1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Driver for I2C adapter in Rockchip RK3xxx SoC
4 *
5 * Max Schwarz <max.schwarz@online.de>
6 * based on the patches by Rockchip Inc.
7 */
8
9 #include <linux/kernel.h>
10 #include <linux/module.h>
11 #include <linux/i2c.h>
12 #include <linux/interrupt.h>
13 #include <linux/iopoll.h>
14 #include <linux/errno.h>
15 #include <linux/err.h>
16 #include <linux/platform_device.h>
17 #include <linux/io.h>
18 #include <linux/of_address.h>
19 #include <linux/of_irq.h>
20 #include <linux/spinlock.h>
21 #include <linux/clk.h>
22 #include <linux/wait.h>
23 #include <linux/mfd/syscon.h>
24 #include <linux/regmap.h>
25 #include <linux/math64.h>
26
27
28 /* Register Map */
29 #define REG_CON 0x00 /* control register */
30 #define REG_CLKDIV 0x04 /* clock divisor register */
31 #define REG_MRXADDR 0x08 /* slave address for REGISTER_TX */
32 #define REG_MRXRADDR 0x0c /* slave register address for REGISTER_TX */
33 #define REG_MTXCNT 0x10 /* number of bytes to be transmitted */
34 #define REG_MRXCNT 0x14 /* number of bytes to be received */
35 #define REG_IEN 0x18 /* interrupt enable */
36 #define REG_IPD 0x1c /* interrupt pending */
37 #define REG_FCNT 0x20 /* finished count */
38
39 /* Data buffer offsets */
40 #define TXBUFFER_BASE 0x100
41 #define RXBUFFER_BASE 0x200
42
43 /* REG_CON bits */
44 #define REG_CON_EN BIT(0)
45 enum {
46 REG_CON_MOD_TX = 0, /* transmit data */
47 REG_CON_MOD_REGISTER_TX, /* select register and restart */
48 REG_CON_MOD_RX, /* receive data */
49 REG_CON_MOD_REGISTER_RX, /* broken: transmits read addr AND writes
50 * register addr */
51 };
52 #define REG_CON_MOD(mod) ((mod) << 1)
53 #define REG_CON_MOD_MASK (BIT(1) | BIT(2))
54 #define REG_CON_START BIT(3)
55 #define REG_CON_STOP BIT(4)
56 #define REG_CON_LASTACK BIT(5) /* 1: send NACK after last received byte */
57 #define REG_CON_ACTACK BIT(6) /* 1: stop if NACK is received */
58
59 #define REG_CON_TUNING_MASK GENMASK_ULL(15, 8)
60
61 #define REG_CON_SDA_CFG(cfg) ((cfg) << 8)
62 #define REG_CON_STA_CFG(cfg) ((cfg) << 12)
63 #define REG_CON_STO_CFG(cfg) ((cfg) << 14)
64
65 /* REG_MRXADDR bits */
66 #define REG_MRXADDR_VALID(x) BIT(24 + (x)) /* [x*8+7:x*8] of MRX[R]ADDR valid */
67
68 /* REG_IEN/REG_IPD bits */
69 #define REG_INT_BTF BIT(0) /* a byte was transmitted */
70 #define REG_INT_BRF BIT(1) /* a byte was received */
71 #define REG_INT_MBTF BIT(2) /* master data transmit finished */
72 #define REG_INT_MBRF BIT(3) /* master data receive finished */
73 #define REG_INT_START BIT(4) /* START condition generated */
74 #define REG_INT_STOP BIT(5) /* STOP condition generated */
75 #define REG_INT_NAKRCV BIT(6) /* NACK received */
76 #define REG_INT_ALL 0x7f
77
78 /* Constants */
79 #define WAIT_TIMEOUT 1000 /* ms */
80 #define DEFAULT_SCL_RATE (100 * 1000) /* Hz */
81
82 /**
83 * struct i2c_spec_values - I2C specification values for various modes
84 * @min_hold_start_ns: min hold time (repeated) START condition
85 * @min_low_ns: min LOW period of the SCL clock
86 * @min_high_ns: min HIGH period of the SCL cloc
