Root/drivers/char/pc8736x_gpio.c

1/* linux/drivers/char/pc8736x_gpio.c
2
3   National Semiconductor PC8736x GPIO driver. Allows a user space
4   process to play with the GPIO pins.
5
6   Copyright (c) 2005,2006 Jim Cromie <jim.cromie@gmail.com>
7
8   adapted from linux/drivers/char/scx200_gpio.c
9   Copyright (c) 2001,2002 Christer Weinigel <wingel@nano-system.com>,
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/io.h>
19#include <linux/ioport.h>
20#include <linux/mutex.h>
21#include <linux/nsc_gpio.h>
22#include <linux/platform_device.h>
23#include <asm/uaccess.h>
24
25#define DEVNAME "pc8736x_gpio"
26
27MODULE_AUTHOR("Jim Cromie <jim.cromie@gmail.com>");
28MODULE_DESCRIPTION("NatSemi/Winbond PC-8736x GPIO Pin Driver");
29MODULE_LICENSE("GPL");
30
31static int major; /* default to dynamic major */
32module_param(major, int, 0);
33MODULE_PARM_DESC(major, "Major device number");
34
35static DEFINE_MUTEX(pc8736x_gpio_config_lock);
36static unsigned pc8736x_gpio_base;
37static u8 pc8736x_gpio_shadow[4];
38
39#define SIO_BASE1 0x2E /* 1st command-reg to check */
40#define SIO_BASE2 0x4E /* alt command-reg to check */
41
42#define SIO_SID 0x20 /* SuperI/O ID Register */
43#define SIO_SID_PC87365 0xe5 /* Expected value in ID Register for PC87365 */
44#define SIO_SID_PC87366 0xe9 /* Expected value in ID Register for PC87366 */
45
46#define SIO_CF1 0x21 /* chip config, bit0 is chip enable */
47
48#define PC8736X_GPIO_RANGE 16 /* ioaddr range */
49#define PC8736X_GPIO_CT 32 /* minors matching 4 8 bit ports */
50
51#define SIO_UNIT_SEL 0x7 /* unit select reg */
52#define SIO_UNIT_ACT 0x30 /* unit enable */
53#define SIO_GPIO_UNIT 0x7 /* unit number of GPIO */
54#define SIO_VLM_UNIT 0x0D
55#define SIO_TMS_UNIT 0x0E
56
57/* config-space addrs to read/write each unit's runtime addr */
58#define SIO_BASE_HADDR 0x60
59#define SIO_BASE_LADDR 0x61
60
61/* GPIO config-space pin-control addresses */
62#define SIO_GPIO_PIN_SELECT 0xF0
63#define SIO_GPIO_PIN_CONFIG 0xF1
64#define SIO_GPIO_PIN_EVENT 0xF2
65
66static unsigned char superio_cmd = 0;
67static unsigned char selected_device = 0xFF; /* bogus start val */
68
69/* GPIO port runtime access, functionality */
70static int port_offset[] = { 0, 4, 8, 10 }; /* non-uniform offsets ! */
71/* static int event_capable[] = { 1, 1, 0, 0 }; ports 2,3 are hobbled */
72
73#define PORT_OUT 0
74#define PORT_IN 1
75#define PORT_EVT_EN 2
76#define PORT_EVT_STST 3
77
78static struct platform_device *pdev; /* use in dev_*() */
79
80static inline void superio_outb(int addr, int val)
81{
82    outb_p(addr, superio_cmd);
83    outb_p(val, superio_cmd + 1);
84}
85
86static inline int superio_inb(int addr)
87{
88    outb_p(addr, superio_cmd);
89    return inb_p(superio_cmd + 1);
90}
91
92static int pc8736x_superio_present(void)
93{
94    int id;
95
96    /* try the 2 possible values, read a hardware reg to verify */
97    superio_cmd = SIO_BASE1;
98    id = superio_inb(SIO_SID);
99    if (id == SIO_SID_PC87365 || id == SIO_SID_PC87366)
100        return superio_cmd;
101
102    superio_cmd = SIO_BASE2;
103    id = superio_inb(SIO_SID);
104    if (id == SIO_SID_PC87365 || id == SIO_SID_PC87366)
105        return superio_cmd;
106
107    return 0;
108}
109
110static void device_select(unsigned devldn)
111{
112    superio_outb(SIO_UNIT_SEL, devldn);
113    selected_device = devldn;
114}
115
116static void select_pin(unsigned iminor)
117{
118    /* select GPIO port/pin from device minor number */
119    device_select(SIO_GPIO_UNIT);
120    superio_outb(SIO_GPIO_PIN_SELECT,
121             ((iminor << 1) & 0xF0) | (iminor & 0x7));
122}
123
