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/drivers/sbus/char/bbc_i2c.c

https://bitbucket.org/cyanogenmod/android_kernel_asus_tf300t
C | 438 lines | 334 code | 86 blank | 18 comment | 48 complexity | eda8c9e69e8fa29079ca9c4a6c114d6e MD5 | raw file
Possible License(s): LGPL-2.0, AGPL-1.0, GPL-2.0
  1/* bbc_i2c.c: I2C low-level driver for BBC device on UltraSPARC-III
  2 *            platforms.
  3 *
  4 * Copyright (C) 2001, 2008 David S. Miller (davem@davemloft.net)
  5 */
  6
  7#include <linux/module.h>
  8#include <linux/kernel.h>
  9#include <linux/types.h>
 10#include <linux/slab.h>
 11#include <linux/sched.h>
 12#include <linux/wait.h>
 13#include <linux/delay.h>
 14#include <linux/init.h>
 15#include <linux/interrupt.h>
 16#include <linux/of.h>
 17#include <linux/of_device.h>
 18#include <asm/bbc.h>
 19#include <asm/io.h>
 20
 21#include "bbc_i2c.h"
 22
 23/* Convert this driver to use i2c bus layer someday... */
 24#define I2C_PCF_PIN	0x80
 25#define I2C_PCF_ESO	0x40
 26#define I2C_PCF_ES1	0x20
 27#define I2C_PCF_ES2	0x10
 28#define I2C_PCF_ENI	0x08
 29#define I2C_PCF_STA	0x04
 30#define I2C_PCF_STO	0x02
 31#define I2C_PCF_ACK	0x01
 32
 33#define I2C_PCF_START    (I2C_PCF_PIN | I2C_PCF_ESO | I2C_PCF_ENI | I2C_PCF_STA | I2C_PCF_ACK)
 34#define I2C_PCF_STOP     (I2C_PCF_PIN | I2C_PCF_ESO | I2C_PCF_STO | I2C_PCF_ACK)
 35#define I2C_PCF_REPSTART (              I2C_PCF_ESO | I2C_PCF_STA | I2C_PCF_ACK)
 36#define I2C_PCF_IDLE     (I2C_PCF_PIN | I2C_PCF_ESO               | I2C_PCF_ACK)
 37
 38#define I2C_PCF_INI 0x40   /* 1 if not initialized */
 39#define I2C_PCF_STS 0x20
 40#define I2C_PCF_BER 0x10
 41#define I2C_PCF_AD0 0x08
 42#define I2C_PCF_LRB 0x08
 43#define I2C_PCF_AAS 0x04
 44#define I2C_PCF_LAB 0x02
 45#define I2C_PCF_BB  0x01
 46
 47/* The BBC devices have two I2C controllers.  The first I2C controller
 48 * connects mainly to configuration proms (NVRAM, cpu configuration,
 49 * dimm types, etc.).  Whereas the second I2C controller connects to
 50 * environmental control devices such as fans and temperature sensors.
 51 * The second controller also connects to the smartcard reader, if present.