87 * @min_setup_start_ns: min set-up time for a repeated START conditio
88 * @max_data_hold_ns: max data hold time
89 * @min_data_setup_ns: min data set-up time
90 * @min_setup_stop_ns: min set-up time for STOP condition
91 * @min_hold_buffer_ns: min bus free time between a STOP and
92 * START condition
93 */
94 struct i2c_spec_values {
95 unsigned long min_hold_start_ns;
96 unsigned long min_low_ns;
97 unsigned long min_high_ns;
98 unsigned long min_setup_start_ns;
99 unsigned long max_data_hold_ns;
100 unsigned long min_data_setup_ns;
101 unsigned long min_setup_stop_ns;
102 unsigned long min_hold_buffer_ns;
103 };
104
105 static const struct i2c_spec_values standard_mode_spec = {
106 .min_hold_start_ns = 4000,
107 .min_low_ns = 4700,
108 .min_high_ns = 4000,
109 .min_setup_start_ns = 4700,
110 .max_data_hold_ns = 3450,
111 .min_data_setup_ns = 250,
112 .min_setup_stop_ns = 4000,
113 .min_hold_buffer_ns = 4700,
114 };
115
116 static const struct i2c_spec_values fast_mode_spec = {
117 .min_hold_start_ns = 600,
118 .min_low_ns = 1300,
119 .min_high_ns = 600,
120 .min_setup_start_ns = 600,
121 .max_data_hold_ns = 900,
122 .min_data_setup_ns = 100,
123 .min_setup_stop_ns = 600,
124 .min_hold_buffer_ns = 1300,
125 };
126
127 static const struct i2c_spec_values fast_mode_plus_spec = {
128 .min_hold_start_ns = 260,
129 .min_low_ns = 500,
130 .min_high_ns = 260,
131 .min_setup_start_ns = 260,
132 .max_data_hold_ns = 400,
133 .min_data_setup_ns = 50,
134 .min_setup_stop_ns = 260,
135 .min_hold_buffer_ns = 500,
136 };
137
138 /**
139 * struct rk3x_i2c_calced_timings - calculated V1 timings
140 * @div_low: Divider output for low
141 * @div_high: Divider output for high
142 * @tuning: Used to adjust setup/hold data time,
143 * setup/hold start time and setup stop time for
144 * v1's calc_timings, the tuning should all be 0
145 * for old hardware anyone using v0's calc_timings.
146 */
147 struct rk3x_i2c_calced_timings {
148 unsigned long div_low;
149 unsigned long div_high;
150 unsigned int tuning;
151 };
152
153 enum rk3x_i2c_state {
154 STATE_IDLE,
155 STATE_START,
156 STATE_READ,
157 STATE_WRITE,
158 STATE_STOP
159 };
160
161 /**
162 * struct rk3x_i2c_soc_data - SOC-specific data
163 * @grf_offset: offset inside the grf regmap for setting the i2c type
164 * @calc_timings: Callback function for i2c timing information calculated
165 */
166 struct rk3x_i2c_soc_data {
167 int grf_offset;
168 int (*calc_timings)(unsigned long, struct i2c_timings *,
169 struct rk3x_i2c_calced_timings *);
170 };
171
172 /**
173 * struct rk3x_i2c - private data of the controller
174 * @adap: corresponding I2C adapter
175 * @dev: device for this controller
176 * @soc_data: related soc data struct
177 * @regs: virtual memory area
178 * @clk: function clk for rk3399 or function & Bus clks for others
179 * @pclk: Bus clk for rk3399
180 * @clk_rate_nb: i2c clk rate change notify
181 * @t: I2C known timing information
182 * @lock: spinlock for the i2c bus
183 * @wait: the waitqueue to wait for i2c transfer
184 * @busy: the condition for the event to wait for
185 * @msg: current i2c message
186 * @addr: addr of i2c slave device
