linux/drivers/sbus/char/display7seg.c
Arnd Bergmann 1832f2d8ff compat_ioctl: move more drivers to compat_ptr_ioctl
The .ioctl and .compat_ioctl file operations have the same prototype so
they can both point to the same function, which works great almost all
the time when all the commands are compatible.

One exception is the s390 architecture, where a compat pointer is only
31 bit wide, and converting it into a 64-bit pointer requires calling
compat_ptr(). Most drivers here will never run in s390, but since we now
have a generic helper for it, it's easy enough to use it consistently.

I double-checked all these drivers to ensure that all ioctl arguments
are used as pointers or are ignored, but are not interpreted as integer
values.

Acked-by: Jason Gunthorpe <jgg@mellanox.com>
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Acked-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: David Sterba <dsterba@suse.com>
Acked-by: Darren Hart (VMware) <dvhart@infradead.org>
Acked-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Acked-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Acked-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
2019-10-23 17:23:44 +02:00

274 lines
6.2 KiB
C

// SPDX-License-Identifier: GPL-2.0-only
/* display7seg.c - Driver implementation for the 7-segment display
* present on Sun Microsystems CP1400 and CP1500
*
* Copyright (c) 2000 Eric Brower (ebrower@usa.net)
*/
#include <linux/device.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/fs.h>
#include <linux/errno.h>
#include <linux/major.h>
#include <linux/miscdevice.h>
#include <linux/ioport.h> /* request_region */
#include <linux/slab.h>
#include <linux/mutex.h>
#include <linux/of.h>
#include <linux/of_device.h>
#include <linux/atomic.h>
#include <linux/uaccess.h> /* put_/get_user */
#include <asm/io.h>
#include <asm/display7seg.h>
#define DRIVER_NAME "d7s"
#define PFX DRIVER_NAME ": "
static DEFINE_MUTEX(d7s_mutex);
static int sol_compat = 0; /* Solaris compatibility mode */
/* Solaris compatibility flag -
* The Solaris implementation omits support for several
* documented driver features (ref Sun doc 806-0180-03).
* By default, this module supports the documented driver
* abilities, rather than the Solaris implementation:
*
* 1) Device ALWAYS reverts to OBP-specified FLIPPED mode
* upon closure of device or module unload.
* 2) Device ioctls D7SIOCRD/D7SIOCWR honor toggling of
* FLIP bit
*
* If you wish the device to operate as under Solaris,
* omitting above features, set this parameter to non-zero.
*/
module_param(sol_compat, int, 0);
MODULE_PARM_DESC(sol_compat,
"Disables documented functionality omitted from Solaris driver");
MODULE_AUTHOR("Eric Brower <ebrower@usa.net>");
MODULE_DESCRIPTION("7-Segment Display driver for Sun Microsystems CP1400/1500");
MODULE_LICENSE("GPL");
MODULE_SUPPORTED_DEVICE("d7s");
struct d7s {
void __iomem *regs;
bool flipped;
};
struct d7s *d7s_device;
/*
* Register block address- see header for details
* -----------------------------------------
* | DP | ALARM | FLIP | 4 | 3 | 2 | 1 | 0 |
* -----------------------------------------
*
* DP - Toggles decimal point on/off
* ALARM - Toggles "Alarm" LED green/red
* FLIP - Inverts display for upside-down mounted board
* bits 0-4 - 7-segment display contents
*/
static atomic_t d7s_users = ATOMIC_INIT(0);
static int d7s_open(struct inode *inode, struct file *f)
{
if (D7S_MINOR != iminor(inode))
return -ENODEV;
atomic_inc(&d7s_users);
return 0;
}
static int d7s_release(struct inode *inode, struct file *f)
{
