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e1d5b659 RR |
1 | /* |
2 | * i2c-xiic.c | |
3 | * Copyright (c) 2002-2007 Xilinx Inc. | |
4 | * Copyright (c) 2009-2010 Intel Corporation | |
5 | * | |
6 | * This program is free software; you can redistribute it and/or modify | |
7 | * it under the terms of the GNU General Public License version 2 as | |
8 | * published by the Free Software Foundation. | |
9 | * | |
10 | * This program is distributed in the hope that it will be useful, | |
11 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
12 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
13 | * GNU General Public License for more details. | |
14 | * | |
e1d5b659 RR |
15 | * |
16 | * This code was implemented by Mocean Laboratories AB when porting linux | |
17 | * to the automotive development board Russellville. The copyright holder | |
18 | * as seen in the header is Intel corporation. | |
19 | * Mocean Laboratories forked off the GNU/Linux platform work into a | |
25985edc | 20 | * separate company called Pelagicore AB, which committed the code to the |
e1d5b659 RR |
21 | * kernel. |
22 | */ | |
23 | ||
24 | /* Supports: | |
25 | * Xilinx IIC | |
26 | */ | |
27 | #include <linux/kernel.h> | |
28 | #include <linux/module.h> | |
e1d5b659 | 29 | #include <linux/errno.h> |
168e722d | 30 | #include <linux/err.h> |
02ca6c40 | 31 | #include <linux/delay.h> |
e1d5b659 RR |
32 | #include <linux/platform_device.h> |
33 | #include <linux/i2c.h> | |
34 | #include <linux/interrupt.h> | |
35 | #include <linux/wait.h> | |
36 | #include <linux/i2c-xiic.h> | |
37 | #include <linux/io.h> | |
5a0e3ad6 | 38 | #include <linux/slab.h> |
4edd65e6 | 39 | #include <linux/of.h> |
e1d5b659 RR |
40 | |
41 | #define DRIVER_NAME "xiic-i2c" | |
42 | ||
43 | enum xilinx_i2c_state { | |
44 | STATE_DONE, | |
45 | STATE_ERROR, | |
46 | STATE_START | |
47 | }; | |
48 | ||
48ef3ca9 TG |
49 | enum xiic_endian { |
50 | LITTLE, | |
51 | BIG | |
52 | }; | |
53 | ||
e1d5b659 RR |
54 | /** |
55 | * struct xiic_i2c - Internal representation of the XIIC I2C bus | |
56 | * @base: Memory base of the HW registers | |
57 | * @wait: Wait queue for callers | |
58 | * @adap: Kernel adapter representation | |
59 | * @tx_msg: Messages from above to be sent | |
60 | * @lock: Mutual exclusion | |
61 | * @tx_pos: Current pos in TX message | |
62 | * @nmsgs: Number of messages in tx_msg | |
63 | * @state: See STATE_ | |
64 | * @rx_msg: Current RX message | |
65 | * @rx_pos: Position within current RX message | |
66 | */ | |
67 | struct xiic_i2c { | |
68 | void __iomem *base; | |
69 | wait_queue_head_t wait; | |
70 | struct i2c_adapter adap; | |
71 | struct i2c_msg *tx_msg; | |
72 | spinlock_t lock; | |
f1e9f89a | 73 | unsigned int tx_pos; |
e1d5b659 RR |
74 | unsigned int nmsgs; |
75 | enum xilinx_i2c_state state; | |
76 | struct i2c_msg *rx_msg; | |
77 | int rx_pos; | |
48ef3ca9 | 78 | enum xiic_endian endianness; |
e1d5b659 RR |
79 | }; |
80 | ||
81 | ||
82 | #define XIIC_MSB_OFFSET 0 | |
83 | #define XIIC_REG_OFFSET (0x100+XIIC_MSB_OFFSET) | |
84 | ||
85 | /* | |
86 | * Register offsets in bytes from RegisterBase. Three is added to the | |
87 | * base offset to access LSB (IBM style) of the word | |
88 | */ | |
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 */ | |
99 | ||
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 */ | |
108 | ||
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 */ | |
118 | ||
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 */ | |
128 | ||
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 */ | |
