1 // SPDX-License-Identifier: GPL-2.0-only
4 * Copyright (c) 2002-2007 Xilinx Inc.
5 * Copyright (c) 2009-2010 Intel Corporation
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
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>
29 #include <linux/slab.h>
31 #include <linux/clk.h>
32 #include <linux/pm_runtime.h>
34 #define DRIVER_NAME "xiic-i2c"
36 enum xilinx_i2c_state {
48 * struct xiic_i2c - Internal representation of the XIIC I2C bus
49 * @dev: Pointer to device structure
50 * @base: Memory base of the HW registers
51 * @wait: Wait queue for callers
52 * @adap: Kernel adapter representation
53 * @tx_msg: Messages from above to be sent
54 * @lock: Mutual exclusion
55 * @tx_pos: Current pos in TX message
56 * @nmsgs: Number of messages in tx_msg
57 * @rx_msg: Current RX message
58 * @rx_pos: Position within current RX message
59 * @endianness: big/little-endian byte order
60 * @clk: Pointer to AXI4-lite input clock
62 * @singlemaster: Indicates bus is single master
67 wait_queue_head_t wait;
68 struct i2c_adapter adap;
69 struct i2c_msg *tx_msg;
73 struct i2c_msg *rx_msg;
75 enum xiic_endian endianness;
77 enum xilinx_i2c_state state;
82 #define XIIC_MSB_OFFSET 0
83 #define XIIC_REG_OFFSET (0x100+XIIC_MSB_OFFSET)
86 * Register offsets in bytes from RegisterBase. Three is added to the
87 * base offset to access LSB (IBM style) of the word
89 #define XIIC_CR_REG_OFFSET (0x00+XIIC_REG_OFFSET) /* Control Register */
90 #define XIIC_SR_REG_OFFSET (0x04+XIIC_REG_OFFSET) /* Status Register */
91 #define XIIC_DTR_REG_OFFSET (0x08+XIIC_REG_OFFSET) /* Data Tx Register */
92 #define XIIC_DRR_REG_OFFSET (0x0C+XIIC_REG_OFFSET) /* Data Rx Register */
93 #define XIIC_ADR_REG_OFFSET (0x10+XIIC_REG_OFFSET) /* Address Register */
94 #define XIIC_TFO_REG_OFFSET (0x14+XIIC_REG_OFFSET) /* Tx FIFO Occupancy */
95 #define XIIC_RFO_REG_OFFSET (0x18+XIIC_REG_OFFSET) /* Rx FIFO Occupancy */
96 #define XIIC_TBA_REG_OFFSET (0x1C+XIIC_REG_OFFSET) /* 10 Bit Address reg */
97 #define XIIC_RFD_REG_OFFSET (0x20+XIIC_REG_OFFSET) /* Rx FIFO Depth reg */
98 #define XIIC_GPO_REG_OFFSET (0x24+XIIC_REG_OFFSET) /* Output Register */
100 /* Control Register masks */
101 #define XIIC_CR_ENABLE_DEVICE_MASK 0x01 /* Device enable = 1 */
102 #define XIIC_CR_TX_FIFO_RESET_MASK 0x02 /* Transmit FIFO reset=1 */
103 #define XIIC_CR_MSMS_MASK 0x04 /* Master starts Txing=1 */
104 #define XIIC_CR_DIR_IS_TX_MASK 0x08 /* Dir of tx. Txing=1 */
105 #define XIIC_CR_NO_ACK_MASK 0x10 /* Tx Ack. NO ack = 1 */
106 #define XIIC_CR_REPEATED_START_MASK 0x20 /* Repeated start = 1 */
107 #define XIIC_CR_GENERAL_CALL_MASK 0x40 /* Gen Call enabled = 1 */
109 /* Status Register masks */
110 #define XIIC_SR_GEN_CALL_MASK 0x01 /* 1=a mstr issued a GC */
111 #define XIIC_SR_ADDR_AS_SLAVE_MASK 0x02 /* 1=when addr as slave */
112 #define XIIC_SR_BUS_BUSY_MASK 0x04 /* 1 = bus is busy */
113 #define XIIC_SR_MSTR_RDING_SLAVE_MASK 0x08 /* 1=Dir: mstr <-- slave */
114 #define XIIC_SR_TX_FIFO_FULL_MASK 0x10 /* 1 = Tx FIFO full */
