2 * SuperH Mobile I2C Controller
4 * Copyright (C) 2008 Magnus Damm
6 * Portions of the code based on out-of-tree driver i2c-sh7343.c
7 * Copyright (c) 2006 Carlos Munoz <carlos@kenati.com>
9 * This program is free software; you can redistribute it and/or modify
10 * it under the terms of the GNU General Public License as published by
11 * the Free Software Foundation; either version 2 of the License
13 * This program is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 * GNU General Public License for more details.
18 * You should have received a copy of the GNU General Public License
19 * along with this program; if not, write to the Free Software
20 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
23 #include <linux/kernel.h>
24 #include <linux/module.h>
25 #include <linux/init.h>
26 #include <linux/delay.h>
27 #include <linux/platform_device.h>
28 #include <linux/interrupt.h>
29 #include <linux/i2c.h>
30 #include <linux/err.h>
31 #include <linux/clk.h>
34 /* Transmit operation: */
44 /* BUS: S A8 ACK D8(1) ACK P */
45 /* IRQ: DTE WAIT WAIT */
51 /* BUS: S A8 ACK D8(1) ACK D8(2) ACK P */
52 /* IRQ: DTE WAIT WAIT WAIT */
55 /* ICDR: A8 D8(1) D8(2) */
57 /* 3 bytes or more, +---------+ gets repeated */
60 /* Receive operation: */
62 /* 0 byte receive - not supported since slave may hold SDA low */
64 /* 1 byte receive [TX] | [RX] */
65 /* BUS: S A8 ACK | D8(1) ACK P */
66 /* IRQ: DTE WAIT | WAIT DTE */
67 /* ICIC: -DTE | +DTE */
68 /* ICCR: 0x94 0x81 | 0xc0 */
69 /* ICDR: A8 | D8(1) */
71 /* 2 byte receive [TX]| [RX] */
72 /* BUS: S A8 ACK | D8(1) ACK D8(2) ACK P */
73 /* IRQ: DTE WAIT | WAIT WAIT DTE */
74 /* ICIC: -DTE | +DTE */
75 /* ICCR: 0x94 0x81 | 0xc0 */
76 /* ICDR: A8 | D8(1) D8(2) */
78 /* 3 byte receive [TX] | [RX] */
79 /* BUS: S A8 ACK | D8(1) ACK D8(2) ACK D8(3) ACK P */
80 /* IRQ: DTE WAIT | WAIT WAIT WAIT DTE */
81 /* ICIC: -DTE | +DTE */
82 /* ICCR: 0x94 0x81 | 0xc0 */
83 /* ICDR: A8 | D8(1) D8(2) D8(3) */
85 /* 4 bytes or more, this part is repeated +---------+ */
88 /* Interrupt order and BUSY flag */
90 /* SDA ___\___XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXAAAAAAAAA___/ */
91 /* SCL \_/1\_/2\_/3\_/4\_/5\_/6\_/7\_/8\___/9\_____/ */
93 /* S D7 D6 D5 D4 D3 D2 D1 D0 P */
95 /* WAIT IRQ ________________________________/ \___________ */
96 /* TACK IRQ ____________________________________/ \_______ */
97 /* DTE IRQ __________________________________________/ \_ */
98 /* AL IRQ XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX */
99 /* _______________________________________________ */
103 enum sh_mobile_i2c_op {
114 struct sh_mobile_i2c_data {
117 struct i2c_adapter adap;
124 wait_queue_head_t wait;
130 #define NORMAL_SPEED 100000 /* FAST_SPEED 400000 */
132 /* Register offsets */
133 #define ICDR(pd) (pd->reg + 0x00)
134 #define ICCR(pd) (pd->reg + 0x04)
135 #define ICSR(pd) (pd->reg + 0x08)
136 #define ICIC(pd) (pd->reg + 0x0c)
137 #define ICCL(pd) (pd->reg + 0x10)
138 #define ICCH(pd) (pd->reg + 0x14)
141 #define ICCR_ICE 0x80
142 #define ICCR_RACK 0x40
143 #define ICCR_TRS 0x10
144 #define ICCR_BBSY 0x04
145 #define ICCR_SCP 0x01
147 #define ICSR_SCLM 0x80
148 #define ICSR_SDAM 0x40
150 #define ICSR_BUSY 0x10
152 #define ICSR_TACK 0x04
153 #define ICSR_WAIT 0x02
154 #define ICSR_DTE 0x01
156 #define ICIC_ALE 0x08
157 #define ICIC_TACKE 0x04
158 #define ICIC_WAITE 0x02
159 #define ICIC_DTEE 0x01
161 static void activate_ch(struct sh_mobile_i2c_data *pd)
163 unsigned long i2c_clk;
168 /* Make sure the clock is enabled */
171 /* Get clock rate after clock is enabled */
172 i2c_clk = clk_get_rate(pd->clk);
174 /* Calculate the value for iccl. From the data sheet:
175 * iccl = (p clock / transfer rate) * (L / (L + H))
176 * where L and H are the SCL low/high ratio (5/4 in this case).
