1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * i2c-xiic.c
4 * Copyright (c) 2002-2007 Xilinx Inc.
5 * Copyright (c) 2009-2010 Intel Corporation
6 *
7 * This code was implemented by Mocean Laboratories AB when porting linux
8 * to the automotive development board Russellville. The copyright holder
9 * as seen in the header is Intel corporation.
10 * Mocean Laboratories forked off the GNU/Linux platform work into a
11 * separate company called Pelagicore AB, which committed the code to the
12 * kernel.
13 */
14
15 /* Supports:
16 * Xilinx IIC
17 */
18 #include <linux/kernel.h>
19 #include <linux/module.h>
20 #include <linux/errno.h>
21 #include <linux/err.h>
22 #include <linux/delay.h>
23 #include <linux/platform_device.h>
24 #include <linux/i2c.h>
25 #include <linux/interrupt.h>
26 #include <linux/wait.h>
27 #include <linux/platform_data/i2c-xiic.h>
28 #include <linux/io.h>
29 #include <linux/slab.h>
30 #include <linux/of.h>
31 #include <linux/clk.h>
32 #include <linux/pm_runtime.h>
33
34 #define DRIVER_NAME "xiic-i2c"
35
36 enum xilinx_i2c_state {
37 STATE_DONE,
38 STATE_ERROR,
39 STATE_START
40 };
41
42 enum xiic_endian {
43 LITTLE,
44 BIG
45 };
46
47 /**
48 * struct xiic_i2c - Internal representation of the XIIC I2C bus
49 * @base: Memory base of the HW registers
50 * @wait: Wait queue for callers
51 * @adap: Kernel adapter representation
52 * @tx_msg: Messages from above to be sent
53 * @lock: Mutual exclusion
54 * @tx_pos: Current pos in TX message
55 * @nmsgs: Number of messages in tx_msg
56 * @state: See STATE_
57 * @rx_msg: Current RX message
58 * @rx_pos: Position within current RX message
59 * @endianness: big/little-endian byte order
60 */
61 struct xiic_i2c {
62 struct device *dev;
63 void __iomem *base;
64 wait_queue_head_t wait;
65 struct i2c_adapter adap;
66 struct i2c_msg *tx_msg;
67 struct mutex lock;
68 unsigned int tx_pos;
69 unsigned int nmsgs;
70 enum xilinx_i2c_state state;
71 struct i2c_msg *rx_msg;
72 int rx_pos;
73 enum xiic_endian endianness;
74 struct clk *clk;
75 };
76
77
78 #define XIIC_MSB_OFFSET 0
79 #define XIIC_REG_OFFSET (0x100+XIIC_MSB_OFFSET)
80
81 /*
82 * Register offsets in bytes from RegisterBase. Three is added to the
83 * base offset to access LSB (IBM style) of the word
84 */
85 #define XIIC_CR_REG_OFFSET (0x00+XIIC_REG_OFFSET) /* Control Register */
86 #define XIIC_SR_REG_OFFSET (0x04+XIIC_REG_OFFSET) /* Status Register */
87 #define XIIC_DTR_REG_OFFSET (0x08+XIIC_REG_OFFSET) /* Data Tx Register */
88 #define XIIC_DRR_REG_OFFSET (0x0C+XIIC_REG_OFFSET) /* Data Rx Register */
89 #define XIIC_ADR_REG_OFFSET (0x10+XIIC_REG_OFFSET) /* Address Register */
90 #define XIIC_TFO_REG_OFFSET (0x14+XIIC_REG_OFFSET) /* Tx FIFO Occupancy */
91 #define XIIC_RFO_REG_OFFSET (0x18+XIIC_REG_OFFSET) /* Rx FIFO Occupancy */
92 #define XIIC_TBA_REG_OFFSET (0x1C+XIIC_REG_OFFSET) /* 10 Bit Address reg */
93 #define XIIC_RFD_REG_OFFSET (0x20+XIIC_REG_OFFSET) /* Rx FIFO Depth reg */
94 #define XIIC_GPO_REG_OFFSET (0x24+XIIC_REG_OFFSET) /* Output Register */
95
96 /* Control Register masks */
97 #define XIIC_CR_ENABLE_DEVICE_MASK 0x01 /* Device enable = 1 */
98 #define XIIC_CR_TX_FIFO_RESET_MASK 0x02 /* Transmit FIFO reset=1 */
99 #define XIIC_CR_MSMS_MASK 0x04 /* Master starts Txing=1 */
100 #define XIIC_CR_DIR_IS_TX_MASK 0x08 /* Dir of tx. Txing=1 */
101 #define XIIC_CR_NO_ACK_MASK 0x10 /* Tx Ack. NO ack = 1 */
102 #define XIIC_CR_REPEATED_START_MASK 0x20 /* Repeated start = 1 */
