[PATCH v2] watchdog: Add DA906x PMIC watchdog driver.
Guenter Roeck
linux at roeck-us.net
Tue Aug 12 09:12:53 PDT 2014
On 08/12/2014 02:56 AM, Markus Pargmann wrote:
> From: Krystian Garbaciak <krystian.garbaciak at diasemi.com>
>
> This driver supports watchdog device inside DA906x PMIC.
>
> Signed-off-by: Krystian Garbaciak <krystian.garbaciak at diasemi.com>
> Signed-off-by: Philipp Zabel <p.zabel at pengutronix.de>
> Signed-off-by: Markus Pargmann <mpa at pengutronix.de>
What is different to v1 ?
> ---
> drivers/watchdog/Kconfig | 7 ++
> drivers/watchdog/Makefile | 1 +
> drivers/watchdog/da9063_wdt.c | 226 +++++++++++++++++++++++++++++++++++
> include/linux/mfd/da9063/registers.h | 1 +
> 4 files changed, 235 insertions(+)
> create mode 100644 drivers/watchdog/da9063_wdt.c
>
> diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
> index c845527b503a..8d5c9b33552a 100644
> --- a/drivers/watchdog/Kconfig
> +++ b/drivers/watchdog/Kconfig
> @@ -87,6 +87,13 @@ config DA9055_WATCHDOG
> This driver can also be built as a module. If so, the module
> will be called da9055_wdt.
>
> +config DA9063_WATCHDOG
> + tristate "Dialog DA9063 Watchdog"
> + depends on MFD_DA9063
> + select WATCHDOG_CORE
> + help
> + Support for the watchdog in the DA9063 PMIC.
> +
> 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 7b8a91ed20e7..ce4a7632d863 100644
> --- a/drivers/watchdog/Makefile
> +++ b/drivers/watchdog/Makefile
> @@ -172,6 +172,7 @@ 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_DA9063_WATCHDOG) += da9063_wdt.o
> obj-$(CONFIG_GPIO_WATCHDOG) += gpio_wdt.o
> obj-$(CONFIG_WM831X_WATCHDOG) += wm831x_wdt.o
> obj-$(CONFIG_WM8350_WATCHDOG) += wm8350_wdt.o
> diff --git a/drivers/watchdog/da9063_wdt.c b/drivers/watchdog/da9063_wdt.c
> new file mode 100644
> index 000000000000..befd6314f3f4
> --- /dev/null
> +++ b/drivers/watchdog/da9063_wdt.c
> @@ -0,0 +1,226 @@
> +/*
> + * Watchdog driver for DA9063 PMICs.
> + *
> + * Copyright(c) 2012 Dialog Semiconductor Ltd.
> + *
> + * Author: Mariusz Wojtasik <mariusz.wojtasik at diasemi.com>
> + *
> + * 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.
> + */
> +
> +#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/mfd/da9063/registers.h>
> +#include <linux/mfd/da9063/core.h>
> +#include <linux/regmap.h>
> +
> +/*
> + * Watchdog selector to timeout in seconds.
> + * 0: WDT disabled;
> + * others: timeout = 2048 ms * 2^(TWDSCALE-1).
> + */
> +static const int wdt_timeout[] = { 0, 2, 4, 8, 16, 32, 65, 131 };
> +#define DA9063_TWDSCALE_DISABLE 0
> +#define DA9063_TWDSCALE_MIN 1
> +#define DA9063_TWDSCALE_MAX (ARRAY_SIZE(wdt_timeout) - 1)
> +#define DA9063_WDT_MIN_TIMEOUT wdt_timeout[DA9063_TWDSCALE_MIN]
> +#define DA9063_WDT_MAX_TIMEOUT wdt_timeout[DA9063_TWDSCALE_MAX]
> +#define DA9063_WDG_TIMEOUT wdt_timeout[3]
> +
> +struct da9063_watchdog {
> + struct da9063 *da9063;
> + struct watchdog_device *wdtdev;
> + struct mutex lock;
> +};
> +
> +static int da9063_wdt_timeout_to_sel(int secs)
> +{
> + int i;
> +
> + for (i = DA9063_TWDSCALE_MIN; i <= DA9063_TWDSCALE_MAX; i++) {
> + if (wdt_timeout[i] >= secs)
> + return i;
> + }
> +
> + return 0;
It might be better to return -EINVAL and use it in the calling code.
