From: Guenter Roeck <linux@roeck-us.net>
To: Johan Hovold <johan@kernel.org>,
Andrey Smirnov <andrew.smirnov@gmail.com>
Cc: linux-kernel@vger.kernel.org, linux-watchdog@vger.kernel.org,
cphealy@gmail.com, Lucas Stach <l.stach@pengutronix.de>,
Nikita Yushchenko <nikita.yoush@cogentembedded.com>,
Lee Jones <lee.jones@linaro.org>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Pavel Machek <pavel@ucw.cz>,
Andy Shevchenko <andy.shevchenko@gmail.com>,
Rob Herring <robh@kernel.org>,
Sebastian Reichel <sebastian.reichel@collabora.co.uk>
Subject: Re: [PATCH v10 4/5] watchdog: Add RAVE SP watchdog driver
Date: Sun, 5 Nov 2017 10:34:15 -0800 [thread overview]
Message-ID: <2a09a907-cc64-232d-95c3-56da9ae05f4a@roeck-us.net> (raw)
In-Reply-To: <20171105154725.GA11226@localhost>
On 11/05/2017 07:47 AM, Johan Hovold wrote:
> On Tue, Oct 31, 2017 at 09:36:55AM -0700, Andrey Smirnov wrote:
>> This driver provides access to RAVE SP watchdog functionality.
>>
>> Cc: linux-kernel@vger.kernel.org
>> Cc: linux-watchdog@vger.kernel.org
>> Cc: cphealy@gmail.com
>> Cc: Lucas Stach <l.stach@pengutronix.de>
>> Cc: Nikita Yushchenko <nikita.yoush@cogentembedded.com>
>> Cc: Lee Jones <lee.jones@linaro.org>
>> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
>> Cc: Pavel Machek <pavel@ucw.cz>
>> Cc: Andy Shevchenko <andy.shevchenko@gmail.com>
>> Cc: Guenter Roeck <linux@roeck-us.net>
>> Cc: Rob Herring <robh@kernel.org>
>> Cc: Johan Hovold <johan@kernel.org>
>> Cc: Sebastian Reichel <sebastian.reichel@collabora.co.uk>
>> Signed-off-by: Nikita Yushchenko <nikita.yoush@cogentembedded.com>
>> Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
>
>> +static const struct of_device_id rave_sp_wdt_of_match[] = {
>> + { .compatible = "zii,rave-sp-watchdog" },
>> + {}
>> +};
>
>> +static const struct of_device_id rave_sp_wdt_variants[] = {
>> + { .compatible = COMPATIBLE_RAVE_SP_NIU, .data = &rave_sp_wdt_legacy },
>> + { .compatible = COMPATIBLE_RAVE_SP_MEZZ, .data = &rave_sp_wdt_legacy },
>> + { .compatible = COMPATIBLE_RAVE_SP_ESB, .data = &rave_sp_wdt_legacy },
>> + { .compatible = COMPATIBLE_RAVE_SP_RDU1, .data = &rave_sp_wdt_rdu },
>> + { .compatible = COMPATIBLE_RAVE_SP_RDU2, .data = &rave_sp_wdt_rdu },
>> + { /* sentinel */ }
>> +};
>> +
>> +static int rave_sp_wdt_probe(struct platform_device *pdev)
>> +{
>> + struct device *dev = &pdev->dev;
>> + const struct of_device_id *id;
>> + struct watchdog_device *wdd;
>> + struct rave_sp_wdt *sp_wd;
>> + struct nvmem_cell *cell;
>> + __le16 timeout = 0;
>> + int ret;
>> +
>> + id = of_match_device(rave_sp_wdt_variants, dev->parent);
>
> So as I already mentioned in a comment on an earlier version of the MFD
> driver, I find this matching on the parent of_node to be an odd
> pattern, which also does not seem to have any precedent in mainline.
>
> It seems you really should be using two compatible strings for the
> watchdog (for the legacy and rdu variants) rather than keep an entry for
> every parent compatible-string in every child/cell driver (which all
> need to be kept in sync).
>
> But let's see what Rob and Lee says about this.