177 * We also round off the result.
180 denom = NORMAL_SPEED * 9;
181 tmp = num * 10 / denom;
183 pd->iccl = (u_int8_t)((num/denom) + 1);
185 pd->iccl = (u_int8_t)(num/denom);
187 /* Calculate the value for icch. From the data sheet:
188 icch = (p clock / transfer rate) * (H / (L + H)) */
190 tmp = num * 10 / denom;
192 pd->icch = (u_int8_t)((num/denom) + 1);
194 pd->icch = (u_int8_t)(num/denom);
196 /* Enable channel and configure rx ack */
197 iowrite8(ioread8(ICCR(pd)) | ICCR_ICE, ICCR(pd));
199 /* Mask all interrupts */
200 iowrite8(0, ICIC(pd));
203 iowrite8(pd->iccl, ICCL(pd));
204 iowrite8(pd->icch, ICCH(pd));
207 static void deactivate_ch(struct sh_mobile_i2c_data *pd)
209 /* Clear/disable interrupts */
210 iowrite8(0, ICSR(pd));
211 iowrite8(0, ICIC(pd));
213 /* Disable channel */
214 iowrite8(ioread8(ICCR(pd)) & ~ICCR_ICE, ICCR(pd));
217 clk_disable(pd->clk);
220 static unsigned char i2c_op(struct sh_mobile_i2c_data *pd,
221 enum sh_mobile_i2c_op op, unsigned char data)
223 unsigned char ret = 0;
226 dev_dbg(pd->dev, "op %d, data in 0x%02x\n", op, data);
228 spin_lock_irqsave(&pd->lock, flags);
231 case OP_START: /* issue start and trigger DTE interrupt */
232 iowrite8(0x94, ICCR(pd));
234 case OP_TX_FIRST: /* disable DTE interrupt and write data */
235 iowrite8(ICIC_WAITE | ICIC_ALE | ICIC_TACKE, ICIC(pd));
236 iowrite8(data, ICDR(pd));
238 case OP_TX: /* write data */
239 iowrite8(data, ICDR(pd));
241 case OP_TX_STOP: /* write data and issue a stop afterwards */
242 iowrite8(data, ICDR(pd));
243 iowrite8(0x90, ICCR(pd));
245 case OP_TX_TO_RX: /* select read mode */
246 iowrite8(0x81, ICCR(pd));
248 case OP_RX: /* just read data */
249 ret = ioread8(ICDR(pd));
251 case OP_RX_STOP: /* enable DTE interrupt, issue stop */
252 iowrite8(ICIC_DTEE | ICIC_WAITE | ICIC_ALE | ICIC_TACKE,
254 iowrite8(0xc0, ICCR(pd));
256 case OP_RX_STOP_DATA: /* enable DTE interrupt, read data, issue stop */
257 iowrite8(ICIC_DTEE | ICIC_WAITE | ICIC_ALE | ICIC_TACKE,
259 ret = ioread8(ICDR(pd));
260 iowrite8(0xc0, ICCR(pd));
264 spin_unlock_irqrestore(&pd->lock, flags);
266 dev_dbg(pd->dev, "op %d, data out 0x%02x\n", op, ret);
270 static int sh_mobile_i2c_is_first_byte(struct sh_mobile_i2c_data *pd)
278 static int sh_mobile_i2c_is_last_byte(struct sh_mobile_i2c_data *pd)
280 if (pd->pos == (pd->msg->len - 1))
286 static void sh_mobile_i2c_get_data(struct sh_mobile_i2c_data *pd,
291 *buf = (pd->msg->addr & 0x7f) << 1;
292 *buf |= (pd->msg->flags & I2C_M_RD) ? 1 : 0;
295 *buf = pd->msg->buf[pd->pos];
299 static int sh_mobile_i2c_isr_tx(struct sh_mobile_i2c_data *pd)
303 if (pd->pos == pd->msg->len)
306 sh_mobile_i2c_get_data(pd, &data);
308 if (sh_mobile_i2c_is_last_byte(pd))
309 i2c_op(pd, OP_TX_STOP, data);
310 else if (sh_mobile_i2c_is_first_byte(pd))
311 i2c_op(pd, OP_TX_FIRST, data);
