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 enum sh_mobile_i2c_op {
43 struct sh_mobile_i2c_data {
46 struct i2c_adapter adap;
53 wait_queue_head_t wait;
59 #define NORMAL_SPEED 100000 /* FAST_SPEED 400000 */
61 /* Register offsets */
62 #define ICDR(pd) (pd->reg + 0x00)
63 #define ICCR(pd) (pd->reg + 0x04)
64 #define ICSR(pd) (pd->reg + 0x08)
65 #define ICIC(pd) (pd->reg + 0x0c)
66 #define ICCL(pd) (pd->reg + 0x10)
67 #define ICCH(pd) (pd->reg + 0x14)
71 #define ICCR_RACK 0x40
73 #define ICCR_BBSY 0x04
76 #define ICSR_SCLM 0x80
77 #define ICSR_SDAM 0x40
79 #define ICSR_BUSY 0x10
81 #define ICSR_TACK 0x04
82 #define ICSR_WAIT 0x02
86 #define ICIC_TACKE 0x04
87 #define ICIC_WAITE 0x02
88 #define ICIC_DTEE 0x01
90 static void activate_ch(struct sh_mobile_i2c_data *pd)
92 /* Make sure the clock is enabled */
95 /* Enable channel and configure rx ack */
96 iowrite8(ioread8(ICCR(pd)) | ICCR_ICE, ICCR(pd));
98 /* Mask all interrupts */
99 iowrite8(0, ICIC(pd));
102 iowrite8(pd->iccl, ICCL(pd));
103 iowrite8(pd->icch, ICCH(pd));
106 static void deactivate_ch(struct sh_mobile_i2c_data *pd)
108 /* Clear/disable interrupts */
109 iowrite8(0, ICSR(pd));
110 iowrite8(0, ICIC(pd));
112 /* Disable channel */
113 iowrite8(ioread8(ICCR(pd)) & ~ICCR_ICE, ICCR(pd));
116 clk_disable(pd->clk);
119 static unsigned char i2c_op(struct sh_mobile_i2c_data *pd,
120 enum sh_mobile_i2c_op op, unsigned char data)
122 unsigned char ret = 0;
125 dev_dbg(pd->dev, "op %d, data in 0x%02x\n", op, data);
127 spin_lock_irqsave(&pd->lock, flags);
131 iowrite8(0x94, ICCR(pd));
134 iowrite8(data, ICDR(pd));
137 iowrite8(data, ICDR(pd));
138 iowrite8(0x90, ICCR(pd));
139 iowrite8(ICIC_ALE | ICIC_TACKE, ICIC(pd));
142 iowrite8(data, ICDR(pd));
143 iowrite8(0x81, ICCR(pd));
146 ret = ioread8(ICDR(pd));
149 ret = ioread8(ICDR(pd));
150 iowrite8(0xc0, ICCR(pd));
154 spin_unlock_irqrestore(&pd->lock, flags);
156 dev_dbg(pd->dev, "op %d, data out 0x%02x\n", op, ret);
160 static irqreturn_t sh_mobile_i2c_isr(int irq, void *dev_id)
162 struct platform_device *dev = dev_id;
163 struct sh_mobile_i2c_data *pd = platform_get_drvdata(dev);
164 struct i2c_msg *msg = pd->msg;
165 unsigned char data, sr;
168 sr = ioread8(ICSR(pd));
171 dev_dbg(pd->dev, "i2c_isr 0x%02x 0x%02x %s %d %d!\n", sr, pd->sr,
172 (msg->flags & I2C_M_RD) ? "read" : "write",
175 if (sr & (ICSR_AL | ICSR_TACK)) {
176 iowrite8(0, ICIC(pd)); /* disable interrupts */
181 if (pd->pos == msg->len) {
182 i2c_op(pd, OP_RX_ONLY, 0);
188 data = (msg->addr & 0x7f) << 1;
189 data |= (msg->flags & I2C_M_RD) ? 1 : 0;
191 data = msg->buf[pd->pos];
193 if ((pd->pos == -1) || !(msg->flags & I2C_M_RD)) {
194 if (msg->flags & I2C_M_RD)
195 i2c_op(pd, OP_TX_TO_RX, data);
196 else if (pd->pos == (msg->len - 1)) {
197 i2c_op(pd, OP_TX_STOP, data);
200 i2c_op(pd, OP_TX_ONLY, data);
202 if (pd->pos == (msg->len - 1))
203 data = i2c_op(pd, OP_RX_STOP, 0);
205 data = i2c_op(pd, OP_RX_ONLY, 0);
207 msg->buf[pd->pos] = data;
220 static int start_ch(struct sh_mobile_i2c_data *pd, struct i2c_msg *usr_msg)
222 /* Initialize channel registers */
223 iowrite8(ioread8(ICCR(pd)) & ~ICCR_ICE, ICCR(pd));
225 /* Enable channel and configure rx ack */
226 iowrite8(ioread8(ICCR(pd)) | ICCR_ICE, ICCR(pd));
229 iowrite8(pd->iccl, ICCL(pd));
230 iowrite8(pd->icch, ICCH(pd));
236 /* Enable all interrupts except wait */
237 iowrite8(ioread8(ICIC(pd)) | ICIC_ALE | ICIC_TACKE | ICIC_DTEE,
242 static int sh_mobile_i2c_xfer(struct i2c_adapter *adapter,
243 struct i2c_msg *msgs,
246 struct sh_mobile_i2c_data *pd = i2c_get_adapdata(adapter);
250 int i, k, retry_count;
254 /* Process all messages */
255 for (i = 0; i < num; i++) {
258 err = start_ch(pd, msg);
262 i2c_op(pd, OP_START, 0);
264 /* The interrupt handler takes care of the rest... */
265 k = wait_event_timeout(pd->wait,
266 pd->sr & (ICSR_TACK | SW_DONE),
269 dev_err(pd->dev, "Transfer request timed out\n");
273 val = ioread8(ICSR(pd));
275 dev_dbg(pd->dev, "val 0x%02x pd->sr 0x%02x\n", val, pd->sr);
277 if ((val | pd->sr) & (ICSR_TACK | ICSR_AL)) {
282 /* the interrupt handler may wake us up before the
283 * transfer is finished, so poll the hardware
287 if (!(!(val & ICSR_BUSY) && (val & ICSR_SCLM) &&
288 (val & ICSR_SDAM))) {
294 dev_err(pd->dev, "Polling timed out\n");
306 static u32 sh_mobile_i2c_func(struct i2c_adapter *adapter)
308 return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
311 static struct i2c_algorithm sh_mobile_i2c_algorithm = {
312 .functionality = sh_mobile_i2c_func,
313 .master_xfer = sh_mobile_i2c_xfer,
316 static void sh_mobile_i2c_setup_channel(struct platform_device *dev)
318 struct sh_mobile_i2c_data *pd = platform_get_drvdata(dev);
319 unsigned long peripheral_clk = clk_get_rate(pd->clk);
324 spin_lock_init(&pd->lock);
325 init_waitqueue_head(&pd->wait);
327 /* Calculate the value for iccl. From the data sheet:
328 * iccl = (p clock / transfer rate) * (L / (L + H))
329 * where L and H are the SCL low/high ratio (5/4 in this case).