132 | ||
133 | /* The following constants specify groups of interrupts that are typically | |
134 | * enabled or disables at the same time | |
135 | */ | |
136 | #define XIIC_TX_INTERRUPTS \ | |
137 | (XIIC_INTR_TX_ERROR_MASK | XIIC_INTR_TX_EMPTY_MASK | XIIC_INTR_TX_HALF_MASK) | |
138 | ||
139 | #define XIIC_TX_RX_INTERRUPTS (XIIC_INTR_RX_FULL_MASK | XIIC_TX_INTERRUPTS) | |
140 | ||
141 | /* The following constants are used with the following macros to specify the | |
142 | * operation, a read or write operation. | |
143 | */ | |
144 | #define XIIC_READ_OPERATION 1 | |
145 | #define XIIC_WRITE_OPERATION 0 | |
146 | ||
147 | /* | |
148 | * Tx Fifo upper bit masks. | |
149 | */ | |
150 | #define XIIC_TX_DYN_START_MASK 0x0100 /* 1 = Set dynamic start */ | |
151 | #define XIIC_TX_DYN_STOP_MASK 0x0200 /* 1 = Set dynamic stop */ | |
152 | ||
153 | /* | |
154 | * The following constants define the register offsets for the Interrupt | |
155 | * registers. There are some holes in the memory map for reserved addresses | |
156 | * to allow other registers to be added and still match the memory map of the | |
157 | * interrupt controller registers | |
158 | */ | |
159 | #define XIIC_DGIER_OFFSET 0x1C /* Device Global Interrupt Enable Register */ | |
160 | #define XIIC_IISR_OFFSET 0x20 /* Interrupt Status Register */ | |
161 | #define XIIC_IIER_OFFSET 0x28 /* Interrupt Enable Register */ | |
162 | #define XIIC_RESETR_OFFSET 0x40 /* Reset Register */ | |
163 | ||
164 | #define XIIC_RESET_MASK 0xAUL | |
165 | ||
166 | /* | |
167 | * The following constant is used for the device global interrupt enable | |
168 | * register, to enable all interrupts for the device, this is the only bit | |
169 | * in the register | |
170 | */ | |
171 | #define XIIC_GINTR_ENABLE_MASK 0x80000000UL | |
172 | ||
173 | #define xiic_tx_space(i2c) ((i2c)->tx_msg->len - (i2c)->tx_pos) | |
174 | #define xiic_rx_space(i2c) ((i2c)->rx_msg->len - (i2c)->rx_pos) | |
175 | ||
176 | static void xiic_start_xfer(struct xiic_i2c *i2c); | |
177 | static void __xiic_start_xfer(struct xiic_i2c *i2c); | |
178 | ||
48ef3ca9 TG |
179 | /* |
180 | * For the register read and write functions, a little-endian and big-endian | |
181 | * version are necessary. Endianness is detected during the probe function. | |
182 | * Only the least significant byte [doublet] of the register are ever | |
183 | * accessed. This requires an offset of 3 [2] from the base address for | |
184 | * big-endian systems. | |
185 | */ | |
186 | ||
e1d5b659 RR |
187 | static inline void xiic_setreg8(struct xiic_i2c *i2c, int reg, u8 value) |
188 | { | |
48ef3ca9 TG |
189 | if (i2c->endianness == LITTLE) |
190 | iowrite8(value, i2c->base + reg); | |
191 | else | |
192 | iowrite8(value, i2c->base + reg + 3); | |
e1d5b659 RR |
193 | } |
194 | ||
195 | static inline u8 xiic_getreg8(struct xiic_i2c *i2c, int reg) | |
196 | { | |
48ef3ca9 TG |
197 | u8 ret; |
198 | ||
199 | if (i2c->endianness == LITTLE) | |
200 | ret = ioread8(i2c->base + reg); | |
201 | else | |
202 | ret = ioread8(i2c->base + reg + 3); | |
203 | return ret; | |
e1d5b659 RR |
204 | } |
205 | ||
206 | static inline void xiic_setreg16(struct xiic_i2c *i2c, int reg, u16 value) | |
207 | { | |
48ef3ca9 TG |
208 | if (i2c->endianness == LITTLE) |
209 | iowrite16(value, i2c->base + reg); | |
210 | else | |
211 | iowrite16be(value, i2c->base + reg + 2); | |
e1d5b659 RR |
212 | } |
213 | ||
214 | static inline void xiic_setreg32(struct xiic_i2c *i2c, int reg, int value) | |
215 | { | |
48ef3ca9 TG |
