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/of_i2c.h>
31 #include <linux/err.h>
32 #include <linux/pm_runtime.h>
33 #include <linux/clk.h>
35 #include <linux/slab.h>
36 #include <linux/i2c/i2c-sh_mobile.h>
38 /* Transmit operation: */
41 /* BUS: S A8 ACK P(*) */
48 /* BUS: S A8 ACK D8(1) ACK P(*) */
49 /* IRQ: DTE WAIT WAIT */
55 /* BUS: S A8 ACK D8(1) ACK D8(2) ACK P(*) */
56 /* IRQ: DTE WAIT WAIT WAIT */
59 /* ICDR: A8 D8(1) D8(2) */
61 /* 3 bytes or more, +---------+ gets repeated */
64 /* Receive operation: */
66 /* 0 byte receive - not supported since slave may hold SDA low */
68 /* 1 byte receive [TX] | [RX] */
69 /* BUS: S A8 ACK | D8(1) ACK P(*) */
70 /* IRQ: DTE WAIT | WAIT DTE */
71 /* ICIC: -DTE | +DTE */
72 /* ICCR: 0x94 0x81 | 0xc0 */
73 /* ICDR: A8 | D8(1) */
75 /* 2 byte receive [TX]| [RX] */
76 /* BUS: S A8 ACK | D8(1) ACK D8(2) ACK P(*) */
77 /* IRQ: DTE WAIT | WAIT WAIT DTE */
78 /* ICIC: -DTE | +DTE */
79 /* ICCR: 0x94 0x81 | 0xc0 */
80 /* ICDR: A8 | D8(1) D8(2) */
82 /* 3 byte receive [TX] | [RX] (*) */
83 /* BUS: S A8 ACK | D8(1) ACK D8(2) ACK D8(3) ACK P */
84 /* IRQ: DTE WAIT | WAIT WAIT WAIT DTE */
85 /* ICIC: -DTE | +DTE */
86 /* ICCR: 0x94 0x81 | 0xc0 */
87 /* ICDR: A8 | D8(1) D8(2) D8(3) */
89 /* 4 bytes or more, this part is repeated +---------+ */
92 /* Interrupt order and BUSY flag */
94 /* SDA ___\___XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXAAAAAAAAA___/ */
95 /* SCL \_/1\_/2\_/3\_/4\_/5\_/6\_/7\_/8\___/9\_____/ */
97 /* S D7 D6 D5 D4 D3 D2 D1 D0 P(*) */
99 /* WAIT IRQ ________________________________/ \___________ */
100 /* TACK IRQ ____________________________________/ \_______ */
101 /* DTE IRQ __________________________________________/ \_ */
102 /* AL IRQ XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX */
103 /* _______________________________________________ */
106 /* (*) The STOP condition is only sent by the master at the end of the last */
107 /* I2C message or if the I2C_M_STOP flag is set. Similarly, the BUSY bit is */
108 /* only cleared after the STOP condition, so, between messages we have to */
109 /* poll for the DTE bit. */
112 enum sh_mobile_i2c_op {
123 struct sh_mobile_i2c_data {
126 struct i2c_adapter adap;
127 unsigned long bus_speed;
128 unsigned int clks_per_count;
136 wait_queue_head_t wait;
143 #define IIC_FLAG_HAS_ICIC67 (1 << 0)
145 #define STANDARD_MODE 100000
146 #define FAST_MODE 400000
148 /* Register offsets */
157 #define ICCR_ICE 0x80
158 #define ICCR_RACK 0x40
159 #define ICCR_TRS 0x10
160 #define ICCR_BBSY 0x04
161 #define ICCR_SCP 0x01
163 #define ICSR_SCLM 0x80
164 #define ICSR_SDAM 0x40
166 #define ICSR_BUSY 0x10
168 #define ICSR_TACK 0x04
169 #define ICSR_WAIT 0x02
170 #define ICSR_DTE 0x01
172 #define ICIC_ICCLB8 0x80
173 #define ICIC_ICCHB8 0x40
174 #define ICIC_ALE 0x08
175 #define ICIC_TACKE 0x04
176 #define ICIC_WAITE 0x02
177 #define ICIC_DTEE 0x01
179 static void iic_wr(struct sh_mobile_i2c_data *pd, int offs, unsigned char data)
184 iowrite8(data, pd->reg + offs);
187 static unsigned char iic_rd(struct sh_mobile_i2c_data *pd, int offs)
189 return ioread8(pd->reg + offs);
192 static void iic_set_clr(struct sh_mobile_i2c_data *pd, int offs,
193 unsigned char set, unsigned char clr)
195 iic_wr(pd, offs, (iic_rd(pd, offs) | set) & ~clr);
198 static u32 sh_mobile_i2c_iccl(unsigned long count_khz, u32 tLOW, u32 tf, int offset)
201 * Conditional expression:
202 * ICCL >= COUNT_CLK * (tLOW + tf)
204 * SH-Mobile IIC hardware starts counting the LOW period of
205 * the SCL signal (tLOW) as soon as it pulls the SCL line.
