bybrooklyn/linux
1
0
Fork 0
mirror of https://github.com/torvalds/linux.git synced 2026-04-18 06:44:00 -04:00
Code Issues Packages Projects Releases Wiki Activity
Files
d37ec2fbab55d732aae48ef2c877fb2d5ab08cd7
linux/drivers/watchdog/ni903x_wdt.c
Rafael J. Wysocki d37ec2fbab watchdog: ni903x_wdt: Convert to a platform driver 
In all cases in which a struct acpi_driver is used for binding a driver
to an ACPI device object, a corresponding platform device is created by
the ACPI core and that device is regarded as a proper representation of
underlying hardware.  Accordingly, a struct platform_driver should be
used by driver code to bind to that device.  There are multiple reasons
why drivers should not bind directly to ACPI device objects [1].

In particular, registering a watchdog device under a struct acpi_device
is questionable because it causes the watchdog to be hidden in the ACPI
bus sysfs hierarchy and it goes against the general rule that a struct
acpi_device can only be a parent of another struct acpi_device.

Overall, it is better to bind drivers to platform devices than to their
ACPI companions, so convert the ni903x_wdt watchdog ACPI driver to a
platform one.

While this is not expected to alter functionality, it changes sysfs
layout and so it will be visible to user space.

Note that after this change it actually makes sense to look for
the "timeout-sec" property via device_property_read_u32() under the
device passed to watchdog_init_timeout() because it has an fwnode
handle (unlike a struct acpi_device which is an fwnode itself).

Link: https://lore.kernel.org/all/2396510.ElGaqSPkdT@rafael.j.wysocki/ [1]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://patch.msgid.link/13996583.uLZWGnKmhe@rafael.j.wysocki
2026-04-07 21:06:59 +02:00

