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Message-ID: <79a5ec82-da71-57c3-d7bb-11607cb71bb4@roeck-us.net>
Date: Wed, 27 Apr 2022 06:03:19 -0700
From: Guenter Roeck <linux@...ck-us.net>
To: Jean-Jacques Hiblot <jjhiblot@...phandler.com>,
wim@...ux-watchdog.org, geert+renesas@...der.be,
tzungbi@...nel.org, linux-watchdog@...r.kernel.org
Cc: linux-renesas-soc@...r.kernel.org, linux-kernel@...r.kernel.org,
Phil Edworthy <phil.edworthy@...esas.com>
Subject: Re: [PATCH v6 2/2] watchdog: Add Renesas RZ/N1 Watchdog driver
On 4/13/22 01:25, Jean-Jacques Hiblot wrote:
> From: Phil Edworthy <phil.edworthy@...esas.com>
>
> This is a driver for the standard WDT on the RZ/N1 devices. This WDT has
> very limited timeout capabilities. However, it can reset the device.
> To do so, the corresponding bits in the SysCtrl RSTEN register need to
> be enabled. This is not done by this driver.
>
> Signed-off-by: Phil Edworthy <phil.edworthy@...esas.com>
> Signed-off-by: Jean-Jacques Hiblot <jjhiblot@...phandler.com>
> Reviewed-by: Tzung-Bi Shih <tzungbi@...nel.org>
> ---
> drivers/watchdog/Kconfig | 8 ++
> drivers/watchdog/Makefile | 1 +
> drivers/watchdog/rzn1_wdt.c | 203 ++++++++++++++++++++++++++++++++++++
> 3 files changed, 212 insertions(+)
> create mode 100644 drivers/watchdog/rzn1_wdt.c
>
> diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
> index c4e82a8d863f..4d5e503c8950 100644
> --- a/drivers/watchdog/Kconfig
> +++ b/drivers/watchdog/Kconfig
> @@ -883,6 +883,14 @@ config RENESAS_RZAWDT
> This driver adds watchdog support for the integrated watchdogs in the
> Renesas RZ/A SoCs. These watchdogs can be used to reset a system.
>
> +config RENESAS_RZN1WDT
> + tristate "Renesas RZ/N1 watchdog"
> + depends on ARCH_RENESAS || COMPILE_TEST
> + select WATCHDOG_CORE
> + help
> + This driver adds watchdog support for the integrated watchdogs in the
> + Renesas RZ/N1 SoCs. These watchdogs can be used to reset a system.
> +
> config RENESAS_RZG2LWDT
> tristate "Renesas RZ/G2L WDT Watchdog"
> depends on ARCH_RENESAS || COMPILE_TEST
> diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
> index f7da867e8782..38d38564f47b 100644
> --- a/drivers/watchdog/Makefile
> +++ b/drivers/watchdog/Makefile
> @@ -84,6 +84,7 @@ obj-$(CONFIG_LPC18XX_WATCHDOG) += lpc18xx_wdt.o
> obj-$(CONFIG_BCM7038_WDT) += bcm7038_wdt.o
> obj-$(CONFIG_RENESAS_WDT) += renesas_wdt.o
> obj-$(CONFIG_RENESAS_RZAWDT) += rza_wdt.o
> +obj-$(CONFIG_RENESAS_RZN1WDT) += rzn1_wdt.o
> obj-$(CONFIG_RENESAS_RZG2LWDT) += rzg2l_wdt.o
> obj-$(CONFIG_ASPEED_WATCHDOG) += aspeed_wdt.o
> obj-$(CONFIG_STM32_WATCHDOG) += stm32_iwdg.o
> diff --git a/drivers/watchdog/rzn1_wdt.c b/drivers/watchdog/rzn1_wdt.c
> new file mode 100644
> index 000000000000..fa32716727b7
> --- /dev/null
> +++ b/drivers/watchdog/rzn1_wdt.c
> @@ -0,0 +1,203 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Renesas RZ/N1 Watchdog timer.
> + * This is a 12-bit timer driver from a (62.5/16384) MHz clock. It can't even
> + * cope with 2 seconds.
> + *
> + * Copyright 2018 Renesas Electronics Europe Ltd.
> + *
> + * Derived from Ralink RT288x watchdog timer.
> + */
> +
> +#include <linux/clk.h>
> +#include <linux/interrupt.h>
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/of_address.h>
> +#include <linux/of_irq.h>
> +#include <linux/platform_device.h>
> +#include <linux/reboot.h>
> +#include <linux/watchdog.h>
> +
> +#define DEFAULT_TIMEOUT 60
> +
> +#define RZN1_WDT_RETRIGGER 0x0
> +#define RZN1_WDT_RETRIGGER_RELOAD_VAL 0
> +#define RZN1_WDT_RETRIGGER_RELOAD_VAL_MASK 0xfff
> +#define RZN1_WDT_RETRIGGER_PRESCALE BIT(12)
> +#define RZN1_WDT_RETRIGGER_ENABLE BIT(13)
> +#define RZN1_WDT_RETRIGGER_WDSI (0x2 << 14)
> +
> +#define RZN1_WDT_PRESCALER 16384
> +#define RZN1_WDT_MAX 4095
> +
> +struct rzn1_watchdog {
> + struct watchdog_device wdtdev;
> + void __iomem *base;
> + unsigned long clk_rate;
Nit: Whenever clk_rate is used, it is divided by 1000.
It might be better to store and use clk_rate_khz instead.
Guenter
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