/* Reset flipped state to OBP default only if
* no other users have the device open and we
* are not operating in solaris-compat mode
*/
if (atomic_dec_and_test(&d7s_users) && !sol_compat) {
struct d7s *p = d7s_device;
u8 regval = 0;
regval = readb(p->regs);
if (p->flipped)
regval |= D7S_FLIP;
else
regval &= ~D7S_FLIP;
writeb(regval, p->regs);
}
return 0;
}
static long d7s_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
struct d7s *p = d7s_device;
u8 regs = readb(p->regs);
int error = 0;
u8 ireg = 0;
if (D7S_MINOR != iminor(file_inode(file)))
return -ENODEV;
mutex_lock(&d7s_mutex);
switch (cmd) {
case D7SIOCWR:
/* assign device register values we mask-out D7S_FLIP
* if in sol_compat mode
*/
if (get_user(ireg, (int __user *) arg)) {
error = -EFAULT;
break;
}
if (sol_compat) {
if (regs & D7S_FLIP)
ireg |= D7S_FLIP;
else
ireg &= ~D7S_FLIP;
}
writeb(ireg, p->regs);
break;
case D7SIOCRD:
/* retrieve device register values
* NOTE: Solaris implementation returns D7S_FLIP bit
* as toggled by user, even though it does not honor it.
* This driver will not misinform you about the state
* of your hardware while in sol_compat mode
*/
if (put_user(regs, (int __user *) arg)) {
error = -EFAULT;
break;
}
break;
case D7SIOCTM:
/* toggle device mode-- flip display orientation */
regs ^= D7S_FLIP;
writeb(regs, p->regs);
break;
}
mutex_unlock(&d7s_mutex);
return error;
}
static const struct file_operations d7s_fops = {
.owner = THIS_MODULE,
.unlocked_ioctl = d7s_ioctl,
.compat_ioctl = compat_ptr_ioctl,
.open = d7s_open,
.release = d7s_release,
.llseek = noop_llseek,
};
static struct miscdevice d7s_miscdev = {
.minor = D7S_MINOR,
.name = DRIVER_NAME,
.fops = &d7s_fops
};
static int d7s_probe(struct platform_device *op)
{
struct device_node *opts;
int err = -EINVAL;
struct d7s *p;
u8 regs;
if (d7s_device)
goto out;
p = devm_kzalloc(&op->dev, sizeof(*p), GFP_KERNEL);
err = -ENOMEM;
if (!p)
goto out;
p->regs = of_ioremap(&op->resource[0], 0, sizeof(u8), "d7s");
if (!p->regs) {
printk(KERN_ERR PFX "Cannot map chip registers\n");
goto out_free;
}
err = misc_register(&d7s_miscdev);
if (err) {
printk(KERN_ERR PFX "Unable to acquire miscdevice minor %i\n",
D7S_MINOR);
goto out_iounmap;
}
/* OBP option "d7s-flipped?" is honored as default for the
* device, and reset default when detached
*/
regs = readb(p->regs);
opts = of_find_node_by_path("/options");
if (opts &&
of_get_property(opts, "d7s-flipped?", NULL))
p->flipped = true;
if (p->flipped)
regs |= D7S_FLIP;
else
regs &= ~D7S_FLIP;
writeb(regs, p->regs);
printk(KERN_INFO PFX "7-Segment Display%pOF at [%s:0x%llx] %s\n",
op->dev.of_node,
(regs & D7S_FLIP) ? " (FLIPPED)" : "",
op->resource[0].start,
sol_compat ? "in sol_compat mode" : "");
dev_set_drvdata(&op->dev, p);
d7s_device = p;
err = 0;
of_node_put(opts);
out:
return err;
out_iounmap:
of_iounmap(&op->resource[0], p->regs, sizeof(u8));
out_free:
goto out;
}
static int d7s_remove(struct platform_device *op)
{
struct d7s *p = dev_get_drvdata(&op->dev);
u8 regs = readb(p->regs);
/* Honor OBP d7s-flipped? unless operating in solaris-compat mode */
if (sol_compat) {
if (p->flipped)
regs |= D7S_FLIP;
else
regs &= ~D7S_FLIP;
writeb(regs, p->regs);
}
misc_deregister(&d7s_miscdev);
of_iounmap(&op->resource[0], p->regs, sizeof(u8));
return 0;
}
static const struct of_device_id d7s_match[] = {
{
.name = "display7seg",
},
{},
};
MODULE_DEVICE_TABLE(of, d7s_match);
static struct platform_driver d7s_driver = {
.driver = {
.name = DRIVER_NAME,
.of_match_table = d7s_match,
},
.probe = d7s_probe,
.remove = d7s_remove,
};
module_platform_driver(d7s_driver);