115 #define XIIC_SR_RX_FIFO_FULL_MASK 0x20 /* 1 = Rx FIFO full */
116 #define XIIC_SR_RX_FIFO_EMPTY_MASK 0x40 /* 1 = Rx FIFO empty */
117 #define XIIC_SR_TX_FIFO_EMPTY_MASK 0x80 /* 1 = Tx FIFO empty */
119 /* Interrupt Status Register masks Interrupt occurs when... */
120 #define XIIC_INTR_ARB_LOST_MASK 0x01 /* 1 = arbitration lost */
121 #define XIIC_INTR_TX_ERROR_MASK 0x02 /* 1=Tx error/msg complete */
122 #define XIIC_INTR_TX_EMPTY_MASK 0x04 /* 1 = Tx FIFO/reg empty */
123 #define XIIC_INTR_RX_FULL_MASK 0x08 /* 1=Rx FIFO/reg=OCY level */
124 #define XIIC_INTR_BNB_MASK 0x10 /* 1 = Bus not busy */
125 #define XIIC_INTR_AAS_MASK 0x20 /* 1 = when addr as slave */
126 #define XIIC_INTR_NAAS_MASK 0x40 /* 1 = not addr as slave */
127 #define XIIC_INTR_TX_HALF_MASK 0x80 /* 1 = TX FIFO half empty */
129 /* The following constants specify the depth of the FIFOs */
130 #define IIC_RX_FIFO_DEPTH 16 /* Rx fifo capacity */
131 #define IIC_TX_FIFO_DEPTH 16 /* Tx fifo capacity */
133 /* The following constants specify groups of interrupts that are typically
134 * enabled or disables at the same time
136 #define XIIC_TX_INTERRUPTS \
137 (XIIC_INTR_TX_ERROR_MASK | XIIC_INTR_TX_EMPTY_MASK | XIIC_INTR_TX_HALF_MASK)
139 #define XIIC_TX_RX_INTERRUPTS (XIIC_INTR_RX_FULL_MASK | XIIC_TX_INTERRUPTS)
142 * Tx Fifo upper bit masks.
144 #define XIIC_TX_DYN_START_MASK 0x0100 /* 1 = Set dynamic start */
145 #define XIIC_TX_DYN_STOP_MASK 0x0200 /* 1 = Set dynamic stop */
148 * The following constants define the register offsets for the Interrupt
149 * registers. There are some holes in the memory map for reserved addresses
150 * to allow other registers to be added and still match the memory map of the
151 * interrupt controller registers
153 #define XIIC_DGIER_OFFSET 0x1C /* Device Global Interrupt Enable Register */
154 #define XIIC_IISR_OFFSET 0x20 /* Interrupt Status Register */
155 #define XIIC_IIER_OFFSET 0x28 /* Interrupt Enable Register */
156 #define XIIC_RESETR_OFFSET 0x40 /* Reset Register */
158 #define XIIC_RESET_MASK 0xAUL
160 #define XIIC_PM_TIMEOUT 1000 /* ms */
161 /* timeout waiting for the controller to respond */
162 #define XIIC_I2C_TIMEOUT (msecs_to_jiffies(1000))
164 * The following constant is used for the device global interrupt enable
165 * register, to enable all interrupts for the device, this is the only bit
168 #define XIIC_GINTR_ENABLE_MASK 0x80000000UL
170 #define xiic_tx_space(i2c) ((i2c)->tx_msg->len - (i2c)->tx_pos)
171 #define xiic_rx_space(i2c) ((i2c)->rx_msg->len - (i2c)->rx_pos)
173 static int xiic_start_xfer(struct xiic_i2c *i2c);
174 static void __xiic_start_xfer(struct xiic_i2c *i2c);
177 * For the register read and write functions, a little-endian and big-endian
178 * version are necessary. Endianness is detected during the probe function.
179 * Only the least significant byte [doublet] of the register are ever
180 * accessed. This requires an offset of 3 [2] from the base address for
181 * big-endian systems.
