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