124static inline u32 pc8736x_gpio_configure_fn(unsigned index, u32 mask, u32 bits,
125                        u32 func_slct)
126{
127    u32 config, new_config;
128
129    mutex_lock(&pc8736x_gpio_config_lock);
130
131    device_select(SIO_GPIO_UNIT);
132    select_pin(index);
133
134    /* read current config value */
135    config = superio_inb(func_slct);
136
137    /* set new config */
138    new_config = (config & mask) | bits;
139    superio_outb(func_slct, new_config);
140
141    mutex_unlock(&pc8736x_gpio_config_lock);
142
143    return config;
144}
145
146static u32 pc8736x_gpio_configure(unsigned index, u32 mask, u32 bits)
147{
148    return pc8736x_gpio_configure_fn(index, mask, bits,
149                     SIO_GPIO_PIN_CONFIG);
150}
151
152static int pc8736x_gpio_get(unsigned minor)
153{
154    int port, bit, val;
155
156    port = minor >> 3;
157    bit = minor & 7;
158    val = inb_p(pc8736x_gpio_base + port_offset[port] + PORT_IN);
159    val >>= bit;
160    val &= 1;
161
162    dev_dbg(&pdev->dev, "_gpio_get(%d from %x bit %d) == val %d\n",
163        minor, pc8736x_gpio_base + port_offset[port] + PORT_IN, bit,
164        val);
165
166    return val;
167}
168
169static void pc8736x_gpio_set(unsigned minor, int val)
170{
171    int port, bit, curval;
172
173    minor &= 0x1f;
174    port = minor >> 3;
175    bit = minor & 7;
176    curval = inb_p(pc8736x_gpio_base + port_offset[port] + PORT_OUT);
177
178    dev_dbg(&pdev->dev, "addr:%x cur:%x bit-pos:%d cur-bit:%x + new:%d -> bit-new:%d\n",
179        pc8736x_gpio_base + port_offset[port] + PORT_OUT,
180        curval, bit, (curval & ~(1 << bit)), val, (val << bit));
181
182    val = (curval & ~(1 << bit)) | (val << bit);
183
184    dev_dbg(&pdev->dev, "gpio_set(minor:%d port:%d bit:%d)"
185        " %2x -> %2x\n", minor, port, bit, curval, val);
186
187    outb_p(val, pc8736x_gpio_base + port_offset[port] + PORT_OUT);
188
189    curval = inb_p(pc8736x_gpio_base + port_offset[port] + PORT_OUT);
190    val = inb_p(pc8736x_gpio_base + port_offset[port] + PORT_IN);
191
192    dev_dbg(&pdev->dev, "wrote %x, read: %x\n", curval, val);
193    pc8736x_gpio_shadow[port] = val;
194}
195
196static int pc8736x_gpio_current(unsigned minor)
197{
198    int port, bit;
199    minor &= 0x1f;
200    port = minor >> 3;
201    bit = minor & 7;
202    return ((pc8736x_gpio_shadow[port] >> bit) & 0x01);
203}
204
205static void pc8736x_gpio_change(unsigned index)
206{
207    pc8736x_gpio_set(index, !pc8736x_gpio_current(index));
208}
209
210static struct nsc_gpio_ops pc8736x_gpio_ops = {
211    .owner = THIS_MODULE,
212    .gpio_config = pc8736x_gpio_configure,
213    .gpio_dump = nsc_gpio_dump,
214    .gpio_get = pc8736x_gpio_get,
215    .gpio_set = pc8736x_gpio_set,
216    .gpio_change = pc8736x_gpio_change,
217    .gpio_current = pc8736x_gpio_current
218};
219
220static int pc8736x_gpio_open(struct inode *inode, struct file *file)
221{
222    unsigned m = iminor(inode);
223    file->private_data = &pc8736x_gpio_ops;
224
225    dev_dbg(&pdev->dev, "open %d\n", m);
226
227    if (m >= PC8736X_GPIO_CT)
228        return -EINVAL;
229    return nonseekable_open(inode, file);
230}
231
232static const struct file_operations pc8736x_gpio_fileops = {
233    .owner = THIS_MODULE,
234    .open = pc8736x_gpio_open,
235    .write = nsc_gpio_write,
236    .read = nsc_gpio_read,
237    .llseek = no_llseek,
238};
239
240static void __init pc8736x_init_shadow(void)
241{
242    int port;
243
244    /* read the current values driven on the GPIO signals */
245    for (port = 0; port < 4; ++port)
246        pc8736x_gpio_shadow[port]
