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-rw-r--r--drivers/i2c/busses/i2c-sh_mobile.c271
1 files changed, 208 insertions, 63 deletions
diff --git a/drivers/i2c/busses/i2c-sh_mobile.c b/drivers/i2c/busses/i2c-sh_mobile.c
index 840e634fa31f..640cbb237328 100644
--- a/drivers/i2c/busses/i2c-sh_mobile.c
+++ b/drivers/i2c/busses/i2c-sh_mobile.c
@@ -31,13 +31,84 @@
31#include <linux/clk.h> 31#include <linux/clk.h>
32#include <linux/io.h> 32#include <linux/io.h>
33 33
34/* Transmit operation: */
35/* */
36/* 0 byte transmit */
37/* BUS: S A8 ACK P */
38/* IRQ: DTE WAIT */
39/* ICIC: */
40/* ICCR: 0x94 0x90 */
41/* ICDR: A8 */
42/* */
43/* 1 byte transmit */
44/* BUS: S A8 ACK D8(1) ACK P */
45/* IRQ: DTE WAIT WAIT */
46/* ICIC: -DTE */
47/* ICCR: 0x94 0x90 */
48/* ICDR: A8 D8(1) */
49/* */
50/* 2 byte transmit */
51/* BUS: S A8 ACK D8(1) ACK D8(2) ACK P */
52/* IRQ: DTE WAIT WAIT WAIT */
53/* ICIC: -DTE */
54/* ICCR: 0x94 0x90 */
55/* ICDR: A8 D8(1) D8(2) */
56/* */
57/* 3 bytes or more, +---------+ gets repeated */
58/* */
59/* */
60/* Receive operation: */
61/* */
62/* 0 byte receive - not supported since slave may hold SDA low */
63/* */
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) */
70/* */
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) */
77/* */
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) */
84/* */
85/* 4 bytes or more, this part is repeated +---------+ */
86/* */
87/* */
88/* Interrupt order and BUSY flag */
89/* ___ _ */
90/* SDA ___\___XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXAAAAAAAAA___/ */
91/* SCL \_/1\_/2\_/3\_/4\_/5\_/6\_/7\_/8\___/9\_____/ */
92/* */
93/* S D7 D6 D5 D4 D3 D2 D1 D0 P */
94/* ___ */
95/* WAIT IRQ ________________________________/ \___________ */
96/* TACK IRQ ____________________________________/ \_______ */
97/* DTE IRQ __________________________________________/ \_ */
98/* AL IRQ XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX */
99/* _______________________________________________ */
100/* BUSY __/ \_ */
101/* */
102
34enum sh_mobile_i2c_op { 103enum sh_mobile_i2c_op {
35 OP_START = 0, 104 OP_START = 0,
36 OP_TX_ONLY, 105 OP_TX_FIRST,
106 OP_TX,
37 OP_TX_STOP, 107 OP_TX_STOP,
38 OP_TX_TO_RX, 108 OP_TX_TO_RX,
39 OP_RX_ONLY, 109 OP_RX,
40 OP_RX_STOP, 110 OP_RX_STOP,
111 OP_RX_STOP_DATA,
41}; 112};
42 113
43struct sh_mobile_i2c_data { 114struct sh_mobile_i2c_data {
@@ -127,25 +198,34 @@ static unsigned char i2c_op(struct sh_mobile_i2c_data *pd,
127 spin_lock_irqsave(&pd->lock, flags); 198 spin_lock_irqsave(&pd->lock, flags);
128 199
129 switch (op) { 200 switch (op) {
130 case OP_START: 201 case OP_START: /* issue start and trigger DTE interrupt */