313 i2c_op(pd, OP_TX, data);
319 static int sh_mobile_i2c_isr_rx(struct sh_mobile_i2c_data *pd)
326 sh_mobile_i2c_get_data(pd, &data);
328 if (sh_mobile_i2c_is_first_byte(pd))
329 i2c_op(pd, OP_TX_FIRST, data);
331 i2c_op(pd, OP_TX, data);
336 i2c_op(pd, OP_TX_TO_RX, 0);
340 real_pos = pd->pos - 2;
342 if (pd->pos == pd->msg->len) {
344 i2c_op(pd, OP_RX_STOP, 0);
347 data = i2c_op(pd, OP_RX_STOP_DATA, 0);
349 data = i2c_op(pd, OP_RX, 0);
352 pd->msg->buf[real_pos] = data;
356 return pd->pos == (pd->msg->len + 2);
359 static irqreturn_t sh_mobile_i2c_isr(int irq, void *dev_id)
361 struct platform_device *dev = dev_id;
362 struct sh_mobile_i2c_data *pd = platform_get_drvdata(dev);
366 sr = ioread8(ICSR(pd));
367 pd->sr |= sr; /* remember state */
369 dev_dbg(pd->dev, "i2c_isr 0x%02x 0x%02x %s %d %d!\n", sr, pd->sr,
370 (pd->msg->flags & I2C_M_RD) ? "read" : "write",
371 pd->pos, pd->msg->len);
373 if (sr & (ICSR_AL | ICSR_TACK)) {
374 /* don't interrupt transaction - continue to issue stop */
375 iowrite8(sr & ~(ICSR_AL | ICSR_TACK), ICSR(pd));
377 } else if (pd->msg->flags & I2C_M_RD)
378 wakeup = sh_mobile_i2c_isr_rx(pd);
380 wakeup = sh_mobile_i2c_isr_tx(pd);
382 if (sr & ICSR_WAIT) /* TODO: add delay here to support slow acks */
383 iowrite8(sr & ~ICSR_WAIT, ICSR(pd));
393 static int start_ch(struct sh_mobile_i2c_data *pd, struct i2c_msg *usr_msg)
395 if (usr_msg->len == 0 && (usr_msg->flags & I2C_M_RD)) {
396 dev_err(pd->dev, "Unsupported zero length i2c read\n");
400 /* Initialize channel registers */
401 iowrite8(ioread8(ICCR(pd)) & ~ICCR_ICE, ICCR(pd));
403 /* Enable channel and configure rx ack */
404 iowrite8(ioread8(ICCR(pd)) | ICCR_ICE, ICCR(pd));
407 iowrite8(pd->iccl, ICCL(pd));
408 iowrite8(pd->icch, ICCH(pd));
414 /* Enable all interrupts to begin with */
415 iowrite8(ICIC_WAITE | ICIC_ALE | ICIC_TACKE | ICIC_DTEE, ICIC(pd));
419 static int sh_mobile_i2c_xfer(struct i2c_adapter *adapter,
420 struct i2c_msg *msgs,
423 struct sh_mobile_i2c_data *pd = i2c_get_adapdata(adapter);
427 int i, k, retry_count;
431 /* Process all messages */
432 for (i = 0; i < num; i++) {
435 err = start_ch(pd, msg);
439 i2c_op(pd, OP_START, 0);
441 /* The interrupt handler takes care of the rest... */
442 k = wait_event_timeout(pd->wait,
443 pd->sr & (ICSR_TACK | SW_DONE),
446 dev_err(pd->dev, "Transfer request timed out\n");
450 val = ioread8(ICSR(pd));
452 dev_dbg(pd->dev, "val 0x%02x pd->sr 0x%02x\n", val, pd->sr);
454 /* the interrupt handler may wake us up before the
455 * transfer is finished, so poll the hardware
458 if (val & ICSR_BUSY) {
464 dev_err(pd->dev, "Polling timed out\n");
468 /* handle missing acknowledge and arbitration lost */
469 if ((val | pd->sr) & (ICSR_TACK | ICSR_AL)) {
482 static u32 sh_mobile_i2c_func(struct i2c_adapter *adapter)
