[PATCH v2 2/2] watchdog: digicolor: driver for Conexant Digicolor CX92755 SoC
Guenter Roeck
linux at roeck-us.net
Thu Mar 26 22:20:10 PDT 2015
On 03/26/2015 12:59 AM, Baruch Siach wrote:
> This commit add a driver for the watchdog functionality of the Conexant CX92755
> SoC, from the Digicolor series of SoCs. Of 8 system timers provided by the
> CX92755, the first one, timer A, can reset the chip when its counter reaches
> zero. This driver uses this capability to provide userspace with a standard
> watchdog, using the watchdog timer driver core framework. This driver also
> implements a reboot handler for the reboot(2) system call.
>
> The watchdog driver shares the timer registers with the CX92755 timer driver
> (drivers/clocksource/timer-digicolor.c). The timer driver, however, uses only
> timers other than A, so both drivers should coexist.
>
> Signed-off-by: Baruch Siach <baruch at tkos.co.il>
Almost there. Couple of nitpicks below.
Thanks,
Guenter
> ---
> v2:
> Address the comments of Guenter Roeck:
>
> * Set default timeout to max_timeout
> * Move watchdog timer set code to a helper routine to avoid code duplication
> * Update watchdog timer on .set_timeout callback
> * Fix iomap leak on error path
> * Change restart registration error message to a warning
> * Use devm_clk_get() to acquire the clock
> ---
> drivers/watchdog/Kconfig | 10 ++
> drivers/watchdog/Makefile | 1 +
> drivers/watchdog/digicolor_wdt.c | 206 +++++++++++++++++++++++++++++++++++++++
> 3 files changed, 217 insertions(+)
> create mode 100644 drivers/watchdog/digicolor_wdt.c
>
> diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
> index 16f202350997..7d73d6c78cf6 100644
> --- a/drivers/watchdog/Kconfig
> +++ b/drivers/watchdog/Kconfig
> @@ -515,6 +515,16 @@ config MEDIATEK_WATCHDOG
> To compile this driver as a module, choose M here: the
> module will be called mtk_wdt.
>
> +config DIGICOLOR_WATCHDOG
> + tristate "Conexant Digicolor SoCs watchdog support"
> + depends on ARCH_DIGICOLOR
> + select WATCHDOG_CORE
> + help
> + Say Y here to include support for the watchdog timer
> + in Conexant Digicolor SoCs.
> + To compile this driver as a module, choose M here: the
> + module will be called digicolor_wdt.
> +
> # AVR32 Architecture
>
> config AT32AP700X_WDT
> diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
> index 5c19294d1c30..0721f10e8d13 100644
> --- a/drivers/watchdog/Makefile
> +++ b/drivers/watchdog/Makefile
> @@ -64,6 +64,7 @@ obj-$(CONFIG_BCM_KONA_WDT) += bcm_kona_wdt.o
> obj-$(CONFIG_TEGRA_WATCHDOG) += tegra_wdt.o
> obj-$(CONFIG_MESON_WATCHDOG) += meson_wdt.o
> obj-$(CONFIG_MEDIATEK_WATCHDOG) += mtk_wdt.o
> +obj-$(CONFIG_DIGICOLOR_WATCHDOG) += digicolor_wdt.o
>
> # AVR32 Architecture
> obj-$(CONFIG_AT32AP700X_WDT) += at32ap700x_wdt.o
> diff --git a/drivers/watchdog/digicolor_wdt.c b/drivers/watchdog/digicolor_wdt.c
> new file mode 100644
> index 000000000000..99981c54c1b9
> --- /dev/null
> +++ b/drivers/watchdog/digicolor_wdt.c
> @@ -0,0 +1,206 @@
> +/*
> + * Watchdog driver for Conexant Digicolor
> + *
> + * Copyright (C) 2015 Paradox Innovation 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.
> + */
> +
> +#include <linux/types.h>
> +#include <linux/module.h>
> +#include <linux/io.h>
> +#include <linux/delay.h>
> +#include <linux/clk.h>
> +#include <linux/watchdog.h>
> +#include <linux/reboot.h>
> +#include <linux/platform_device.h>
> +#include <linux/of_address.h>
> +
> +#define TIMER_A_CONTROL 0
> +#define TIMER_A_COUNT 4
> +
> +#define TIMER_A_ENABLE_COUNT BIT(0)
> +#define TIMER_A_ENABLE_WATCHDOG BIT(1)
> +
> +struct dc_wdt {
> + void __iomem *base;
> + struct clk *clk;
> + struct notifier_block restart_handler;
> + spinlock_t lock;
> +};
> +
> +static unsigned timeout;
> +module_param(timeout, uint, 0);
> +MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds");
> +
> +static void dc_wdt_set(struct dc_wdt *wdt, u32 ticks)
> +{
> + unsigned long flags;
> +
> + spin_lock_irqsave(&wdt->lock, flags);
> +
> + writel_relaxed(0, wdt->base + TIMER_A_CONTROL);
> + writel_relaxed(ticks, wdt->base + TIMER_A_COUNT);
> + writel_relaxed(TIMER_A_ENABLE_COUNT | TIMER_A_ENABLE_WATCHDOG,
> + wdt->base + TIMER_A_CONTROL);
> +
> + spin_unlock_irqrestore(&wdt->lock, flags);
> +}
> +
> +static int dc_restart_handler(struct notifier_block *this, unsigned long mode,
> + void *cmd)
> +{
> + struct dc_wdt *wdt = container_of(this, struct dc_wdt, restart_handler);
> +
> + dc_wdt_set(wdt, 1);
> + /* wait for reset to assert... */
> + mdelay(500);
> +
> + return NOTIFY_DONE;
> +}
> +
> +static int dc_wdt_start(struct watchdog_device *wdog)
> +{
> + struct dc_wdt *wdt = watchdog_get_drvdata(wdog);
> +
> + dc_wdt_set(wdt, wdog->timeout * clk_get_rate(wdt->clk));
> +
> + return 0;
> +}
> +
> +static int dc_wdt_stop(struct watchdog_device *wdog)
> +{
> + struct dc_wdt *wdt = watchdog_get_drvdata(wdog);
> +
> + writel_relaxed(0, wdt->base + TIMER_A_CONTROL);
> +
> + return 0;
> +}
> +
> +static int dc_wdt_set_timeout(struct watchdog_device *wdog, unsigned int t)
> +{
> + struct dc_wdt *wdt = watchdog_get_drvdata(wdog);
> +
> + dc_wdt_set(wdt, t * clk_get_rate(wdt->clk));
> + wdog->timeout = t;
> +
> + return 0;
> +}
> +
> +static unsigned int dc_wdt_get_timeleft(struct watchdog_device *wdog)
> +{
> + struct dc_wdt *wdt = watchdog_get_drvdata(wdog);
> + uint32_t count = readl_relaxed(wdt->base + TIMER_A_COUNT);
> +
> + return (count / clk_get_rate(wdt->clk));
Unnecessary ( ).