131 iowrite8(0x94, ICCR(pd)); 202 iowrite8(0x94, ICCR(pd));
132 break; 203 break;
133 case OP_TX_ONLY: 204 case OP_TX_FIRST: /* disable DTE interrupt and write data */
205 iowrite8(ICIC_WAITE | ICIC_ALE | ICIC_TACKE, ICIC(pd));
134 iowrite8(data, ICDR(pd)); 206 iowrite8(data, ICDR(pd));
135 break; 207 break;
136 case OP_TX_STOP: 208 case OP_TX: /* write data */
137 iowrite8(data, ICDR(pd)); 209 iowrite8(data, ICDR(pd));
138 iowrite8(0x90, ICCR(pd));
139 iowrite8(ICIC_ALE | ICIC_TACKE, ICIC(pd));
140 break; 210 break;
141 case OP_TX_TO_RX: 211 case OP_TX_STOP: /* write data and issue a stop afterwards */
142 iowrite8(data, ICDR(pd)); 212 iowrite8(data, ICDR(pd));
213 iowrite8(0x90, ICCR(pd));
214 break;
215 case OP_TX_TO_RX: /* select read mode */
143 iowrite8(0x81, ICCR(pd)); 216 iowrite8(0x81, ICCR(pd));
144 break; 217 break;
145 case OP_RX_ONLY: 218 case OP_RX: /* just read data */
146 ret = ioread8(ICDR(pd)); 219 ret = ioread8(ICDR(pd));
147 break; 220 break;
148 case OP_RX_STOP: 221 case OP_RX_STOP: /* enable DTE interrupt, issue stop */
222 iowrite8(ICIC_DTEE | ICIC_WAITE | ICIC_ALE | ICIC_TACKE,
223 ICIC(pd));
224 iowrite8(0xc0, ICCR(pd));
225 break;
226 case OP_RX_STOP_DATA: /* enable DTE interrupt, read data, issue stop */
227 iowrite8(ICIC_DTEE | ICIC_WAITE | ICIC_ALE | ICIC_TACKE,
228 ICIC(pd));
149 ret = ioread8(ICDR(pd)); 229 ret = ioread8(ICDR(pd));
150 iowrite8(0xc0, ICCR(pd)); 230 iowrite8(0xc0, ICCR(pd));
151 break; 231 break;
@@ -157,58 +237,120 @@ static unsigned char i2c_op(struct sh_mobile_i2c_data *pd,
157 return ret; 237 return ret;
158} 238}
159 239
240static int sh_mobile_i2c_is_first_byte(struct sh_mobile_i2c_data *pd)
241{
242 if (pd->pos == -1)
243 return 1;
244
245 return 0;
246}
247
248static int sh_mobile_i2c_is_last_byte(struct sh_mobile_i2c_data *pd)
249{
250 if (pd->pos == (pd->msg->len - 1))
251 return 1;
252
253 return 0;
254}
255
256static void sh_mobile_i2c_get_data(struct sh_mobile_i2c_data *pd,
257 unsigned char *buf)
258{
259 switch (pd->pos) {
260 case -1:
261 *buf = (pd->msg->addr & 0x7f) << 1;
262 *buf |= (pd->msg->flags & I2C_M_RD) ? 1 : 0;
263 break;
264 default:
265 *buf = pd->msg->buf[pd->pos];
266 }
267}
268
269static int sh_mobile_i2c_isr_tx(struct sh_mobile_i2c_data *pd)
270{
271 unsigned char data;
272
273 if (pd->pos == pd->msg->len)
274 return 1;
275
276 sh_mobile_i2c_get_data(pd, &data);
277
278 if (sh_mobile_i2c_is_last_byte(pd))
279 i2c_op(pd, OP_TX_STOP, data);
280 else if (sh_mobile_i2c_is_first_byte(pd))
281 i2c_op(pd, OP_TX_FIRST, data);
282 else
283 i2c_op(pd, OP_TX, data);
284
285 pd->pos++;
286 return 0;
287}
288
289static int sh_mobile_i2c_isr_rx(struct sh_mobile_i2c_data *pd)