206 * In order to meet the tLOW timing spec, we need to take into
207 * account the fall time of SCL signal (tf). Default tf value
208 * should be 0.3 us, for safety.
210 return (((count_khz * (tLOW + tf)) + 5000) / 10000) + offset;
213 static u32 sh_mobile_i2c_icch(unsigned long count_khz, u32 tHIGH, u32 tf, int offset)
216 * Conditional expression:
217 * ICCH >= COUNT_CLK * (tHIGH + tf)
219 * SH-Mobile IIC hardware is aware of SCL transition period 'tr',
220 * and can ignore it. SH-Mobile IIC controller starts counting
221 * the HIGH period of the SCL signal (tHIGH) after the SCL input
222 * voltage increases at VIH.
224 * Afterward it turned out calculating ICCH using only tHIGH spec
225 * will result in violation of the tHD;STA timing spec. We need
226 * to take into account the fall time of SDA signal (tf) at START
227 * condition, in order to meet both tHIGH and tHD;STA specs.
229 return (((count_khz * (tHIGH + tf)) + 5000) / 10000) + offset;
232 static void sh_mobile_i2c_init(struct sh_mobile_i2c_data *pd)
234 unsigned long i2c_clk_khz;
238 /* Get clock rate after clock is enabled */
240 i2c_clk_khz = clk_get_rate(pd->clk) / 1000;
241 i2c_clk_khz /= pd->clks_per_count;
243 if (pd->bus_speed == STANDARD_MODE) {
244 tLOW = 47; /* tLOW = 4.7 us */
245 tHIGH = 40; /* tHD;STA = tHIGH = 4.0 us */
246 tf = 3; /* tf = 0.3 us */
247 offset = 0; /* No offset */
248 } else if (pd->bus_speed == FAST_MODE) {
249 tLOW = 13; /* tLOW = 1.3 us */
250 tHIGH = 6; /* tHD;STA = tHIGH = 0.6 us */
251 tf = 3; /* tf = 0.3 us */
252 offset = 0; /* No offset */
254 dev_err(pd->dev, "unrecognized bus speed %lu Hz\n",
259 pd->iccl = sh_mobile_i2c_iccl(i2c_clk_khz, tLOW, tf, offset);
260 /* one more bit of ICCL in ICIC */
261 if ((pd->iccl > 0xff) && (pd->flags & IIC_FLAG_HAS_ICIC67))
262 pd->icic |= ICIC_ICCLB8;
264 pd->icic &= ~ICIC_ICCLB8;
266 pd->icch = sh_mobile_i2c_icch(i2c_clk_khz, tHIGH, tf, offset);
267 /* one more bit of ICCH in ICIC */
268 if ((pd->icch > 0xff) && (pd->flags & IIC_FLAG_HAS_ICIC67))
269 pd->icic |= ICIC_ICCHB8;
271 pd->icic &= ~ICIC_ICCHB8;
274 clk_disable(pd->clk);
277 static void activate_ch(struct sh_mobile_i2c_data *pd)
279 /* Wake up device and enable clock */
280 pm_runtime_get_sync(pd->dev);
283 /* Enable channel and configure rx ack */
284 iic_set_clr(pd, ICCR, ICCR_ICE, 0);
286 /* Mask all interrupts */
290 iic_wr(pd, ICCL, pd->iccl & 0xff);
291 iic_wr(pd, ICCH, pd->icch & 0xff);
294 static void deactivate_ch(struct sh_mobile_i2c_data *pd)
296 /* Clear/disable interrupts */
300 /* Disable channel */
301 iic_set_clr(pd, ICCR, 0, ICCR_ICE);
303 /* Disable clock and mark device as idle */
304 clk_disable(pd->clk);
305 pm_runtime_put_sync(pd->dev);
308 static unsigned char i2c_op(struct sh_mobile_i2c_data *pd,
309 enum sh_mobile_i2c_op op, unsigned char data)
311 unsigned char ret = 0;
314 dev_dbg(pd->dev, "op %d, data in 0x%02x\n", op, data);
316 spin_lock_irqsave(&pd->lock, flags);
319 case OP_START: /* issue start and trigger DTE interrupt */
320 iic_wr(pd, ICCR, 0x94);
322 case OP_TX_FIRST: /* disable DTE interrupt and write data */
323 iic_wr(pd, ICIC, ICIC_WAITE | ICIC_ALE | ICIC_TACKE);
324 iic_wr(pd, ICDR, data);
326 case OP_TX: /* write data */
327 iic_wr(pd, ICDR, data);