 52 */
 53
 54static void set_device_claimage(struct bbc_i2c_bus *bp, struct platform_device *op, int val)
 55{
 56	int i;
 57
 58	for (i = 0; i < NUM_CHILDREN; i++) {
 59		if (bp->devs[i].device == op) {
 60			bp->devs[i].client_claimed = val;
 61			return;
 62		}
 63	}
 64}
 65
 66#define claim_device(BP,ECHILD)		set_device_claimage(BP,ECHILD,1)
 67#define release_device(BP,ECHILD)	set_device_claimage(BP,ECHILD,0)
 68
 69struct platform_device *bbc_i2c_getdev(struct bbc_i2c_bus *bp, int index)
 70{
 71	struct platform_device *op = NULL;
 72	int curidx = 0, i;
 73
 74	for (i = 0; i < NUM_CHILDREN; i++) {
 75		if (!(op = bp->devs[i].device))
 76			break;
 77		if (curidx == index)
 78			goto out;
 79		op = NULL;
 80		curidx++;
 81	}
 82
 83out:
 84	if (curidx == index)
 85		return op;
 86	return NULL;
 87}
 88
 89struct bbc_i2c_client *bbc_i2c_attach(struct bbc_i2c_bus *bp, struct platform_device *op)
 90{
 91	struct bbc_i2c_client *client;
 92	const u32 *reg;
 93
 94	client = kzalloc(sizeof(*client), GFP_KERNEL);
 95	if (!client)
 96		return NULL;
 97	client->bp = bp;
 98	client->op = op;
 99
100	reg = of_get_property(op->dev.of_node, "reg", NULL);
101	if (!reg) {
102		kfree(client);
103		return NULL;
104	}
105
106	client->bus = reg[0];
107	client->address = reg[1];
108
109	claim_device(bp, op);
110
111	return client;
112}
113
114void bbc_i2c_detach(struct bbc_i2c_client *client)
115{
116	struct bbc_i2c_bus *bp = client->bp;
117	struct platform_device *op = client->op;
118
119	release_device(bp, op);
120	kfree(client);
121}
122
123static int wait_for_pin(struct bbc_i2c_bus *bp, u8 *status)
124{
125	DECLARE_WAITQUEUE(wait, current);
126	int limit = 32;
127	int ret = 1;
128
129	bp->waiting = 1;
130	add_wait_queue(&bp->wq, &wait);
131	while (limit-- > 0) {
132		long val;
133
134		val = wait_event_interruptible_timeout(
135				bp->wq,
136				(((*status = readb(bp->i2c_control_regs + 0))
137				  & I2C_PCF_PIN) == 0),
138				msecs_to_jiffies(250));
139		if (val > 0) {
140			ret = 0;
141			break;
142		}
143	}
144	remove_wait_queue(&bp->wq, &wait);
145	bp->waiting = 0;
146
147	return ret;
148}
149
150int bbc_i2c_writeb(struct bbc_i2c_client *client, unsigned char val, int off)
151{
152	struct bbc_i2c_bus *bp = client->bp;
153	int address = client->address;
154	u8 status;
155	int ret = -1;
156
157	if (bp->i2c_bussel_reg != NULL)
158		writeb(client->bus, bp->i2c_bussel_reg);
159
160	writeb(address, bp->i2c_control_regs + 0x1);
161	writeb(I2C_PCF_START, bp->i2c_control_regs + 0x0);
162	if (wait_for_pin(bp, &status))
163		goto out;
164
165	writeb(off, bp->i2c_control_regs + 0x1);
166	if (wait_for_pin(bp, &status) ||
167	    (status & I2C_PCF_LRB) != 0)
168		goto out;
169
170	writeb(val, bp->i2c_control_regs + 0x1);
171	if (wait_for_pin(bp, &status))
172		goto out;
173
174	ret = 0;
175
176out:
177	writeb(I2C_PCF_STOP, bp->i2c_control_regs + 0x0);
178	return ret;
179}
180
181int bbc_i2c_readb(struct bbc_i2c_client *client, unsigned char *byte, int off)
182{
183	struct bbc_i2c_bus *bp = client->bp;
184	unsigned char address = client->address, status;
185	int ret = -1;
186
187	if (bp->i2c_bussel_reg != NULL)
188		writeb(client->bus, bp->i2c_bussel_reg);
189
190	writeb(address, bp->i2c_control_regs + 0x1);
191	writeb(I2C_PCF_START, bp->i2c_control_regs + 0x0);
192	if (wait_for_pin(bp, &status))
193		goto out;
194
195	writeb(off, bp->i2c_control_regs + 0x1);
196	if (wait_for_pin(bp, &status) ||
197	    (status & I2C_PCF_LRB) != 0)
198		goto out;
199
200	writeb(I2C_PCF_STOP, bp->i2c_control_regs + 0x0);
201
202	address |= 0x1; /* READ */
203
204	writeb(address, bp->i2c_control_regs + 0x1);
205	writeb(I2C_PCF_START, bp->i2c_control_regs + 0x0);
206	if (wait_for_pin(bp, &status))
207		goto out;
208
209	/* Set PIN back to one so the device sends the first
210	 * byte.