184 static inline void xiic_setreg8(struct xiic_i2c *i2c, int reg, u8 value)
186 if (i2c->endianness == LITTLE)
187 iowrite8(value, i2c->base + reg);
189 iowrite8(value, i2c->base + reg + 3);
192 static inline u8 xiic_getreg8(struct xiic_i2c *i2c, int reg)
196 if (i2c->endianness == LITTLE)
197 ret = ioread8(i2c->base + reg);
199 ret = ioread8(i2c->base + reg + 3);
203 static inline void xiic_setreg16(struct xiic_i2c *i2c, int reg, u16 value)
205 if (i2c->endianness == LITTLE)
206 iowrite16(value, i2c->base + reg);
208 iowrite16be(value, i2c->base + reg + 2);
211 static inline void xiic_setreg32(struct xiic_i2c *i2c, int reg, int value)
213 if (i2c->endianness == LITTLE)
214 iowrite32(value, i2c->base + reg);
216 iowrite32be(value, i2c->base + reg);
219 static inline int xiic_getreg32(struct xiic_i2c *i2c, int reg)
223 if (i2c->endianness == LITTLE)
224 ret = ioread32(i2c->base + reg);
226 ret = ioread32be(i2c->base + reg);
230 static inline void xiic_irq_dis(struct xiic_i2c *i2c, u32 mask)
232 u32 ier = xiic_getreg32(i2c, XIIC_IIER_OFFSET);
233 xiic_setreg32(i2c, XIIC_IIER_OFFSET, ier & ~mask);
236 static inline void xiic_irq_en(struct xiic_i2c *i2c, u32 mask)
238 u32 ier = xiic_getreg32(i2c, XIIC_IIER_OFFSET);
239 xiic_setreg32(i2c, XIIC_IIER_OFFSET, ier | mask);
242 static inline void xiic_irq_clr(struct xiic_i2c *i2c, u32 mask)
244 u32 isr = xiic_getreg32(i2c, XIIC_IISR_OFFSET);
245 xiic_setreg32(i2c, XIIC_IISR_OFFSET, isr & mask);
248 static inline void xiic_irq_clr_en(struct xiic_i2c *i2c, u32 mask)
250 xiic_irq_clr(i2c, mask);
251 xiic_irq_en(i2c, mask);
254 static int xiic_clear_rx_fifo(struct xiic_i2c *i2c)
257 unsigned long timeout;
259 timeout = jiffies + XIIC_I2C_TIMEOUT;
260 for (sr = xiic_getreg8(i2c, XIIC_SR_REG_OFFSET);
261 !(sr & XIIC_SR_RX_FIFO_EMPTY_MASK);
262 sr = xiic_getreg8(i2c, XIIC_SR_REG_OFFSET)) {
263 xiic_getreg8(i2c, XIIC_DRR_REG_OFFSET);
264 if (time_after(jiffies, timeout)) {
265 dev_err(i2c->dev, "Failed to clear rx fifo\n");
273 static int xiic_reinit(struct xiic_i2c *i2c)
277 xiic_setreg32(i2c, XIIC_RESETR_OFFSET, XIIC_RESET_MASK);
279 /* Set receive Fifo depth to maximum (zero based). */
280 xiic_setreg8(i2c, XIIC_RFD_REG_OFFSET, IIC_RX_FIFO_DEPTH - 1);
283 xiic_setreg8(i2c, XIIC_CR_REG_OFFSET, XIIC_CR_TX_FIFO_RESET_MASK);
285 /* Enable IIC Device, remove Tx Fifo reset & disable general call. */
286 xiic_setreg8(i2c, XIIC_CR_REG_OFFSET, XIIC_CR_ENABLE_DEVICE_MASK);
288 /* make sure RX fifo is empty */
289 ret = xiic_clear_rx_fifo(i2c);
293 /* Enable interrupts */
294 xiic_setreg32(i2c, XIIC_DGIER_OFFSET, XIIC_GINTR_ENABLE_MASK);
296 xiic_irq_clr_en(i2c, XIIC_INTR_ARB_LOST_MASK);