290{
291 unsigned char data;
292 int real_pos;
293
294 do {
295 if (pd->pos <= -1) {
296 sh_mobile_i2c_get_data(pd, &data);
297
298 if (sh_mobile_i2c_is_first_byte(pd))
299 i2c_op(pd, OP_TX_FIRST, data);
300 else
301 i2c_op(pd, OP_TX, data);
302 break;
303 }
304
305 if (pd->pos == 0) {
306 i2c_op(pd, OP_TX_TO_RX, 0);
307 break;
308 }
309
310 real_pos = pd->pos - 2;
311
312 if (pd->pos == pd->msg->len) {
313 if (real_pos < 0) {
314 i2c_op(pd, OP_RX_STOP, 0);
315 break;
316 }
317 data = i2c_op(pd, OP_RX_STOP_DATA, 0);
318 } else
319 data = i2c_op(pd, OP_RX, 0);
320
321 pd->msg->buf[real_pos] = data;
322 } while (0);
323
324 pd->pos++;
325 return pd->pos == (pd->msg->len + 2);
326}
327
160static irqreturn_t sh_mobile_i2c_isr(int irq, void *dev_id) 328static irqreturn_t sh_mobile_i2c_isr(int irq, void *dev_id)
161{ 329{
162 struct platform_device *dev = dev_id; 330 struct platform_device *dev = dev_id;
163 struct sh_mobile_i2c_data *pd = platform_get_drvdata(dev); 331 struct sh_mobile_i2c_data *pd = platform_get_drvdata(dev);
164 struct i2c_msg *msg = pd->msg; 332 unsigned char sr;
165 unsigned char data, sr; 333 int wakeup;
166 int wakeup = 0;
167 334
168 sr = ioread8(ICSR(pd)); 335 sr = ioread8(ICSR(pd));
169 pd->sr |= sr; 336 pd->sr |= sr; /* remember state */
170 337
171 dev_dbg(pd->dev, "i2c_isr 0x%02x 0x%02x %s %d %d!\n", sr, pd->sr, 338 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", 339 (pd->msg->flags & I2C_M_RD) ? "read" : "write",
173 pd->pos, msg->len); 340 pd->pos, pd->msg->len);
174 341
175 if (sr & (ICSR_AL | ICSR_TACK)) { 342 if (sr & (ICSR_AL | ICSR_TACK)) {
176 iowrite8(0, ICIC(pd)); /* disable interrupts */ 343 /* don't interrupt transaction - continue to issue stop */
177 wakeup = 1; 344 iowrite8(sr & ~(ICSR_AL | ICSR_TACK), ICSR(pd));
178 goto do_wakeup; 345 wakeup = 0;
179 } 346 } else if (pd->msg->flags & I2C_M_RD)
347 wakeup = sh_mobile_i2c_isr_rx(pd);
348 else
349 wakeup = sh_mobile_i2c_isr_tx(pd);
180 350
181 if (pd->pos == msg->len) { 351 if (sr & ICSR_WAIT) /* TODO: add delay here to support slow acks */
182 i2c_op(pd, OP_RX_ONLY, 0); 352 iowrite8(sr & ~ICSR_WAIT, ICSR(pd));
183 wakeup = 1;
184 goto do_wakeup;
185 }
186 353
187 if (pd->pos == -1) {
188 data = (msg->addr & 0x7f) << 1;
189 data |= (msg->flags & I2C_M_RD) ? 1 : 0;
190 } else
191 data = msg->buf[pd->pos];
192
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);
198 wakeup = 1;
199 } else
200 i2c_op(pd, OP_TX_ONLY, data);
201 } else {
202 if (pd->pos == (msg->len - 1))
203 data = i2c_op(pd, OP_RX_STOP, 0);
204 else
205 data = i2c_op(pd, OP_RX_ONLY, 0);
206
207 msg->buf[pd->pos] = data;
208 }
209 pd->pos++;
210
211 do_wakeup:
