bcm2835-pm: Move bcm2835-watchdog's DT probe to an MFD.

The PM block that the wdt driver was binding to actually has multiple
features we want to expose (power domains, reset, watchdog).  Move the
DT attachment to a MFD driver and make WDT probe against MFD.

Signed-off-by: Eric Anholt <eric@anholt.net>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Acked-by: Stefan Wahren <stefan.wahren@i2se.com>
Signed-off-by: Stefan Wahren <stefan.wahren@i2se.com>

arch/arm/mach-bcm/Kconfig

@@ -167,6 +167,7 @@ config ARCH_BCM2835
 	select BCM2835_TIMER
 	select PINCTRL
 	select PINCTRL_BCM2835
+	select MFD_CORE
 	help
 	  This enables support for the Broadcom BCM2835 and BCM2836 SoCs.
 	  This SoC is used in the Raspberry Pi and Roku 2 devices.

drivers/mfd/Makefile

@@ -10,6 +10,7 @@ obj-$(CONFIG_MFD_88PM805)	+= 88pm805.o 88pm80x.o
 obj-$(CONFIG_MFD_ACT8945A)	+= act8945a.o
 obj-$(CONFIG_MFD_SM501)		+= sm501.o
 obj-$(CONFIG_MFD_ASIC3)		+= asic3.o tmio_core.o
+obj-$(CONFIG_ARCH_BCM2835)	+= bcm2835-pm.o
 obj-$(CONFIG_MFD_BCM590XX)	+= bcm590xx.o
 obj-$(CONFIG_MFD_BD9571MWV)	+= bd9571mwv.o
 cros_ec_core-objs		:= cros_ec.o

drivers/mfd/bcm2835-pm.c

@@ -0,0 +1,64 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * PM MFD driver for Broadcom BCM2835
+ *
+ * This driver binds to the PM block and creates the MFD device for
+ * the WDT driver.
+ */
+
+#include <linux/delay.h>
+#include <linux/io.h>
+#include <linux/mfd/bcm2835-pm.h>
+#include <linux/mfd/core.h>
+#include <linux/module.h>
+#include <linux/of_address.h>
+#include <linux/of_platform.h>
+#include <linux/platform_device.h>
+#include <linux/types.h>
+#include <linux/watchdog.h>
+
+static const struct mfd_cell bcm2835_pm_devs[] = {
+	{ .name = "bcm2835-wdt" },
+};
+
+static int bcm2835_pm_probe(struct platform_device *pdev)
+{
+	struct resource *res;
+	struct device *dev = &pdev->dev;
+	struct bcm2835_pm *pm;
+
+	pm = devm_kzalloc(dev, sizeof(*pm), GFP_KERNEL);
+	if (!pm)
+		return -ENOMEM;
+	platform_set_drvdata(pdev, pm);
+
+	pm->dev = dev;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	pm->base = devm_ioremap_resource(dev, res);
+	if (IS_ERR(pm->base))
+		return PTR_ERR(pm->base);
+
+	return devm_mfd_add_devices(dev, -1,
+				    bcm2835_pm_devs, ARRAY_SIZE(bcm2835_pm_devs),
+				    NULL, 0, NULL);
+}
+
+static const struct of_device_id bcm2835_pm_of_match[] = {
+	{ .compatible = "brcm,bcm2835-pm-wdt", },
+	{},
+};
+MODULE_DEVICE_TABLE(of, bcm2835_pm_of_match);
+
+static struct platform_driver bcm2835_pm_driver = {
+	.probe		= bcm2835_pm_probe,
+	.driver = {
+		.name =	"bcm2835-pm",
+		.of_match_table = bcm2835_pm_of_match,
+	},
+};
+module_platform_driver(bcm2835_pm_driver);
+
+MODULE_AUTHOR("Eric Anholt <eric@anholt.net>");
+MODULE_DESCRIPTION("Driver for Broadcom BCM2835 PM MFD");
+MODULE_LICENSE("GPL");

drivers/watchdog/bcm2835_wdt.c

@@ -12,6 +12,7 @@
 
 #include <linux/delay.h>
 #include <linux/types.h>
+#include <linux/mfd/bcm2835-pm.h>
 #include <linux/module.h>
 #include <linux/io.h>
 #include <linux/watchdog.h>
@@ -47,6 +48,8 @@ struct bcm2835_wdt {
 	spinlock_t		lock;
 };
 
+static struct bcm2835_wdt *bcm2835_power_off_wdt;
+
 static unsigned int heartbeat;
 static bool nowayout = WATCHDOG_NOWAYOUT;
 
@@ -148,10 +151,7 @@ static struct watchdog_device bcm2835_wdt_wdd = {
  */
 static void bcm2835_power_off(void)
 {
-	struct device_node *np =
+	struct bcm2835_wdt *wdt = bcm2835_power_off_wdt;
-		of_find_compatible_node(NULL, NULL, "brcm,bcm2835-pm-wdt");
-	struct platform_device *pdev = of_find_device_by_node(np);
-	struct bcm2835_wdt *wdt = platform_get_drvdata(pdev);
 	u32 val;
 
 	/*
@@ -169,7 +169,7 @@ static void bcm2835_power_off(void)
 
 static int bcm2835_wdt_probe(struct platform_device *pdev)
 {
-	struct resource *res;
+	struct bcm2835_pm *pm = dev_get_drvdata(pdev->dev.parent);
 	struct device *dev = &pdev->dev;
 	struct bcm2835_wdt *wdt;
 	int err;
@@ -181,10 +181,7 @@ static int bcm2835_wdt_probe(struct platform_device *pdev)
 
 	spin_lock_init(&wdt->lock);
 
-	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	wdt->base = pm->base;
-	wdt->base = devm_ioremap_resource(dev, res);
-	if (IS_ERR(wdt->base))
-		return PTR_ERR(wdt->base);
 
 	watchdog_set_drvdata(&bcm2835_wdt_wdd, wdt);
 	watchdog_init_timeout(&bcm2835_wdt_wdd, heartbeat, dev);
@@ -211,8 +208,10 @@ static int bcm2835_wdt_probe(struct platform_device *pdev)
 		return err;
 	}
 
-	if (pm_power_off == NULL)
+	if (pm_power_off == NULL) {
 		pm_power_off = bcm2835_power_off;
+		bcm2835_power_off_wdt = wdt;
+	}
 
 	dev_info(dev, "Broadcom BCM2835 watchdog timer");
 	return 0;
@@ -226,18 +225,11 @@ static int bcm2835_wdt_remove(struct platform_device *pdev)
 	return 0;
 }
 
-static const struct of_device_id bcm2835_wdt_of_match[] = {
-	{ .compatible = "brcm,bcm2835-pm-wdt", },
-	{},
-};
-MODULE_DEVICE_TABLE(of, bcm2835_wdt_of_match);
-
 static struct platform_driver bcm2835_wdt_driver = {
 	.probe		= bcm2835_wdt_probe,
 	.remove		= bcm2835_wdt_remove,
 	.driver = {
 		.name =		"bcm2835-wdt",
-		.of_match_table = bcm2835_wdt_of_match,
 	},
 };
 module_platform_driver(bcm2835_wdt_driver);

include/linux/mfd/bcm2835-pm.h

@@ -0,0 +1,13 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+
+#ifndef BCM2835_MFD_PM_H
+#define BCM2835_MFD_PM_H
+
+#include <linux/regmap.h>
+
+struct bcm2835_pm {
+	struct device *dev;
+	void __iomem *base;
+};
+
+#endif /* BCM2835_MFD_PM_H */