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1// SPDX-License-Identifier: GPL-2.0-only2/* display7seg.c - Driver implementation for the 7-segment display3 * present on Sun Microsystems CP1400 and CP15004 *5 * Copyright (c) 2000 Eric Brower (ebrower@usa.net)6 */7 8#include <linux/device.h>9#include <linux/kernel.h>10#include <linux/module.h>11#include <linux/fs.h>12#include <linux/errno.h>13#include <linux/major.h>14#include <linux/miscdevice.h>15#include <linux/ioport.h> /* request_region */16#include <linux/slab.h>17#include <linux/mutex.h>18#include <linux/of.h>19#include <linux/platform_device.h>20#include <linux/atomic.h>21#include <linux/uaccess.h> /* put_/get_user */22#include <asm/io.h>23 24#include <asm/display7seg.h>25 26#define DRIVER_NAME "d7s"27#define PFX DRIVER_NAME ": "28 29static DEFINE_MUTEX(d7s_mutex);30static int sol_compat = 0; /* Solaris compatibility mode */31 32/* Solaris compatibility flag -33 * The Solaris implementation omits support for several34 * documented driver features (ref Sun doc 806-0180-03). 35 * By default, this module supports the documented driver 36 * abilities, rather than the Solaris implementation:37 *38 * 1) Device ALWAYS reverts to OBP-specified FLIPPED mode39 * upon closure of device or module unload.40 * 2) Device ioctls D7SIOCRD/D7SIOCWR honor toggling of41 * FLIP bit42 *43 * If you wish the device to operate as under Solaris,44 * omitting above features, set this parameter to non-zero.45 */46module_param(sol_compat, int, 0);47MODULE_PARM_DESC(sol_compat, 48 "Disables documented functionality omitted from Solaris driver");49 50MODULE_AUTHOR("Eric Brower <ebrower@usa.net>");51MODULE_DESCRIPTION("7-Segment Display driver for Sun Microsystems CP1400/1500");52MODULE_LICENSE("GPL");53 54struct d7s {55 void __iomem *regs;56 bool flipped;57};58struct d7s *d7s_device;59 60/*61 * Register block address- see header for details62 * -----------------------------------------63 * | DP | ALARM | FLIP | 4 | 3 | 2 | 1 | 0 |64 * -----------------------------------------65 *66 * DP - Toggles decimal point on/off 67 * ALARM - Toggles "Alarm" LED green/red68 * FLIP - Inverts display for upside-down mounted board69 * bits 0-4 - 7-segment display contents70 */71static atomic_t d7s_users = ATOMIC_INIT(0);72 73static int d7s_open(struct inode *inode, struct file *f)74{75 if (D7S_MINOR != iminor(inode))76 return -ENODEV;77 atomic_inc(&d7s_users);78 return 0;79}80 81static int d7s_release(struct inode *inode, struct file *f)82{83 /* Reset flipped state to OBP default only if84 * no other users have the device open and we85 * are not operating in solaris-compat mode86 */87 if (atomic_dec_and_test(&d7s_users) && !sol_compat) {88 struct d7s *p = d7s_device;89 u8 regval = 0;90 91 regval = readb(p->regs);92 if (p->flipped)93 regval |= D7S_FLIP;94 else95 regval &= ~D7S_FLIP;96 writeb(regval, p->regs);97 }98 99 return 0;100}101 102static long d7s_ioctl(struct file *file, unsigned int cmd, unsigned long arg)103{104 struct d7s *p = d7s_device;105 u8 regs = readb(p->regs);106 int error = 0;107 u8 ireg = 0;108 109 if (D7S_MINOR != iminor(file_inode(file)))110 return -ENODEV;111 112 mutex_lock(&d7s_mutex);113 switch (cmd) {114 case D7SIOCWR:115 /* assign device register values we mask-out D7S_FLIP116 * if in sol_compat mode117 */118 