103 #define XIIC_CR_GENERAL_CALL_MASK 0x40 /* Gen Call enabled = 1 */
104
105 /* Status Register masks */
106 #define XIIC_SR_GEN_CALL_MASK 0x01 /* 1=a mstr issued a GC */
107 #define XIIC_SR_ADDR_AS_SLAVE_MASK 0x02 /* 1=when addr as slave */
108 #define XIIC_SR_BUS_BUSY_MASK 0x04 /* 1 = bus is busy */
109 #define XIIC_SR_MSTR_RDING_SLAVE_MASK 0x08 /* 1=Dir: mstr <-- slave */
110 #define XIIC_SR_TX_FIFO_FULL_MASK 0x10 /* 1 = Tx FIFO full */
111 #define XIIC_SR_RX_FIFO_FULL_MASK 0x20 /* 1 = Rx FIFO full */
112 #define XIIC_SR_RX_FIFO_EMPTY_MASK 0x40 /* 1 = Rx FIFO empty */
113 #define XIIC_SR_TX_FIFO_EMPTY_MASK 0x80 /* 1 = Tx FIFO empty */
114
115 /* Interrupt Status Register masks Interrupt occurs when... */
116 #define XIIC_INTR_ARB_LOST_MASK 0x01 /* 1 = arbitration lost */
117 #define XIIC_INTR_TX_ERROR_MASK 0x02 /* 1=Tx error/msg complete */
118 #define XIIC_INTR_TX_EMPTY_MASK 0x04 /* 1 = Tx FIFO/reg empty */
119 #define XIIC_INTR_RX_FULL_MASK 0x08 /* 1=Rx FIFO/reg=OCY level */
120 #define XIIC_INTR_BNB_MASK 0x10 /* 1 = Bus not busy */
121 #define XIIC_INTR_AAS_MASK 0x20 /* 1 = when addr as slave */
122 #define XIIC_INTR_NAAS_MASK 0x40 /* 1 = not addr as slave */
123 #define XIIC_INTR_TX_HALF_MASK 0x80 /* 1 = TX FIFO half empty */
124
125 /* The following constants specify the depth of the FIFOs */
126 #define IIC_RX_FIFO_DEPTH 16 /* Rx fifo capacity */
127 #define IIC_TX_FIFO_DEPTH 16 /* Tx fifo capacity */
128
129 /* The following constants specify groups of interrupts that are typically
130 * enabled or disables at the same time
131 */
132 #define XIIC_TX_INTERRUPTS \
133 (XIIC_INTR_TX_ERROR_MASK | XIIC_INTR_TX_EMPTY_MASK | XIIC_INTR_TX_HALF_MASK)
134
135 #define XIIC_TX_RX_INTERRUPTS (XIIC_INTR_RX_FULL_MASK | XIIC_TX_INTERRUPTS)
136
137 /*
138 * Tx Fifo upper bit masks.
139 */
140 #define XIIC_TX_DYN_START_MASK 0x0100 /* 1 = Set dynamic start */
141 #define XIIC_TX_DYN_STOP_MASK 0x0200 /* 1 = Set dynamic stop */
142
143 /*
144 * The following constants define the register offsets for the Interrupt
145 * registers. There are some holes in the memory map for reserved addresses
146 * to allow other registers to be added and still match the memory map of the
147 * interrupt controller registers
148 */
149 #define XIIC_DGIER_OFFSET 0x1C /* Device Global Interrupt Enable Register */
150 #define XIIC_IISR_OFFSET 0x20 /* Interrupt Status Register */
151 #define XIIC_IIER_OFFSET 0x28 /* Interrupt Enable Register */
152 #define XIIC_RESETR_OFFSET 0x40 /* Reset Register */
153
154 #define XIIC_RESET_MASK 0xAUL
155
156 #define XIIC_PM_TIMEOUT 1000 /* ms */
157 /*
158 * The following constant is used for the device global interrupt enable
159 * register, to enable all interrupts for the device, this is the only bit
160 * in the register
161 */
162 #define XIIC_GINTR_ENABLE_MASK 0x80000000UL
163
164 #define xiic_tx_space(i2c) ((i2c)->tx_msg->len - (i2c)->tx_pos)
165 #define xiic_rx_space(i2c) ((i2c)->rx_msg->len - (i2c)->rx_pos)
166
167 static void xiic_start_xfer(struct xiic_i2c *i2c);
168 static void __xiic_start_xfer(struct xiic_i2c *i2c);
169
170 /*
171 * For the register read and write functions, a little-endian and big-endian
172 * version are necessary. Endianness is detected during the probe function.
173 * Only the least significant byte [doublet] of the register are ever
174 * accessed. This requires an offset of 3 [2] from the base address for
175 * big-endian systems.