187 * @mode: mode of i2c transfer
188 * @is_last_msg: flag determines whether it is the last msg in this transfer
189 * @state: state of i2c transfer
190 * @processed: byte length which has been send or received
191 * @error: error code for i2c transfer
192 */
193 struct rk3x_i2c {
194 struct i2c_adapter adap;
195 struct device *dev;
196 const struct rk3x_i2c_soc_data *soc_data;
197
198 /* Hardware resources */
199 void __iomem *regs;
200 struct clk *clk;
201 struct clk *pclk;
202 struct notifier_block clk_rate_nb;
203
204 /* Settings */
205 struct i2c_timings t;
206
207 /* Synchronization & notification */
208 spinlock_t lock;
209 wait_queue_head_t wait;
210 bool busy;
211
212 /* Current message */
213 struct i2c_msg *msg;
214 u8 addr;
215 unsigned int mode;
216 bool is_last_msg;
217
218 /* I2C state machine */
219 enum rk3x_i2c_state state;
220 unsigned int processed;
221 int error;
222 };
223
i2c_writel(struct rk3x_i2c * i2c,u32 value,unsigned int offset)224 static inline void i2c_writel(struct rk3x_i2c *i2c, u32 value,
225 unsigned int offset)
226 {
227 writel(value, i2c->regs + offset);
228 }
229
i2c_readl(struct rk3x_i2c * i2c,unsigned int offset)230 static inline u32 i2c_readl(struct rk3x_i2c *i2c, unsigned int offset)
231 {
232 return readl(i2c->regs + offset);
233 }
234
235 /* Reset all interrupt pending bits */
rk3x_i2c_clean_ipd(struct rk3x_i2c * i2c)236 static inline void rk3x_i2c_clean_ipd(struct rk3x_i2c *i2c)
237 {
238 i2c_writel(i2c, REG_INT_ALL, REG_IPD);
239 }
240
241 /**
242 * rk3x_i2c_start - Generate a START condition, which triggers a REG_INT_START interrupt.
243 * @i2c: target controller data
244 */
rk3x_i2c_start(struct rk3x_i2c * i2c)245 static void rk3x_i2c_start(struct rk3x_i2c *i2c)
246 {
247 u32 val = i2c_readl(i2c, REG_CON) & REG_CON_TUNING_MASK;
248
249 i2c_writel(i2c, REG_INT_START, REG_IEN);
250
251 /* enable adapter with correct mode, send START condition */
252 val |= REG_CON_EN | REG_CON_MOD(i2c->mode) | REG_CON_START;
253
254 /* if we want to react to NACK, set ACTACK bit */
255 if (!(i2c->msg->flags & I2C_M_IGNORE_NAK))
256 val |= REG_CON_ACTACK;
257
258 i2c_writel(i2c, val, REG_CON);
259 }
260
261 /**
262 * rk3x_i2c_stop - Generate a STOP condition, which triggers a REG_INT_STOP interrupt.
263 * @i2c: target controller data
264 * @error: Error code to return in rk3x_i2c_xfer
265 */
rk3x_i2c_stop(struct rk3x_i2c * i2c,int error)266 static void rk3x_i2c_stop(struct rk3x_i2c *i2c, int error)
267 {
268 unsigned int ctrl;
269
270 i2c->processed = 0;
271 i2c->msg = NULL;
272 i2c->error = error;
273
274 if (i2c->is_last_msg) {
275 /* Enable stop interrupt */
276 i2c_writel(i2c, REG_INT_STOP, REG_IEN);
277
278 i2c->state = STATE_STOP;
279
280 ctrl = i2c_readl(i2c, REG_CON);
281 ctrl |= REG_CON_STOP;
282 i2c_writel(i2c, ctrl, REG_CON);
283 } else {
284 /* Signal rk3x_i2c_xfer to start the next message. */
285 i2c->busy = false;
286 i2c->state = STATE_IDLE;
287
288 /*
289 * The HW is actually not capable of REPEATED START. But we can
290 * get the intended effect by resetting its internal state
291 * and issuing an ordinary START.
