Hi, On Tue, Jan 22, 2019 at 08:03:09PM +0200, Matti Vaittinen wrote: > On Tue, Jan 22, 2019 at 09:40:56AM -0800, Guenter Roeck wrote: > > On Tue, Jan 22, 2019 at 07:10:23PM +0200, Matti Vaittinen wrote: > > > On Tue, Jan 22, 2019 at 07:47:50AM -0800, Guenter Roeck wrote: > > > > On Tue, Jan 22, 2019 at 11:48:36AM +0200, Matti Vaittinen wrote: > > > > > Initial support for watchdog block included in ROHM BD70528 > > > > > power management IC. > > > > > > > > > > Configurations for low power states are still to be checked. > > > > > > > > > > Signed-off-by: Matti Vaittinen > > > > > --- > > > > > drivers/watchdog/Kconfig | 12 +++ > > > > > drivers/watchdog/Makefile | 1 + > > > > > drivers/watchdog/bd70528_wdt.c | 161 +++++++++++++++++++++++++++++++++++++++++ > > > > > 3 files changed, 174 insertions(+) > > > > > create mode 100644 drivers/watchdog/bd70528_wdt.c > > > > > > > > > > diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig > > > > > index 57f017d74a97..f30e3a3e886e 100644 > > > > > --- a/drivers/watchdog/Kconfig > > > > > +++ b/drivers/watchdog/Kconfig > > > > > @@ -90,6 +90,18 @@ config SOFT_WATCHDOG_PRETIMEOUT > > > > > watchdog. Be aware that governors might affect the watchdog because it > > > > > is purely software, e.g. the panic governor will stall it! > > > > > > > > > > +config BD70528_WATCHDOG > > > > > + tristate "ROHM BD70528 PMIC Watchdog" > > > > > + depends on MFD_ROHM_BD70528 > > > > > + select WATCHDOG_CORE > > > > > + help > > > > > + Support for the watchdog in the ROHM BD70528 PMIC. Watchdog trigger > > > > > + cause system reset. > > > > > + > > > > > + Say Y here to include support for the ROHM BD70528 watchdog. > > > > > + Alternatively say M to compile the driver as a module, > > > > > + which will be called bd70528_wdt. > > > > > + > > > > > config DA9052_WATCHDOG > > > > > tristate "Dialog DA9052 Watchdog" > > > > > depends on PMIC_DA9052 || COMPILE_TEST > > > > > diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile > > > > > index a0917ef28e07..1ce87a3b1172 100644 > > > > > --- a/drivers/watchdog/Makefile > > > > > +++ b/drivers/watchdog/Makefile > > > > > @@ -204,6 +204,7 @@ obj-$(CONFIG_WATCHDOG_SUN4V) += sun4v_wdt.o > > > > > obj-$(CONFIG_XEN_WDT) += xen_wdt.o > > > > > > > > > > # Architecture Independent > > > > > +obj-$(CONFIG_BD70528_WATCHDOG) += bd70528_wdt.o > > > > > obj-$(CONFIG_DA9052_WATCHDOG) += da9052_wdt.o > > > > > obj-$(CONFIG_DA9055_WATCHDOG) += da9055_wdt.o > > > > > obj-$(CONFIG_DA9062_WATCHDOG) += da9062_wdt.o > > > > > diff --git a/drivers/watchdog/bd70528_wdt.c b/drivers/watchdog/bd70528_wdt.c > > > > > new file mode 100644 > > > > > index 000000000000..e9a32566f595 > > > > > --- /dev/null > > > > > +++ b/drivers/watchdog/bd70528_wdt.c > > > > > @@ -0,0 +1,161 @@ > > > > > +// SPDX-License-Identifier: GPL-2.0 > > > > > +// Copyright (C) 2018 ROHM Semiconductors > > > > > +// ROHM BD70528MWV watchdog driver > > > > > + > > > > > +#include > > > > > +#include > > > > > +#include > > > > > +#include > > > > > +#include > > > > > +#include > > > > > +#include > > > > > +#include > > > > > + > > > > > +static int bd70528_wdt_set(struct bd70528 *bd70528, int enable) > > > > > +{ > > > > > + int ret; > > > > > + > > > > > + if (bd70528->rtc_timer_lock) > > > > > + mutex_lock(bd70528->rtc_timer_lock); > > > > > > > > This looks awkward. I don't think the if() is necessary. > > > > > > Right. Now when only bd70528 MFD