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_platform.h>
18 #include <linux/platform_device.h>
19 #include <asm/bbc.h>
20 #include <asm/io.h>
21
22 #include "bbc_i2c.h"
23
24 /* Convert this driver to use i2c bus layer someday... */
25 #define I2C_PCF_PIN 0x80
26 #define I2C_PCF_ESO 0x40
27 #define I2C_PCF_ES1 0x20
28 #define I2C_PCF_ES2 0x10
29 #define I2C_PCF_ENI 0x08
30 #define I2C_PCF_STA 0x04
31 #define I2C_PCF_STO 0x02
32 #define I2C_PCF_ACK 0x01
33
34 #define I2C_PCF_START (I2C_PCF_PIN | I2C_PCF_ESO | I2C_PCF_ENI | I2C_PCF_STA | I2C_PCF_ACK)
35 #define I2C_PCF_STOP (I2C_PCF_PIN | I2C_PCF_ESO | I2C_PCF_STO | I2C_PCF_ACK)
36 #define I2C_PCF_REPSTART ( I2C_PCF_ESO | I2C_PCF_STA | I2C_PCF_ACK)
37 #define I2C_PCF_IDLE (I2C_PCF_PIN | I2C_PCF_ESO | I2C_PCF_ACK)
38
39 #define I2C_PCF_INI 0x40 /* 1 if not initialized */
40 #define I2C_PCF_STS 0x20
41 #define I2C_PCF_BER 0x10
42 #define I2C_PCF_AD0 0x08
43 #define I2C_PCF_LRB 0x08
44 #define I2C_PCF_AAS 0x04
45 #define I2C_PCF_LAB 0x02
46 #define I2C_PCF_BB 0x01
47
48 /* The BBC devices have two I2C controllers. The first I2C controller
49 * connects mainly to configuration proms (NVRAM, cpu configuration,
50 * dimm types, etc.). Whereas the second I2C controller connects to
51 * environmental control devices such as fans and temperature sensors.
52 * The second controller also connects to the smartcard reader, if present.
53 */
54
set_device_claimage(struct bbc_i2c_bus * bp,struct platform_device * op,int val)55 static void set_device_claimage(struct bbc_i2c_bus *bp, struct platform_device *op, int val)
56 {
57 int i;
58
59 for (i = 0; i < NUM_CHILDREN; i++) {
60 if (bp->devs[i].device == op) {
61 bp->devs[i].client_claimed = val;
62 return;
63 }
64 }
65 }
66
67 #define claim_device(BP,ECHILD) set_device_claimage(BP,ECHILD,1)
68 #define release_device(BP,ECHILD) set_device_claimage(BP,ECHILD,0)
69
bbc_i2c_getdev(struct bbc_i2c_bus * bp,int index)70 struct platform_device *bbc_i2c_getdev(struct bbc_i2c_bus *bp, int index)
71 {
72 struct platform_device *op = NULL;
73 int curidx = 0, i;
74
75 for (i = 0; i < NUM_CHILDREN; i++) {
76 if (!(op = bp->devs[i].device))
77 break;
78 if (curidx == index)
79 goto out;
80 op = NULL;
81 curidx++;
82 }
83
84 out:
85 if (curidx == index)
86 return op;
87 return NULL;
88 }
89
bbc_i2c_attach(struct bbc_i2c_bus * bp,struct platform_device * op)90 struct bbc_i2c_client *bbc_i2c_attach(struct bbc_i2c_bus *bp, struct platform_device *op)
91 {
92 struct bbc_i2c_client *client;
93 const u32 *reg;
94
95 client = kzalloc(sizeof(*client), GFP_KERNEL);
96 if (!client)
97 return NULL;
98 client->bp = bp;
99 client->op = op;
100
101 reg = of_get_property(op->dev.of_node, "reg", NULL);
102 if (!reg) {
103 kfree(client);
104 return NULL;
105 }
106
107 client->bus = reg[0];
108 client->address = reg[1];
109
110 claim_device(bp, op);
111
112 return client;
113 }
114
bbc_i2c_detach(struct bbc_i2c_client * client)115 void bbc_i2c_detach(struct bbc_i2c_client *client)
116 {
117 struct bbc_i2c_bus *bp = client->bp;
118 struct platform_device *op = client->op;
119
120 release_device(bp, op);
121 kfree(client);
122 }
123
wait_for_pin(struct bbc_i2c_bus * bp,u8 * status)124 static int wait_for_pin(struct bbc_i2c_bus *bp, u8 *status)
125 {
126 DECLARE_WAITQUEUE(wait, current);
127 int limit = 32;
128 int ret = 1;
129
130 bp->waiting = 1;
131 add_wait_queue(&bp->wq, &wait);
132 while (limit-- > 0) {
133 long val;
134
135 val = wait_event_interruptible_timeout(
136 bp->wq,
137 (((*status = readb(bp->i2c_control_regs + 0))
138 & I2C_PCF_PIN) == 0),
139 msecs_to_jiffies(250));