292 */
293 ctrl = i2c_readl(i2c, REG_CON) & REG_CON_TUNING_MASK;
294 i2c_writel(i2c, ctrl, REG_CON);
295
296 /* signal that we are finished with the current msg */
297 wake_up(&i2c->wait);
298 }
299 }
300
301 /**
302 * rk3x_i2c_prepare_read - Setup a read according to i2c->msg
303 * @i2c: target controller data
304 */
rk3x_i2c_prepare_read(struct rk3x_i2c * i2c)305 static void rk3x_i2c_prepare_read(struct rk3x_i2c *i2c)
306 {
307 unsigned int len = i2c->msg->len - i2c->processed;
308 u32 con;
309
310 con = i2c_readl(i2c, REG_CON);
311
312 /*
313 * The hw can read up to 32 bytes at a time. If we need more than one
314 * chunk, send an ACK after the last byte of the current chunk.
315 */
316 if (len > 32) {
317 len = 32;
318 con &= ~REG_CON_LASTACK;
319 } else {
320 con |= REG_CON_LASTACK;
321 }
322
323 /* make sure we are in plain RX mode if we read a second chunk */
324 if (i2c->processed != 0) {
325 con &= ~REG_CON_MOD_MASK;
326 con |= REG_CON_MOD(REG_CON_MOD_RX);
327 }
328
329 i2c_writel(i2c, con, REG_CON);
330 i2c_writel(i2c, len, REG_MRXCNT);
331 }
332
333 /**
334 * rk3x_i2c_fill_transmit_buf - Fill the transmit buffer with data from i2c->msg
335 * @i2c: target controller data
336 */
rk3x_i2c_fill_transmit_buf(struct rk3x_i2c * i2c)337 static void rk3x_i2c_fill_transmit_buf(struct rk3x_i2c *i2c)
338 {
339 unsigned int i, j;
340 u32 cnt = 0;
341 u32 val;
342 u8 byte;
343
344 for (i = 0; i < 8; ++i) {
345 val = 0;
346 for (j = 0; j < 4; ++j) {
347 if ((i2c->processed == i2c->msg->len) && (cnt != 0))
348 break;
349
350 if (i2c->processed == 0 && cnt == 0)
351 byte = (i2c->addr & 0x7f) << 1;
352 else
353 byte = i2c->msg->buf[i2c->processed++];
354
355 val |= byte << (j * 8);
356 cnt++;
357 }
358
359 i2c_writel(i2c, val, TXBUFFER_BASE + 4 * i);
360
361 if (i2c->processed == i2c->msg->len)
362 break;
363 }
364
365 i2c_writel(i2c, cnt, REG_MTXCNT);
366 }
367
368
369 /* IRQ handlers for individual states */
370
rk3x_i2c_handle_start(struct rk3x_i2c * i2c,unsigned int ipd)371 static void rk3x_i2c_handle_start(struct rk3x_i2c *i2c, unsigned int ipd)
372 {
373 if (!(ipd & REG_INT_START)) {
374 rk3x_i2c_stop(i2c, -EIO);
375 dev_warn(i2c->dev, "unexpected irq in START: 0x%x\n", ipd);
376 rk3x_i2c_clean_ipd(i2c);
377 return;
378 }
379
380 /* ack interrupt */
381 i2c_writel(i2c, REG_INT_START, REG_IPD);
382
383 /* disable start bit */
384 i2c_writel(i2c, i2c_readl(i2c, REG_CON) & ~REG_CON_START, REG_CON);
385
386 /* enable appropriate interrupts and transition */
387 if (i2c->mode == REG_CON_MOD_TX) {
388 i2c_writel(i2c, REG_INT_MBTF | REG_INT_NAKRCV, REG_IEN);
389 i2c->state = STATE_WRITE;
390 rk3x_i2c_fill_transmit_buf(i2c);
391 } else {
392 /* in any other case, we are going to be reading. */
393 i2c_writel(i2c, REG_INT_MBRF | REG_INT_NAKRCV, REG_IEN);
394 i2c->state = STATE_READ;
395 rk3x_i2c_prepare_read(i2c);
396 }
397 }
398
