1// SPDX-License-Identifier: GPL-2.0-only
2/* bbc_i2c.c: I2C low-level driver for BBC device on UltraSPARC-III
3 *            platforms.
4 *
5 * Copyright (C) 2001, 2008 David S. Miller (davem@davemloft.net)
6 */
7
8#include <linux/module.h>
9#include <linux/kernel.h>
10#include <linux/types.h>
11#include <linux/slab.h>
12#include <linux/sched.h>
13#include <linux/wait.h>
14#include <linux/delay.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		ret = bbc_i2c_writeb(client, *buf, off);
237		if (ret < 0)
238			break;
239		len--;
240		buf++;
241		off++;
242	}
243	return ret;
244}
245
246int bbc_i2c_read_buf(struct bbc_i2c_client *client,
247		     char *buf, int len, int off)
248{
249	int ret = 0;
250
251	while (len > 0) {
252		ret = bbc_i2c_readb(client, buf, off);
253		if (ret < 0)
254			break;
255		len--;
256		buf++;
257		off++;
258	}
259
260	return ret;
261}
262
263EXPORT_SYMBOL(bbc_i2c_getdev);
264EXPORT_SYMBOL(bbc_i2c_attach);
265EXPORT_SYMBOL(bbc_i2c_detach);
266EXPORT_SYMBOL(bbc_i2c_writeb);
267EXPORT_SYMBOL(bbc_i2c_readb);
268EXPORT_SYMBOL(bbc_i2c_write_buf);
269EXPORT_SYMBOL(bbc_i2c_read_buf);
270
271static irqreturn_t bbc_i2c_interrupt(int irq, void *dev_id)
272{
273	struct bbc_i2c_bus *bp = dev_id;
274
275	/* PIN going from set to clear is the only event which
276	 * makes the i2c assert an interrupt.
277	 */
278	if (bp->waiting &&
279	    !(readb(bp->i2c_control_regs + 0x0) & I2C_PCF_PIN))
280		wake_up_interruptible(&bp->wq);
281
282	return IRQ_HANDLED;
283}
284
285static void reset_one_i2c(struct bbc_i2c_bus *bp)
286{
287	writeb(I2C_PCF_PIN, bp->i2c_control_regs + 0x0);
288	writeb(bp->own, bp->i2c_control_regs + 0x1);
289	writeb(I2C_PCF_PIN | I2C_PCF_ES1, bp->i2c_control_regs + 0x0);
290	writeb(bp->clock, bp->i2c_control_regs + 0x1);
291	writeb(I2C_PCF_IDLE, bp->i2c_control_regs + 0x0);
292}
293
294static struct bbc_i2c_bus * attach_one_i2c(struct platform_device *op, int index)
295{
296	struct bbc_i2c_bus *bp;
297	struct device_node *dp;
298	int entry;
299
300	bp = kzalloc(sizeof(*bp), GFP_KERNEL);
301	if (!bp)
302		return NULL;
303
304	INIT_LIST_HEAD(&bp->temps);
305	INIT_LIST_HEAD(&bp->fans);
306
307	bp->i2c_control_regs = of_ioremap(&op->resource[0], 0, 0x2, "bbc_i2c_regs");
308	if (!bp->i2c_control_regs)
309		goto fail;
310
311	if (op->num_resources == 2) {
312		bp->i2c_bussel_reg = of_ioremap(&op->resource[1], 0, 0x1, "bbc_i2c_bussel");
313		if (!bp->i2c_bussel_reg)
314			goto fail;
315	}
316
317	bp->waiting = 0;
318	init_waitqueue_head(&bp->wq);
319	if (request_irq(op->archdata.irqs[0], bbc_i2c_interrupt,
320			IRQF_SHARED, "bbc_i2c", bp))
321		goto fail;
322
323	bp->index = index;
324	bp->op = op;
325
326	spin_lock_init(&bp->lock);
327
328	entry = 0;
329	for (dp = op->dev.of_node->child;
330	     dp && entry < 8;
331	     dp = dp->sibling, entry++) {
332		struct platform_device *child_op;
333
334		child_op = of_find_device_by_node(dp);
335		bp->devs[entry].device = child_op;
336		bp->devs[entry].client_claimed = 0;
337	}
338
339	writeb(I2C_PCF_PIN, bp->i2c_control_regs + 0x0);
340	bp->own = readb(bp->i2c_control_regs + 0x01);
341	writeb(I2C_PCF_PIN | I2C_PCF_ES1, bp->i2c_control_regs + 0x0);
342	bp->clock = readb(bp->i2c_control_regs + 0x01);
343
344	printk(KERN_INFO "i2c-%d: Regs at %p, %d devices, own %02x, clock %02x.\n",
345	       bp->index, bp->i2c_control_regs, entry, bp->own, bp->clock);
346
347	reset_one_i2c(bp);
348
349	return bp;
350
351fail:
352	if (bp->i2c_bussel_reg)
353		of_iounmap(&op->resource[1], bp->i2c_bussel_reg, 1);
354	if (bp->i2c_control_regs)
355		of_iounmap(&op->resource[0], bp->i2c_control_regs, 2);
356	kfree(bp);
357	return NULL;
358}
359
360extern int bbc_envctrl_init(struct bbc_i2c_bus *bp);
361extern void bbc_envctrl_cleanup(struct bbc_i2c_bus *bp);
362
363static int bbc_i2c_probe(struct platform_device *op)
364{
365	struct bbc_i2c_bus *bp;
366	int err, index = 0;
367
368	bp = attach_one_i2c(op, index);
369	if (!bp)
370		return -EINVAL;
371
372	err = bbc_envctrl_init(bp);
373	if (err) {
374		free_irq(op->archdata.irqs[0], bp);
375		if (bp->i2c_bussel_reg)
376			of_iounmap(&op->resource[0], bp->i2c_bussel_reg, 1);
377		if (bp->i2c_control_regs)
378			of_iounmap(&op->resource[1], bp->i2c_control_regs, 2);
379		kfree(bp);
380	} else {
381		dev_set_drvdata(&op->dev, bp);
382	}
383
384	return err;
385}
386
387static int bbc_i2c_remove(struct platform_device *op)
388{
389	struct bbc_i2c_bus *bp = dev_get_drvdata(&op->dev);
390
391	bbc_envctrl_cleanup(bp);
392
393	free_irq(op->archdata.irqs[0], bp);
394
395	if (bp->i2c_bussel_reg)
396		of_iounmap(&op->resource[0], bp->i2c_bussel_reg, 1);
397	if (bp->i2c_control_regs)
398		of_iounmap(&op->resource[1], bp->i2c_control_regs, 2);
399
400	kfree(bp);
401
402	return 0;
403}
404
405static const struct of_device_id bbc_i2c_match[] = {
406	{
407		.name = "i2c",
408		.compatible = "SUNW,bbc-i2c",
409	},
410	{},
411};
412MODULE_DEVICE_TABLE(of, bbc_i2c_match);
413
414static struct platform_driver bbc_i2c_driver = {
415	.driver = {
416		.name = "bbc_i2c",
417		.of_match_table = bbc_i2c_match,
418	},
419	.probe		= bbc_i2c_probe,
420	.remove		= bbc_i2c_remove,
421};
422
423module_platform_driver(bbc_i2c_driver);
424
425MODULE_LICENSE("GPL");
426