212 if (wakeup) { 354 if (wakeup) {
213 pd->sr |= SW_DONE; 355 pd->sr |= SW_DONE;
214 wake_up(&pd->wait); 356 wake_up(&pd->wait);
@@ -219,6 +361,11 @@ static irqreturn_t sh_mobile_i2c_isr(int irq, void *dev_id)
219 361
220static int start_ch(struct sh_mobile_i2c_data *pd, struct i2c_msg *usr_msg) 362static int start_ch(struct sh_mobile_i2c_data *pd, struct i2c_msg *usr_msg)
221{ 363{
364 if (usr_msg->len == 0 && (usr_msg->flags & I2C_M_RD)) {
365 dev_err(pd->dev, "Unsupported zero length i2c read\n");
366 return -EIO;
367 }
368
222 /* Initialize channel registers */ 369 /* Initialize channel registers */
223 iowrite8(ioread8(ICCR(pd)) & ~ICCR_ICE, ICCR(pd)); 370 iowrite8(ioread8(ICCR(pd)) & ~ICCR_ICE, ICCR(pd));
224 371
@@ -233,9 +380,8 @@ static int start_ch(struct sh_mobile_i2c_data *pd, struct i2c_msg *usr_msg)
233 pd->pos = -1; 380 pd->pos = -1;
234 pd->sr = 0; 381 pd->sr = 0;
235 382
236 /* Enable all interrupts except wait */ 383 /* Enable all interrupts to begin with */
237 iowrite8(ioread8(ICIC(pd)) | ICIC_ALE | ICIC_TACKE | ICIC_DTEE, 384 iowrite8(ICIC_WAITE | ICIC_ALE | ICIC_TACKE | ICIC_DTEE, ICIC(pd));
238 ICIC(pd));
239 return 0; 385 return 0;
240} 386}
241 387
@@ -268,25 +414,18 @@ static int sh_mobile_i2c_xfer(struct i2c_adapter *adapter,
268 if (!k) 414 if (!k)
269 dev_err(pd->dev, "Transfer request timed out\n"); 415 dev_err(pd->dev, "Transfer request timed out\n");
270 416
271 retry_count = 10; 417 retry_count = 1000;
272again: 418again:
273 val = ioread8(ICSR(pd)); 419 val = ioread8(ICSR(pd));
274 420
275 dev_dbg(pd->dev, "val 0x%02x pd->sr 0x%02x\n", val, pd->sr); 421 dev_dbg(pd->dev, "val 0x%02x pd->sr 0x%02x\n", val, pd->sr);
276 422
277 if ((val | pd->sr) & (ICSR_TACK | ICSR_AL)) {
278 err = -EIO;
279 break;
280 }
281
282 /* the interrupt handler may wake us up before the 423 /* the interrupt handler may wake us up before the
283 * transfer is finished, so poll the hardware 424 * transfer is finished, so poll the hardware
284 * until we're done. 425 * until we're done.
285 */ 426 */
286 427 if (val & ICSR_BUSY) {
287 if (!(!(val & ICSR_BUSY) && (val & ICSR_SCLM) && 428 udelay(10);
288 (val & ICSR_SDAM))) {
289 msleep(1);
290 if (retry_count--) 429 if (retry_count--)
291 goto again; 430 goto again;
292 431
@@ -294,6 +433,12 @@ again:
294 dev_err(pd->dev, "Polling timed out\n"); 433 dev_err(pd->dev, "Polling timed out\n");
295 break; 434 break;
296 } 435 }
436
437 /* handle missing acknowledge and arbitration lost */
438 if ((val | pd->sr) & (ICSR_TACK | ICSR_AL)) {
439 err = -EIO;
440 break;
441 }
297 } 442 }
298 443
299 deactivate_ch(pd); 444 deactivate_ch(pd);
generated by cgit v1.2.2 (git 2.25.0) at 2025-12-26 21:00:05 -0500