216 | if (i2c->endianness == LITTLE) |
217 | iowrite32(value, i2c->base + reg); | |
218 | else | |
219 | iowrite32be(value, i2c->base + reg); | |
e1d5b659 RR |
220 | } |
221 | ||
222 | static inline int xiic_getreg32(struct xiic_i2c *i2c, int reg) | |
223 | { | |
48ef3ca9 TG |
224 | u32 ret; |
225 | ||
226 | if (i2c->endianness == LITTLE) | |
227 | ret = ioread32(i2c->base + reg); | |
228 | else | |
229 | ret = ioread32be(i2c->base + reg); | |
230 | return ret; | |
e1d5b659 RR |
231 | } |
232 | ||
233 | static inline void xiic_irq_dis(struct xiic_i2c *i2c, u32 mask) | |
234 | { | |
235 | u32 ier = xiic_getreg32(i2c, XIIC_IIER_OFFSET); | |
236 | xiic_setreg32(i2c, XIIC_IIER_OFFSET, ier & ~mask); | |
237 | } | |
238 | ||
239 | static inline void xiic_irq_en(struct xiic_i2c *i2c, u32 mask) | |
240 | { | |
241 | u32 ier = xiic_getreg32(i2c, XIIC_IIER_OFFSET); | |
242 | xiic_setreg32(i2c, XIIC_IIER_OFFSET, ier | mask); | |
243 | } | |
244 | ||
245 | static inline void xiic_irq_clr(struct xiic_i2c *i2c, u32 mask) | |
246 | { | |
247 | u32 isr = xiic_getreg32(i2c, XIIC_IISR_OFFSET); | |
248 | xiic_setreg32(i2c, XIIC_IISR_OFFSET, isr & mask); | |
249 | } | |
250 | ||
251 | static inline void xiic_irq_clr_en(struct xiic_i2c *i2c, u32 mask) | |
252 | { | |
253 | xiic_irq_clr(i2c, mask); | |
254 | xiic_irq_en(i2c, mask); | |
255 | } | |
256 | ||
257 | static void xiic_clear_rx_fifo(struct xiic_i2c *i2c) | |
258 | { | |
259 | u8 sr; | |
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 | } | |
265 | ||
266 | static void xiic_reinit(struct xiic_i2c *i2c) | |
267 | { | |
268 | xiic_setreg32(i2c, XIIC_RESETR_OFFSET, XIIC_RESET_MASK); | |
269 | ||
270 | /* Set receive Fifo depth to maximum (zero based). */ | |
271 | xiic_setreg8(i2c, XIIC_RFD_REG_OFFSET, IIC_RX_FIFO_DEPTH - 1); | |
272 | ||
273 | /* Reset Tx Fifo. */ | |
274 | xiic_setreg8(i2c, XIIC_CR_REG_OFFSET, XIIC_CR_TX_FIFO_RESET_MASK); | |
275 | ||
276 | /* Enable IIC Device, remove Tx Fifo reset & disable general call. */ | |
277 | xiic_setreg8(i2c, XIIC_CR_REG_OFFSET, XIIC_CR_ENABLE_DEVICE_MASK); | |
278 | ||
279 | /* make sure RX fifo is empty */ | |
280 | xiic_clear_rx_fifo(i2c); | |
281 | ||
282 | /* Enable interrupts */ | |
283 | xiic_setreg32(i2c, XIIC_DGIER_OFFSET, XIIC_GINTR_ENABLE_MASK); | |
284 | ||
285 | xiic_irq_clr_en(i2c, XIIC_INTR_AAS_MASK | XIIC_INTR_ARB_LOST_MASK); | |
286 | } | |
287 | ||
288 | static void xiic_deinit(struct xiic_i2c *i2c) | |
289 | { | |
290 | u8 cr; | |
291 | ||
292 | xiic_setreg32(i2c, XIIC_RESETR_OFFSET, XIIC_RESET_MASK); | |
293 | ||
294 | /* Disable IIC Device. */ | |
295 | cr = xiic_getreg8(i2c, XIIC_CR_REG_OFFSET); | |
296 | xiic_setreg8(i2c, XIIC_CR_REG_OFFSET, cr & ~XIIC_CR_ENABLE_DEVICE_MASK); | |
297 | } | |
298 | ||
299 | static void xiic_read_rx(struct xiic_i2c *i2c) | |
300 | { | |
301 | u8 bytes_in_fifo; | |
302 | int i; | |
303 | ||
304 | bytes_in_fifo = xiic_getreg8(i2c, XIIC_RFO_REG_OFFSET) + 1; | |
305 | ||
f1e9f89a KA |
306 | dev_dbg(i2c->adap.dev.parent, |
307 | "%s entry, bytes in fifo: %d, msg: %d, SR: 0x%x, CR: 0x%x\n", | |
e1d5b659 RR |
308 | __func__, bytes_in_fifo, xiic_rx_space(i2c), |
309 | xiic_getreg8(i2c, XIIC_SR_REG_OFFSET), | |
310 | xiic_getreg8(i2c, XIIC_CR_REG_OFFSET)); | |
311 | ||
312 | if (bytes_in_fifo > xiic_rx_space(i2c)) | |
313 | bytes_in_fifo = xiic_rx_space(i2c); | |
314 | ||
315 | for (i = 0; i < bytes_in_fifo; i++) | |
316 | i2c->rx_msg->buf[i2c->rx_pos++] = | |
317 | xiic_getreg8(i2c, XIIC_DRR_REG_OFFSET); | |
318 | ||
319 | xiic_setreg8(i2c, XIIC_RFD_REG_OFFSET, | |