484 return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
487 static struct i2c_algorithm sh_mobile_i2c_algorithm = {
488 .functionality = sh_mobile_i2c_func,
489 .master_xfer = sh_mobile_i2c_xfer,
492 static int sh_mobile_i2c_hook_irqs(struct platform_device *dev, int hook)
494 struct resource *res;
500 while ((res = platform_get_resource(dev, IORESOURCE_IRQ, k))) {
501 for (n = res->start; hook && n <= res->end; n++) {
502 if (request_irq(n, sh_mobile_i2c_isr, IRQF_DISABLED,
503 dev->dev.bus_id, dev))
510 return k > 0 ? 0 : -ENOENT;
516 for (q = k; k >= 0; k--) {
517 for (m = n; m >= res->start; m--)
520 res = platform_get_resource(dev, IORESOURCE_IRQ, k - 1);
527 static int sh_mobile_i2c_probe(struct platform_device *dev)
529 struct sh_mobile_i2c_data *pd;
530 struct i2c_adapter *adap;
531 struct resource *res;
536 pd = kzalloc(sizeof(struct sh_mobile_i2c_data), GFP_KERNEL);
538 dev_err(&dev->dev, "cannot allocate private data\n");
542 snprintf(clk_name, sizeof(clk_name), "i2c%d", dev->id);
543 pd->clk = clk_get(&dev->dev, clk_name);
544 if (IS_ERR(pd->clk)) {
545 dev_err(&dev->dev, "cannot get clock \"%s\"\n", clk_name);
546 ret = PTR_ERR(pd->clk);
550 ret = sh_mobile_i2c_hook_irqs(dev, 1);
552 dev_err(&dev->dev, "cannot request IRQ\n");
557 platform_set_drvdata(dev, pd);
559 res = platform_get_resource(dev, IORESOURCE_MEM, 0);
561 dev_err(&dev->dev, "cannot find IO resource\n");
566 size = (res->end - res->start) + 1;
568 pd->reg = ioremap(res->start, size);
569 if (pd->reg == NULL) {
570 dev_err(&dev->dev, "cannot map IO\n");
575 /* setup the private data */
577 i2c_set_adapdata(adap, pd);
579 adap->owner = THIS_MODULE;
580 adap->algo = &sh_mobile_i2c_algorithm;
581 adap->dev.parent = &dev->dev;
585 strlcpy(adap->name, dev->name, sizeof(adap->name));
587 spin_lock_init(&pd->lock);
588 init_waitqueue_head(&pd->wait);
590 ret = i2c_add_numbered_adapter(adap);
592 dev_err(&dev->dev, "cannot add numbered adapter\n");
601 sh_mobile_i2c_hook_irqs(dev, 0);
609 static int sh_mobile_i2c_remove(struct platform_device *dev)
611 struct sh_mobile_i2c_data *pd = platform_get_drvdata(dev);
613 i2c_del_adapter(&pd->adap);
615 sh_mobile_i2c_hook_irqs(dev, 0);
621 static struct platform_driver sh_mobile_i2c_driver = {
623 .name = "i2c-sh_mobile",
624 .owner = THIS_MODULE,
626 .probe = sh_mobile_i2c_probe,
627 .remove = sh_mobile_i2c_remove,
630 static int __init sh_mobile_i2c_adap_init(void)
632 return platform_driver_register(&sh_mobile_i2c_driver);
635 static void __exit sh_mobile_i2c_adap_exit(void)
637 platform_driver_unregister(&sh_mobile_i2c_driver);
640 module_init(sh_mobile_i2c_adap_init);
641 module_exit(sh_mobile_i2c_adap_exit);
643 MODULE_DESCRIPTION("SuperH Mobile I2C Bus Controller driver");
644 MODULE_AUTHOR("Magnus Damm");
645 MODULE_LICENSE("GPL v2");