176 */
177
xiic_setreg8(struct xiic_i2c * i2c,int reg,u8 value)178 static inline void xiic_setreg8(struct xiic_i2c *i2c, int reg, u8 value)
179 {
180 if (i2c->endianness == LITTLE)
181 iowrite8(value, i2c->base + reg);
182 else
183 iowrite8(value, i2c->base + reg + 3);
184 }
185
xiic_getreg8(struct xiic_i2c * i2c,int reg)186 static inline u8 xiic_getreg8(struct xiic_i2c *i2c, int reg)
187 {
188 u8 ret;
189
190 if (i2c->endianness == LITTLE)
191 ret = ioread8(i2c->base + reg);
192 else
193 ret = ioread8(i2c->base + reg + 3);
194 return ret;
195 }
196
xiic_setreg16(struct xiic_i2c * i2c,int reg,u16 value)197 static inline void xiic_setreg16(struct xiic_i2c *i2c, int reg, u16 value)
198 {
199 if (i2c->endianness == LITTLE)
200 iowrite16(value, i2c->base + reg);
201 else
202 iowrite16be(value, i2c->base + reg + 2);
203 }
204
xiic_setreg32(struct xiic_i2c * i2c,int reg,int value)205 static inline void xiic_setreg32(struct xiic_i2c *i2c, int reg, int value)
206 {
207 if (i2c->endianness == LITTLE)
208 iowrite32(value, i2c->base + reg);
209 else
210 iowrite32be(value, i2c->base + reg);
211 }
212
xiic_getreg32(struct xiic_i2c * i2c,int reg)213 static inline int xiic_getreg32(struct xiic_i2c *i2c, int reg)
214 {
215 u32 ret;
216
217 if (i2c->endianness == LITTLE)
218 ret = ioread32(i2c->base + reg);
219 else
220 ret = ioread32be(i2c->base + reg);
221 return ret;
222 }
223
xiic_irq_dis(struct xiic_i2c * i2c,u32 mask)224 static inline void xiic_irq_dis(struct xiic_i2c *i2c, u32 mask)
225 {
226 u32 ier = xiic_getreg32(i2c, XIIC_IIER_OFFSET);
227 xiic_setreg32(i2c, XIIC_IIER_OFFSET, ier & ~mask);
228 }
229
xiic_irq_en(struct xiic_i2c * i2c,u32 mask)230 static inline void xiic_irq_en(struct xiic_i2c *i2c, u32 mask)
231 {
232 u32 ier = xiic_getreg32(i2c, XIIC_IIER_OFFSET);
233 xiic_setreg32(i2c, XIIC_IIER_OFFSET, ier | mask);
234 }
235
xiic_irq_clr(struct xiic_i2c * i2c,u32 mask)236 static inline void xiic_irq_clr(struct xiic_i2c *i2c, u32 mask)
237 {
238 u32 isr = xiic_getreg32(i2c, XIIC_IISR_OFFSET);
239 xiic_setreg32(i2c, XIIC_IISR_OFFSET, isr & mask);
240 }
241
xiic_irq_clr_en(struct xiic_i2c * i2c,u32 mask)242 static inline void xiic_irq_clr_en(struct xiic_i2c *i2c, u32 mask)
243 {
244 xiic_irq_clr(i2c, mask);
245 xiic_irq_en(i2c, mask);
246 }
247
xiic_clear_rx_fifo(struct xiic_i2c * i2c)248 static void xiic_clear_rx_fifo(struct xiic_i2c *i2c)
249 {
250 u8 sr;
251 for (sr = xiic_getreg8(i2c, XIIC_SR_REG_OFFSET);
252 !(sr & XIIC_SR_RX_FIFO_EMPTY_MASK);
253 sr = xiic_getreg8(i2c, XIIC_SR_REG_OFFSET))
254 xiic_getreg8(i2c, XIIC_DRR_REG_OFFSET);
255 }
256
xiic_reinit(struct xiic_i2c * i2c)257 static void xiic_reinit(struct xiic_i2c *i2c)
258 {
259 xiic_setreg32(i2c, XIIC_RESETR_OFFSET, XIIC_RESET_MASK);
260
261 /* Set receive Fifo depth to maximum (zero based). */
262 xiic_setreg8(i2c, XIIC_RFD_REG_OFFSET, IIC_RX_FIFO_DEPTH - 1);
263
264 /* Reset Tx Fifo. */
265 xiic_setreg8(i2c, XIIC_CR_REG_OFFSET, XIIC_CR_TX_FIFO_RESET_MASK);
266
267 /* Enable IIC Device, remove Tx Fifo reset & disable general call. */
268 xiic_setreg8(i2c, XIIC_CR_REG_OFFSET, XIIC_CR_ENABLE_DEVICE_MASK);
269
270 /* make sure RX fifo is empty */
271 xiic_clear_rx_fifo(i2c);
272
273 /* Enable interrupts */
274 xiic_setreg32(i2c, XIIC_DGIER_OFFSET, XIIC_GINTR_ENABLE_MASK);
275
276 xiic_irq_clr_en(i2c, XIIC_INTR_ARB_LOST_MASK);
277 }
278
xiic_deinit(struct xiic_i2c * i2c)279 static void xiic_deinit(struct xiic_i2c *i2c)
280 {
281 u8 cr;
282
283 xiic_setreg32(i2c, XIIC_RESETR_OFFSET, XIIC_RESET_MASK);
284
285 /* Disable IIC Device. */
286 cr = xiic_getreg8(i2c, XIIC_CR_REG_OFFSET);
287 xiic_setreg8(i2c, XIIC_CR_REG_OFFSET, cr & ~XIIC_CR_ENABLE_DEVICE_MASK);
288 }
289
xiic_read_rx(struct xiic_i2c * i2c)290 static void xiic_read_rx(struct xiic_i2c *i2c)
291 {
292 u8 bytes_in_fifo;
293 int i;
294
295 bytes_in_fifo = xiic_getreg8(i2c, XIIC_RFO_REG_OFFSET) + 1;
296
297 dev_dbg(i2c->adap.dev.parent,
298 "%s entry, bytes in fifo: %d, msg: %d, SR: 0x%x, CR: 0x%x\n",
299 __func__, bytes_in_fifo, xiic_rx_space(i2c),
300 xiic_getreg8(i2c, XIIC_SR_REG_OFFSET),
301 xiic_getreg8(i2c, XIIC_CR_REG_OFFSET));
302
303 if (bytes_in_fifo > xiic_rx_space(i2c))
304 bytes_in_fifo = xiic_rx_space(i2c);
305
306 for (i = 0; i < bytes_in_fifo; i++)
307 i2c->rx_msg->buf[i2c->rx_pos++] =
308 xiic_getreg8(i2c, XIIC_DRR_REG_OFFSET);
309
310 xiic_setreg8(i2c, XIIC_RFD_REG_OFFSET,
311 (xiic_rx_space(i2c) > IIC_RX_FIFO_DEPTH) ?