301 static void xiic_deinit(struct xiic_i2c *i2c)
305 xiic_setreg32(i2c, XIIC_RESETR_OFFSET, XIIC_RESET_MASK);
307 /* Disable IIC Device. */
308 cr = xiic_getreg8(i2c, XIIC_CR_REG_OFFSET);
309 xiic_setreg8(i2c, XIIC_CR_REG_OFFSET, cr & ~XIIC_CR_ENABLE_DEVICE_MASK);
312 static void xiic_read_rx(struct xiic_i2c *i2c)
317 bytes_in_fifo = xiic_getreg8(i2c, XIIC_RFO_REG_OFFSET) + 1;
319 dev_dbg(i2c->adap.dev.parent,
320 "%s entry, bytes in fifo: %d, msg: %d, SR: 0x%x, CR: 0x%x\n",
321 __func__, bytes_in_fifo, xiic_rx_space(i2c),
322 xiic_getreg8(i2c, XIIC_SR_REG_OFFSET),
323 xiic_getreg8(i2c, XIIC_CR_REG_OFFSET));
325 if (bytes_in_fifo > xiic_rx_space(i2c))
326 bytes_in_fifo = xiic_rx_space(i2c);
328 for (i = 0; i < bytes_in_fifo; i++)
329 i2c->rx_msg->buf[i2c->rx_pos++] =
330 xiic_getreg8(i2c, XIIC_DRR_REG_OFFSET);
332 xiic_setreg8(i2c, XIIC_RFD_REG_OFFSET,
333 (xiic_rx_space(i2c) > IIC_RX_FIFO_DEPTH) ?
334 IIC_RX_FIFO_DEPTH - 1 : xiic_rx_space(i2c) - 1);
337 static int xiic_tx_fifo_space(struct xiic_i2c *i2c)
339 /* return the actual space left in the FIFO */
340 return IIC_TX_FIFO_DEPTH - xiic_getreg8(i2c, XIIC_TFO_REG_OFFSET) - 1;
343 static void xiic_fill_tx_fifo(struct xiic_i2c *i2c)
345 u8 fifo_space = xiic_tx_fifo_space(i2c);
346 int len = xiic_tx_space(i2c);
348 len = (len > fifo_space) ? fifo_space : len;
350 dev_dbg(i2c->adap.dev.parent, "%s entry, len: %d, fifo space: %d\n",
351 __func__, len, fifo_space);
354 u16 data = i2c->tx_msg->buf[i2c->tx_pos++];
355 if ((xiic_tx_space(i2c) == 0) && (i2c->nmsgs == 1)) {
356 /* last message in transfer -> STOP */
357 data |= XIIC_TX_DYN_STOP_MASK;
358 dev_dbg(i2c->adap.dev.parent, "%s TX STOP\n", __func__);
360 xiic_setreg16(i2c, XIIC_DTR_REG_OFFSET, data);
364 static void xiic_wakeup(struct xiic_i2c *i2c, int code)
373 static irqreturn_t xiic_process(int irq, void *dev_id)
375 struct xiic_i2c *i2c = dev_id;
379 /* Get the interrupt Status from the IPIF. There is no clearing of
380 * interrupts in the IPIF. Interrupts must be cleared at the source.
381 * To find which interrupts are pending; AND interrupts pending with
384 mutex_lock(&i2c->lock);
385 isr = xiic_getreg32(i2c, XIIC_IISR_OFFSET);
386 ier = xiic_getreg32(i2c, XIIC_IIER_OFFSET);
389 dev_dbg(i2c->adap.dev.parent, "%s: IER: 0x%x, ISR: 0x%x, pend: 0x%x\n",
390 __func__, ier, isr, pend);
391 dev_dbg(i2c->adap.dev.parent, "%s: SR: 0x%x, msg: %p, nmsgs: %d\n",
392 __func__, xiic_getreg8(i2c, XIIC_SR_REG_OFFSET),
393 i2c->tx_msg, i2c->nmsgs);
396 /* Service requesting interrupt */
397 if ((pend & XIIC_INTR_ARB_LOST_MASK) ||
398 ((pend & XIIC_INTR_TX_ERROR_MASK) &&
399 !(pend & XIIC_INTR_RX_FULL_MASK))) {
400 /* bus arbritration lost, or...