329 case OP_TX_STOP: /* write data and issue a stop afterwards */
330 iic_wr(pd, ICDR, data);
331 iic_wr(pd, ICCR, pd->send_stop ? 0x90 : 0x94);
333 case OP_TX_TO_RX: /* select read mode */
334 iic_wr(pd, ICCR, 0x81);
336 case OP_RX: /* just read data */
337 ret = iic_rd(pd, ICDR);
339 case OP_RX_STOP: /* enable DTE interrupt, issue stop */
341 ICIC_DTEE | ICIC_WAITE | ICIC_ALE | ICIC_TACKE);
342 iic_wr(pd, ICCR, 0xc0);
344 case OP_RX_STOP_DATA: /* enable DTE interrupt, read data, issue stop */
346 ICIC_DTEE | ICIC_WAITE | ICIC_ALE | ICIC_TACKE);
347 ret = iic_rd(pd, ICDR);
348 iic_wr(pd, ICCR, 0xc0);
352 spin_unlock_irqrestore(&pd->lock, flags);
354 dev_dbg(pd->dev, "op %d, data out 0x%02x\n", op, ret);
358 static bool sh_mobile_i2c_is_first_byte(struct sh_mobile_i2c_data *pd)
360 return pd->pos == -1;
363 static bool sh_mobile_i2c_is_last_byte(struct sh_mobile_i2c_data *pd)
365 return pd->pos == pd->msg->len - 1;
368 static void sh_mobile_i2c_get_data(struct sh_mobile_i2c_data *pd,
373 *buf = (pd->msg->addr & 0x7f) << 1;
374 *buf |= (pd->msg->flags & I2C_M_RD) ? 1 : 0;
377 *buf = pd->msg->buf[pd->pos];
381 static int sh_mobile_i2c_isr_tx(struct sh_mobile_i2c_data *pd)
385 if (pd->pos == pd->msg->len)
388 sh_mobile_i2c_get_data(pd, &data);
390 if (sh_mobile_i2c_is_last_byte(pd))
391 i2c_op(pd, OP_TX_STOP, data);
392 else if (sh_mobile_i2c_is_first_byte(pd))
393 i2c_op(pd, OP_TX_FIRST, data);
395 i2c_op(pd, OP_TX, data);
401 static int sh_mobile_i2c_isr_rx(struct sh_mobile_i2c_data *pd)
408 sh_mobile_i2c_get_data(pd, &data);
410 if (sh_mobile_i2c_is_first_byte(pd))
411 i2c_op(pd, OP_TX_FIRST, data);
413 i2c_op(pd, OP_TX, data);
418 i2c_op(pd, OP_TX_TO_RX, 0);
422 real_pos = pd->pos - 2;
424 if (pd->pos == pd->msg->len) {
426 i2c_op(pd, OP_RX_STOP, 0);
429 data = i2c_op(pd, OP_RX_STOP_DATA, 0);
431 data = i2c_op(pd, OP_RX, 0);
434 pd->msg->buf[real_pos] = data;
438 return pd->pos == (pd->msg->len + 2);
441 static irqreturn_t sh_mobile_i2c_isr(int irq, void *dev_id)
443 struct platform_device *dev = dev_id;
444 struct sh_mobile_i2c_data *pd = platform_get_drvdata(dev);
448 sr = iic_rd(pd, ICSR);
449 pd->sr |= sr; /* remember state */
451 dev_dbg(pd->dev, "i2c_isr 0x%02x 0x%02x %s %d %d!\n", sr, pd->sr,
452 (pd->msg->flags & I2C_M_RD) ? "read" : "write",
453 pd->pos, pd->msg->len);
455 if (sr & (ICSR_AL | ICSR_TACK)) {
456 /* don't interrupt transaction - continue to issue stop */
457 iic_wr(pd, ICSR, sr & ~(ICSR_AL | ICSR_TACK));
459 } else if (pd->msg->flags & I2C_M_RD)
460 wakeup = sh_mobile_i2c_isr_rx(pd);
462 wakeup = sh_mobile_i2c_isr_tx(pd);
464 if (sr & ICSR_WAIT) /* TODO: add delay here to support slow acks */
465 iic_wr(pd, ICSR, sr & ~ICSR_WAIT);
472 /* defeat write posting to avoid spurious WAIT interrupts */
478 static int start_ch(struct sh_mobile_i2c_data *pd, struct i2c_msg *usr_msg,
481 if (usr_msg->len == 0 && (usr_msg->flags & I2C_M_RD)) {
482 dev_err(pd->dev, "Unsupported zero length i2c read\n");
487 /* Initialize channel registers */
488 iic_set_clr(pd, ICCR, 0, ICCR_ICE);
490 /* Enable channel and configure rx ack */
491 iic_set_clr(pd, ICCR, ICCR_ICE, 0);
494 iic_wr(pd, ICCL, pd->iccl & 0xff);
495 iic_wr(pd, ICCH, pd->icch & 0xff);
502 /* Enable all interrupts to begin with */