312 IIC_RX_FIFO_DEPTH - 1 : xiic_rx_space(i2c) - 1);
313 }
314
xiic_tx_fifo_space(struct xiic_i2c * i2c)315 static int xiic_tx_fifo_space(struct xiic_i2c *i2c)
316 {
317 /* return the actual space left in the FIFO */
318 return IIC_TX_FIFO_DEPTH - xiic_getreg8(i2c, XIIC_TFO_REG_OFFSET) - 1;
319 }
320
xiic_fill_tx_fifo(struct xiic_i2c * i2c)321 static void xiic_fill_tx_fifo(struct xiic_i2c *i2c)
322 {
323 u8 fifo_space = xiic_tx_fifo_space(i2c);
324 int len = xiic_tx_space(i2c);
325
326 len = (len > fifo_space) ? fifo_space : len;
327
328 dev_dbg(i2c->adap.dev.parent, "%s entry, len: %d, fifo space: %d\n",
329 __func__, len, fifo_space);
330
331 while (len--) {
332 u16 data = i2c->tx_msg->buf[i2c->tx_pos++];
333 if ((xiic_tx_space(i2c) == 0) && (i2c->nmsgs == 1)) {
334 /* last message in transfer -> STOP */
335 data |= XIIC_TX_DYN_STOP_MASK;
336 dev_dbg(i2c->adap.dev.parent, "%s TX STOP\n", __func__);
337 }
338 xiic_setreg16(i2c, XIIC_DTR_REG_OFFSET, data);
339 }
340 }
341
xiic_wakeup(struct xiic_i2c * i2c,int code)342 static void xiic_wakeup(struct xiic_i2c *i2c, int code)
343 {
344 i2c->tx_msg = NULL;
345 i2c->rx_msg = NULL;
346 i2c->nmsgs = 0;
347 i2c->state = code;
348 wake_up(&i2c->wait);
349 }
350
xiic_process(int irq,void * dev_id)351 static irqreturn_t xiic_process(int irq, void *dev_id)
352 {
353 struct xiic_i2c *i2c = dev_id;
354 u32 pend, isr, ier;
355 u32 clr = 0;
356
357 /* Get the interrupt Status from the IPIF. There is no clearing of
358 * interrupts in the IPIF. Interrupts must be cleared at the source.
359 * To find which interrupts are pending; AND interrupts pending with
360 * interrupts masked.
361 */
362 mutex_lock(&i2c->lock);
363 isr = xiic_getreg32(i2c, XIIC_IISR_OFFSET);
364 ier = xiic_getreg32(i2c, XIIC_IIER_OFFSET);
365 pend = isr & ier;
366
367 dev_dbg(i2c->adap.dev.parent, "%s: IER: 0x%x, ISR: 0x%x, pend: 0x%x\n",
368 __func__, ier, isr, pend);
369 dev_dbg(i2c->adap.dev.parent, "%s: SR: 0x%x, msg: %p, nmsgs: %d\n",
370 __func__, xiic_getreg8(i2c, XIIC_SR_REG_OFFSET),
371 i2c->tx_msg, i2c->nmsgs);
372
373
374 /* Service requesting interrupt */
375 if ((pend & XIIC_INTR_ARB_LOST_MASK) ||
376 ((pend & XIIC_INTR_TX_ERROR_MASK) &&
377 !(pend & XIIC_INTR_RX_FULL_MASK))) {
378 /* bus arbritration lost, or...