401 * Transmit error _OR_ RX completed
402 * if this happens when RX_FULL is not set
403 * this is probably a TX error
406 dev_dbg(i2c->adap.dev.parent, "%s error\n", __func__);
408 /* dynamic mode seem to suffer from problems if we just flushes
409 * fifos and the next message is a TX with len 0 (only addr)
410 * reset the IP instead of just flush fifos
415 xiic_wakeup(i2c, STATE_ERROR);
417 xiic_wakeup(i2c, STATE_ERROR);
419 if (pend & XIIC_INTR_RX_FULL_MASK) {
420 /* Receive register/FIFO is full */
422 clr |= XIIC_INTR_RX_FULL_MASK;
424 dev_dbg(i2c->adap.dev.parent,
425 "%s unexpected RX IRQ\n", __func__);
426 xiic_clear_rx_fifo(i2c);
431 if (xiic_rx_space(i2c) == 0) {
432 /* this is the last part of the message */
435 /* also clear TX error if there (RX complete) */
436 clr |= (isr & XIIC_INTR_TX_ERROR_MASK);
438 dev_dbg(i2c->adap.dev.parent,
439 "%s end of message, nmsgs: %d\n",
440 __func__, i2c->nmsgs);
442 /* send next message if this wasn't the last,
443 * otherwise the transfer will be finialise when
444 * receiving the bus not busy interrupt
446 if (i2c->nmsgs > 1) {
449 dev_dbg(i2c->adap.dev.parent,
450 "%s will start next...\n", __func__);
452 __xiic_start_xfer(i2c);
456 if (pend & XIIC_INTR_BNB_MASK) {
457 /* IIC bus has transitioned to not busy */
458 clr |= XIIC_INTR_BNB_MASK;
460 /* The bus is not busy, disable BusNotBusy interrupt */
461 xiic_irq_dis(i2c, XIIC_INTR_BNB_MASK);
466 if ((i2c->nmsgs == 1) && !i2c->rx_msg &&
467 xiic_tx_space(i2c) == 0)
468 xiic_wakeup(i2c, STATE_DONE);
470 xiic_wakeup(i2c, STATE_ERROR);
472 if (pend & (XIIC_INTR_TX_EMPTY_MASK | XIIC_INTR_TX_HALF_MASK)) {
473 /* Transmit register/FIFO is empty or ½ empty */
476 (XIIC_INTR_TX_EMPTY_MASK | XIIC_INTR_TX_HALF_MASK));
479 dev_dbg(i2c->adap.dev.parent,
480 "%s unexpected TX IRQ\n", __func__);
484 xiic_fill_tx_fifo(i2c);
486 /* current message sent and there is space in the fifo */
487 if (!xiic_tx_space(i2c) && xiic_tx_fifo_space(i2c) >= 2) {
488 dev_dbg(i2c->adap.dev.parent,
489 "%s end of message sent, nmsgs: %d\n",
490 __func__, i2c->nmsgs);
491 if (i2c->nmsgs > 1) {
494 __xiic_start_xfer(i2c);
496 xiic_irq_dis(i2c, XIIC_INTR_TX_HALF_MASK);
498 dev_dbg(i2c->adap.dev.parent,
499 "%s Got TX IRQ but no more to do...\n",
502 } else if (!xiic_tx_space(i2c) && (i2c->nmsgs == 1))
503 /* current frame is sent and is last,
504 * make sure to disable tx half
506 xiic_irq_dis(i2c, XIIC_INTR_TX_HALF_MASK);
509 dev_dbg(i2c->adap.dev.parent, "%s clr: 0x%x\n", __func__, clr);
511 xiic_setreg32(i2c, XIIC_IISR_OFFSET, clr);
512 mutex_unlock(&i2c->lock);
516 static int xiic_bus_busy(struct xiic_i2c *i2c)
518 u8 sr = xiic_getreg8(i2c, XIIC_SR_REG_OFFSET);
520 return (sr & XIIC_SR_BUS_BUSY_MASK) ? -EBUSY : 0;
523 static int xiic_busy(struct xiic_i2c *i2c)
531 /* In single master mode bus can only be busy, when in use by this
532 * driver. If the register indicates bus being busy for some reason we
533 * should ignore it, since bus will never be released and i2c will be
536 if (i2c->singlemaster) {
540 /* for instance if previous transfer was terminated due to TX error
541 * it might be that the bus is on it's way to become available
542 * give it at most 3 ms to wake
544 err = xiic_bus_busy(i2c);
545 while (err && tries--) {
547 err = xiic_bus_busy(i2c);
553 static void xiic_start_recv(struct xiic_i2c *i2c)
556 struct i2c_msg *msg = i2c->rx_msg = i2c->tx_msg;
559 /* Clear and enable Rx full interrupt. */
560 xiic_irq_clr_en(i2c, XIIC_INTR_RX_FULL_MASK | XIIC_INTR_TX_ERROR_MASK);
562 /* we want to get all but last byte, because the TX_ERROR IRQ is used
563 * to inidicate error ACK on the address, and negative ack on the last
564 * received byte, so to not mix them receive all but last.
