Message-Id: <20201020062112.6762-2-a.fatoum@pengutronix.de>
Date:   Tue, 20 Oct 2020 08:21:11 +0200
From:   Ahmad Fatoum <a.fatoum@...gutronix.de>
To:     wim@...ux-watchdog.org, linux@...ck-us.net
Cc:     linux-watchdog@...r.kernel.org, linux-kernel@...r.kernel.org,
        kernel@...gutronix.de, Ahmad Fatoum <a.fatoum@...gutronix.de>
Subject: [PATCH v2 1/2] watchdog: f71808e_wdt: refactor to platform device/driver pair

Driver so far wasn't ported to the driver model and set up its
miscdevice out of the init after probing the I/O ports for a watchdog
with correct vendor and device revision.

Keep the device detection part at init time, but move watchdog setup
to a platform driver probe function.

While at it, refactor some of the driver code we have to now touch
anyway:

 - platform_device_id is used instead of the two big switches mapping
   hardware ID to an enum and then mapping it to a pinconf function
 - we rename f71808e_ and watchdog_data to fintek_wdt, to avoid mix up
   of the generic parts up with the device specific parts

Suggested-by: Guenter Roeck <linux@...ck-us.net>
Signed-off-by: Ahmad Fatoum <a.fatoum@...gutronix.de>
---
 drivers/watchdog/f71808e_wdt.c | 377 +++++++++++++++++++--------------
 1 file changed, 215 insertions(+), 162 deletions(-)

diff --git a/drivers/watchdog/f71808e_wdt.c b/drivers/watchdog/f71808e_wdt.c
index f60beec1bbae..4ff7a2509125 100644
--- a/drivers/watchdog/f71808e_wdt.c
+++ b/drivers/watchdog/f71808e_wdt.c
@@ -9,12 +9,15 @@
 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 
 #include <linux/err.h>
+#include <linux/slab.h>
 #include <linux/fs.h>
 #include <linux/init.h>
 #include <linux/io.h>
 #include <linux/ioport.h>
 #include <linux/miscdevice.h>
 #include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/mod_devicetable.h>
 #include <linux/mutex.h>
 #include <linux/notifier.h>
 #include <linux/reboot.h>
@@ -110,22 +113,6 @@ module_param(start_withtimeout, uint, 0);
 MODULE_PARM_DESC(start_withtimeout, "Start watchdog timer on module load with"
 	" given initial timeout. Zero (default) disables this feature.");
 
-enum chips { f71808fg, f71858fg, f71862fg, f71868, f71869, f71882fg, f71889fg,
-	     f81803, f81865, f81866};
-
-static const char *f71808e_names[] = {
-	"f71808fg",
-	"f71858fg",
-	"f71862fg",
-	"f71868",
-	"f71869",
-	"f71882fg",
-	"f71889fg",
-	"f81803",
-	"f81865",
-	"f81866",
-};
-
 /* Super-I/O Function prototypes */
 static inline int superio_inb(int base, int reg);
 static inline int superio_inw(int base, int reg);
@@ -136,9 +123,17 @@ static inline int superio_enter(int base);
 static inline void superio_select(int base, int ld);
 static inline void superio_exit(int base);
 
-struct watchdog_data {
+struct fintek_wdt;
+
+struct fintek_wdt_variant {
+	u16 id;
+	void (*pinconf)(struct fintek_wdt *wd);
+	const char *identity_override;
+};
+
+struct fintek_wdt {
 	unsigned short	sioaddr;
-	enum chips	type;
+	const struct fintek_wdt_variant *variant;
 	unsigned long	opened;
 	struct mutex	lock;
 	char		expect_close;
@@ -152,10 +147,15 @@ struct watchdog_data {
 	char		caused_reboot;	/* last reboot was by the watchdog */
 };
 
-static struct watchdog_data watchdog = {
+static struct fintek_wdt watchdog = {
 	.lock = __MUTEX_INITIALIZER(watchdog.lock),
 };
 
+static inline bool has_f81865_wdo_conf(struct fintek_wdt *wd)
+{
+	return wd->variant->id == SIO_F81865_ID || wd->variant->id == SIO_F81866_ID;
+}
+
 /* Super I/O functions */
 static inline int superio_inb(int base, int reg)
 {
@@ -247,7 +247,7 @@ static int watchdog_set_pulse_width(unsigned int pw)
 	int err = 0;
 	unsigned int t1 = 25, t2 = 125, t3 = 5000;
 