140 if (val > 0) {
141 ret = 0;
142 break;
143 }
144 }
145 remove_wait_queue(&bp->wq, &wait);
146 bp->waiting = 0;
147
148 return ret;
149 }
150
bbc_i2c_writeb(struct bbc_i2c_client * client,unsigned char val,int off)151 int bbc_i2c_writeb(struct bbc_i2c_client *client, unsigned char val, int off)
152 {
153 struct bbc_i2c_bus *bp = client->bp;
154 int address = client->address;
155 u8 status;
156 int ret = -1;
157
158 if (bp->i2c_bussel_reg != NULL)
159 writeb(client->bus, bp->i2c_bussel_reg);
160
161 writeb(address, bp->i2c_control_regs + 0x1);
162 writeb(I2C_PCF_START, bp->i2c_control_regs + 0x0);
163 if (wait_for_pin(bp, &status))
164 goto out;
165
166 writeb(off, bp->i2c_control_regs + 0x1);
167 if (wait_for_pin(bp, &status) ||
168 (status & I2C_PCF_LRB) != 0)
169 goto out;
170
171 writeb(val, bp->i2c_control_regs + 0x1);
172 if (wait_for_pin(bp, &status))
173 goto out;
174
175 ret = 0;
176
177 out:
178 writeb(I2C_PCF_STOP, bp->i2c_control_regs + 0x0);
179 return ret;
180 }
181
bbc_i2c_readb(struct bbc_i2c_client * client,unsigned char * byte,int off)182 int bbc_i2c_readb(struct bbc_i2c_client *client, unsigned char *byte, int off)
183 {
184 struct bbc_i2c_bus *bp = client->bp;
185 unsigned char address = client->address, status;
186 int ret = -1;
187
188 if (bp->i2c_bussel_reg != NULL)
189 writeb(client->bus, bp->i2c_bussel_reg);
190
191 writeb(address, bp->i2c_control_regs + 0x1);
192 writeb(I2C_PCF_START, bp->i2c_control_regs + 0x0);
193 if (wait_for_pin(bp, &status))
194 goto out;
195
196 writeb(off, bp->i2c_control_regs + 0x1);
197 if (wait_for_pin(bp, &status) ||
198 (status & I2C_PCF_LRB) != 0)
199 goto out;
200
201 writeb(I2C_PCF_STOP, bp->i2c_control_regs + 0x0);
202
203 address |= 0x1; /* READ */
204
205 writeb(address, bp->i2c_control_regs + 0x1);
206 writeb(I2C_PCF_START, bp->i2c_control_regs + 0x0);
207 if (wait_for_pin(bp, &status))
208 goto out;
209
210 /* Set PIN back to one so the device sends the first
211 * byte.
212 */
213 (void) readb(bp->i2c_control_regs + 0x1);
214 if (wait_for_pin(bp, &status))
215 goto out;
216
217 writeb(I2C_PCF_ESO | I2C_PCF_ENI, bp->i2c_control_regs + 0x0);
218 *byte = readb(bp->i2c_control_regs + 0x1);
219 if (wait_for_pin(bp, &status))
220 goto out;
221
222 ret = 0;
223
224 out:
225 writeb(I2C_PCF_STOP, bp->i2c_control_regs + 0x0);
226 (void) readb(bp->i2c_control_regs + 0x1);
227
228 return ret;
229 }
230
bbc_i2c_write_buf(struct bbc_i2c_client * client,char * buf,int len,int off)231 int bbc_i2c_write_buf(struct bbc_i2c_client *client,
232 char *buf, int len, int off)
233 {
234 int ret = 0;
235
236 while (len > 0) {
237 ret = bbc_i2c_writeb(client, *buf, off);
238 if (ret < 0)
239 break;
240 len--;
241 buf++;
242 off++;
243 }
244 return ret;
245 }
246
bbc_i2c_read_buf(struct bbc_i2c_client * client,char * buf,int len,int off)247 int bbc_i2c_read_buf(struct bbc_i2c_client *client,
248 char *buf, int len, int off)
249 {
250 int ret = 0;
251
252 while (len > 0) {
253 ret = bbc_i2c_readb(client, buf, off);
254 if (ret < 0)
255 break;
256 len--;
257 buf++;
258 off++;
259 }
260
261 return ret;
262 }
263
264 EXPORT_SYMBOL(bbc_i2c_getdev);
265 EXPORT_SYMBOL(bbc_i2c_attach);
266 EXPORT_SYMBOL(bbc_i2c_detach);
267 EXPORT_SYMBOL(bbc_i2c_writeb);
268 EXPORT_SYMBOL(bbc_i2c_readb);
269 EXPORT_SYMBOL(bbc_i2c_write_buf);
270 EXPORT_SYMBOL(bbc_i2c_read_buf);
271
bbc_i2c_interrupt(int irq,void * dev_id)272 static irqreturn_t bbc_i2c_interrupt(int irq, void *dev_id)
273 {
274 struct bbc_i2c_bus *bp = dev_id;
275
276 /* PIN going from set to clear is the only event which
277 * makes the i2c assert an interrupt.