503 iic_wr(pd, ICIC, ICIC_DTEE | ICIC_WAITE | ICIC_ALE | ICIC_TACKE);
507 static int poll_dte(struct sh_mobile_i2c_data *pd)
511 for (i = 1000; i; i--) {
512 u_int8_t val = iic_rd(pd, ICSR);
524 dev_warn(pd->dev, "Timeout polling for DTE!\n");
531 static int poll_busy(struct sh_mobile_i2c_data *pd)
535 for (i = 1000; i; i--) {
536 u_int8_t val = iic_rd(pd, ICSR);
538 dev_dbg(pd->dev, "val 0x%02x pd->sr 0x%02x\n", val, pd->sr);
540 /* the interrupt handler may wake us up before the
541 * transfer is finished, so poll the hardware
544 if (!(val & ICSR_BUSY)) {
545 /* handle missing acknowledge and arbitration lost */
546 if ((val | pd->sr) & (ICSR_TACK | ICSR_AL))
555 dev_err(pd->dev, "Polling timed out\n");
562 static int sh_mobile_i2c_xfer(struct i2c_adapter *adapter,
563 struct i2c_msg *msgs,
566 struct sh_mobile_i2c_data *pd = i2c_get_adapdata(adapter);
573 /* Process all messages */
574 for (i = 0; i < num; i++) {
575 bool do_start = pd->send_stop || !i;
577 pd->send_stop = i == num - 1 || msg->flags & I2C_M_STOP;
579 err = start_ch(pd, msg, do_start);
584 i2c_op(pd, OP_START, 0);
586 /* The interrupt handler takes care of the rest... */
587 k = wait_event_timeout(pd->wait,
588 pd->sr & (ICSR_TACK | SW_DONE),
591 dev_err(pd->dev, "Transfer request timed out\n");
611 static u32 sh_mobile_i2c_func(struct i2c_adapter *adapter)
613 return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | I2C_FUNC_PROTOCOL_MANGLING;
616 static struct i2c_algorithm sh_mobile_i2c_algorithm = {
617 .functionality = sh_mobile_i2c_func,
618 .master_xfer = sh_mobile_i2c_xfer,
621 static int sh_mobile_i2c_hook_irqs(struct platform_device *dev, int hook)
623 struct resource *res;
627 while ((res = platform_get_resource(dev, IORESOURCE_IRQ, k))) {
628 for (n = res->start; hook && n <= res->end; n++) {
629 if (request_irq(n, sh_mobile_i2c_isr, 0,
630 dev_name(&dev->dev), dev)) {
631 for (n--; n >= res->start; n--)
641 return k > 0 ? 0 : -ENOENT;
649 res = platform_get_resource(dev, IORESOURCE_IRQ, k);
650 for (n = res->start; n <= res->end; n++)
659 static int sh_mobile_i2c_probe(struct platform_device *dev)
661 struct i2c_sh_mobile_platform_data *pdata = dev->dev.platform_data;
662 struct sh_mobile_i2c_data *pd;
663 struct i2c_adapter *adap;
664 struct resource *res;
668 pd = kzalloc(sizeof(struct sh_mobile_i2c_data), GFP_KERNEL);
670 dev_err(&dev->dev, "cannot allocate private data\n");
674 pd->clk = clk_get(&dev->dev, NULL);
675 if (IS_ERR(pd->clk)) {
676 dev_err(&dev->dev, "cannot get clock\n");
677 ret = PTR_ERR(pd->clk);
681 ret = sh_mobile_i2c_hook_irqs(dev, 1);
683 dev_err(&dev->dev, "cannot request IRQ\n");
688 platform_set_drvdata(dev, pd);
690 res = platform_get_resource(dev, IORESOURCE_MEM, 0);
692 dev_err(&dev->dev, "cannot find IO resource\n");
697 size = resource_size(res);
699 pd->reg = ioremap(res->start, size);
700 if (pd->reg == NULL) {
701 dev_err(&dev->dev, "cannot map IO\n");
706 /* Use platform data bus speed or STANDARD_MODE */
707 pd->bus_speed = STANDARD_MODE;
708 if (pdata && pdata->bus_speed)
709 pd->bus_speed = pdata->bus_speed;
710 pd->clks_per_count = 1;
711 if (pdata && pdata->clks_per_count)
712 pd->clks_per_count = pdata->clks_per_count;
714 /* The IIC blocks on SH-Mobile ARM processors
715 * come with two new bits in ICIC.
