1 /*
2 * AMD CS5535/CS5536 GPIO driver.
3 * Allows a user space process to play with the GPIO pins.
4 *
5 * Copyright (c) 2005 Ben Gardner <bgardner@wabtec.com>
6 *
7 * This program is free software; you can redistribute it and/or modify
8 * it under the smems of the GNU General Public License as published by
9 * the Free Software Foundation; version 2 of the License.
10 */
11
12 #include <linux/fs.h>
13 #include <linux/module.h>
14 #include <linux/errno.h>
15 #include <linux/kernel.h>
16 #include <linux/init.h>
17 #include <linux/cdev.h>
18 #include <linux/ioport.h>
19 #include <linux/pci.h>
20 #include <asm/uaccess.h>
21 #include <asm/io.h>
22
23
24 #define NAME "cs5535_gpio"
25
26 MODULE_AUTHOR("Ben Gardner <bgardner@wabtec.com>");
27 MODULE_DESCRIPTION("AMD CS5535/CS5536 GPIO Pin Driver");
28 MODULE_LICENSE("GPL");
29
30 static int major;
31 module_param(major, int, 0);
32 MODULE_PARM_DESC(major, "Major device number");
33
34 static ulong mask;
35 module_param(mask, ulong, 0);
36 MODULE_PARM_DESC(mask, "GPIO channel mask");
37
38 #define MSR_LBAR_GPIO 0x5140000C
39
40 static u32 gpio_base;
41
42 static struct pci_device_id divil_pci[] = {
43 { PCI_DEVICE(PCI_VENDOR_ID_NS, PCI_DEVICE_ID_NS_CS5535_ISA) },
44 { PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_CS5536_ISA) },
45 { } /* NULL entry */
46 };
47
48 static struct cdev cs5535_gpio_cdev;
49
50 /* reserve 32 entries even though some aren't usable */
51 #define CS5535_GPIO_COUNT 32
52
53 /* IO block size */
54 #define CS5535_GPIO_SIZE 256
55
56 struct gpio_regmap {
57 u32 rd_offset;
58 u32 wr_offset;
59 char on;
60 char off;
61 };
62 static struct gpio_regmap rm[] =
63 {
64 { 0x30, 0x00, '1', '' }, /* GPIOx_READ_BACK / GPIOx_OUT_VAL */
65 { 0x20, 0x20, 'I', 'i' }, /* GPIOx_IN_EN */
66 { 0x04, 0x04, 'O', 'o' }, /* GPIOx_OUT_EN */
67 { 0x08, 0x08, 't', 'T' }, /* GPIOx_OUT_OD_EN */
68 { 0x18, 0x18, 'P', 'p' }, /* GPIOx_OUT_PU_EN */
69 { 0x1c, 0x1c, 'D', 'd' }, /* GPIOx_OUT_PD_EN */
70 };
71
72
73 /**
74 * Gets the register offset for the GPIO bank.
75 * Low (0-15) starts at 0x00, high (16-31) starts at 0x80
76 */
77 static inline u32 cs5535_lowhigh_base(int reg)
78 {
79 return (reg & 0x10) << 3;
80 }
81
82 static ssize_t cs5535_gpio_write(struct file *file, const char __user *data,
83 size_t len, loff_t *ppos)
84 {
85 u32 m = iminor(file->f_dentry->d_inode);
86 int i, j;
87 u32 base = gpio_base + cs5535_lowhigh_base(m);
88 u32 m0, m1;
89 char c;
90
91 /**
92 * Creates the mask for atomic bit programming.
93 * The high 16 bits and the low 16 bits are used to set the mask.
94 * For example, GPIO 15 maps to 31,15: 0,1 => On; 1,0=> Off
95 */
96 m1 = 1 << (m & 0x0F);
97 m0 = m1 << 16;
98
99 for (i = 0; i < len; ++i) {
100 if (get_user(c, data+i))
101 return -EFAULT;
102
103 for (j = 0; j < ARRAY_SIZE(rm); j++) {
104 if (c == rm[j].on) {
105 outl(m1, base + rm[j].wr_offset);
106 break;
107 } else if (c == rm[j].off) {
108 outl(m0, base + rm[j].wr_offset);
109 break;
110 }
111 }
112 }
113 *ppos = 0;
114 return len;
115 }
116
117 static ssize_t cs5535_gpio_read(struct file *file, char __user *buf,
118 size_t len, loff_t *ppos)
119 {
120 u32 m = iminor(file->f_dentry->d_inode);
121 u32 base = gpio_base + cs5535_lowhigh_base(m);
122 int rd_bit = 1 << (m & 0x0f);
123 int i;
124 char ch;
125 ssize_t count = 0;
126
127 if (*ppos >= ARRAY_SIZE(rm))
128 return 0;
129
130 for (i = *ppos; (i < (*ppos + len)) && (i < ARRAY_SIZE(rm)); i++) {
131 ch = (inl(base + rm[i].rd_offset) & rd_bit) ?