rk3x_i2c_handle_write(struct rk3x_i2c * i2c,unsigned int ipd)399 static void rk3x_i2c_handle_write(struct rk3x_i2c *i2c, unsigned int ipd)
400 {
401 if (!(ipd & REG_INT_MBTF)) {
402 rk3x_i2c_stop(i2c, -EIO);
403 dev_err(i2c->dev, "unexpected irq in WRITE: 0x%x\n", ipd);
404 rk3x_i2c_clean_ipd(i2c);
405 return;
406 }
407
408 /* ack interrupt */
409 i2c_writel(i2c, REG_INT_MBTF, REG_IPD);
410
411 /* are we finished? */
412 if (i2c->processed == i2c->msg->len)
413 rk3x_i2c_stop(i2c, i2c->error);
414 else
415 rk3x_i2c_fill_transmit_buf(i2c);
416 }
417
rk3x_i2c_handle_read(struct rk3x_i2c * i2c,unsigned int ipd)418 static void rk3x_i2c_handle_read(struct rk3x_i2c *i2c, unsigned int ipd)
419 {
420 unsigned int i;
421 unsigned int len = i2c->msg->len - i2c->processed;
422 u32 val;
423 u8 byte;
424
425 /* we only care for MBRF here. */
426 if (!(ipd & REG_INT_MBRF))
427 return;
428
429 /* ack interrupt (read also produces a spurious START flag, clear it too) */
430 i2c_writel(i2c, REG_INT_MBRF | REG_INT_START, REG_IPD);
431
432 /* Can only handle a maximum of 32 bytes at a time */
433 if (len > 32)
434 len = 32;
435
436 /* read the data from receive buffer */
437 for (i = 0; i < len; ++i) {
438 if (i % 4 == 0)
439 val = i2c_readl(i2c, RXBUFFER_BASE + (i / 4) * 4);
440
441 byte = (val >> ((i % 4) * 8)) & 0xff;
442 i2c->msg->buf[i2c->processed++] = byte;
443 }
444
445 /* are we finished? */
446 if (i2c->processed == i2c->msg->len)
447 rk3x_i2c_stop(i2c, i2c->error);
448 else
449 rk3x_i2c_prepare_read(i2c);
450 }
451
rk3x_i2c_handle_stop(struct rk3x_i2c * i2c,unsigned int ipd)452 static void rk3x_i2c_handle_stop(struct rk3x_i2c *i2c, unsigned int ipd)
453 {
454 unsigned int con;
455
456 if (!(ipd & REG_INT_STOP)) {
457 rk3x_i2c_stop(i2c, -EIO);
458 dev_err(i2c->dev, "unexpected irq in STOP: 0x%x\n", ipd);
459 rk3x_i2c_clean_ipd(i2c);
460 return;
461 }
462
463 /* ack interrupt */
464 i2c_writel(i2c, REG_INT_STOP, REG_IPD);
465
466 /* disable STOP bit */
467 con = i2c_readl(i2c, REG_CON);
468 con &= ~REG_CON_STOP;
469 i2c_writel(i2c, con, REG_CON);
470
471 i2c->busy = false;
472 i2c->state = STATE_IDLE;
473
474 /* signal rk3x_i2c_xfer that we are finished */
475 wake_up(&i2c->wait);
476 }
477
rk3x_i2c_irq(int irqno,void * dev_id)478 static irqreturn_t rk3x_i2c_irq(int irqno, void *dev_id)
479 {
480 struct rk3x_i2c *i2c = dev_id;
481 unsigned int ipd;
482
483 spin_lock(&i2c->lock);
484
485 ipd = i2c_readl(i2c, REG_IPD);
486 if (i2c->state == STATE_IDLE) {
487 dev_warn(i2c->dev, "irq in STATE_IDLE, ipd = 0x%x\n", ipd);
488 rk3x_i2c_clean_ipd(i2c);
489 goto out;
490 }
491
492 dev_dbg(i2c->dev, "IRQ: state %d, ipd: %x\n", i2c->state, ipd);
493
494 /* Clean interrupt bits we don't care about */
495 ipd &= ~(REG_INT_BRF | REG_INT_BTF);
496
497 if (ipd & REG_INT_NAKRCV) {
498 /*
499 * We got a NACK in the last operation. Depending on whether
500 * IGNORE_NAK is set, we have to stop the operation and report
501 * an error.
