[PATCH] watchdog: Add MAX6370 watchdog timer driver

Pali Rohár pali at kernel.org
Thu May 5 19:15:41 CEST 2022 

On Thursday 05 May 2022 11:36:09 Pali Rohár wrote:
> On Tuesday 03 May 2022 07:16:34 Stefan Roese wrote:
> > On 02.05.22 18:41, Pali Rohár wrote:
> > > MAX6370 watchdog is available e.g. on Freescale P1/P2 RDB-PC boards.
> > > 
> > > Signed-off-by: Pali Rohár <pali at kernel.org>
> > > ---
> > >   drivers/watchdog/Kconfig       |   7 ++
> > >   drivers/watchdog/Makefile      |   1 +
> > >   drivers/watchdog/max6370_wdt.c | 119 +++++++++++++++++++++++++++++++++
> > >   3 files changed, 127 insertions(+)
> > >   create mode 100644 drivers/watchdog/max6370_wdt.c
> > > 
> > > diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
> > > index f90f0ca02bce..1801698ac512 100644
> > > --- a/drivers/watchdog/Kconfig
> > > +++ b/drivers/watchdog/Kconfig
> > > @@ -167,6 +167,13 @@ config WDT_GPIO
> > >   	  doc/device-tree-bindings/watchdog/gpio-wdt.txt for
> > >   	  information on how to describe the watchdog in device tree.
> > > +config WDT_MAX6370
> > > +	bool "MAX6370 watchdog timer support"
> > > +	depends on WDT
> > > +	select DM_GPIO
> > > +	help
> > > +	  Select this to enable max6370 watchdog timer.
> > > +
> > >   config WDT_MPC8xx
> > >   	bool "MPC8xx watchdog timer support"
> > >   	depends on WDT && MPC8xx
> > > diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
> > > index a35bd559f51b..f999e4126b4f 100644
> > > --- a/drivers/watchdog/Makefile
> > > +++ b/drivers/watchdog/Makefile
> > > @@ -27,6 +27,7 @@ obj-$(CONFIG_WDT_CORTINA) += cortina_wdt.o
> > >   obj-$(CONFIG_WDT_ORION) += orion_wdt.o
> > >   obj-$(CONFIG_WDT_CDNS) += cdns_wdt.o
> > >   obj-$(CONFIG_WDT_GPIO) += gpio_wdt.o
> > > +obj-$(CONFIG_WDT_MAX6370) += max6370_wdt.o
> > >   obj-$(CONFIG_WDT_MPC8xx) += mpc8xx_wdt.o
> > >   obj-$(CONFIG_WDT_MT7620) += mt7620_wdt.o
> > >   obj-$(CONFIG_WDT_MT7621) += mt7621_wdt.o
> > > diff --git a/drivers/watchdog/max6370_wdt.c b/drivers/watchdog/max6370_wdt.c
> > > new file mode 100644
> > > index 000000000000..556c6a4b6d6b
> > > --- /dev/null
> > > +++ b/drivers/watchdog/max6370_wdt.c
> > > @@ -0,0 +1,119 @@
> > > +// SPDX-License-Identifier: GPL-2.0+
> > > +// (C) 2022 Pali Rohár <pali at kernel.org>
> > > +
> > > +#include <common.h>
> > 
> > AFAIK, it's not recommended any more to include "common.h" in general.
> 
> Hello! I checked that driver compiles without any errors/warnings also
> when common.h is removed. So it can be dropped.

I have tested this driver on P2020 board. Together with P2020 board code
workaround which I sent in separate patch, watchdog is working correctly
https://patchwork.ozlabs.org/project/uboot/patch/20220501122314.32626-2-pali@kernel.org/