-	if (watchdog.type == f71868) {
+	if (watchdog.variant->id == SIO_F71868_ID) {
 		t1 = 30;
 		t2 = 150;
 		t3 = 6000;
@@ -309,7 +309,6 @@ static int watchdog_keepalive(void)
 static int watchdog_start(void)
 {
 	int err;
-	u8 tmp;
 
 	/* Make sure we don't die as soon as the watchdog is enabled below */
 	err = watchdog_keepalive();
@@ -323,81 +322,12 @@ static int watchdog_start(void)
 	superio_select(watchdog.sioaddr, SIO_F71808FG_LD_WDT);
 
 	/* Watchdog pin configuration */
-	switch (watchdog.type) {
-	case f71808fg:
-		/* Set pin 21 to GPIO23/WDTRST#, then to WDTRST# */
-		superio_clear_bit(watchdog.sioaddr, SIO_REG_MFUNCT2, 3);
-		superio_clear_bit(watchdog.sioaddr, SIO_REG_MFUNCT3, 3);
-		break;
-
-	case f71862fg:
-		if (f71862fg_pin == 63) {
-			/* SPI must be disabled first to use this pin! */
-			superio_clear_bit(watchdog.sioaddr, SIO_REG_ROM_ADDR_SEL, 6);
-			superio_set_bit(watchdog.sioaddr, SIO_REG_MFUNCT3, 4);
-		} else if (f71862fg_pin == 56) {
-			superio_set_bit(watchdog.sioaddr, SIO_REG_MFUNCT1, 1);
-		}
-		break;
-
-	case f71868:
-	case f71869:
-		/* GPIO14 --> WDTRST# */
-		superio_clear_bit(watchdog.sioaddr, SIO_REG_MFUNCT1, 4);
-		break;
-
-	case f71882fg:
-		/* Set pin 56 to WDTRST# */
-		superio_set_bit(watchdog.sioaddr, SIO_REG_MFUNCT1, 1);
-		break;
-
-	case f71889fg:
-		/* set pin 40 to WDTRST# */
-		superio_outb(watchdog.sioaddr, SIO_REG_MFUNCT3,
-			superio_inb(watchdog.sioaddr, SIO_REG_MFUNCT3) & 0xcf);
-		break;
-
-	case f81803:
-		/* Enable TSI Level register bank */
-		superio_clear_bit(watchdog.sioaddr, SIO_REG_CLOCK_SEL, 3);
-		/* Set pin 27 to WDTRST# */
-		superio_outb(watchdog.sioaddr, SIO_REG_TSI_LEVEL_SEL, 0x5f &
-			superio_inb(watchdog.sioaddr, SIO_REG_TSI_LEVEL_SEL));
-		break;
-
-	case f81865:
-		/* Set pin 70 to WDTRST# */
-		superio_clear_bit(watchdog.sioaddr, SIO_REG_MFUNCT3, 5);
-		break;
-
-	case f81866:
-		/*
-		 * GPIO1 Control Register when 27h BIT3:2 = 01 & BIT0 = 0.
-		 * The PIN 70(GPIO15/WDTRST) is controlled by 2Ch:
-		 *     BIT5: 0 -> WDTRST#
-		 *           1 -> GPIO15
-		 */
-		tmp = superio_inb(watchdog.sioaddr, SIO_F81866_REG_PORT_SEL);
-		tmp &= ~(BIT(3) | BIT(0));
-		tmp |= BIT(2);
-		superio_outb(watchdog.sioaddr, SIO_F81866_REG_PORT_SEL, tmp);
-
-		superio_clear_bit(watchdog.sioaddr, SIO_F81866_REG_GPIO1, 5);
-		break;
-
-	default:
-		/*
-		 * 'default' label to shut up the compiler and catch
-		 * programmer errors
-		 */
-		err = -ENODEV;
-		goto exit_superio;
-	}
+	watchdog.variant->pinconf(&watchdog);
 
 	superio_select(watchdog.sioaddr, SIO_F71808FG_LD_WDT);
 	superio_set_bit(watchdog.sioaddr, SIO_REG_ENABLE, 0);
 
-	if (watchdog.type == f81865 || watchdog.type == f81866)
+	if (has_f81865_wdo_conf(&watchdog))
 		superio_set_bit(watchdog.sioaddr, F81865_REG_WDO_CONF,
 				F81865_FLAG_WDOUT_EN);
 	else
@@ -425,7 +355,6 @@ static int watchdog_start(void)
 				F71808FG_FLAG_WD_PULSE);
 	}
 