320 | (xiic_rx_space(i2c) > IIC_RX_FIFO_DEPTH) ? | |
321 | IIC_RX_FIFO_DEPTH - 1 : xiic_rx_space(i2c) - 1); | |
322 | } | |
323 | ||
324 | static int xiic_tx_fifo_space(struct xiic_i2c *i2c) | |
325 | { | |
326 | /* return the actual space left in the FIFO */ | |
327 | return IIC_TX_FIFO_DEPTH - xiic_getreg8(i2c, XIIC_TFO_REG_OFFSET) - 1; | |
328 | } | |
329 | ||
330 | static void xiic_fill_tx_fifo(struct xiic_i2c *i2c) | |
331 | { | |
332 | u8 fifo_space = xiic_tx_fifo_space(i2c); | |
333 | int len = xiic_tx_space(i2c); | |
334 | ||
335 | len = (len > fifo_space) ? fifo_space : len; | |
336 | ||
337 | dev_dbg(i2c->adap.dev.parent, "%s entry, len: %d, fifo space: %d\n", | |
338 | __func__, len, fifo_space); | |
339 | ||
340 | while (len--) { | |
341 | u16 data = i2c->tx_msg->buf[i2c->tx_pos++]; | |
342 | if ((xiic_tx_space(i2c) == 0) && (i2c->nmsgs == 1)) { | |
343 | /* last message in transfer -> STOP */ | |
344 | data |= XIIC_TX_DYN_STOP_MASK; | |
345 | dev_dbg(i2c->adap.dev.parent, "%s TX STOP\n", __func__); | |
c39e8e43 SF |
346 | } |
347 | xiic_setreg16(i2c, XIIC_DTR_REG_OFFSET, data); | |
e1d5b659 RR |
348 | } |
349 | } | |
350 | ||
351 | static void xiic_wakeup(struct xiic_i2c *i2c, int code) | |
352 | { | |
353 | i2c->tx_msg = NULL; | |
354 | i2c->rx_msg = NULL; | |
355 | i2c->nmsgs = 0; | |
356 | i2c->state = code; | |
357 | wake_up(&i2c->wait); | |
358 | } | |
359 | ||
360 | static void xiic_process(struct xiic_i2c *i2c) | |
361 | { | |
362 | u32 pend, isr, ier; | |
363 | u32 clr = 0; | |
364 | ||
365 | /* Get the interrupt Status from the IPIF. There is no clearing of | |
366 | * interrupts in the IPIF. Interrupts must be cleared at the source. | |
367 | * To find which interrupts are pending; AND interrupts pending with | |
368 | * interrupts masked. | |
369 | */ | |
370 | isr = xiic_getreg32(i2c, XIIC_IISR_OFFSET); | |
371 | ier = xiic_getreg32(i2c, XIIC_IIER_OFFSET); | |
372 | pend = isr & ier; | |
373 | ||
f1e9f89a KA |
374 | dev_dbg(i2c->adap.dev.parent, "%s: IER: 0x%x, ISR: 0x%x, pend: 0x%x\n", |
375 | __func__, ier, isr, pend); | |
376 | dev_dbg(i2c->adap.dev.parent, "%s: SR: 0x%x, msg: %p, nmsgs: %d\n", | |
377 | __func__, xiic_getreg8(i2c, XIIC_SR_REG_OFFSET), | |
e1d5b659 RR |
378 | i2c->tx_msg, i2c->nmsgs); |
379 | ||
380 | /* Do not processes a devices interrupts if the device has no | |
381 | * interrupts pending | |
382 | */ | |
383 | if (!pend) | |
384 | return; | |
385 | ||
386 | /* Service requesting interrupt */ | |
387 | if ((pend & XIIC_INTR_ARB_LOST_MASK) || | |
388 | ((pend & XIIC_INTR_TX_ERROR_MASK) && | |
389 | !(pend & XIIC_INTR_RX_FULL_MASK))) { | |
390 | /* bus arbritration lost, or... | |
391 | * Transmit error _OR_ RX completed | |
392 | * if this happens when RX_FULL is not set | |
393 | * this is probably a TX error | |
394 | */ | |
395 | ||
396 | dev_dbg(i2c->adap.dev.parent, "%s error\n", __func__); | |
397 | ||
398 | /* dynamic mode seem to suffer from problems if we just flushes | |
399 | * fifos and the next message is a TX with len 0 (only addr) | |
400 | * reset the IP instead of just flush fifos | |
401 | */ | |
402 | xiic_reinit(i2c); | |
403 | ||
404 | if (i2c->tx_msg) | |
405 | xiic_wakeup(i2c, STATE_ERROR); | |
406 | ||
407 | } else if (pend & XIIC_INTR_RX_FULL_MASK) { | |
408 | /* Receive register/FIFO is full */ | |
409 | ||
410 | clr = XIIC_INTR_RX_FULL_MASK; | |
411 | if (!i2c->rx_msg) { | |
412 | dev_dbg(i2c->adap.dev.parent, | |
413 | "%s unexpexted RX IRQ\n", __func__); | |
414 | xiic_clear_rx_fifo(i2c); | |