211	 */
212	(void) readb(bp->i2c_control_regs + 0x1);
213	if (wait_for_pin(bp, &status))
214		goto out;
215
216	writeb(I2C_PCF_ESO | I2C_PCF_ENI, bp->i2c_control_regs + 0x0);
217	*byte = readb(bp->i2c_control_regs + 0x1);
218	if (wait_for_pin(bp, &status))
219		goto out;
220
221	ret = 0;
222
223out:
224	writeb(I2C_PCF_STOP, bp->i2c_control_regs + 0x0);
225	(void) readb(bp->i2c_control_regs + 0x1);
226
227	return ret;
228}
229
230int bbc_i2c_write_buf(struct bbc_i2c_client *client,
231		      char *buf, int len, int off)
232{
233	int ret = 0;
234
235	while (len > 0) {
236		int err = bbc_i2c_writeb(client, *buf, off);
237
238		if (err < 0) {
239			ret = err;
240			break;
241		}
242
243		len--;
244		buf++;
245		off++;
246	}
247	return ret;
248}
249
250int bbc_i2c_read_buf(struct bbc_i2c_client *client,
251		     char *buf, int len, int off)
252{
253	int ret = 0;
254
255	while (len > 0) {
256		int err = bbc_i2c_readb(client, buf, off);
257		if (err < 0) {
258			ret = err;
259			break;
260		}
261		len--;
262		buf++;
263		off++;
264	}
265
266	return ret;
267}
268
269EXPORT_SYMBOL(bbc_i2c_getdev);
270EXPORT_SYMBOL(bbc_i2c_attach);
271EXPORT_SYMBOL(bbc_i2c_detach);
272EXPORT_SYMBOL(bbc_i2c_writeb);
273EXPORT_SYMBOL(bbc_i2c_readb);
274EXPORT_SYMBOL(bbc_i2c_write_buf);
275EXPORT_SYMBOL(bbc_i2c_read_buf);
276
277static irqreturn_t bbc_i2c_interrupt(int irq, void *dev_id)
278{
279	struct bbc_i2c_bus *bp = dev_id;
280
281	/* PIN going from set to clear is the only event which
282	 * makes the i2c assert an interrupt.
283	 */
284	if (bp->waiting &&
285	    !(readb(bp->i2c_control_regs + 0x0) & I2C_PCF_PIN))
286		wake_up_interruptible(&bp->wq);
287
288	return IRQ_HANDLED;
289}
290
291static void __init reset_one_i2c(struct bbc_i2c_bus *bp)
292{
293	writeb(I2C_PCF_PIN, bp->i2c_control_regs + 0x0);
294	writeb(bp->own, bp->i2c_control_regs + 0x1);
295	writeb(I2C_PCF_PIN | I2C_PCF_ES1, bp->i2c_control_regs + 0x0);
296	writeb(bp->clock, bp->i2c_control_regs + 0x1);
297	writeb(I2C_PCF_IDLE, bp->i2c_control_regs + 0x0);
298}
299
300static struct bbc_i2c_bus * __init attach_one_i2c(struct platform_device *op, int index)
301{
302	struct bbc_i2c_bus *bp;
303	struct device_node *dp;
304	int entry;
305
306	bp = kzalloc(sizeof(*bp), GFP_KERNEL);
307	if (!bp)
308		return NULL;
309
310	bp->i2c_control_regs = of_ioremap(&op->resource[0], 0, 0x2, "bbc_i2c_regs");
311	if (!bp->i2c_control_regs)
312		goto fail;
313
314	bp->i2c_bussel_reg = of_ioremap(&op->resource[1], 0, 0x1, "bbc_i2c_bussel");
315	if (!bp->i2c_bussel_reg)
316		goto fail;
317
318	bp->waiting = 0;
319	init_waitqueue_head(&bp->wq);
320	if (request_irq(op->archdata.irqs[0], bbc_i2c_interrupt,
321			IRQF_SHARED, "bbc_i2c", bp))
322		goto fail;
323
324	bp->index = index;
325	bp->op = op;
326
327	spin_lock_init(&bp->lock);
328