> +}
> +
> +static int da9063_wdt_disable(struct da9063 *da9063)
> +{
> + return regmap_update_bits(da9063->regmap, DA9063_REG_CONTROL_D,
> + DA9063_TWDSCALE_MASK,
> + DA9063_TWDSCALE_DISABLE << DA9063_TWDSCALE_SHIFT);
> +}
> +
> +static int _da9063_wdt_set_timeout(struct da9063 *da9063, unsigned int regval)
> +{
> + if (regval < DA9063_TWDSCALE_MIN || regval > DA9063_TWDSCALE_MAX)
> + return -EINVAL;
> +
> + return regmap_update_bits(da9063->regmap, DA9063_REG_CONTROL_D,
> + DA9063_TWDSCALE_MASK, regval << DA9063_TWDSCALE_SHIFT);
> +}
> +
> +static int _da9063_wdt_kick(struct da9063 *da9063)
> +{
> + return regmap_write(da9063->regmap, DA9063_REG_CONTROL_F,
> + DA9063_WATCHDOG);
> +}
> +
> +static int da9063_wdt_start(struct watchdog_device *wdd)
> +{
> + struct da9063_watchdog *wdt = watchdog_get_drvdata(wdd);
> + unsigned int selector;
> + int ret = 0;
> +
> + mutex_lock(&wdt->lock);
> + selector = da9063_wdt_timeout_to_sel(wdt->wdtdev->timeout);
> + ret = _da9063_wdt_set_timeout(wdt->da9063, selector);
> + if (ret) {
> + dev_err(wdt->da9063->dev, "Watchdog failed to start (err = %d)\n",
> + ret);
> + }
> + mutex_unlock(&wdt->lock);
> +
> + return ret;
> +}
> +
> +static int da9063_wdt_stop(struct watchdog_device *wdd)
> +{
> + struct da9063_watchdog *wdt = watchdog_get_drvdata(wdd);
> + int ret = 0;
> +
> + mutex_lock(&wdt->lock);
> + ret = da9063_wdt_disable(wdt->da9063);
> + if (ret)
> + dev_alert(wdt->da9063->dev,
> + "Watchdog failed to stop (err = %d)\n", ret);
> + mutex_unlock(&wdt->lock);
> +
> + return ret;
> +}
> +
> +static int da9063_wdt_ping(struct watchdog_device *wdd)
> +{
> + struct da9063_watchdog *wdt = watchdog_get_drvdata(wdd);
> + int ret = 0;
> +
> + mutex_lock(&wdt->lock);
> + ret = _da9063_wdt_kick(wdt->da9063);
> + if (ret)
> + dev_alert(wdt->da9063->dev, "Failed to ping the watchdog (err = %d)\n",
> + ret);
> + mutex_unlock(&wdt->lock);
> +
> + return ret;
> +}
> +
> +static int da9063_wdt_set_timeout(struct watchdog_device *wdd,
> + unsigned int timeout)
> +{
> + struct da9063_watchdog *wdt = watchdog_get_drvdata(wdd);
> + unsigned int selector;
> + int ret;
> +
> + selector = da9063_wdt_timeout_to_sel(timeout);
> + if (selector == 0) {
> + dev_err(wdt->da9063->dev, "Unsupported watchdog timeout (select from: 2, 4, 8, 16, 32, 65, 131)\n");
This error case should never happen, since the range is checked by the calling code.
Besides, the error message is wrong. You do accept the entire range of [1 .. 131],
not just selected values.
Overall the error checking is inconsistent. Above you don't check the return code
but depend on _da9063_wdt_set_timeout to detect a range error.