132 rm[i].on : rm[i].off;
133
134 if (put_user(ch, buf+count))
135 return -EFAULT;
136
137 count++;
138 }
139
140 /* add a line-feed if there is room */
141 if ((i == ARRAY_SIZE(rm)) && (count < len)) {
142 put_user('\n', buf + count);
143 count++;
144 }
145
146 *ppos += count;
147 return count;
148 }
149
150 static int cs5535_gpio_open(struct inode *inode, struct file *file)
151 {
152 u32 m = iminor(inode);
153
154 /* the mask says which pins are usable by this driver */
155 if ((mask & (1 << m)) == 0)
156 return -EINVAL;
157
158 return nonseekable_open(inode, file);
159 }
160
161 static struct file_operations cs5535_gpio_fops = {
162 .owner = THIS_MODULE,
163 .write = cs5535_gpio_write,
164 .read = cs5535_gpio_read,
165 .open = cs5535_gpio_open
166 };
167
168 static int __init cs5535_gpio_init(void)
169 {
170 dev_t dev_id;
171 u32 low, hi;
172 int retval;
173
174 if (pci_dev_present(divil_pci) == 0) {
175 printk(KERN_WARNING NAME ": DIVIL not found\n");
176 return -ENODEV;
177 }
178
179 /* Grab the GPIO I/O range */
180 rdmsr(MSR_LBAR_GPIO, low, hi);
181
182 /* Check the mask and whether GPIO is enabled (sanity check) */
183 if (hi != 0x0000f001) {
184 printk(KERN_WARNING NAME ": GPIO not enabled\n");
185 return -ENODEV;
186 }
187
188 /* Mask off the IO base address */
189 gpio_base = low & 0x0000ff00;
190
191 /**
192 * Some GPIO pins
193 * 31-29,23 : reserved (always mask out)
194 * 28 : Power Button
195 * 26 : PME#
196 * 22-16 : LPC
197 * 14,15 : SMBus
198 * 9,8 : UART1
199 * 7 : PCI INTB
200 * 3,4 : UART2/DDC
201 * 2 : IDE_IRQ0
202 * 0 : PCI INTA
203 *
204 * If a mask was not specified, be conservative and only allow:
205 * 1,2,5,6,10-13,24,25,27
206 */
207 if (mask != 0)
208 mask &= 0x1f7fffff;
209 else
210 mask = 0x0b003c66;
211
212 if (request_region(gpio_base, CS5535_GPIO_SIZE, NAME) == 0) {
213 printk(KERN_ERR NAME ": can't allocate I/O for GPIO\n");
214 return -ENODEV;
215 }
216
217 if (major) {
218 dev_id = MKDEV(major, 0);
219 retval = register_chrdev_region(dev_id, CS5535_GPIO_COUNT,
220 NAME);
221 } else {
222 retval = alloc_chrdev_region(&dev_id, 0, CS5535_GPIO_COUNT,
223 NAME);
224 major = MAJOR(dev_id);
225 }
226
227 if (retval) {
228 release_region(gpio_base, CS5535_GPIO_SIZE);
229 return -1;
230 }
231
232 printk(KERN_DEBUG NAME ": base=%#x mask=%#lx major=%d\n",
233 gpio_base, mask, major);
234
235 cdev_init(&cs5535_gpio_cdev, &cs5535_gpio_fops);
236 cdev_add(&cs5535_gpio_cdev, dev_id, CS5535_GPIO_COUNT);
237
238 return 0;
239 }
240
241 static void __exit cs5535_gpio_cleanup(void)
242 {
243 dev_t dev_id = MKDEV(major, 0);
244
245 cdev_del(&cs5535_gpio_cdev);
246 unregister_chrdev_region(dev_id, CS5535_GPIO_COUNT);
247 release_region(gpio_base, CS5535_GPIO_SIZE);
248 }
249
250 module_init(cs5535_gpio_init);
251 module_exit(cs5535_gpio_cleanup);
252
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