-exit_superio:
 	superio_exit(watchdog.sioaddr);
 exit_unlock:
 	mutex_unlock(&watchdog.lock);
@@ -665,21 +594,39 @@ static struct notifier_block watchdog_notifier = {
 	.notifier_call = watchdog_notify_sys,
 };
 
-static int __init watchdog_init(int sioaddr)
+static int fintek_wdt_probe(struct platform_device *pdev)
 {
+	const struct platform_device_id *id;
+	unsigned short sioaddr;
+	struct resource *res;
 	int wdt_conf, err = 0;
+	const char *identity;
+
+	if (watchdog_miscdev.parent)
+		return -EBUSY;
+
+	watchdog_miscdev.parent = &pdev->dev;
+
+	res = platform_get_resource(pdev, IORESOURCE_IO, 0);
+	if (!res)
+		return -ENXIO;
+
+	id = platform_get_device_id(pdev);
+	watchdog.variant = (void *)id->driver_data;
+	if (!watchdog.variant)
+		return -ENODEV;
 
 	/* No need to lock watchdog.lock here because no entry points
 	 * into the module have been registered yet.
 	 */
-	watchdog.sioaddr = sioaddr;
+	watchdog.sioaddr = res->start;
 	watchdog.ident.options = WDIOF_MAGICCLOSE
 				| WDIOF_KEEPALIVEPING
 				| WDIOF_CARDRESET;
 
-	snprintf(watchdog.ident.identity,
-		sizeof(watchdog.ident.identity), "%s watchdog",
-		f71808e_names[watchdog.type]);
+	identity = watchdog.variant->identity_override ?: id->name;
+
+	memcpy(watchdog.ident.identity, identity, sizeof(watchdog.ident.identity));
 
 	err = superio_enter(sioaddr);
 	if (err)
@@ -772,73 +719,176 @@ static int __init watchdog_init(int sioaddr)
 	return err;
 }
 