565 * In the case where there is only one byte to receive
566 * we can check if ERROR and RX full is set at the same time
568 rx_watermark = msg->len;
569 if (rx_watermark > IIC_RX_FIFO_DEPTH)
570 rx_watermark = IIC_RX_FIFO_DEPTH;
571 xiic_setreg8(i2c, XIIC_RFD_REG_OFFSET, rx_watermark - 1);
573 local_irq_save(flags);
574 if (!(msg->flags & I2C_M_NOSTART))
575 /* write the address */
576 xiic_setreg16(i2c, XIIC_DTR_REG_OFFSET,
577 i2c_8bit_addr_from_msg(msg) | XIIC_TX_DYN_START_MASK);
579 xiic_irq_clr_en(i2c, XIIC_INTR_BNB_MASK);
581 xiic_setreg16(i2c, XIIC_DTR_REG_OFFSET,
582 msg->len | ((i2c->nmsgs == 1) ? XIIC_TX_DYN_STOP_MASK : 0));
583 local_irq_restore(flags);
586 /* very last, enable bus not busy as well */
587 xiic_irq_clr_en(i2c, XIIC_INTR_BNB_MASK);
589 /* the message is tx:ed */
590 i2c->tx_pos = msg->len;
593 static void xiic_start_send(struct xiic_i2c *i2c)
595 struct i2c_msg *msg = i2c->tx_msg;
597 xiic_irq_clr(i2c, XIIC_INTR_TX_ERROR_MASK);
599 dev_dbg(i2c->adap.dev.parent, "%s entry, msg: %p, len: %d",
600 __func__, msg, msg->len);
601 dev_dbg(i2c->adap.dev.parent, "%s entry, ISR: 0x%x, CR: 0x%x\n",
602 __func__, xiic_getreg32(i2c, XIIC_IISR_OFFSET),
603 xiic_getreg8(i2c, XIIC_CR_REG_OFFSET));
605 if (!(msg->flags & I2C_M_NOSTART)) {
606 /* write the address */
607 u16 data = i2c_8bit_addr_from_msg(msg) |
608 XIIC_TX_DYN_START_MASK;
609 if ((i2c->nmsgs == 1) && msg->len == 0)
610 /* no data and last message -> add STOP */
611 data |= XIIC_TX_DYN_STOP_MASK;
613 xiic_setreg16(i2c, XIIC_DTR_REG_OFFSET, data);
616 xiic_fill_tx_fifo(i2c);
618 /* Clear any pending Tx empty, Tx Error and then enable them. */
619 xiic_irq_clr_en(i2c, XIIC_INTR_TX_EMPTY_MASK | XIIC_INTR_TX_ERROR_MASK |
623 static irqreturn_t xiic_isr(int irq, void *dev_id)
625 struct xiic_i2c *i2c = dev_id;
627 irqreturn_t ret = IRQ_NONE;
628 /* Do not processes a devices interrupts if the device has no
632 dev_dbg(i2c->adap.dev.parent, "%s entry\n", __func__);
634 isr = xiic_getreg32(i2c, XIIC_IISR_OFFSET);
635 ier = xiic_getreg32(i2c, XIIC_IIER_OFFSET);
638 ret = IRQ_WAKE_THREAD;
643 static void __xiic_start_xfer(struct xiic_i2c *i2c)
646 int fifo_space = xiic_tx_fifo_space(i2c);
647 dev_dbg(i2c->adap.dev.parent, "%s entry, msg: %p, fifos space: %d\n",
648 __func__, i2c->tx_msg, fifo_space);
655 i2c->state = STATE_START;
656 while ((fifo_space >= 2) && (first || (i2c->nmsgs > 1))) {
664 if (i2c->tx_msg->flags & I2C_M_RD) {
665 /* we dont date putting several reads in the FIFO */
666 xiic_start_recv(i2c);
669 xiic_start_send(i2c);
670 if (xiic_tx_space(i2c) != 0) {
671 /* the message could not be completely sent */
676 fifo_space = xiic_tx_fifo_space(i2c);
679 /* there are more messages or the current one could not be completely
680 * put into the FIFO, also enable the half empty interrupt
682 if (i2c->nmsgs > 1 || xiic_tx_space(i2c))