> + return -EINVAL;
> + }
> +
> + mutex_lock(&wdt->lock);
> +
> + ret = _da9063_wdt_set_timeout(wdt->da9063, selector);
> + if (ret)
> + dev_err(wdt->da9063->dev, "Failed to set watchdog timeout (err = %d)\n",
> + ret);
> + else
> + wdd->timeout = wdt_timeout[selector];
> +
> + mutex_unlock(&wdt->lock);
> +
> + return ret;
> +}
> +
> +static const struct watchdog_info da9063_watchdog_info = {
> + .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
> + .identity = "DA9063 Watchdog",
> +};
> +
> +static const struct watchdog_ops da9063_watchdog_ops = {
> + .owner = THIS_MODULE,
> + .start = da9063_wdt_start,
> + .stop = da9063_wdt_stop,
> + .ping = da9063_wdt_ping,
> + .set_timeout = da9063_wdt_set_timeout,
> +};
> +
> +static struct watchdog_device da9063_watchdog_device = {
> + .info = &da9063_watchdog_info,
> + .ops = &da9063_watchdog_ops,
> +};
> +
> +static int da9063_wdt_probe(struct platform_device *pdev)
> +{
> + int ret;
> + struct da9063 *da9063 = dev_get_drvdata(pdev->dev.parent);
> + struct da9063_watchdog *wdt;
> +
> + if (!da9063)
> + return -EPROBE_DEFER;
> +
> + wdt = devm_kzalloc(&pdev->dev, sizeof(*wdt), GFP_KERNEL);
> + if (!wdt)
> + return -ENOMEM;
> +
> + wdt->da9063 = da9063;
> + wdt->wdtdev = &da9063_watchdog_device;
> + mutex_init(&wdt->lock);
> +
> + if (IS_ENABLED(CONFIG_WATCHDOG_NOWAYOUT))
> + set_bit(WDOG_NO_WAY_OUT, &wdt->wdtdev->status);
> +
Why not use watchdog_set_nowayout, or initialize .status with
WATCHDOG_NOWAYOUT_INIT_STATUS, as suggested in the API documentation ?
> + wdt->wdtdev->min_timeout = DA9063_WDT_MIN_TIMEOUT;
> + wdt->wdtdev->max_timeout = DA9063_WDT_MAX_TIMEOUT;
> + wdt->wdtdev->timeout = DA9063_WDG_TIMEOUT;
> +
Why don't you set those variables directly in da9063_watchdog_device ?
If you want to set it here, you might as well set ops and info
and get rid of the static variable (by including the entire structure
in wdt, not just a pointer to it).
> + ret = watchdog_register_device(wdt->wdtdev);
> + if (ret) {
> + dev_err(da9063->dev, "da9063-watchdog registration failed (err = %d)",
> + ret);
> + return ret;
> + }
> +
> + watchdog_set_drvdata(wdt->wdtdev, wdt);
> +
This creates a race condition, because at least in theory an access could
already occur between the watchdog registration above and this code.
> + return 0;
> +}
> +
> +static int da9063_wdt_remove(struct platform_device *pdev)
> +{
> + watchdog_unregister_device(&da9063_watchdog_device);
> +
> + return 0;
> +}
> +
> +static struct platform_driver da9063_wdt_driver = {
> + .probe = da9063_wdt_probe,
> + .remove = da9063_wdt_remove,
> + .driver = {
> + .name = DA9063_DRVNAME_WATCHDOG,
> + },
> +};
> +module_platform_driver(da9063_wdt_driver);
> +
> +MODULE_AUTHOR("Mariusz Wojtasik <mariusz.wojtasik at diasemi.com>");
> +MODULE_DESCRIPTION("Watchdog driver for Dialog DA9063");
> +MODULE_LICENSE("GPL");
> +MODULE_ALIAS("platform:" DA9063_DRVNAME_WATCHDOG);
> diff --git a/include/linux/mfd/da9063/registers.h b/include/linux/mfd/da9063/registers.h
> index 09a85c699da1..e11a66894afc 100644
> --- a/include/linux/mfd/da9063/registers.h
> +++ b/include/linux/mfd/da9063/registers.h
> @@ -431,6 +431,7 @@
>
> /* DA9063_REG_CONTROL_D (addr=0x11) */
> #define DA9063_TWDSCALE_MASK 0x07
> +#define DA9063_TWDSCALE_SHIFT 0x00
That is unnecessary. Why shift if there is nothing to shift ?
It just adds unnecessary complexity to the code.
> #define DA9063_BLINK_FRQ_MASK 0x38
> #define DA9063_BLINK_FRQ_OFF 0x00
> #define DA9063_BLINK_FRQ_1S0 0x08
>
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