379 * Transmit error _OR_ RX completed
380 * if this happens when RX_FULL is not set
381 * this is probably a TX error
382 */
383
384 dev_dbg(i2c->adap.dev.parent, "%s error\n", __func__);
385
386 /* dynamic mode seem to suffer from problems if we just flushes
387 * fifos and the next message is a TX with len 0 (only addr)
388 * reset the IP instead of just flush fifos
389 */
390 xiic_reinit(i2c);
391
392 if (i2c->rx_msg)
393 xiic_wakeup(i2c, STATE_ERROR);
394 if (i2c->tx_msg)
395 xiic_wakeup(i2c, STATE_ERROR);
396 }
397 if (pend & XIIC_INTR_RX_FULL_MASK) {
398 /* Receive register/FIFO is full */
399
400 clr |= XIIC_INTR_RX_FULL_MASK;
401 if (!i2c->rx_msg) {
402 dev_dbg(i2c->adap.dev.parent,
403 "%s unexpected RX IRQ\n", __func__);
404 xiic_clear_rx_fifo(i2c);
405 goto out;
406 }
407
408 xiic_read_rx(i2c);
409 if (xiic_rx_space(i2c) == 0) {
410 /* this is the last part of the message */
411 i2c->rx_msg = NULL;
412
413 /* also clear TX error if there (RX complete) */
414 clr |= (isr & XIIC_INTR_TX_ERROR_MASK);
415
416 dev_dbg(i2c->adap.dev.parent,
417 "%s end of message, nmsgs: %d\n",
418 __func__, i2c->nmsgs);
419
420 /* send next message if this wasn't the last,
421 * otherwise the transfer will be finialise when
422 * receiving the bus not busy interrupt
423 */
424 if (i2c->nmsgs > 1) {
425 i2c->nmsgs--;
426 i2c->tx_msg++;
427 dev_dbg(i2c->adap.dev.parent,
428 "%s will start next...\n", __func__);
429
430 __xiic_start_xfer(i2c);
431 }
432 }
433 }
434 if (pend & XIIC_INTR_BNB_MASK) {
435 /* IIC bus has transitioned to not busy */
436 clr |= XIIC_INTR_BNB_MASK;
437
438 /* The bus is not busy, disable BusNotBusy interrupt */
439 xiic_irq_dis(i2c, XIIC_INTR_BNB_MASK);
440
441 if (!i2c->tx_msg)
442 goto out;
443
444 if ((i2c->nmsgs == 1) && !i2c->rx_msg &&
445 xiic_tx_space(i2c) == 0)
446 xiic_wakeup(i2c, STATE_DONE);
447 else
448 xiic_wakeup(i2c, STATE_ERROR);
449 }
450 if (pend & (XIIC_INTR_TX_EMPTY_MASK | XIIC_INTR_TX_HALF_MASK)) {
451 /* Transmit register/FIFO is empty or ½ empty */
452
453 clr |= (pend &
454 (XIIC_INTR_TX_EMPTY_MASK | XIIC_INTR_TX_HALF_MASK));
455
456 if (!i2c->tx_msg) {
457 dev_dbg(i2c->adap.dev.parent,
458 "%s unexpected TX IRQ\n", __func__);
459 goto out;
460 }
461
462 xiic_fill_tx_fifo(i2c);
463
464 /* current message sent and there is space in the fifo */
465 if (!xiic_tx_space(i2c) && xiic_tx_fifo_space(i2c) >= 2) {
466 dev_dbg(i2c->adap.dev.parent,
467 "%s end of message sent, nmsgs: %d\n",
468 __func__, i2c->nmsgs);
469 if (i2c->nmsgs > 1) {
470 i2c->nmsgs--;
471 i2c->tx_msg++;
472 __xiic_start_xfer(i2c);
473 } else {
474 xiic_irq_dis(i2c, XIIC_INTR_TX_HALF_MASK);
475
476 dev_dbg(i2c->adap.dev.parent,
477 "%s Got TX IRQ but no more to do...\n",
478 __func__);
479 }
480 } else if (!xiic_tx_space(i2c) && (i2c->nmsgs == 1))
481 /* current frame is sent and is last,
482 * make sure to disable tx half
483 */
484 xiic_irq_dis(i2c, XIIC_INTR_TX_HALF_MASK);
485 }
486 out:
487 dev_dbg(i2c->adap.dev.parent, "%s clr: 0x%x\n", __func__, clr);
488
489 xiic_setreg32(i2c, XIIC_IISR_OFFSET, clr);
490 mutex_unlock(&i2c->lock);
491 return IRQ_HANDLED;
492 }
493
xiic_bus_busy(struct xiic_i2c * i2c)494 static int xiic_bus_busy(struct xiic_i2c *i2c)
495 {
496 u8 sr = xiic_getreg8(i2c, XIIC_SR_REG_OFFSET);
497
498 return (sr & XIIC_SR_BUS_BUSY_MASK) ? -EBUSY : 0;
499 }
500
xiic_busy(struct xiic_i2c * i2c)501 static int xiic_busy(struct xiic_i2c *i2c)
502 {
503 int tries = 3;
504 int err;
505
506 if (i2c->tx_msg)
507 return -EBUSY;
508
509 /* for instance if previous transfer was terminated due to TX error
510 * it might be that the bus is on it's way to become available
511 * give it at most 3 ms to wake
512 */
513 err = xiic_bus_busy(i2c);
514 while (err && tries--) {
515 msleep(1);
516 err = xiic_bus_busy(i2c);
517 }
518
519 return err;
520 }
521
xiic_start_recv(struct xiic_i2c * i2c)522 static void xiic_start_recv(struct xiic_i2c *i2c)
523 {
524 u8 rx_watermark;
525 struct i2c_msg *msg = i2c->rx_msg = i2c->tx_msg;
526 unsigned long flags;
527
528 /* Clear and enable Rx full interrupt. */
529 xiic_irq_clr_en(i2c, XIIC_INTR_RX_FULL_MASK | XIIC_INTR_TX_ERROR_MASK);
530
531 /* we want to get all but last byte, because the TX_ERROR IRQ is used
532 * to inidicate error ACK on the address, and negative ack on the last
533 * received byte, so to not mix them receive all but last.