683 xiic_irq_clr_en(i2c, XIIC_INTR_TX_HALF_MASK);
687 static int xiic_start_xfer(struct xiic_i2c *i2c)
690 mutex_lock(&i2c->lock);
692 ret = xiic_reinit(i2c);
694 __xiic_start_xfer(i2c);
696 mutex_unlock(&i2c->lock);
701 static int xiic_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
703 struct xiic_i2c *i2c = i2c_get_adapdata(adap);
706 dev_dbg(adap->dev.parent, "%s entry SR: 0x%x\n", __func__,
707 xiic_getreg8(i2c, XIIC_SR_REG_OFFSET));
709 err = pm_runtime_resume_and_get(i2c->dev);
713 err = xiic_busy(i2c);
720 err = xiic_start_xfer(i2c);
722 dev_err(adap->dev.parent, "Error xiic_start_xfer\n");
726 if (wait_event_timeout(i2c->wait, (i2c->state == STATE_ERROR) ||
727 (i2c->state == STATE_DONE), HZ)) {
728 err = (i2c->state == STATE_DONE) ? num : -EIO;
738 pm_runtime_mark_last_busy(i2c->dev);
739 pm_runtime_put_autosuspend(i2c->dev);
743 static u32 xiic_func(struct i2c_adapter *adap)
745 return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
748 static const struct i2c_algorithm xiic_algorithm = {
749 .master_xfer = xiic_xfer,
750 .functionality = xiic_func,
753 static const struct i2c_adapter_quirks xiic_quirks = {
757 static const struct i2c_adapter xiic_adapter = {
758 .owner = THIS_MODULE,
760 .class = I2C_CLASS_DEPRECATED,
761 .algo = &xiic_algorithm,
762 .quirks = &xiic_quirks,
766 static int xiic_i2c_probe(struct platform_device *pdev)
768 struct xiic_i2c *i2c;
769 struct xiic_i2c_platform_data *pdata;
770 struct resource *res;
775 i2c = devm_kzalloc(&pdev->dev, sizeof(*i2c), GFP_KERNEL);
779 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
780 i2c->base = devm_ioremap_resource(&pdev->dev, res);
781 if (IS_ERR(i2c->base))
782 return PTR_ERR(i2c->base);
784 irq = platform_get_irq(pdev, 0);
788 pdata = dev_get_platdata(&pdev->dev);
790 /* hook up driver to tree */
791 platform_set_drvdata(pdev, i2c);
792 i2c->adap = xiic_adapter;
793 i2c_set_adapdata(&i2c->adap, i2c);
794 i2c->adap.dev.parent = &pdev->dev;
795 i2c->adap.dev.of_node = pdev->dev.of_node;
797 mutex_init(&i2c->lock);
798 init_waitqueue_head(&i2c->wait);
800 i2c->clk = devm_clk_get(&pdev->dev, NULL);
801 if (IS_ERR(i2c->clk))
802 return dev_err_probe(&pdev->dev, PTR_ERR(i2c->clk),
803 "input clock not found.\n");
805 ret = clk_prepare_enable(i2c->clk);
807 dev_err(&pdev->dev, "Unable to enable clock.\n");
810 i2c->dev = &pdev->dev;
811 pm_runtime_set_autosuspend_delay(i2c->dev, XIIC_PM_TIMEOUT);
812 pm_runtime_use_autosuspend(i2c->dev);
813 pm_runtime_set_active(i2c->dev);
814 pm_runtime_enable(i2c->dev);
815 ret = devm_request_threaded_irq(&pdev->dev, irq, xiic_isr,
816 xiic_process, IRQF_ONESHOT,
820 dev_err(&pdev->dev, "Cannot claim IRQ\n");
825 of_property_read_bool(pdev->dev.of_node, "single-master");
829 * Try to reset the TX FIFO. Then check the EMPTY flag. If it is not
830 * set, assume that the endianness was wrong and swap.