> +}
> +
> +static struct watchdog_ops dc_wdt_ops = {
> + .owner = THIS_MODULE,
> + .start = dc_wdt_start,
> + .stop = dc_wdt_stop,
> + .set_timeout = dc_wdt_set_timeout,
> + .get_timeleft = dc_wdt_get_timeleft,
> +};
> +
> +static struct watchdog_info dc_wdt_info = {
> + .options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE
> + | WDIOF_KEEPALIVEPING,
> + .identity = "Conexant Digicolor Watchdog",
> +};
> +
> +static struct watchdog_device dc_wdt_wdd = {
> + .info = &dc_wdt_info,
> + .ops = &dc_wdt_ops,
> + .min_timeout = 1,
> +};
> +
> +static int dc_wdt_probe(struct platform_device *pdev)
> +{
> + struct device *dev = &pdev->dev;
> + struct device_node *np = dev->of_node;
> + struct dc_wdt *wdt;
> + int ret;
> +
> + wdt = devm_kzalloc(dev, sizeof(struct dc_wdt), GFP_KERNEL);
> + if (!wdt)
> + return -ENOMEM;
> + platform_set_drvdata(pdev, wdt);
> +
> + wdt->base = of_iomap(np, 0);
> + if (!wdt->base) {
> + dev_err(dev, "Failed to remap watchdog regs");
> + return -ENODEV;
> + }
> +
> + wdt->clk = devm_clk_get(&pdev->dev, NULL);
> + if (IS_ERR(wdt->clk)) {
> + ret = PTR_ERR(wdt->clk);
> + goto err_clk;
> + }
> + dc_wdt_wdd.max_timeout = U32_MAX / clk_get_rate(wdt->clk);
> + dc_wdt_wdd.timeout = dc_wdt_wdd.max_timeout;
> +
> + spin_lock_init(&wdt->lock);
> +
> + watchdog_set_drvdata(&dc_wdt_wdd, wdt);
> + watchdog_init_timeout(&dc_wdt_wdd, timeout, dev);
> + ret = watchdog_register_device(&dc_wdt_wdd);
> + if (ret) {
> + dev_err(dev, "Failed to register watchdog device");
> + goto err_wdt;
> + }
> +
> + wdt->restart_handler.notifier_call = dc_restart_handler;
> + wdt->restart_handler.priority = 128;
> + ret = register_restart_handler(&wdt->restart_handler);
> + if (ret)
> + dev_warn(&pdev->dev, "cannot register restart handler\n");
> +
> + return 0;
> +
> +err_wdt:
> +err_clk:
Please use only one label.
> + iounmap(wdt->base);
> + return ret;
> +}
> +
> +static int dc_wdt_remove(struct platform_device *pdev)
> +{
> + struct dc_wdt *wdt = platform_get_drvdata(pdev);
> +
> + unregister_restart_handler(&wdt->restart_handler);
> + watchdog_unregister_device(&dc_wdt_wdd);
> + iounmap(wdt->base);
> +
> + return 0;
> +}
> +
> +static void dc_wdt_shutdown(struct platform_device *pdev)
> +{
> + dc_wdt_stop(&dc_wdt_wdd);
> +}
> +
> +static const struct of_device_id dc_wdt_of_match[] = {
> + { .compatible = "cnxt,cx92755-wdt", },
> + {},
> +};
> +MODULE_DEVICE_TABLE(of, dc_wdt_of_match);
> +
> +static struct platform_driver dc_wdt_driver = {
> + .probe = dc_wdt_probe,
> + .remove = dc_wdt_remove,
> + .shutdown = dc_wdt_shutdown,
> + .driver = {
> + .name = "digicolor-wdt",
> + .of_match_table = dc_wdt_of_match,
> + },
> +};
> +module_platform_driver(dc_wdt_driver);
> +
> +MODULE_AUTHOR("Baruch Siach <baruch at tkos.co.il>");
> +MODULE_DESCRIPTION("Driver for Conexant Digicolor watchdog timer");
> +MODULE_LICENSE("GPL");
>
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