534 * In the case where there is only one byte to receive
535 * we can check if ERROR and RX full is set at the same time
536 */
537 rx_watermark = msg->len;
538 if (rx_watermark > IIC_RX_FIFO_DEPTH)
539 rx_watermark = IIC_RX_FIFO_DEPTH;
540 xiic_setreg8(i2c, XIIC_RFD_REG_OFFSET, rx_watermark - 1);
541
542 local_irq_save(flags);
543 if (!(msg->flags & I2C_M_NOSTART))
544 /* write the address */
545 xiic_setreg16(i2c, XIIC_DTR_REG_OFFSET,
546 i2c_8bit_addr_from_msg(msg) | XIIC_TX_DYN_START_MASK);
547
548 xiic_irq_clr_en(i2c, XIIC_INTR_BNB_MASK);
549
550 xiic_setreg16(i2c, XIIC_DTR_REG_OFFSET,
551 msg->len | ((i2c->nmsgs == 1) ? XIIC_TX_DYN_STOP_MASK : 0));
552 local_irq_restore(flags);
553
554 if (i2c->nmsgs == 1)
555 /* very last, enable bus not busy as well */
556 xiic_irq_clr_en(i2c, XIIC_INTR_BNB_MASK);
557
558 /* the message is tx:ed */
559 i2c->tx_pos = msg->len;
560 }
561
xiic_start_send(struct xiic_i2c * i2c)562 static void xiic_start_send(struct xiic_i2c *i2c)
563 {
564 struct i2c_msg *msg = i2c->tx_msg;
565
566 xiic_irq_clr(i2c, XIIC_INTR_TX_ERROR_MASK);
567
568 dev_dbg(i2c->adap.dev.parent, "%s entry, msg: %p, len: %d",
569 __func__, msg, msg->len);
570 dev_dbg(i2c->adap.dev.parent, "%s entry, ISR: 0x%x, CR: 0x%x\n",
571 __func__, xiic_getreg32(i2c, XIIC_IISR_OFFSET),
572 xiic_getreg8(i2c, XIIC_CR_REG_OFFSET));
573
574 if (!(msg->flags & I2C_M_NOSTART)) {
575 /* write the address */
576 u16 data = i2c_8bit_addr_from_msg(msg) |
577 XIIC_TX_DYN_START_MASK;
578 if ((i2c->nmsgs == 1) && msg->len == 0)
579 /* no data and last message -> add STOP */
580 data |= XIIC_TX_DYN_STOP_MASK;
581
582 xiic_setreg16(i2c, XIIC_DTR_REG_OFFSET, data);
583 }
584
585 xiic_fill_tx_fifo(i2c);
586
587 /* Clear any pending Tx empty, Tx Error and then enable them. */
588 xiic_irq_clr_en(i2c, XIIC_INTR_TX_EMPTY_MASK | XIIC_INTR_TX_ERROR_MASK |
589 XIIC_INTR_BNB_MASK);
590 }
591
xiic_isr(int irq,void * dev_id)592 static irqreturn_t xiic_isr(int irq, void *dev_id)
593 {
594 struct xiic_i2c *i2c = dev_id;
595 u32 pend, isr, ier;
596 irqreturn_t ret = IRQ_NONE;
597 /* Do not processes a devices interrupts if the device has no
598 * interrupts pending
599 */
600
601 dev_dbg(i2c->adap.dev.parent, "%s entry\n", __func__);
602
603 isr = xiic_getreg32(i2c, XIIC_IISR_OFFSET);
604 ier = xiic_getreg32(i2c, XIIC_IIER_OFFSET);
605 pend = isr & ier;
606 if (pend)
607 ret = IRQ_WAKE_THREAD;
608
609 return ret;
610 }
611
__xiic_start_xfer(struct xiic_i2c * i2c)612 static void __xiic_start_xfer(struct xiic_i2c *i2c)
613 {
614 int first = 1;
615 int fifo_space = xiic_tx_fifo_space(i2c);
616 dev_dbg(i2c->adap.dev.parent, "%s entry, msg: %p, fifos space: %d\n",
617 __func__, i2c->tx_msg, fifo_space);
618
619 if (!i2c->tx_msg)
620 return;
621
622 i2c->rx_pos = 0;
623 i2c->tx_pos = 0;
624 i2c->state = STATE_START;
625 while ((fifo_space >= 2) && (first || (i2c->nmsgs > 1))) {
626 if (!first) {
627 i2c->nmsgs--;
628 i2c->tx_msg++;
629 i2c->tx_pos = 0;
630 } else
631 first = 0;
632
633 if (i2c->tx_msg->flags & I2C_M_RD) {
634 /* we dont date putting several reads in the FIFO */
635 xiic_start_recv(i2c);
636 return;
637 } else {
638 xiic_start_send(i2c);
639 if (xiic_tx_space(i2c) != 0) {
640 /* the message could not be completely sent */
641 break;
642 }
643 }
644
645 fifo_space = xiic_tx_fifo_space(i2c);
646 }
647
648 /* there are more messages or the current one could not be completely
649 * put into the FIFO, also enable the half empty interrupt
650 */
651 if (i2c->nmsgs > 1 || xiic_tx_space(i2c))
652 xiic_irq_clr_en(i2c, XIIC_INTR_TX_HALF_MASK);
653
654 }
655