247            = inb_p(pc8736x_gpio_base + port_offset[port]
248                + PORT_OUT);
249
250}
251
252static struct cdev pc8736x_gpio_cdev;
253
254static int __init pc8736x_gpio_init(void)
255{
256    int rc;
257    dev_t devid;
258
259    pdev = platform_device_alloc(DEVNAME, 0);
260    if (!pdev)
261        return -ENOMEM;
262
263    rc = platform_device_add(pdev);
264    if (rc) {
265        rc = -ENODEV;
266        goto undo_platform_dev_alloc;
267    }
268    dev_info(&pdev->dev, "NatSemi pc8736x GPIO Driver Initializing\n");
269
270    if (!pc8736x_superio_present()) {
271        rc = -ENODEV;
272        dev_err(&pdev->dev, "no device found\n");
273        goto undo_platform_dev_add;
274    }
275    pc8736x_gpio_ops.dev = &pdev->dev;
276
277    /* Verify that chip and it's GPIO unit are both enabled.
278       My BIOS does this, so I take minimum action here
279     */
280    rc = superio_inb(SIO_CF1);
281    if (!(rc & 0x01)) {
282        rc = -ENODEV;
283        dev_err(&pdev->dev, "device not enabled\n");
284        goto undo_platform_dev_add;
285    }
286    device_select(SIO_GPIO_UNIT);
287    if (!superio_inb(SIO_UNIT_ACT)) {
288        rc = -ENODEV;
289        dev_err(&pdev->dev, "GPIO unit not enabled\n");
290        goto undo_platform_dev_add;
291    }
292
293    /* read the GPIO unit base addr that chip responds to */
294    pc8736x_gpio_base = (superio_inb(SIO_BASE_HADDR) << 8
295                 | superio_inb(SIO_BASE_LADDR));
296
297    if (!request_region(pc8736x_gpio_base, PC8736X_GPIO_RANGE, DEVNAME)) {
298        rc = -ENODEV;
299        dev_err(&pdev->dev, "GPIO ioport %x busy\n",
300            pc8736x_gpio_base);
301        goto undo_platform_dev_add;
302    }
303    dev_info(&pdev->dev, "GPIO ioport %x reserved\n", pc8736x_gpio_base);
304
305    if (major) {
306        devid = MKDEV(major, 0);
307        rc = register_chrdev_region(devid, PC8736X_GPIO_CT, DEVNAME);
308    } else {
309        rc = alloc_chrdev_region(&devid, 0, PC8736X_GPIO_CT, DEVNAME);
310        major = MAJOR(devid);
311    }
312
313    if (rc < 0) {
314        dev_err(&pdev->dev, "register-chrdev failed: %d\n", rc);
315        goto undo_request_region;
316    }
317    if (!major) {
318        major = rc;
319        dev_dbg(&pdev->dev, "got dynamic major %d\n", major);
320    }
321
322    pc8736x_init_shadow();
323
324    /* ignore minor errs, and succeed */
325    cdev_init(&pc8736x_gpio_cdev, &pc8736x_gpio_fileops);
326    cdev_add(&pc8736x_gpio_cdev, devid, PC8736X_GPIO_CT);
327
328    return 0;
329
330undo_request_region:
331    release_region(pc8736x_gpio_base, PC8736X_GPIO_RANGE);
332undo_platform_dev_add:
333    platform_device_del(pdev);
334undo_platform_dev_alloc:
335    platform_device_put(pdev);
336
337    return rc;
338}
339
340static void __exit pc8736x_gpio_cleanup(void)
341{
342    dev_dbg(&pdev->dev, "cleanup\n");
343
344    cdev_del(&pc8736x_gpio_cdev);
345    unregister_chrdev_region(MKDEV(major,0), PC8736X_GPIO_CT);
346    release_region(pc8736x_gpio_base, PC8736X_GPIO_RANGE);
347
348    platform_device_unregister(pdev);
349}
350
351module_init(pc8736x_gpio_init);
352module_exit(pc8736x_gpio_cleanup);
353

Archive Download this file

Branches:
ben-wpan
ben-wpan-stefan
javiroman/ks7010
jz-2.6.34
jz-2.6.34-rc5
jz-2.6.34-rc6
jz-2.6.34-rc7
jz-2.6.35
jz-2.6.36
jz-2.6.37
jz-2.6.38
jz-2.6.39
jz-3.0
jz-3.1
jz-3.11
jz-3.12
jz-3.13
jz-3.15
jz-3.16
jz-3.18-dt
jz-3.2
jz-3.3
jz-3.4
jz-3.5
jz-3.6
jz-3.6-rc2-pwm
jz-3.9
jz-3.9-clk
jz-3.9-rc8
jz47xx
jz47xx-2.6.38
master

Tags:
od-2011-09-04
od-2011-09-18
v2.6.34-rc5
v2.6.34-rc6
v2.6.34-rc7
v3.9



interactive