> > Looks good, other than this:
> > 
> > Reviewed-by: Stefan Roese <sr at denx.de>
> > 
> > Thanks,
> > Stefan
> > 
> > > +#include <asm/io.h>
> > > +#include <asm-generic/gpio.h>
> > > +#include <dm.h>
> > > +#include <linux/delay.h>
> > > +#include <wdt.h>
> > > +
> > > +#define MAX6370_SET_MASK	0x7
> > > +#define MAX6370_SET_1MS		0x0
> > > +#define MAX6370_SET_10MS	0x1
> > > +#define MAX6370_SET_30MS	0x2
> > > +#define MAX6370_SET_DISABLE	0x3
> > > +#define MAX6370_SET_100MS	0x4
> > > +#define MAX6370_SET_1S		0x5
> > > +#define MAX6370_SET_10S		0x6
> > > +#define MAX6370_SET_60S		0x7
> > > +
> > > +#define MAX6370_WDI		0x8
> > > +
> > > +struct max6370_wdt {
> > > +	void __iomem *reg;
> > > +	struct gpio_desc gpio_wdi;
> > > +};
> > > +
> > > +static int max6370_wdt_start(struct udevice *dev, u64 ms, ulong flags)
> > > +{
> > > +	struct max6370_wdt *wdt = dev_get_priv(dev);
> > > +	u8 val;
> > > +
> > > +	val = readb(wdt->reg);
> > > +	val &= ~MAX6370_SET_MASK;
> > > +
> > > +	if (ms <= 1)
> > > +		val |= MAX6370_SET_1MS;
> > > +	else if (ms <= 10)
> > > +		val |= MAX6370_SET_10MS;
> > > +	else if (ms <= 30)
> > > +		val |= MAX6370_SET_30MS;
> > > +	else if (ms <= 100)
> > > +		val |= MAX6370_SET_100MS;
> > > +	else if (ms <= 1000)
> > > +		val |= MAX6370_SET_1S;
> > > +	else if (ms <= 10000)
> > > +		val |= MAX6370_SET_10S;
> > > +	else
> > > +		val |= MAX6370_SET_60S;
> > > +
> > > +	writeb(val, wdt->reg);
> > > +
> > > +	return 0;
> > > +}
> > > +
> > > +static int max6370_wdt_stop(struct udevice *dev)
> > > +{
> > > +	struct max6370_wdt *wdt = dev_get_priv(dev);
> > > +	u8 val;
> > > +
> > > +	val = readb(wdt->reg);
> > > +	val &= ~MAX6370_SET_MASK;
> > > +	val |= MAX6370_SET_DISABLE;
> > > +	writeb(val, wdt->reg);
> > > +
> > > +	return 0;
> > > +}
> > > +
> > > +static int max6370_wdt_reset(struct udevice *dev)
> > > +{
> > > +	struct max6370_wdt *wdt = dev_get_priv(dev);
> > > +	u8 val;
> > > +
> > > +	if (dm_gpio_is_valid(&wdt->gpio_wdi)) {
> > > +		dm_gpio_set_value(&wdt->gpio_wdi, 1);
> > > +		udelay(1);
> > > +		dm_gpio_set_value(&wdt->gpio_wdi, 0);
> > > +	} else {
> > > +		val = readb(wdt->reg);
> > > +		writeb(val | MAX6370_WDI, wdt->reg);
> > > +		writeb(val & ~MAX6370_WDI, wdt->reg);
> > > +	}
> > > +
> > > +	return 0;
> > > +}
> > > +
> > > +static int max6370_wdt_probe(struct udevice *dev)
> > > +{
> > > +	struct max6370_wdt *wdt = dev_get_priv(dev);
> > > +
> > > +	wdt->reg = dev_read_addr_ptr(dev);
> > > +	if (!wdt->reg)
> > > +		return -EINVAL;
> > > +
> > > +	/* WDI gpio is optional */
> > > +	gpio_request_by_name(dev, "gpios", 0, &wdt->gpio_wdi, GPIOD_IS_OUT);
> > > +
> > > +	return 0;
> > > +}
> > > +
> > > +static const struct wdt_ops max6370_wdt_ops = {
> > > +	.start = max6370_wdt_start,
> > > +	.stop = max6370_wdt_stop,
> > > +	.reset = max6370_wdt_reset,
> > > +};
> > > +
> > > +static const struct udevice_id max6370_wdt_ids[] = {
> > > +	{ .compatible = "maxim,max6370" },
> > > +	{}
> > > +};
> > > +
> > > +U_BOOT_DRIVER(max6370_wdt) = {
> > > +	.name = "max6370_wdt",
> > > +	.id = UCLASS_WDT,
> > > +	.of_match = max6370_wdt_ids,
> > > +	.probe = max6370_wdt_probe,
> > > +	.priv_auto = sizeof(struct max6370_wdt),
> > > +	.ops = &max6370_wdt_ops,
> > > +};
> > 
> > Viele Grüße,
> > Stefan Roese
> > 
> > -- 
> > DENX Software Engineering GmbH,      Managing Director: Wolfgang Denk
> > HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
> > Phone: (+49)-8142-66989-51 Fax: (+49)-8142-66989-80 Email: sr at denx.de

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