driver uses this WDT this if is not > > > required. > > > > > That doesn't warrant the conditional. It just bloats the code. > > If there is only one user, the mutex will always be acquired. > > Yep. What I meant was that the only possible parent is bd70528 MFD > driver which always initializes the mutex pointer. So pointer should be > always set. I can imagine some other ROHM PMIC having almost identical > watchdog block - in which case we might want to re-use this WDT driver > with this PMIC. And if this PMIC has no RTC, then we may not need this > mutex. But this is all speculation and I will remove check - or see how > this changes when I see what to do with the driver's private data. > > > > > > +static const struct watchdog_info bd70528_wdt_info = { > > > > > + .identity = "bd70528-wdt", > > > > > + .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE, > > > > > +}; > > > > > + > > > > > +static const struct watchdog_ops bd70528_wdt_ops = { > > > > > + .start = bd70528_wdt_start, > > > > > + .stop = bd70528_wdt_stop, > > > > > + /* > > > > > + * bd70528 WDT ping is same as enable. Eg, writing 'enable' to enabled > > > > > + * WDT will restart the timeout > > > > > + */ > > > > Unnecessary comment. > > > > > > > > > > Ok. I will remove the comment if this is obvious to others. For me it > > > was not obvious. I was first writing a separate ping and start functions > > > untill I realized that it is the same operation. But this was my first > > > WDT driver so I don't know if this is a normal for all WDTs. > > > > > It is documented as part of the API. > I'd better read the documentation then. Thanks for pointing this out. > I'll remove the comment. > > > > > > +static int bd70528_wdt_probe(struct platform_device *pdev) > > > > > +{ > > > > > + struct bd70528 *tmp; > > > > > + struct bd70528 *bd70528; > > > > > + int ret; > > > > > + > > > > > + tmp = dev_get_drvdata(pdev->dev.parent); > > > > > + if (!tmp) { > > > > > + dev_err(&pdev->dev, "No MFD driver data\n"); > > > > > + return -EINVAL; > > > > > + } > > > > > + bd70528 = devm_kzalloc(&pdev->dev, sizeof(*bd70528), GFP_KERNEL); > > > > > + if (!bd70528) > > > > > + return -ENOMEM; > > > > > + > > > > > + *bd70528 = *tmp; > > > > > + bd70528->chip.dev = &pdev->dev; > > > > > > > > This is wrong. > > > > You should not copy the parent's driver data but have local driver > > > > data as needed which then points to the parent's driver data if > > > > needed. I assume this is why the mutex is a pointer, but that > > > > just shows that the whole approach is wrong. > > > > > > Mutex is a pointer because we want to use same mutex from WDT and RTC. > > > We can sure point to parent data but then we still need our own dev > > > pointer. So we can have a struct with pointer to parent data and dev > > > pointer - but I'm not at all sure it is any clearer. > > > > As I said, that is wrong. To say it in plaintext, I won't accept > > the driver if it copies the parent's driver data. The driver should > > have and use its own driver data, and only maintain a pointer to > > its parent's driver data. And most definitely you don't want to > > copy and use any device data structure from the parent. > > Allright. At the moment the WDT driver only needs regmap pointer from > parent. I'm not sure if it will later need DT or "chip type" - but I > will change this. You probably want to use this: dev_get_regmap(pdev->dev.parent, NULL); -- Sebastian