415 | goto out; | |
416 | } | |
417 | ||
418 | xiic_read_rx(i2c); | |
419 | if (xiic_rx_space(i2c) == 0) { | |
420 | /* this is the last part of the message */ | |
421 | i2c->rx_msg = NULL; | |
422 | ||
423 | /* also clear TX error if there (RX complete) */ | |
424 | clr |= (isr & XIIC_INTR_TX_ERROR_MASK); | |
425 | ||
426 | dev_dbg(i2c->adap.dev.parent, | |
427 | "%s end of message, nmsgs: %d\n", | |
428 | __func__, i2c->nmsgs); | |
429 | ||
430 | /* send next message if this wasn't the last, | |
431 | * otherwise the transfer will be finialise when | |
432 | * receiving the bus not busy interrupt | |
433 | */ | |
434 | if (i2c->nmsgs > 1) { | |
435 | i2c->nmsgs--; | |
436 | i2c->tx_msg++; | |
437 | dev_dbg(i2c->adap.dev.parent, | |
438 | "%s will start next...\n", __func__); | |
439 | ||
440 | __xiic_start_xfer(i2c); | |
441 | } | |
442 | } | |
443 | } else if (pend & XIIC_INTR_BNB_MASK) { | |
444 | /* IIC bus has transitioned to not busy */ | |
445 | clr = XIIC_INTR_BNB_MASK; | |
446 | ||
447 | /* The bus is not busy, disable BusNotBusy interrupt */ | |
448 | xiic_irq_dis(i2c, XIIC_INTR_BNB_MASK); | |
449 | ||
450 | if (!i2c->tx_msg) | |
451 | goto out; | |
452 | ||
453 | if ((i2c->nmsgs == 1) && !i2c->rx_msg && | |
454 | xiic_tx_space(i2c) == 0) | |
455 | xiic_wakeup(i2c, STATE_DONE); | |
456 | else | |
457 | xiic_wakeup(i2c, STATE_ERROR); | |
458 | ||
459 | } else if (pend & (XIIC_INTR_TX_EMPTY_MASK | XIIC_INTR_TX_HALF_MASK)) { | |
d36b6910 | 460 | /* Transmit register/FIFO is empty or ½ empty */ |
e1d5b659 RR |
461 | |
462 | clr = pend & | |
463 | (XIIC_INTR_TX_EMPTY_MASK | XIIC_INTR_TX_HALF_MASK); | |
464 | ||
465 | if (!i2c->tx_msg) { | |
466 | dev_dbg(i2c->adap.dev.parent, | |
467 | "%s unexpexted TX IRQ\n", __func__); | |
468 | goto out; | |
469 | } | |
470 | ||
471 | xiic_fill_tx_fifo(i2c); | |
472 | ||
473 | /* current message sent and there is space in the fifo */ | |
474 | if (!xiic_tx_space(i2c) && xiic_tx_fifo_space(i2c) >= 2) { | |
475 | dev_dbg(i2c->adap.dev.parent, | |
476 | "%s end of message sent, nmsgs: %d\n", | |
477 | __func__, i2c->nmsgs); | |
478 | if (i2c->nmsgs > 1) { | |
479 | i2c->nmsgs--; | |
480 | i2c->tx_msg++; | |
481 | __xiic_start_xfer(i2c); | |
482 | } else { | |
483 | xiic_irq_dis(i2c, XIIC_INTR_TX_HALF_MASK); | |
484 | ||
485 | dev_dbg(i2c->adap.dev.parent, | |
486 | "%s Got TX IRQ but no more to do...\n", | |
487 | __func__); | |
488 | } | |
489 | } else if (!xiic_tx_space(i2c) && (i2c->nmsgs == 1)) | |
490 | /* current frame is sent and is last, | |
491 | * make sure to disable tx half | |
492 | */ | |
493 | xiic_irq_dis(i2c, XIIC_INTR_TX_HALF_MASK); | |
494 | } else { | |
495 | /* got IRQ which is not acked */ | |
496 | dev_err(i2c->adap.dev.parent, "%s Got unexpected IRQ\n", | |
497 | __func__); | |
498 | clr = pend; | |
499 | } | |
500 | out: | |
501 | dev_dbg(i2c->adap.dev.parent, "%s clr: 0x%x\n", __func__, clr); | |
502 | ||
503 | xiic_setreg32(i2c, XIIC_IISR_OFFSET, clr); | |
504 | } | |
505 | ||
506 | static int xiic_bus_busy(struct xiic_i2c *i2c) | |
507 | { | |
508 | u8 sr = xiic_getreg8(i2c, XIIC_SR_REG_OFFSET); | |
509 | ||
510 | return (sr & XIIC_SR_BUS_BUSY_MASK) ? -EBUSY : 0; | |
511 | } | |
512 | ||
513 | static int xiic_busy(struct xiic_i2c *i2c) | |
514 | { | |
515 | int tries = 3; | |
516 | int err; | |
517 | ||
518 | if (i2c->tx_msg) | |
519 | return -EBUSY; | |
520 | ||
521 | /* for instance if previous transfer was terminated due to TX error | |
522 | * it might be that the bus is on it's way to become available | |
