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/drivers/char/pc8736x_gpio.c

https://bitbucket.org/ndreys/linux-sunxi
C | 353 lines | 256 code | 73 blank | 24 comment | 20 complexity | 83d832c1c7e2080d72e67ef9002359ad MD5 | raw file
Possible License(s): GPL-2.0, LGPL-2.0, AGPL-1.0
  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_del(pdev);
349	platform_device_put(pdev);
350}
351
352module_init(pc8736x_gpio_init);
353module_exit(pc8736x_gpio_cleanup);