xiic_start_xfer(struct xiic_i2c * i2c)656 static void xiic_start_xfer(struct xiic_i2c *i2c)
657 {
658 mutex_lock(&i2c->lock);
659 xiic_reinit(i2c);
660 __xiic_start_xfer(i2c);
661 mutex_unlock(&i2c->lock);
662 }
663
xiic_xfer(struct i2c_adapter * adap,struct i2c_msg * msgs,int num)664 static int xiic_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
665 {
666 struct xiic_i2c *i2c = i2c_get_adapdata(adap);
667 int err;
668
669 dev_dbg(adap->dev.parent, "%s entry SR: 0x%x\n", __func__,
670 xiic_getreg8(i2c, XIIC_SR_REG_OFFSET));
671
672 err = pm_runtime_get_sync(i2c->dev);
673 if (err < 0)
674 return err;
675
676 err = xiic_busy(i2c);
677 if (err)
678 goto out;
679
680 i2c->tx_msg = msgs;
681 i2c->nmsgs = num;
682
683 xiic_start_xfer(i2c);
684
685 if (wait_event_timeout(i2c->wait, (i2c->state == STATE_ERROR) ||
686 (i2c->state == STATE_DONE), HZ)) {
687 err = (i2c->state == STATE_DONE) ? num : -EIO;
688 goto out;
689 } else {
690 i2c->tx_msg = NULL;
691 i2c->rx_msg = NULL;
692 i2c->nmsgs = 0;
693 err = -ETIMEDOUT;
694 goto out;
695 }
696 out:
697 pm_runtime_mark_last_busy(i2c->dev);
698 pm_runtime_put_autosuspend(i2c->dev);
699 return err;
700 }
701
xiic_func(struct i2c_adapter * adap)702 static u32 xiic_func(struct i2c_adapter *adap)
703 {
704 return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
705 }
706
707 static const struct i2c_algorithm xiic_algorithm = {
708 .master_xfer = xiic_xfer,
709 .functionality = xiic_func,
710 };
711
712 static const struct i2c_adapter_quirks xiic_quirks = {
713 .max_read_len = 255,
714 };
715
716 static const struct i2c_adapter xiic_adapter = {
717 .owner = THIS_MODULE,
718 .name = DRIVER_NAME,
719 .class = I2C_CLASS_DEPRECATED,
720 .algo = &xiic_algorithm,
721 .quirks = &xiic_quirks,
722 };
723
724
xiic_i2c_probe(struct platform_device * pdev)725 static int xiic_i2c_probe(struct platform_device *pdev)
726 {
727 struct xiic_i2c *i2c;
728 struct xiic_i2c_platform_data *pdata;
729 struct resource *res;
730 int ret, irq;
731 u8 i;
732 u32 sr;
733
734 i2c = devm_kzalloc(&pdev->dev, sizeof(*i2c), GFP_KERNEL);
735 if (!i2c)
736 return -ENOMEM;
737
738 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
739 i2c->base = devm_ioremap_resource(&pdev->dev, res);
740 if (IS_ERR(i2c->base))
741 return PTR_ERR(i2c->base);
742
743 irq = platform_get_irq(pdev, 0);
744 if (irq < 0)
745 return irq;
746
747 pdata = dev_get_platdata(&pdev->dev);
748
749 /* hook up driver to tree */
750 platform_set_drvdata(pdev, i2c);
751 i2c->adap = xiic_adapter;
752 i2c_set_adapdata(&i2c->adap, i2c);
753 i2c->adap.dev.parent = &pdev->dev;
754 i2c->adap.dev.of_node = pdev->dev.of_node;
755
756 mutex_init(&i2c->lock);
757 init_waitqueue_head(&i2c->wait);
758
759 i2c->clk = devm_clk_get(&pdev->dev, NULL);
760 if (IS_ERR(i2c->clk)) {
761 dev_err(&pdev->dev, "input clock not found.\n");
762 return PTR_ERR(i2c->clk);
763 }
764 ret = clk_prepare_enable(i2c->clk);
765 if (ret) {
766 dev_err(&pdev->dev, "Unable to enable clock.\n");
767 return ret;
768 }
769 i2c->dev = &pdev->dev;
770 pm_runtime_enable(i2c->dev);
771 pm_runtime_set_autosuspend_delay(i2c->dev, XIIC_PM_TIMEOUT);
772 pm_runtime_use_autosuspend(i2c->dev);
773 pm_runtime_set_active(i2c->dev);
774 ret = devm_request_threaded_irq(&pdev->dev, irq, xiic_isr,
775 xiic_process, IRQF_ONESHOT,
776 pdev->name, i2c);
777
778 if (ret < 0) {
779 dev_err(&pdev->dev, "Cannot claim IRQ\n");
780 goto err_clk_dis;
781 }
782
783 /*
784 * Detect endianness
785 * Try to reset the TX FIFO. Then check the EMPTY flag. If it is not
786 * set, assume that the endianness was wrong and swap.