329	entry = 0;
330	for (dp = op->dev.of_node->child;
331	     dp && entry < 8;
332	     dp = dp->sibling, entry++) {
333		struct platform_device *child_op;
334
335		child_op = of_find_device_by_node(dp);
336		bp->devs[entry].device = child_op;
337		bp->devs[entry].client_claimed = 0;
338	}
339
340	writeb(I2C_PCF_PIN, bp->i2c_control_regs + 0x0);
341	bp->own = readb(bp->i2c_control_regs + 0x01);
342	writeb(I2C_PCF_PIN | I2C_PCF_ES1, bp->i2c_control_regs + 0x0);
343	bp->clock = readb(bp->i2c_control_regs + 0x01);
344
345	printk(KERN_INFO "i2c-%d: Regs at %p, %d devices, own %02x, clock %02x.\n",
346	       bp->index, bp->i2c_control_regs, entry, bp->own, bp->clock);
347
348	reset_one_i2c(bp);
349
350	return bp;
351
352fail:
353	if (bp->i2c_bussel_reg)
354		of_iounmap(&op->resource[1], bp->i2c_bussel_reg, 1);
355	if (bp->i2c_control_regs)
356		of_iounmap(&op->resource[0], bp->i2c_control_regs, 2);
357	kfree(bp);
358	return NULL;
359}
360
361extern int bbc_envctrl_init(struct bbc_i2c_bus *bp);
362extern void bbc_envctrl_cleanup(struct bbc_i2c_bus *bp);
363
364static int __devinit bbc_i2c_probe(struct platform_device *op)
365{
366	struct bbc_i2c_bus *bp;
367	int err, index = 0;
368
369	bp = attach_one_i2c(op, index);
370	if (!bp)
371		return -EINVAL;
372
373	err = bbc_envctrl_init(bp);
374	if (err) {
375		free_irq(op->archdata.irqs[0], bp);
376		if (bp->i2c_bussel_reg)
377			of_iounmap(&op->resource[0], bp->i2c_bussel_reg, 1);
378		if (bp->i2c_control_regs)
379			of_iounmap(&op->resource[1], bp->i2c_control_regs, 2);
380		kfree(bp);
381	} else {
382		dev_set_drvdata(&op->dev, bp);
383	}
384
385	return err;
386}
387
388static int __devexit bbc_i2c_remove(struct platform_device *op)
389{
390	struct bbc_i2c_bus *bp = dev_get_drvdata(&op->dev);
391
392	bbc_envctrl_cleanup(bp);
393
394	free_irq(op->archdata.irqs[0], bp);
395
396	if (bp->i2c_bussel_reg)
397		of_iounmap(&op->resource[0], bp->i2c_bussel_reg, 1);
398	if (bp->i2c_control_regs)
399		of_iounmap(&op->resource[1], bp->i2c_control_regs, 2);
400
401	kfree(bp);
402
403	return 0;
404}
405
406static const struct of_device_id bbc_i2c_match[] = {
407	{
408		.name = "i2c",
409		.compatible = "SUNW,bbc-i2c",
410	},
411	{},
412};
413MODULE_DEVICE_TABLE(of, bbc_i2c_match);
414
415static struct platform_driver bbc_i2c_driver = {
416	.driver = {
417		.name = "bbc_i2c",
418		.owner = THIS_MODULE,
419		.of_match_table = bbc_i2c_match,
420	},
421	.probe		= bbc_i2c_probe,
422	.remove		= __devexit_p(bbc_i2c_remove),
423};
424
425static int __init bbc_i2c_init(void)
426{
427	return platform_driver_register(&bbc_i2c_driver);
428}
429
430static void __exit bbc_i2c_exit(void)
431{
432	platform_driver_unregister(&bbc_i2c_driver);
433}
434
435module_init(bbc_i2c_init);
436module_exit(bbc_i2c_exit);
437
438MODULE_LICENSE("GPL");