832 i2c->endianness = LITTLE;
833 xiic_setreg32(i2c, XIIC_CR_REG_OFFSET, XIIC_CR_TX_FIFO_RESET_MASK);
834 /* Reset is cleared in xiic_reinit */
835 sr = xiic_getreg32(i2c, XIIC_SR_REG_OFFSET);
836 if (!(sr & XIIC_SR_TX_FIFO_EMPTY_MASK))
837 i2c->endianness = BIG;
839 ret = xiic_reinit(i2c);
841 dev_err(&pdev->dev, "Cannot xiic_reinit\n");
845 /* add i2c adapter to i2c tree */
846 ret = i2c_add_adapter(&i2c->adap);
853 /* add in known devices to the bus */
854 for (i = 0; i < pdata->num_devices; i++)
855 i2c_new_client_device(&i2c->adap, pdata->devices + i);
861 pm_runtime_set_suspended(&pdev->dev);
862 pm_runtime_disable(&pdev->dev);
863 clk_disable_unprepare(i2c->clk);
867 static int xiic_i2c_remove(struct platform_device *pdev)
869 struct xiic_i2c *i2c = platform_get_drvdata(pdev);
872 /* remove adapter & data */
873 i2c_del_adapter(&i2c->adap);
875 ret = pm_runtime_resume_and_get(i2c->dev);
880 pm_runtime_put_sync(i2c->dev);
881 clk_disable_unprepare(i2c->clk);
882 pm_runtime_disable(&pdev->dev);
883 pm_runtime_set_suspended(&pdev->dev);
884 pm_runtime_dont_use_autosuspend(&pdev->dev);
889 #if defined(CONFIG_OF)
890 static const struct of_device_id xiic_of_match[] = {
891 { .compatible = "xlnx,xps-iic-2.00.a", },
894 MODULE_DEVICE_TABLE(of, xiic_of_match);
897 static int __maybe_unused xiic_i2c_runtime_suspend(struct device *dev)
899 struct xiic_i2c *i2c = dev_get_drvdata(dev);
901 clk_disable(i2c->clk);
906 static int __maybe_unused xiic_i2c_runtime_resume(struct device *dev)
908 struct xiic_i2c *i2c = dev_get_drvdata(dev);
911 ret = clk_enable(i2c->clk);
913 dev_err(dev, "Cannot enable clock.\n");
920 static const struct dev_pm_ops xiic_dev_pm_ops = {
921 SET_RUNTIME_PM_OPS(xiic_i2c_runtime_suspend,
922 xiic_i2c_runtime_resume, NULL)
924 static struct platform_driver xiic_i2c_driver = {
925 .probe = xiic_i2c_probe,
926 .remove = xiic_i2c_remove,
929 .of_match_table = of_match_ptr(xiic_of_match),
930 .pm = &xiic_dev_pm_ops,
934 module_platform_driver(xiic_i2c_driver);
936 MODULE_AUTHOR("info@mocean-labs.com");
937 MODULE_DESCRIPTION("Xilinx I2C bus driver");
938 MODULE_LICENSE("GPL v2");
939 MODULE_ALIAS("platform:"DRIVER_NAME);