-static int __init f71808e_find(int sioaddr)
+static void f71808fg_pinconf(struct fintek_wdt *wd)
 {
+	/* Set pin 21 to GPIO23/WDTRST#, then to WDTRST# */
+	superio_clear_bit(wd->sioaddr, SIO_REG_MFUNCT2, 3);
+	superio_clear_bit(wd->sioaddr, SIO_REG_MFUNCT3, 3);
+}
+
+static void f71862fg_pinconf(struct fintek_wdt *wd)
+{
+	if (f71862fg_pin == 63) {
+		/* SPI must be disabled first to use this pin! */
+		superio_clear_bit(wd->sioaddr, SIO_REG_ROM_ADDR_SEL, 6);
+		superio_set_bit(wd->sioaddr, SIO_REG_MFUNCT3, 4);
+	} else if (f71862fg_pin == 56) {
+		superio_set_bit(wd->sioaddr, SIO_REG_MFUNCT1, 1);
+	}
+}
+
+static void f71868_pinconf(struct fintek_wdt *wd)
+{
+	/* GPIO14 --> WDTRST# */
+	superio_clear_bit(wd->sioaddr, SIO_REG_MFUNCT1, 4);
+}
+
+static void f71882fg_pinconf(struct fintek_wdt *wd)
+{
+	/* Set pin 56 to WDTRST# */
+	superio_set_bit(wd->sioaddr, SIO_REG_MFUNCT1, 1);
+}
+
+static void f71889fg_pinconf(struct fintek_wdt *wd)
+{
+	/* set pin 40 to WDTRST# */
+	superio_outb(wd->sioaddr, SIO_REG_MFUNCT3,
+		     superio_inb(wd->sioaddr, SIO_REG_MFUNCT3) & 0xcf);
+}
+
+static void f81803_pinconf(struct fintek_wdt *wd)
+{
+	/* Enable TSI Level register bank */
+	superio_clear_bit(wd->sioaddr, SIO_REG_CLOCK_SEL, 3);
+	/* Set pin 27 to WDTRST# */
+	superio_outb(wd->sioaddr, SIO_REG_TSI_LEVEL_SEL, 0x5f &
+		     superio_inb(wd->sioaddr, SIO_REG_TSI_LEVEL_SEL));
+}
+
+static void f81865_pinconf(struct fintek_wdt *wd)
+{
+	/* Set pin 70 to WDTRST# */
+	superio_clear_bit(wd->sioaddr, SIO_REG_MFUNCT3, 5);
+}
+
+static void f81866_pinconf(struct fintek_wdt *wd)
+{
+	u8 tmp;
+	/*
+	 * GPIO1 Control Register when 27h BIT3:2 = 01 & BIT0 = 0.
+	 * The PIN 70(GPIO15/WDTRST) is controlled by 2Ch:
+	 *     BIT5: 0 -> WDTRST#
+	 *           1 -> GPIO15
+	 */
+	tmp = superio_inb(wd->sioaddr, SIO_F81866_REG_PORT_SEL);
+	tmp &= ~(BIT(3) | BIT(0));
+	tmp |= BIT(2);
+	superio_outb(wd->sioaddr, SIO_F81866_REG_PORT_SEL, tmp);
+
+	superio_clear_bit(wd->sioaddr, SIO_F81866_REG_GPIO1, 5);
+}
+
+#define FINTEK_DRV_DATA(...) \
+	(kernel_ulong_t)(&(struct fintek_wdt_variant) { __VA_ARGS__ })
+
+/*
+ * Array is used by both platform bus to map name to driver data and by
+ * init below to map id in driver_data to name for device creation.
+ */
+static const struct platform_device_id fintek_wdt_id_table[] = {
+	{ "f71808fg watchdog", FINTEK_DRV_DATA(SIO_F71808_ID,  f71808fg_pinconf) },
+	{ "f71862fg watchdog", FINTEK_DRV_DATA(SIO_F71862_ID,  f71862fg_pinconf) },
+	{ "f71868 watchdog",   FINTEK_DRV_DATA(SIO_F71868_ID,  f71868_pinconf) },
+	{ "f71869 watchdog",   FINTEK_DRV_DATA(SIO_F71869_ID,  f71868_pinconf) },
+	/* For backwards-compatibility, we define a different watchdog identity name */
+	{ "f71869a watchdog",  FINTEK_DRV_DATA(SIO_F71869A_ID, f71868_pinconf,
+					       .identity_override = "f71869 watchdog") },
+	{ "f71882fg watchdog", FINTEK_DRV_DATA(SIO_F71882_ID,  f71882fg_pinconf) },
+	{ "f71889fg watchdog", FINTEK_DRV_DATA(SIO_F71889_ID,  f71889fg_pinconf) },
+	{ "f81803 watchdog",   FINTEK_DRV_DATA(SIO_F81803_ID,  f81803_pinconf) },
+	{ "f81865 watchdog",   FINTEK_DRV_DATA(SIO_F81865_ID,  f81865_pinconf) },
+	{ "f81866 watchdog",   FINTEK_DRV_DATA(SIO_F81866_ID,  f81866_pinconf) },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(platform, fintek_wdt_id_table);
+
+/* Confirmed (by datasheet) not to have a watchdog.
+ * We list this here anyway to maintain backwards-compatibility in not warning about them
+ */
+static const u16 fintek_no_wdt_table[] = { SIO_F71858_ID, 0 };
+
+static int fintek_wdt_remove(struct platform_device *pdev)
+{
+	if (watchdog_is_running()) {
+		pr_warn("Watchdog timer still running, stopping it\n");
+		watchdog_stop();
+	}
+	misc_deregister(&watchdog_miscdev);
+	unregister_reboot_notifier(&watchdog_notifier);
+	return 0;
+}
+
+static struct platform_driver fintek_wdt_driver = {
+	.probe		= fintek_wdt_probe,
+	.remove		= fintek_wdt_remove,
+	.id_table	= fintek_wdt_id_table,
+	.driver		= {
+		.name	= DRVNAME,
+	},
+};
+
+static struct platform_device *fintek_wdt_pdev;
+
+static __init const char *fintek_wdt_find(int sioaddr)
+{
+	const char *name = ERR_PTR(-ENODEV);
+	const struct platform_device_id *id;
+	struct fintek_wdt_variant *variant;
 	u16 devid;
-	int err = superio_enter(sioaddr);
+	const u16 *pdevid;
+	int err;
+
+	err = superio_enter(sioaddr);
 	if (err)
-		return err;
+		return ERR_PTR(err);
 
 	devid = superio_inw(sioaddr, SIO_REG_MANID);
 	if (devid != SIO_FINTEK_ID) {
 		pr_debug("Not a Fintek device\n");
-		err = -ENODEV;
-		goto exit;
+		goto out;
 	}
 