if (get_user(ireg, (int __user *) arg)) {119 error = -EFAULT;120 break;121 }122 if (sol_compat) {123 if (regs & D7S_FLIP)124 ireg |= D7S_FLIP;125 else126 ireg &= ~D7S_FLIP;127 }128 writeb(ireg, p->regs);129 break;130 131 case D7SIOCRD:132 /* retrieve device register values133 * NOTE: Solaris implementation returns D7S_FLIP bit134 * as toggled by user, even though it does not honor it.135 * This driver will not misinform you about the state136 * of your hardware while in sol_compat mode137 */138 if (put_user(regs, (int __user *) arg)) {139 error = -EFAULT;140 break;141 }142 break;143 144 case D7SIOCTM:145 /* toggle device mode-- flip display orientation */146 regs ^= D7S_FLIP;147 writeb(regs, p->regs);148 break;149 }150 mutex_unlock(&d7s_mutex);151 152 return error;153}154 155static const struct file_operations d7s_fops = {156 .owner = THIS_MODULE,157 .unlocked_ioctl = d7s_ioctl,158 .compat_ioctl = compat_ptr_ioctl,159 .open = d7s_open,160 .release = d7s_release,161 .llseek = noop_llseek,162};163 164static struct miscdevice d7s_miscdev = {165 .minor = D7S_MINOR,166 .name = DRIVER_NAME,167 .fops = &d7s_fops168};169 170static int d7s_probe(struct platform_device *op)171{172 struct device_node *opts;173 int err = -EINVAL;174 struct d7s *p;175 u8 regs;176 177 if (d7s_device)178 goto out;179 180 p = devm_kzalloc(&op->dev, sizeof(*p), GFP_KERNEL);181 err = -ENOMEM;182 if (!p)183 goto out;184 185 p->regs = of_ioremap(&op->resource[0], 0, sizeof(u8), "d7s");186 if (!p->regs) {187 printk(KERN_ERR PFX "Cannot map chip registers\n");188 goto out;189 }190 191 err = misc_register(&d7s_miscdev);192 if (err) {193 printk(KERN_ERR PFX "Unable to acquire miscdevice minor %i\n",194 D7S_MINOR);195 goto out_iounmap;196 }197 198 /* OBP option "d7s-flipped?" is honored as default for the199 * device, and reset default when detached200 */201 regs = readb(p->regs);202 opts = of_find_node_by_path("/options");203 if (opts)204 p->flipped = of_property_read_bool(opts, "d7s-flipped?");205 206 if (p->flipped)207 regs |= D7S_FLIP;208 else209 regs &= ~D7S_FLIP;210 211 writeb(regs, p->regs);212 213 printk(KERN_INFO PFX "7-Segment Display%pOF at [%s:0x%llx] %s\n",214 op->dev.of_node,215 (regs & D7S_FLIP) ? " (FLIPPED)" : "",216 op->resource[0].start,217 sol_compat ? "in sol_compat mode" : "");218 219 dev_set_drvdata(&op->dev, p);220 d7s_device = p;221 err = 0;222 of_node_put(opts);223 224out:225 return err;226 227out_iounmap:228 of_iounmap(&op->resource[0], p->regs, sizeof(u8));229 goto out;230}231 232static void d7s_remove(struct platform_device *op)233{234 struct d7s *p = dev_get_drvdata(&op->dev);235 u8 regs = readb(p->regs);236 237 /* Honor OBP d7s-flipped? unless operating in solaris-compat mode */238 if (sol_compat) {239 if (p->flipped)240 regs |= D7S_FLIP;241 else242 regs &= ~D7S_FLIP;243 writeb(regs, p->regs);244 }245 246 misc_deregister(&d7s_miscdev);247 of_iounmap(&op->resource[0], p->regs, sizeof(u8));248}249 250static const struct of_device_id d7s_match[] = {251 {252 .name = "display7seg",253 },254 {},255};256MODULE_DEVICE_TABLE(of, d7s_match);257 258static struct platform_driver d7s_driver = {259 .driver = {260 .name = DRIVER_NAME,261 .of_match_table = d7s_match,262 },263 .probe = d7s_probe,264 .remove_new = d7s_remove,265};266 267module_platform_driver(d7s_driver);268