718 pd->flags |= IIC_FLAG_HAS_ICIC67;
720 sh_mobile_i2c_init(pd);
722 /* Enable Runtime PM for this device.
724 * Also tell the Runtime PM core to ignore children
725 * for this device since it is valid for us to suspend
726 * this I2C master driver even though the slave devices
727 * on the I2C bus may not be suspended.
729 * The state of the I2C hardware bus is unaffected by
730 * the Runtime PM state.
732 pm_suspend_ignore_children(&dev->dev, true);
733 pm_runtime_enable(&dev->dev);
735 /* setup the private data */
737 i2c_set_adapdata(adap, pd);
739 adap->owner = THIS_MODULE;
740 adap->algo = &sh_mobile_i2c_algorithm;
741 adap->dev.parent = &dev->dev;
744 adap->dev.of_node = dev->dev.of_node;
746 strlcpy(adap->name, dev->name, sizeof(adap->name));
748 spin_lock_init(&pd->lock);
749 init_waitqueue_head(&pd->wait);
751 ret = i2c_add_numbered_adapter(adap);
753 dev_err(&dev->dev, "cannot add numbered adapter\n");
758 "I2C adapter %d with bus speed %lu Hz (L/H=%x/%x)\n",
759 adap->nr, pd->bus_speed, pd->iccl, pd->icch);
761 of_i2c_register_devices(adap);
767 sh_mobile_i2c_hook_irqs(dev, 0);
775 static int sh_mobile_i2c_remove(struct platform_device *dev)
777 struct sh_mobile_i2c_data *pd = platform_get_drvdata(dev);
779 i2c_del_adapter(&pd->adap);
781 sh_mobile_i2c_hook_irqs(dev, 0);
783 pm_runtime_disable(&dev->dev);
788 static int sh_mobile_i2c_runtime_nop(struct device *dev)
790 /* Runtime PM callback shared between ->runtime_suspend()
791 * and ->runtime_resume(). Simply returns success.
793 * This driver re-initializes all registers after
794 * pm_runtime_get_sync() anyway so there is no need
795 * to save and restore registers here.
800 static const struct dev_pm_ops sh_mobile_i2c_dev_pm_ops = {
801 .runtime_suspend = sh_mobile_i2c_runtime_nop,
802 .runtime_resume = sh_mobile_i2c_runtime_nop,
805 static const struct of_device_id sh_mobile_i2c_dt_ids[] = {
806 { .compatible = "renesas,rmobile-iic", },
809 MODULE_DEVICE_TABLE(of, sh_mobile_i2c_dt_ids);
811 static struct platform_driver sh_mobile_i2c_driver = {
813 .name = "i2c-sh_mobile",
814 .owner = THIS_MODULE,
815 .pm = &sh_mobile_i2c_dev_pm_ops,
816 .of_match_table = sh_mobile_i2c_dt_ids,
818 .probe = sh_mobile_i2c_probe,
819 .remove = sh_mobile_i2c_remove,
822 static int __init sh_mobile_i2c_adap_init(void)
824 return platform_driver_register(&sh_mobile_i2c_driver);
827 static void __exit sh_mobile_i2c_adap_exit(void)
829 platform_driver_unregister(&sh_mobile_i2c_driver);
832 subsys_initcall(sh_mobile_i2c_adap_init);
833 module_exit(sh_mobile_i2c_adap_exit);
835 MODULE_DESCRIPTION("SuperH Mobile I2C Bus Controller driver");
836 MODULE_AUTHOR("Magnus Damm");
837 MODULE_LICENSE("GPL v2");
838 MODULE_ALIAS("platform:i2c-sh_mobile");