330 * We also round off the result.
332 num = peripheral_clk * 5;
333 denom = NORMAL_SPEED * 9;
334 tmp = num * 10 / denom;
336 pd->iccl = (u_int8_t)((num/denom) + 1);
338 pd->iccl = (u_int8_t)(num/denom);
340 /* Calculate the value for icch. From the data sheet:
341 icch = (p clock / transfer rate) * (H / (L + H)) */
342 num = peripheral_clk * 4;
343 tmp = num * 10 / denom;
345 pd->icch = (u_int8_t)((num/denom) + 1);
347 pd->icch = (u_int8_t)(num/denom);
350 static int sh_mobile_i2c_hook_irqs(struct platform_device *dev, int hook)
352 struct resource *res;
358 while ((res = platform_get_resource(dev, IORESOURCE_IRQ, k))) {
359 for (n = res->start; hook && n <= res->end; n++) {
360 if (request_irq(n, sh_mobile_i2c_isr, IRQF_DISABLED,
361 dev->dev.bus_id, dev))
368 return k > 0 ? 0 : -ENOENT;
374 for (q = k; k >= 0; k--) {
375 for (m = n; m >= res->start; m--)
378 res = platform_get_resource(dev, IORESOURCE_IRQ, k - 1);
385 static int sh_mobile_i2c_probe(struct platform_device *dev)
387 struct sh_mobile_i2c_data *pd;
388 struct i2c_adapter *adap;
389 struct resource *res;
393 pd = kzalloc(sizeof(struct sh_mobile_i2c_data), GFP_KERNEL);
395 dev_err(&dev->dev, "cannot allocate private data\n");
399 pd->clk = clk_get(&dev->dev, "peripheral_clk");
400 if (IS_ERR(pd->clk)) {
401 dev_err(&dev->dev, "cannot get peripheral clock\n");
402 ret = PTR_ERR(pd->clk);
406 ret = sh_mobile_i2c_hook_irqs(dev, 1);
408 dev_err(&dev->dev, "cannot request IRQ\n");
413 platform_set_drvdata(dev, pd);
415 res = platform_get_resource(dev, IORESOURCE_MEM, 0);
417 dev_err(&dev->dev, "cannot find IO resource\n");
422 size = (res->end - res->start) + 1;
424 pd->reg = ioremap(res->start, size);
425 if (pd->reg == NULL) {
426 dev_err(&dev->dev, "cannot map IO\n");
431 /* setup the private data */
433 i2c_set_adapdata(adap, pd);
435 adap->owner = THIS_MODULE;
436 adap->algo = &sh_mobile_i2c_algorithm;
437 adap->dev.parent = &dev->dev;
441 strlcpy(adap->name, dev->name, sizeof(adap->name));
443 sh_mobile_i2c_setup_channel(dev);
445 ret = i2c_add_numbered_adapter(adap);
447 dev_err(&dev->dev, "cannot add numbered adapter\n");
456 sh_mobile_i2c_hook_irqs(dev, 0);
464 static int sh_mobile_i2c_remove(struct platform_device *dev)
466 struct sh_mobile_i2c_data *pd = platform_get_drvdata(dev);
468 i2c_del_adapter(&pd->adap);
470 sh_mobile_i2c_hook_irqs(dev, 0);
476 static struct platform_driver sh_mobile_i2c_driver = {
478 .name = "i2c-sh_mobile",
479 .owner = THIS_MODULE,
481 .probe = sh_mobile_i2c_probe,
482 .remove = sh_mobile_i2c_remove,
485 static int __init sh_mobile_i2c_adap_init(void)
487 return platform_driver_register(&sh_mobile_i2c_driver);
490 static void __exit sh_mobile_i2c_adap_exit(void)
492 platform_driver_unregister(&sh_mobile_i2c_driver);
495 module_init(sh_mobile_i2c_adap_init);
496 module_exit(sh_mobile_i2c_adap_exit);
498 MODULE_DESCRIPTION("SuperH Mobile I2C Bus Controller driver");
499 MODULE_AUTHOR("Magnus Damm");
500 MODULE_LICENSE("GPL v2");