787 */
788 i2c->endianness = LITTLE;
789 xiic_setreg32(i2c, XIIC_CR_REG_OFFSET, XIIC_CR_TX_FIFO_RESET_MASK);
790 /* Reset is cleared in xiic_reinit */
791 sr = xiic_getreg32(i2c, XIIC_SR_REG_OFFSET);
792 if (!(sr & XIIC_SR_TX_FIFO_EMPTY_MASK))
793 i2c->endianness = BIG;
794
795 xiic_reinit(i2c);
796
797 /* add i2c adapter to i2c tree */
798 ret = i2c_add_adapter(&i2c->adap);
799 if (ret) {
800 xiic_deinit(i2c);
801 goto err_clk_dis;
802 }
803
804 if (pdata) {
805 /* add in known devices to the bus */
806 for (i = 0; i < pdata->num_devices; i++)
807 i2c_new_device(&i2c->adap, pdata->devices + i);
808 }
809
810 return 0;
811
812 err_clk_dis:
813 pm_runtime_set_suspended(&pdev->dev);
814 pm_runtime_disable(&pdev->dev);
815 clk_disable_unprepare(i2c->clk);
816 return ret;
817 }
818
xiic_i2c_remove(struct platform_device * pdev)819 static int xiic_i2c_remove(struct platform_device *pdev)
820 {
821 struct xiic_i2c *i2c = platform_get_drvdata(pdev);
822 int ret;
823
824 /* remove adapter & data */
825 i2c_del_adapter(&i2c->adap);
826
827 ret = clk_prepare_enable(i2c->clk);
828 if (ret) {
829 dev_err(&pdev->dev, "Unable to enable clock.\n");
830 return ret;
831 }
832 xiic_deinit(i2c);
833 clk_disable_unprepare(i2c->clk);
834 pm_runtime_disable(&pdev->dev);
835
836 return 0;
837 }
838
839 #if defined(CONFIG_OF)
840 static const struct of_device_id xiic_of_match[] = {
841 { .compatible = "xlnx,xps-iic-2.00.a", },
842 {},
843 };
844 MODULE_DEVICE_TABLE(of, xiic_of_match);
845 #endif
846
xiic_i2c_runtime_suspend(struct device * dev)847 static int __maybe_unused xiic_i2c_runtime_suspend(struct device *dev)
848 {
849 struct xiic_i2c *i2c = dev_get_drvdata(dev);
850
851 clk_disable(i2c->clk);
852
853 return 0;
854 }
855
xiic_i2c_runtime_resume(struct device * dev)856 static int __maybe_unused xiic_i2c_runtime_resume(struct device *dev)
857 {
858 struct xiic_i2c *i2c = dev_get_drvdata(dev);
859 int ret;
860
861 ret = clk_enable(i2c->clk);
862 if (ret) {
863 dev_err(dev, "Cannot enable clock.\n");
864 return ret;
865 }
866
867 return 0;
868 }
869
870 static const struct dev_pm_ops xiic_dev_pm_ops = {
871 SET_RUNTIME_PM_OPS(xiic_i2c_runtime_suspend,
872 xiic_i2c_runtime_resume, NULL)
873 };
874 static struct platform_driver xiic_i2c_driver = {
875 .probe = xiic_i2c_probe,
876 .remove = xiic_i2c_remove,
877 .driver = {
878 .name = DRIVER_NAME,
879 .of_match_table = of_match_ptr(xiic_of_match),
880 .pm = &xiic_dev_pm_ops,
881 },
882 };
883
884 module_platform_driver(xiic_i2c_driver);
885
886 MODULE_AUTHOR("info@mocean-labs.com");
887 MODULE_DESCRIPTION("Xilinx I2C bus driver");
888 MODULE_LICENSE("GPL v2");
889 MODULE_ALIAS("platform:"DRIVER_NAME);
890
