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From:   Johannes Thumshirn <jthumshirn@suse.de>
To:     Wim Van Sebroeck <wim@linux-watchdog.org>,
        Guenter Roeck <linux@roeck-us.net>
Cc:     linux-kernel@vger.kernel.org, linux-watchdog@vger.kernel.org,
        mmoese@suse.de, Johannes Thumshirn <jthumshirn@suse.de>
Subject: [PATCH v2] watchdog: add driver for the MEN 16z069 IP-Core
Date:   Mon, 16 Jul 2018 09:25:10 +0200
Message-Id: <20180716072510.6939-1-jthumshirn@suse.de>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

Add a driver for the MEN 16z069 Watchdog and Reset Controller IP-Core.

Signed-off-by: Johannes Thumshirn <jthumshirn@suse.de>

---
Changes to v1:
* Sorted includes alphabetically
* Indented defines with tabs
* Removed unnecessary timeout validation
* Removed unnecessary masking of values
* Fixed error return in .probe
* Directly accessed drv->wdt
* Removed leftover timeout resetting
---
 MAINTAINERS                   |   6 ++
 drivers/watchdog/Kconfig      |  10 +++
 drivers/watchdog/Makefile     |   1 +
 drivers/watchdog/menz69_wdt.c | 170 ++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 187 insertions(+)
 create mode 100644 drivers/watchdog/menz69_wdt.c

diff --git a/MAINTAINERS b/MAINTAINERS
index 07d1576fc766..67a76f740294 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -9298,6 +9298,12 @@ F:	drivers/leds/leds-menf21bmc.c
 F:	drivers/hwmon/menf21bmc_hwmon.c
 F:	Documentation/hwmon/menf21bmc
 
+MEN Z069 WATCHDOG DRIVER
+M:	Johannes Thumshirn <jth@kernel.org>
+L:	linux-watchdog@vger.kernel.org
+S:	Maintained
+F:	drivers/watchdog/menz069_wdt.c
+
 MESON AO CEC DRIVER FOR AMLOGIC SOCS
 M:	Neil Armstrong <narmstrong@baylibre.com>
 L:	linux-media@lists.freedesktop.org
diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
index 9af07fd92763..df55d65bbb1c 100644
--- a/drivers/watchdog/Kconfig
+++ b/drivers/watchdog/Kconfig
@@ -161,6 +161,16 @@ config MENF21BMC_WATCHDOG
 	  This driver can also be built as a module. If so the module
 	  will be called menf21bmc_wdt.
 