>
>> + if (!id) {
>> + dev_err(dev, "Unknown parent device variant. Bailing out\n");
>> + return -ENODEV;
>> + }
>> +
>> + sp_wd = devm_kzalloc(dev, sizeof(*sp_wd), GFP_KERNEL);
>> + if (!sp_wd)
>> + return -ENOMEM;
>> +
>> + sp_wd->variant = id->data;
>> + sp_wd->sp = dev_get_drvdata(dev->parent);
>> +
>> + wdd = &sp_wd->wdd;
>> + wdd->parent = dev;
>> + wdd->info = &rave_sp_wdt_info;
>> + wdd->ops = &rave_sp_wdt_ops;
>> + wdd->min_timeout = sp_wd->variant->min_timeout;
>> + wdd->max_timeout = sp_wd->variant->max_timeout;
>> + wdd->status = WATCHDOG_NOWAYOUT_INIT_STATUS;
>> + wdd->timeout = 60;
>> +
>> + cell = nvmem_cell_get(dev, "wdt-timeout");
>> + if (!IS_ERR(cell)) {
>> + size_t len;
>> + void *value = nvmem_cell_read(cell, &len);
>> +
>> + if (!IS_ERR(value)) {
>> + memcpy(&timeout, value, min(len, sizeof(timeout)));
>> + kfree(value);
>> + }
>> + nvmem_cell_put(cell);
>> + }
>> + watchdog_init_timeout(wdd, le16_to_cpu(timeout), dev);
>> + watchdog_set_restart_priority(wdd, 255);
>> +
>> + sp_wd->reboot_notifier.notifier_call = rave_sp_wdt_reboot_notifier;
>> + ret = devm_register_reboot_notifier(dev, &sp_wd->reboot_notifier);
>> + if (ret) {
>> + dev_err(dev, "Failed to register reboot notifier\n");
>> + return ret;
>> + }
>> +
>> + /*
>> + * We don't know if watchdog is running now. To be sure, let's
>> + * start it and depend on watchdog core to ping it
>> + */
>> + wdd->max_hw_heartbeat_ms = wdd->max_timeout * 1000;
>> + ret = rave_sp_wdt_start(wdd);
>> + if (ret) {
>> + dev_err(dev, "Watchdog didn't start\n");
>> + return ret;
>> + }
>> +
>> + return devm_watchdog_register_device(dev, wdd);
>
> What about stopping the watchdog on errors here?
>
> And does watchdog core take care of calling stop() on unregister (i.e.
> at unbind)?
>
Both good points. This needs watchdog_stop_on_unregister(), and the
probe function needs to stop the watchdog if registration fails.
Guenter
>> +}
>> +
>> +static struct platform_driver rave_sp_wdt_driver = {
>> + .probe = rave_sp_wdt_probe,
>> + .driver = {
>> + .name = KBUILD_MODNAME,
>> + .of_match_table = rave_sp_wdt_of_match,
>> + },
>> +};
>
> Johan
> --
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>
next prev parent reply other threads:[~2017-11-05 18:34 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-10-31 16:36 [PATCH v10 0/5] ZII RAVE platform driver Andrey Smirnov
2017-10-31 16:36 ` [PATCH v10 1/5] serdev: Make .remove in struct serdev_device_driver optional Andrey Smirnov
2017-11-01 23:48 ` Rob Herring
2017-11-04 11:24 ` Greg Kroah-Hartman
2017-11-04 17:05 ` Sebastian Reichel
2017-10-31 16:36 ` [PATCH v10 2/5] serdev: Introduce devm_serdev_device_open() Andrey Smirnov
2017-11-01 23:48 ` Rob Herring
2017-11-05 15:38 ` Johan Hovold
2017-11-05 22:19 ` Andrey Smirnov
2017-10-31 16:36 ` [PATCH v10 3/5] mfd: Add driver for RAVE Supervisory Processor Andrey Smirnov
2017-11-05 15:38 ` Johan Hovold
2017-11-05 22:02 ` Andrey Smirnov
2017-10-31 16:36 ` [PATCH v10 4/5] watchdog: Add RAVE SP watchdog driver Andrey Smirnov
2017-10-31 17:21 ` Guenter Roeck
2017-11-04 11:24 ` Greg Kroah-Hartman
2017-11-05 15:55 ` Guenter Roeck
2017-11-05 15:47 ` Johan Hovold
2017-11-05 18:34 ` Guenter Roeck [this message]
2017-11-05 21:59 ` Andrey Smirnov
2017-10-31 16:36 ` [PATCH v10 5/5] dt-bindings: watchdog: Add bindings for " Andrey Smirnov
2017-10-31 17:22 ` Guenter Roeck
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