523 | * give it at most 3 ms to wake | |
524 | */ | |
525 | err = xiic_bus_busy(i2c); | |
526 | while (err && tries--) { | |
527 | mdelay(1); | |
528 | err = xiic_bus_busy(i2c); | |
529 | } | |
530 | ||
531 | return err; | |
532 | } | |
533 | ||
534 | static void xiic_start_recv(struct xiic_i2c *i2c) | |
535 | { | |
536 | u8 rx_watermark; | |
537 | struct i2c_msg *msg = i2c->rx_msg = i2c->tx_msg; | |
538 | ||
539 | /* Clear and enable Rx full interrupt. */ | |
540 | xiic_irq_clr_en(i2c, XIIC_INTR_RX_FULL_MASK | XIIC_INTR_TX_ERROR_MASK); | |
541 | ||
542 | /* we want to get all but last byte, because the TX_ERROR IRQ is used | |
543 | * to inidicate error ACK on the address, and negative ack on the last | |
544 | * received byte, so to not mix them receive all but last. | |
545 | * In the case where there is only one byte to receive | |
546 | * we can check if ERROR and RX full is set at the same time | |
547 | */ | |
548 | rx_watermark = msg->len; | |
549 | if (rx_watermark > IIC_RX_FIFO_DEPTH) | |
550 | rx_watermark = IIC_RX_FIFO_DEPTH; | |
551 | xiic_setreg8(i2c, XIIC_RFD_REG_OFFSET, rx_watermark - 1); | |
552 | ||
553 | if (!(msg->flags & I2C_M_NOSTART)) | |
554 | /* write the address */ | |
555 | xiic_setreg16(i2c, XIIC_DTR_REG_OFFSET, | |
556 | (msg->addr << 1) | XIIC_READ_OPERATION | | |
557 | XIIC_TX_DYN_START_MASK); | |
558 | ||
559 | xiic_irq_clr_en(i2c, XIIC_INTR_BNB_MASK); | |
560 | ||
561 | xiic_setreg16(i2c, XIIC_DTR_REG_OFFSET, | |
562 | msg->len | ((i2c->nmsgs == 1) ? XIIC_TX_DYN_STOP_MASK : 0)); | |
563 | if (i2c->nmsgs == 1) | |
564 | /* very last, enable bus not busy as well */ | |
565 | xiic_irq_clr_en(i2c, XIIC_INTR_BNB_MASK); | |
566 | ||
567 | /* the message is tx:ed */ | |
568 | i2c->tx_pos = msg->len; | |
569 | } | |
570 | ||
571 | static void xiic_start_send(struct xiic_i2c *i2c) | |
572 | { | |
573 | struct i2c_msg *msg = i2c->tx_msg; | |
574 | ||
575 | xiic_irq_clr(i2c, XIIC_INTR_TX_ERROR_MASK); | |
576 | ||
f1e9f89a KA |
577 | dev_dbg(i2c->adap.dev.parent, "%s entry, msg: %p, len: %d", |
578 | __func__, msg, msg->len); | |
579 | dev_dbg(i2c->adap.dev.parent, "%s entry, ISR: 0x%x, CR: 0x%x\n", | |
580 | __func__, xiic_getreg32(i2c, XIIC_IISR_OFFSET), | |
e1d5b659 RR |
581 | xiic_getreg8(i2c, XIIC_CR_REG_OFFSET)); |
582 | ||
583 | if (!(msg->flags & I2C_M_NOSTART)) { | |
584 | /* write the address */ | |
585 | u16 data = ((msg->addr << 1) & 0xfe) | XIIC_WRITE_OPERATION | | |
586 | XIIC_TX_DYN_START_MASK; | |
587 | if ((i2c->nmsgs == 1) && msg->len == 0) | |
588 | /* no data and last message -> add STOP */ | |
589 | data |= XIIC_TX_DYN_STOP_MASK; | |
590 | ||
591 | xiic_setreg16(i2c, XIIC_DTR_REG_OFFSET, data); | |
592 | } | |
593 | ||
594 | xiic_fill_tx_fifo(i2c); | |
595 | ||
596 | /* Clear any pending Tx empty, Tx Error and then enable them. */ | |
597 | xiic_irq_clr_en(i2c, XIIC_INTR_TX_EMPTY_MASK | XIIC_INTR_TX_ERROR_MASK | | |
598 | XIIC_INTR_BNB_MASK); | |
599 | } | |
600 | ||
601 | static irqreturn_t xiic_isr(int irq, void *dev_id) | |
602 | { | |
603 | struct xiic_i2c *i2c = dev_id; | |
604 | ||
605 | spin_lock(&i2c->lock); | |
606 | /* disable interrupts globally */ | |
607 | xiic_setreg32(i2c, XIIC_DGIER_OFFSET, 0); | |
608 | ||
609 | dev_dbg(i2c->adap.dev.parent, "%s entry\n", __func__); | |
610 | ||
611 | xiic_process(i2c); | |
612 | ||
613 | xiic_setreg32(i2c, XIIC_DGIER_OFFSET, XIIC_GINTR_ENABLE_MASK); | |
614 | spin_unlock(&i2c->lock); | |
615 | ||
616 | return IRQ_HANDLED; | |
617 | } | |
618 | ||
619 | static void __xiic_start_xfer(struct xiic_i2c *i2c) | |