+config MENZ069_WATCHDOG
+	tristate "MEN 16Z069 Watchdog"
+	depends on MCB || COMPILE_TEST
+	select WATCHDOG_CORE
+	help
+	  Say Y here to include support for the MEN 16Z069 Watchdog.
+
+	  This driver can also be built as a module. If so the module
+	  will be called menz069_wdt.
+
 config TANGOX_WATCHDOG
 	tristate "Sigma Designs SMP86xx/SMP87xx watchdog"
 	select WATCHDOG_CORE
diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
index 1d3c6b094fe5..bf92e7bf9ce0 100644
--- a/drivers/watchdog/Makefile
+++ b/drivers/watchdog/Makefile
@@ -215,4 +215,5 @@ obj-$(CONFIG_MAX77620_WATCHDOG) += max77620_wdt.o
 obj-$(CONFIG_ZIIRAVE_WATCHDOG) += ziirave_wdt.o
 obj-$(CONFIG_SOFT_WATCHDOG) += softdog.o
 obj-$(CONFIG_MENF21BMC_WATCHDOG) += menf21bmc_wdt.o
+obj-$(CONFIG_MENZ069_WATCHDOG) += menz69_wdt.o
 obj-$(CONFIG_RAVE_SP_WATCHDOG) += rave-sp-wdt.o
diff --git a/drivers/watchdog/menz69_wdt.c b/drivers/watchdog/menz69_wdt.c
new file mode 100644
index 000000000000..ed18238c5407
--- /dev/null
+++ b/drivers/watchdog/menz69_wdt.c
@@ -0,0 +1,170 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Watchdog driver for the MEN z069 IP-Core
+ *
+ * Copyright (C) 2018 Johannes Thumshirn <jth@kernel.org>
+ */
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/mcb.h>
+#include <linux/module.h>
+#include <linux/watchdog.h>
+
+struct men_z069_drv {
+	struct watchdog_device wdt;
+	void __iomem *base;
+	struct resource *mem;
+};
+
+#define MEN_Z069_WTR			0x10
+#define MEN_Z069_WTR_WDEN		BIT(15)
+#define MEN_Z069_WTR_WDET_MASK		0x7fff
+#define MEN_Z069_WVR			0x14
+
+#define MEN_Z069_TIMER_FREQ		500 /* 500 Hz */
+#define MEN_Z069_WDT_COUNTER_MIN	1
+#define MEN_Z069_WDT_COUNTER_MAX	0x7fff
+#define MEN_Z069_DEFAULT_TIMEOUT	30
+
+static bool nowayout = WATCHDOG_NOWAYOUT;
+module_param(nowayout, bool, 0);
+MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
+			    __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
+
+static int men_z069_wdt_start(struct watchdog_device *wdt)
+{
+	struct men_z069_drv *drv = watchdog_get_drvdata(wdt);
+	u16 val;
+
+	val = readw(drv->base + MEN_Z069_WTR);
+	val |= MEN_Z069_WTR_WDEN;
+	writew(val, drv->base + MEN_Z069_WTR);
+
+	return 0;
+}
+
+static int men_z069_wdt_stop(struct watchdog_device *wdt)
+{
+	struct men_z069_drv *drv = watchdog_get_drvdata(wdt);
+	u16 val;
+
+	val = readw(drv->base + MEN_Z069_WTR);
+	val &= ~MEN_Z069_WTR_WDEN;
+	writew(val, drv->base + MEN_Z069_WTR);
+
+	return 0;
+}
+
+static int men_z069_wdt_ping(struct watchdog_device *wdt)
+{
+	struct men_z069_drv *drv = watchdog_get_drvdata(wdt);
+	u16 val;
+
+	/* The watchdog trigger value toggles between 0x5555 and 0xaaaa */
+	val = readw(drv->base + MEN_Z069_WVR);
+	val ^= 0xffff;
+	writew(val, drv->base + MEN_Z069_WVR);
+
+	return 0;
+}
+
+static int men_z069_wdt_set_timeout(struct watchdog_device *wdt,
+				    unsigned int timeout)
+{
+	struct men_z069_drv *drv = watchdog_get_drvdata(wdt);
+	u16 reg, val, ena;
+
+	wdt->timeout = timeout;
+	val = timeout * MEN_Z069_TIMER_FREQ;
+
+	reg = readw(drv->base + MEN_Z069_WVR);
+	ena = reg & MEN_Z069_WTR_WDEN;
+	reg = ena | val;
+	writew(reg, drv->base + MEN_Z069_WTR);
+
+	return 0;
+}
+
+static const struct watchdog_info men_z069_info = {
+	.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
+	.identity = "MEN z069 Watchdog",
+};
+
+static const struct watchdog_ops men_z069_ops = {
+	.owner = THIS_MODULE,
+	.start = men_z069_wdt_start,
+	.stop = men_z069_wdt_stop,
+	.ping = men_z069_wdt_ping,
+	.set_timeout = men_z069_wdt_set_timeout,
+};
+
+static struct watchdog_device men_z069_wdt = {
+	.info = &men_z069_info,
+	.ops = &men_z069_ops,
+	.timeout = MEN_Z069_DEFAULT_TIMEOUT,
+	.min_timeout = 1,
+	.max_timeout = MEN_Z069_WDT_COUNTER_MAX / MEN_Z069_TIMER_FREQ,
+};
+
+static int men_z069_probe(struct mcb_device *dev,
+			  const struct mcb_device_id *id)
+{
+	struct men_z069_drv *drv;
+	struct resource *mem;
+
+	drv = devm_kzalloc(&dev->dev, sizeof(struct men_z069_drv), GFP_KERNEL);
+	if (!drv)
+		return -ENOMEM;
+
+	mem = mcb_request_mem(dev, "z069-wdt");
+	if (IS_ERR(mem))
+		return PTR_ERR(mem);
+
+	drv->base = devm_ioremap(&dev->dev, mem->start, resource_size(mem));
+	if (drv->base == NULL)
+		goto release_mem;
+
+	drv->mem = mem;
+
+	drv->wdt = men_z069_wdt;
+	watchdog_init_timeout(&drv->wdt, 0, &dev->dev);
+	watchdog_set_nowayout(&drv->wdt, nowayout);
+	watchdog_set_drvdata(&drv->wdt, drv);
+	drv->wdt.parent = &dev->dev;
+	mcb_set_drvdata(dev, drv);
+
+	return watchdog_register_device(&men_z069_wdt);
+
+release_mem:
+	mcb_release_mem(mem);
+	return -ENOMEM;
+}
+
+static void men_z069_remove(struct mcb_device *dev)
+{
+	struct men_z069_drv *drv = mcb_get_drvdata(dev);
+
+	watchdog_unregister_device(&drv->wdt);
+	mcb_release_mem(drv->mem);
+}
+
+static const struct mcb_device_id men_z069_ids[] = {
+	{ .device = 0x45 },
+	{ }
+};
+MODULE_DEVICE_TABLE(mcb, men_z069_ids);
+
+static struct mcb_driver men_z069_driver = {
+	.driver = {
+		.name = "z069-wdt",
+		.owner = THIS_MODULE,
+	},
+	.probe = men_z069_probe,
+	.remove = men_z069_remove,
+	.id_table = men_z069_ids,
+};
+module_mcb_driver(men_z069_driver);
+
+MODULE_AUTHOR("Johannes Thumshirn <jth@kernel.org>");
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS("mcb:16z069");
-- 
2.16.4