip;
    +
    + wdt->wdtdev.info = &da9062_watchdog_info;
    + wdt->wdtdev.ops = &da9062_watchdog_ops;
    + wdt->wdtdev.min_timeout = DA9062_WDT_MIN_TIMEOUT;
    + wdt->wdtdev.max_timeout = DA9062_WDT_MAX_TIMEOUT;
    + wdt->wdtdev.timeout = DA9062_WDG_DEFAULT_TIMEOUT;
    + wdt->wdtdev.status = WATCHDOG_NOWAYOUT_INIT_STATUS;
    +
    + watchdog_set_drvdata(&wdt->wdtdev, wdt);
    + dev_set_drvdata(&pdev->dev, wdt);
    +
    + ret = watchdog_register_device(&wdt->wdtdev);
    + if (ret < 0) {
    + dev_err(wdt->hw->dev,
    + "watchdog registration failed (%d)\n", ret);
    + return ret;
    + }
    +
    + da9062_set_window_start(wdt);
    +
    + ret = da9062_wdt_ping(&wdt->wdtdev);
    + if (ret < 0)
    + watchdog_unregister_device(&wdt->wdtdev);
    +
    + return ret;
    +}
    +
    +static int da9062_wdt_remove(struct platform_device *pdev)
    +{
    + struct da9062_watchdog *wdt = dev_get_drvdata(&pdev->dev);
    +
    + watchdog_unregister_device(&wdt->wdtdev);
    + return 0;
    +}
    +
    +static struct platform_driver da9062_wdt_driver = {
    + .probe = da9062_wdt_probe,
    + .remove = da9062_wdt_remove,
    + .driver = {
    + .name = "da9062-watchdog",
    + },
    +};
    +module_platform_driver(da9062_wdt_driver);
    +
    +MODULE_AUTHOR("S Twiss <stwiss.opensource@diasemi.com>");
    +MODULE_DESCRIPTION("WDT device driver for Dialog DA9062");
    +MODULE_LICENSE("GPL");
    +MODULE_ALIAS("platform:da9062-watchdog");
    --
    end-of-patch for PATCH V3


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