620 | { | |
621 | int first = 1; | |
622 | int fifo_space = xiic_tx_fifo_space(i2c); | |
623 | dev_dbg(i2c->adap.dev.parent, "%s entry, msg: %p, fifos space: %d\n", | |
624 | __func__, i2c->tx_msg, fifo_space); | |
625 | ||
626 | if (!i2c->tx_msg) | |
627 | return; | |
628 | ||
629 | i2c->rx_pos = 0; | |
630 | i2c->tx_pos = 0; | |
631 | i2c->state = STATE_START; | |
632 | while ((fifo_space >= 2) && (first || (i2c->nmsgs > 1))) { | |
633 | if (!first) { | |
634 | i2c->nmsgs--; | |
635 | i2c->tx_msg++; | |
636 | i2c->tx_pos = 0; | |
637 | } else | |
638 | first = 0; | |
639 | ||
640 | if (i2c->tx_msg->flags & I2C_M_RD) { | |
641 | /* we dont date putting several reads in the FIFO */ | |
642 | xiic_start_recv(i2c); | |
643 | return; | |
644 | } else { | |
645 | xiic_start_send(i2c); | |
646 | if (xiic_tx_space(i2c) != 0) { | |
647 | /* the message could not be completely sent */ | |
648 | break; | |
649 | } | |
650 | } | |
651 | ||
652 | fifo_space = xiic_tx_fifo_space(i2c); | |
653 | } | |
654 | ||
655 | /* there are more messages or the current one could not be completely | |
656 | * put into the FIFO, also enable the half empty interrupt | |
657 | */ | |
658 | if (i2c->nmsgs > 1 || xiic_tx_space(i2c)) | |
659 | xiic_irq_clr_en(i2c, XIIC_INTR_TX_HALF_MASK); | |
660 | ||
661 | } | |
662 | ||
663 | static void xiic_start_xfer(struct xiic_i2c *i2c) | |
664 | { | |
665 | unsigned long flags; | |
666 | ||
667 | spin_lock_irqsave(&i2c->lock, flags); | |
668 | xiic_reinit(i2c); | |
669 | /* disable interrupts globally */ | |
670 | xiic_setreg32(i2c, XIIC_DGIER_OFFSET, 0); | |
671 | spin_unlock_irqrestore(&i2c->lock, flags); | |
672 | ||
673 | __xiic_start_xfer(i2c); | |
674 | xiic_setreg32(i2c, XIIC_DGIER_OFFSET, XIIC_GINTR_ENABLE_MASK); | |
675 | } | |
676 | ||
677 | static int xiic_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num) | |
678 | { | |
679 | struct xiic_i2c *i2c = i2c_get_adapdata(adap); | |
680 | int err; | |
681 | ||
682 | dev_dbg(adap->dev.parent, "%s entry SR: 0x%x\n", __func__, | |
683 | xiic_getreg8(i2c, XIIC_SR_REG_OFFSET)); | |
684 | ||
685 | err = xiic_busy(i2c); | |
686 | if (err) | |
687 | return err; | |
688 | ||
689 | i2c->tx_msg = msgs; | |
690 | i2c->nmsgs = num; | |
691 | ||
692 | xiic_start_xfer(i2c); | |
693 | ||
694 | if (wait_event_timeout(i2c->wait, (i2c->state == STATE_ERROR) || | |
695 | (i2c->state == STATE_DONE), HZ)) | |
696 | return (i2c->state == STATE_DONE) ? num : -EIO; | |
697 | else { | |
698 | i2c->tx_msg = NULL; | |
699 | i2c->rx_msg = NULL; | |
700 | i2c->nmsgs = 0; | |
701 | return -ETIMEDOUT; | |
702 | } | |
703 | } | |
704 | ||
705 | static u32 xiic_func(struct i2c_adapter *adap) | |
706 | { | |
707 | return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL; | |
708 | } | |
709 | ||
710 | static const struct i2c_algorithm xiic_algorithm = { | |
4db5beed WS |
711 | .master_xfer = xiic_xfer, |
712 | .functionality = xiic_func, | |
e1d5b659 RR |
713 | }; |
714 | ||
715 | static struct i2c_adapter xiic_adapter = { | |
4db5beed WS |
716 | .owner = THIS_MODULE, |
717 | .name = DRIVER_NAME, | |
718 | .class = I2C_CLASS_DEPRECATED, | |
719 | .algo = &xiic_algorithm, | |
e1d5b659 RR |
720 | }; |
721 | ||
722 | ||
0b255e92 | 723 | static int xiic_i2c_probe(struct platform_device *pdev) |
e1d5b659 RR |
724 | { |
725 | struct xiic_i2c *i2c; | |
726 | struct xiic_i2c_platform_data *pdata; | |
727 | struct resource *res; | |
728 | int ret, irq; | |
729 | u8 i; | |
48ef3ca9 | 730 | u32 sr; |
e1d5b659 | 731 | |
168e722d KA |