 	devid = force_id ? force_id : superio_inw(sioaddr, SIO_REG_DEVID);
-	switch (devid) {
-	case SIO_F71808_ID:
-		watchdog.type = f71808fg;
-		break;
-	case SIO_F71862_ID:
-		watchdog.type = f71862fg;
-		break;
-	case SIO_F71868_ID:
-		watchdog.type = f71868;
-		break;
-	case SIO_F71869_ID:
-	case SIO_F71869A_ID:
-		watchdog.type = f71869;
-		break;
-	case SIO_F71882_ID:
-		watchdog.type = f71882fg;
-		break;
-	case SIO_F71889_ID:
-		watchdog.type = f71889fg;
-		break;
-	case SIO_F71858_ID:
-		/* Confirmed (by datasheet) not to have a watchdog. */
-		err = -ENODEV;
-		goto exit;
-	case SIO_F81803_ID:
-		watchdog.type = f81803;
-		break;
-	case SIO_F81865_ID:
-		watchdog.type = f81865;
-		break;
-	case SIO_F81866_ID:
-		watchdog.type = f81866;
-		break;
-	default:
-		pr_info("Unrecognized Fintek device: %04x\n",
-			(unsigned int)devid);
-		err = -ENODEV;
-		goto exit;
+	for (id = fintek_wdt_id_table; id->driver_data; id++) {
+		variant = (void *)id->driver_data;
+		if (variant->id == devid) {
+			name = id->name;
+			pr_info("Found %s chip, revision %d\n",
+				name, superio_inb(sioaddr, SIO_REG_DEVREV));
+			goto out;
+		}
+	}
+
+	for (pdevid = fintek_no_wdt_table; *pdevid; pdevid++) {
+		if (*pdevid == devid)
+			goto out;
 	}
 
-	pr_info("Found %s watchdog chip, revision %d\n",
-		f71808e_names[watchdog.type],
-		(int)superio_inb(sioaddr, SIO_REG_DEVREV));
-exit:
+	pr_info("Unrecognized Fintek device: %04x\n", devid);
+out:
 	superio_exit(sioaddr);
-	return err;
+	return name;
 }
 
-static int __init f71808e_init(void)
+static struct resource wdt_res = {
+	.name = "superio port",
+	.flags = IORESOURCE_IO,
+};
+
+static int __init fintek_wdt_init(void)
 {
-	static const unsigned short addrs[] = { 0x2e, 0x4e };
-	int err = -ENODEV;
+	unsigned short addrs[] = { 0x2e, 0x4e };
+	const char *wdt_name;
 	int i;
 
 	if (f71862fg_pin != 63 && f71862fg_pin != 56) {
@@ -846,30 +896,33 @@ static int __init f71808e_init(void)
 		return -EINVAL;
 	}
 
+	platform_driver_register(&fintek_wdt_driver);
+
 	for (i = 0; i < ARRAY_SIZE(addrs); i++) {
-		err = f71808e_find(addrs[i]);
-		if (err == 0)
+		wdt_name = fintek_wdt_find(addrs[i]);
+		if (!IS_ERR(wdt_name))
 			break;
 	}
+
 	if (i == ARRAY_SIZE(addrs))
-		return err;
+		return PTR_ERR(wdt_name);
+
+	wdt_res.start = addrs[i];
+	wdt_res.end = wdt_res.start + 1;
 
-	return watchdog_init(addrs[i]);
+	fintek_wdt_pdev = platform_device_register_simple(wdt_name, -1, &wdt_res, 1);
+	return PTR_ERR_OR_ZERO(fintek_wdt_pdev);
 }
 
-static void __exit f71808e_exit(void)
+static void __exit fintek_wdt_exit(void)
 {
-	if (watchdog_is_running()) {
-		pr_warn("Watchdog timer still running, stopping it\n");
-		watchdog_stop();
-	}
-	misc_deregister(&watchdog_miscdev);
-	unregister_reboot_notifier(&watchdog_notifier);
+	platform_device_unregister(fintek_wdt_pdev);
+	platform_driver_unregister(&fintek_wdt_driver);
 }
 
 MODULE_DESCRIPTION("F71808E Watchdog Driver");
 MODULE_AUTHOR("Giel van Schijndel <me@...tis.eu>");
 MODULE_LICENSE("GPL");
 
-module_init(f71808e_init);
-module_exit(f71808e_exit);
+module_init(fintek_wdt_init);
+module_exit(fintek_wdt_exit);
-- 
2.28.0

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