278 */
279 if (bp->waiting &&
280 !(readb(bp->i2c_control_regs + 0x0) & I2C_PCF_PIN))
281 wake_up_interruptible(&bp->wq);
282
283 return IRQ_HANDLED;
284 }
285
reset_one_i2c(struct bbc_i2c_bus * bp)286 static void reset_one_i2c(struct bbc_i2c_bus *bp)
287 {
288 writeb(I2C_PCF_PIN, bp->i2c_control_regs + 0x0);
289 writeb(bp->own, bp->i2c_control_regs + 0x1);
290 writeb(I2C_PCF_PIN | I2C_PCF_ES1, bp->i2c_control_regs + 0x0);
291 writeb(bp->clock, bp->i2c_control_regs + 0x1);
292 writeb(I2C_PCF_IDLE, bp->i2c_control_regs + 0x0);
293 }
294
attach_one_i2c(struct platform_device * op,int index)295 static struct bbc_i2c_bus * attach_one_i2c(struct platform_device *op, int index)
296 {
297 struct bbc_i2c_bus *bp;
298 struct device_node *dp;
299 int entry;
300
301 bp = kzalloc(sizeof(*bp), GFP_KERNEL);
302 if (!bp)
303 return NULL;
304
305 INIT_LIST_HEAD(&bp->temps);
306 INIT_LIST_HEAD(&bp->fans);
307
308 bp->i2c_control_regs = of_ioremap(&op->resource[0], 0, 0x2, "bbc_i2c_regs");
309 if (!bp->i2c_control_regs)
310 goto fail;
311
312 if (op->num_resources == 2) {
313 bp->i2c_bussel_reg = of_ioremap(&op->resource[1], 0, 0x1, "bbc_i2c_bussel");
314 if (!bp->i2c_bussel_reg)
315 goto fail;
316 }
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
352 fail:
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
bbc_i2c_probe(struct platform_device * op)361 static int bbc_i2c_probe(struct platform_device *op)
362 {
363 struct bbc_i2c_bus *bp;
364 int err, index = 0;
365
366 bp = attach_one_i2c(op, index);
367 if (!bp)
368 return -EINVAL;
369
370 err = bbc_envctrl_init(bp);
371 if (err) {
372 free_irq(op->archdata.irqs[0], bp);
373 if (bp->i2c_bussel_reg)
374 of_iounmap(&op->resource[0], bp->i2c_bussel_reg, 1);
375 if (bp->i2c_control_regs)
376 of_iounmap(&op->resource[1], bp->i2c_control_regs, 2);
377 kfree(bp);
378 } else {
379 dev_set_drvdata(&op->dev, bp);
380 }
381
382 return err;
383 }
384
bbc_i2c_remove(struct platform_device * op)385 static void bbc_i2c_remove(struct platform_device *op)
386 {
387 struct bbc_i2c_bus *bp = dev_get_drvdata(&op->dev);
388
389 bbc_envctrl_cleanup(bp);
390
391 free_irq(op->archdata.irqs[0], bp);
392
393 if (bp->i2c_bussel_reg)
394 of_iounmap(&op->resource[0], bp->i2c_bussel_reg, 1);
395 if (bp->i2c_control_regs)
396 of_iounmap(&op->resource[1], bp->i2c_control_regs, 2);
397
398 kfree(bp);
399 }
400
401 static const struct of_device_id bbc_i2c_match[] = {
402 {
403 .name = "i2c",
404 .compatible = "SUNW,bbc-i2c",
405 },
406 {},
407 };
408 MODULE_DEVICE_TABLE(of, bbc_i2c_match);
409
410 static struct platform_driver bbc_i2c_driver = {
411 .driver = {
412 .name = "bbc_i2c",
413 .of_match_table = bbc_i2c_match,
414 },
415 .probe = bbc_i2c_probe,
416 .remove_new = bbc_i2c_remove,
417 };
418
419 module_platform_driver(bbc_i2c_driver);
420
421 MODULE_DESCRIPTION("UltraSPARC-III bootbus i2c controller driver");
422 MODULE_LICENSE("GPL");
423