732 | i2c = devm_kzalloc(&pdev->dev, sizeof(*i2c), GFP_KERNEL); |
733 | if (!i2c) | |
734 | return -ENOMEM; | |
735 | ||
e1d5b659 | 736 | res = platform_get_resource(pdev, IORESOURCE_MEM, 0); |
168e722d KA |
737 | i2c->base = devm_ioremap_resource(&pdev->dev, res); |
738 | if (IS_ERR(i2c->base)) | |
739 | return PTR_ERR(i2c->base); | |
e1d5b659 RR |
740 | |
741 | irq = platform_get_irq(pdev, 0); | |
742 | if (irq < 0) | |
168e722d | 743 | return irq; |
e1d5b659 | 744 | |
ab0dc7a8 | 745 | pdata = dev_get_platdata(&pdev->dev); |
e1d5b659 | 746 | |
e1d5b659 RR |
747 | /* hook up driver to tree */ |
748 | platform_set_drvdata(pdev, i2c); | |
749 | i2c->adap = xiic_adapter; | |
750 | i2c_set_adapdata(&i2c->adap, i2c); | |
751 | i2c->adap.dev.parent = &pdev->dev; | |
3ac0b337 | 752 | i2c->adap.dev.of_node = pdev->dev.of_node; |
e1d5b659 | 753 | |
e1d5b659 RR |
754 | spin_lock_init(&i2c->lock); |
755 | init_waitqueue_head(&i2c->wait); | |
168e722d KA |
756 | |
757 | ret = devm_request_irq(&pdev->dev, irq, xiic_isr, 0, pdev->name, i2c); | |
758 | if (ret < 0) { | |
e1d5b659 | 759 | dev_err(&pdev->dev, "Cannot claim IRQ\n"); |
168e722d | 760 | return ret; |
e1d5b659 RR |
761 | } |
762 | ||
48ef3ca9 TG |
763 | /* |
764 | * Detect endianness | |
765 | * Try to reset the TX FIFO. Then check the EMPTY flag. If it is not | |
766 | * set, assume that the endianness was wrong and swap. | |
767 | */ | |
768 | i2c->endianness = LITTLE; | |
769 | xiic_setreg32(i2c, XIIC_CR_REG_OFFSET, XIIC_CR_TX_FIFO_RESET_MASK); | |
770 | /* Reset is cleared in xiic_reinit */ | |
771 | sr = xiic_getreg32(i2c, XIIC_SR_REG_OFFSET); | |
772 | if (!(sr & XIIC_SR_TX_FIFO_EMPTY_MASK)) | |
773 | i2c->endianness = BIG; | |
774 | ||
617bdcbc MS |
775 | xiic_reinit(i2c); |
776 | ||
e1d5b659 RR |
777 | /* add i2c adapter to i2c tree */ |
778 | ret = i2c_add_adapter(&i2c->adap); | |
779 | if (ret) { | |
780 | dev_err(&pdev->dev, "Failed to add adapter\n"); | |
168e722d KA |
781 | xiic_deinit(i2c); |
782 | return ret; | |
e1d5b659 RR |
783 | } |
784 | ||
3ac0b337 LPC |
785 | if (pdata) { |
786 | /* add in known devices to the bus */ | |
787 | for (i = 0; i < pdata->num_devices; i++) | |
788 | i2c_new_device(&i2c->adap, pdata->devices + i); | |
789 | } | |
790 | ||
e1d5b659 | 791 | return 0; |
e1d5b659 RR |
792 | } |
793 | ||
0b255e92 | 794 | static int xiic_i2c_remove(struct platform_device *pdev) |
e1d5b659 RR |
795 | { |
796 | struct xiic_i2c *i2c = platform_get_drvdata(pdev); | |
e1d5b659 RR |
797 | |
798 | /* remove adapter & data */ | |
799 | i2c_del_adapter(&i2c->adap); | |
800 | ||
801 | xiic_deinit(i2c); | |
802 | ||
e1d5b659 RR |
803 | return 0; |
804 | } | |
805 | ||
3ac0b337 | 806 | #if defined(CONFIG_OF) |
0b255e92 | 807 | static const struct of_device_id xiic_of_match[] = { |
3ac0b337 LPC |
808 | { .compatible = "xlnx,xps-iic-2.00.a", }, |
809 | {}, | |
810 | }; | |
811 | MODULE_DEVICE_TABLE(of, xiic_of_match); | |
812 | #endif | |
813 | ||
e1d5b659 RR |
814 | static struct platform_driver xiic_i2c_driver = { |
815 | .probe = xiic_i2c_probe, | |
0b255e92 | 816 | .remove = xiic_i2c_remove, |
e1d5b659 | 817 | .driver = { |
e1d5b659 | 818 | .name = DRIVER_NAME, |
3ac0b337 | 819 | .of_match_table = of_match_ptr(xiic_of_match), |
e1d5b659 RR |
820 | }, |
821 | }; | |
822 | ||
a3664b51 | 823 | module_platform_driver(xiic_i2c_driver); |
e1d5b659 RR |
824 | |
825 | MODULE_AUTHOR("info@mocean-labs.com"); | |
826 | MODULE_DESCRIPTION("Xilinx I2C bus driver"); | |
827 | MODULE_LICENSE("GPL v2"); | |
a3664b51 | 828 | MODULE_ALIAS("platform:"DRIVER_NAME); |