257 lines
6.2 KiB
C
Raw Blame History

// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Copyright (C) 2016 National Instruments Corp.
*/
#include <linux/acpi.h>
#include <linux/device.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/watchdog.h>
#define NIWD_CONTROL 0x01
#define NIWD_COUNTER2 0x02
#define NIWD_COUNTER1 0x03
#define NIWD_COUNTER0 0x04
#define NIWD_SEED2 0x05
#define NIWD_SEED1 0x06
#define NIWD_SEED0 0x07
#define NIWD_IO_SIZE 0x08
#define NIWD_CONTROL_MODE 0x80
#define NIWD_CONTROL_PROC_RESET 0x20
#define NIWD_CONTROL_PET 0x10
#define NIWD_CONTROL_RUNNING 0x08
#define NIWD_CONTROL_CAPTURECOUNTER 0x04
#define NIWD_CONTROL_RESET 0x02
#define NIWD_CONTROL_ALARM 0x01
#define NIWD_PERIOD_NS 30720
#define NIWD_MIN_TIMEOUT 1
#define NIWD_MAX_TIMEOUT 515
#define NIWD_DEFAULT_TIMEOUT 60
#define NIWD_NAME "ni903x_wdt"
struct ni903x_wdt {
struct device *dev;
u16 io_base;
struct watchdog_device wdd;
};
static unsigned int timeout;
module_param(timeout, uint, 0);
MODULE_PARM_DESC(timeout,
"Watchdog timeout in seconds. (default="
__MODULE_STRING(NIWD_DEFAULT_TIMEOUT) ")");
static int nowayout = WATCHDOG_NOWAYOUT;
module_param(nowayout, int, S_IRUGO);
MODULE_PARM_DESC(nowayout,
"Watchdog cannot be stopped once started (default="
__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
static void ni903x_start(struct ni903x_wdt *wdt)
{
u8 control = inb(wdt->io_base + NIWD_CONTROL);
outb(control | NIWD_CONTROL_RESET, wdt->io_base + NIWD_CONTROL);
outb(control | NIWD_CONTROL_PET, wdt->io_base + NIWD_CONTROL);
}
static int ni903x_wdd_set_timeout(struct watchdog_device *wdd,
unsigned int timeout)
{
struct ni903x_wdt *wdt = watchdog_get_drvdata(wdd);
u32 counter = timeout * (1000000000 / NIWD_PERIOD_NS);
outb(((0x00FF0000 & counter) >> 16), wdt->io_base + NIWD_SEED2);
outb(((0x0000FF00 & counter) >> 8), wdt->io_base + NIWD_SEED1);
outb((0x000000FF & counter), wdt->io_base + NIWD_SEED0);
wdd->timeout = timeout;
return 0;
}
static unsigned int ni903x_wdd_get_timeleft(struct watchdog_device *wdd)
{
struct ni903x_wdt *wdt = watchdog_get_drvdata(wdd);
u8 control, counter0, counter1, counter2;
u32 counter;
control = inb(wdt->io_base + NIWD_CONTROL);
control |= NIWD_CONTROL_CAPTURECOUNTER;
outb(control, wdt->io_base + NIWD_CONTROL);
counter2 = inb(wdt->io_base + NIWD_COUNTER2);
counter1 = inb(wdt->io_base + NIWD_COUNTER1);
counter0 = inb(wdt->io_base + NIWD_COUNTER0);
counter = (counter2 << 16) | (counter1 << 8) | counter0;
return counter / (1000000000 / NIWD_PERIOD_NS);
}
static int ni903x_wdd_ping(struct watchdog_device *wdd)
{
struct ni903x_wdt *wdt = watchdog_get_drvdata(wdd);
u8 control;
control = inb(wdt->io_base + NIWD_CONTROL);
outb(control | NIWD_CONTROL_PET, wdt->io_base + NIWD_CONTROL);
return 0;
}
static int ni903x_wdd_start(struct watchdog_device *wdd)
{
struct ni903x_wdt *wdt = watchdog_get_drvdata(wdd);
outb(NIWD_CONTROL_RESET | NIWD_CONTROL_PROC_RESET,
wdt->io_base + NIWD_CONTROL);
ni903x_wdd_set_timeout(wdd, wdd->timeout);
ni903x_start(wdt);
return 0;
}
static int ni903x_wdd_stop(struct watchdog_device *wdd)
{
struct ni903x_wdt *wdt = watchdog_get_drvdata(wdd);
outb(NIWD_CONTROL_RESET, wdt->io_base + NIWD_CONTROL);
return 0;
}
static acpi_status ni903x_resources(struct acpi_resource *res, void *data)
{
struct ni903x_wdt *wdt = data;
u16 io_size;
switch (res->type) {
case ACPI_RESOURCE_TYPE_IO:
if (wdt->io_base != 0) {
dev_err(wdt->dev, "too many IO resources\n");
return AE_ERROR;
}
wdt->io_base = res->data.io.minimum;
io_size = res->data.io.address_length;
if (io_size < NIWD_IO_SIZE) {
dev_err(wdt->dev, "memory region too small\n");
return AE_ERROR;
}
if (!devm_request_region(wdt->dev, wdt->io_base, io_size,
NIWD_NAME)) {
dev_err(wdt->dev, "failed to get memory region\n");
return AE_ERROR;
}
return AE_OK;
case ACPI_RESOURCE_TYPE_END_TAG:
default:
/* Ignore unsupported resources, e.g. IRQ */
return AE_OK;
}
}
static const struct watchdog_info ni903x_wdd_info = {
.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
.identity = "NI Watchdog",
};
static const struct watchdog_ops ni903x_wdd_ops = {
.owner = THIS_MODULE,
.start = ni903x_wdd_start,
.stop = ni903x_wdd_stop,
.ping = ni903x_wdd_ping,
.set_timeout = ni903x_wdd_set_timeout,
.get_timeleft = ni903x_wdd_get_timeleft,
};
static int ni903x_acpi_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
struct watchdog_device *wdd;
struct ni903x_wdt *wdt;
acpi_status status;
int ret;
wdt = devm_kzalloc(dev, sizeof(*wdt), GFP_KERNEL);
if (!wdt)
return -ENOMEM;
platform_set_drvdata(pdev, wdt);
wdt->dev = dev;
status = acpi_walk_resources(ACPI_HANDLE(dev), METHOD_NAME__CRS,
ni903x_resources, wdt);
if (ACPI_FAILURE(status) || wdt->io_base == 0) {
dev_err(dev, "failed to get resources\n");
return -ENODEV;
}
wdd = &wdt->wdd;
wdd->info = &ni903x_wdd_info;
wdd->ops = &ni903x_wdd_ops;
wdd->min_timeout = NIWD_MIN_TIMEOUT;
wdd->max_timeout = NIWD_MAX_TIMEOUT;
wdd->timeout = NIWD_DEFAULT_TIMEOUT;
wdd->parent = dev;
watchdog_set_drvdata(wdd, wdt);
watchdog_set_nowayout(wdd, nowayout);
watchdog_init_timeout(wdd, timeout, dev);
ret = watchdog_register_device(wdd);
if (ret)
return ret;
/* Switch from boot mode to user mode */
outb(NIWD_CONTROL_RESET | NIWD_CONTROL_MODE,
wdt->io_base + NIWD_CONTROL);
dev_dbg(dev, "io_base=0x%04X, timeout=%d, nowayout=%d\n",
wdt->io_base, timeout, nowayout);
return 0;
}
static void ni903x_acpi_remove(struct platform_device *pdev)
{
struct ni903x_wdt *wdt = platform_get_drvdata(pdev);
ni903x_wdd_stop(&wdt->wdd);
watchdog_unregister_device(&wdt->wdd);
}
static const struct acpi_device_id ni903x_device_ids[] = {
{"NIC775C", 0},
{"", 0},
};
MODULE_DEVICE_TABLE(acpi, ni903x_device_ids);
static struct platform_driver ni903x_acpi_driver = {
.probe = ni903x_acpi_probe,
.remove = ni903x_acpi_remove,
.driver = {
.name = NIWD_NAME,
.acpi_match_table = ni903x_device_ids,
},
};
module_platform_driver(ni903x_acpi_driver);
MODULE_DESCRIPTION("NI 903x Watchdog");
MODULE_AUTHOR("Jeff Westfahl <jeff.westfahl@ni.com>");
MODULE_AUTHOR("Kyle Roeschley <kyle.roeschley@ni.com>");
MODULE_LICENSE("GPL");
Reference in New Issue View Git Blame Copy Permalink