xref: /openbmc/linux/drivers/char/pc8736x_gpio.c (revision b6dcefde)
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 
27 MODULE_AUTHOR("Jim Cromie <jim.cromie@gmail.com>");
28 MODULE_DESCRIPTION("NatSemi/Winbond PC-8736x GPIO Pin Driver");
29 MODULE_LICENSE("GPL");
30 
31 static int major;		/* default to dynamic major */
32 module_param(major, int, 0);
33 MODULE_PARM_DESC(major, "Major device number");
34 
35 static DEFINE_MUTEX(pc8736x_gpio_config_lock);
36 static unsigned pc8736x_gpio_base;
37 static 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 
66 static unsigned char superio_cmd = 0;
67 static unsigned char selected_device = 0xFF;	/* bogus start val */
68 
69 /* GPIO port runtime access, functionality */
70 static 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 
78 static struct platform_device *pdev;  /* use in dev_*() */
79 
80 static inline void superio_outb(int addr, int val)
81 {
82 	outb_p(addr, superio_cmd);
83 	outb_p(val, superio_cmd + 1);
84 }
85 
86 static inline int superio_inb(int addr)
87 {
88 	outb_p(addr, superio_cmd);
89 	return inb_p(superio_cmd + 1);
90 }
91 
92 static 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 
110 static void device_select(unsigned devldn)
111 {
112 	superio_outb(SIO_UNIT_SEL, devldn);
113 	selected_device = devldn;
114 }
115 
116 static 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 
124 static 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 
146 static 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 
152 static 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 
169 static 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 
196 static 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 
205 static void pc8736x_gpio_change(unsigned index)
206 {
207 	pc8736x_gpio_set(index, !pc8736x_gpio_current(index));
208 }
209 
210 static 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 
220 static 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 
232 static 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 };
238 
239 static void __init pc8736x_init_shadow(void)
240 {
241 	int port;
242 
243 	/* read the current values driven on the GPIO signals */
244 	for (port = 0; port < 4; ++port)
245 		pc8736x_gpio_shadow[port]
246 		    = inb_p(pc8736x_gpio_base + port_offset[port]
247 			    + PORT_OUT);
248 
249 }
250 
251 static struct cdev pc8736x_gpio_cdev;
252 
253 static int __init pc8736x_gpio_init(void)
254 {
255 	int rc;
256 	dev_t devid;
257 
258 	pdev = platform_device_alloc(DEVNAME, 0);
259 	if (!pdev)
260 		return -ENOMEM;
261 
262 	rc = platform_device_add(pdev);
263 	if (rc) {
264 		rc = -ENODEV;
265 		goto undo_platform_dev_alloc;
266 	}
267 	dev_info(&pdev->dev, "NatSemi pc8736x GPIO Driver Initializing\n");
268 
269 	if (!pc8736x_superio_present()) {
270 		rc = -ENODEV;
271 		dev_err(&pdev->dev, "no device found\n");
272 		goto undo_platform_dev_add;
273 	}
274 	pc8736x_gpio_ops.dev = &pdev->dev;
275 
276 	/* Verify that chip and it's GPIO unit are both enabled.
277 	   My BIOS does this, so I take minimum action here
278 	 */
279 	rc = superio_inb(SIO_CF1);
280 	if (!(rc & 0x01)) {
281 		rc = -ENODEV;
282 		dev_err(&pdev->dev, "device not enabled\n");
283 		goto undo_platform_dev_add;
284 	}
285 	device_select(SIO_GPIO_UNIT);
286 	if (!superio_inb(SIO_UNIT_ACT)) {
287 		rc = -ENODEV;
288 		dev_err(&pdev->dev, "GPIO unit not enabled\n");
289 		goto undo_platform_dev_add;
290 	}
291 
292 	/* read the GPIO unit base addr that chip responds to */
293 	pc8736x_gpio_base = (superio_inb(SIO_BASE_HADDR) << 8
294 			     | superio_inb(SIO_BASE_LADDR));
295 
296 	if (!request_region(pc8736x_gpio_base, PC8736X_GPIO_RANGE, DEVNAME)) {
297 		rc = -ENODEV;
298 		dev_err(&pdev->dev, "GPIO ioport %x busy\n",
299 			pc8736x_gpio_base);
300 		goto undo_platform_dev_add;
301 	}
302 	dev_info(&pdev->dev, "GPIO ioport %x reserved\n", pc8736x_gpio_base);
303 
304 	if (major) {
305 		devid = MKDEV(major, 0);
306 		rc = register_chrdev_region(devid, PC8736X_GPIO_CT, DEVNAME);
307 	} else {
308 		rc = alloc_chrdev_region(&devid, 0, PC8736X_GPIO_CT, DEVNAME);
309 		major = MAJOR(devid);
310 	}
311 
312 	if (rc < 0) {
313 		dev_err(&pdev->dev, "register-chrdev failed: %d\n", rc);
314 		goto undo_request_region;
315 	}
316 	if (!major) {
317 		major = rc;
318 		dev_dbg(&pdev->dev, "got dynamic major %d\n", major);
319 	}
320 
321 	pc8736x_init_shadow();
322 
323 	/* ignore minor errs, and succeed */
324 	cdev_init(&pc8736x_gpio_cdev, &pc8736x_gpio_fileops);
325 	cdev_add(&pc8736x_gpio_cdev, devid, PC8736X_GPIO_CT);
326 
327 	return 0;
328 
329 undo_request_region:
330 	release_region(pc8736x_gpio_base, PC8736X_GPIO_RANGE);
331 undo_platform_dev_add:
332 	platform_device_del(pdev);
333 undo_platform_dev_alloc:
334 	platform_device_put(pdev);
335 
336 	return rc;
337 }
338 
339 static void __exit pc8736x_gpio_cleanup(void)
340 {
341 	dev_dbg(&pdev->dev, "cleanup\n");
342 
343 	cdev_del(&pc8736x_gpio_cdev);
344 	unregister_chrdev_region(MKDEV(major,0), PC8736X_GPIO_CT);
345 	release_region(pc8736x_gpio_base, PC8736X_GPIO_RANGE);
346 
347 	platform_device_del(pdev);
348 	platform_device_put(pdev);
349 }
350 
351 module_init(pc8736x_gpio_init);
352 module_exit(pc8736x_gpio_cleanup);
353