502 */
503 i2c_writel(i2c, REG_INT_NAKRCV, REG_IPD);
504
505 ipd &= ~REG_INT_NAKRCV;
506
507 if (!(i2c->msg->flags & I2C_M_IGNORE_NAK))
508 rk3x_i2c_stop(i2c, -ENXIO);
509 }
510
511 /* is there anything left to handle? */
512 if ((ipd & REG_INT_ALL) == 0)
513 goto out;
514
515 switch (i2c->state) {
516 case STATE_START:
517 rk3x_i2c_handle_start(i2c, ipd);
518 break;
519 case STATE_WRITE:
520 rk3x_i2c_handle_write(i2c, ipd);
521 break;
522 case STATE_READ:
523 rk3x_i2c_handle_read(i2c, ipd);
524 break;
525 case STATE_STOP:
526 rk3x_i2c_handle_stop(i2c, ipd);
527 break;
528 case STATE_IDLE:
529 break;
530 }
531
532 out:
533 spin_unlock(&i2c->lock);
534 return IRQ_HANDLED;
535 }
536
537 /**
538 * rk3x_i2c_get_spec - Get timing values of I2C specification
539 * @speed: Desired SCL frequency
540 *
541 * Return: Matched i2c_spec_values.
542 */
rk3x_i2c_get_spec(unsigned int speed)543 static const struct i2c_spec_values *rk3x_i2c_get_spec(unsigned int speed)
544 {
545 if (speed <= I2C_MAX_STANDARD_MODE_FREQ)
546 return &standard_mode_spec;
547 else if (speed <= I2C_MAX_FAST_MODE_FREQ)
548 return &fast_mode_spec;
549 else
550 return &fast_mode_plus_spec;
551 }
552
553 /**
554 * rk3x_i2c_v0_calc_timings - Calculate divider values for desired SCL frequency
555 * @clk_rate: I2C input clock rate
556 * @t: Known I2C timing information
557 * @t_calc: Caculated rk3x private timings that would be written into regs
558 *
559 * Return: %0 on success, -%EINVAL if the goal SCL rate is too slow. In that case
560 * a best-effort divider value is returned in divs. If the target rate is
561 * too high, we silently use the highest possible rate.
562 */
rk3x_i2c_v0_calc_timings(unsigned long clk_rate,struct i2c_timings * t,struct rk3x_i2c_calced_timings * t_calc)563 static int rk3x_i2c_v0_calc_timings(unsigned long clk_rate,
564 struct i2c_timings *t,
565 struct rk3x_i2c_calced_timings *t_calc)
566 {
567 unsigned long min_low_ns, min_high_ns;
568 unsigned long max_low_ns, min_total_ns;
569
570 unsigned long clk_rate_khz, scl_rate_khz;
571
572 unsigned long min_low_div, min_high_div;
573 unsigned long max_low_div;
574
575 unsigned long min_div_for_hold, min_total_div;
576 unsigned long extra_div, extra_low_div, ideal_low_div;
577
578 unsigned long data_hold_buffer_ns = 50;
579 const struct i2c_spec_values *spec;
580 int ret = 0;
581
582 /* Only support standard-mode and fast-mode */
583 if (WARN_ON(t->bus_freq_hz > I2C_MAX_FAST_MODE_FREQ))
584 t->bus_freq_hz = I2C_MAX_FAST_MODE_FREQ;
585
586 /* prevent scl_rate_khz from becoming 0 */
587 if (WARN_ON(t->bus_freq_hz < 1000))
588 t->bus_freq_hz = 1000;
589
590 /*
591 * min_low_ns: The minimum number of ns we need to hold low to
592 * meet I2C specification, should include fall time.
593 * min_high_ns: The minimum number of ns we need to hold high to
594 * meet I2C specification, should include rise time.
595 * max_low_ns: The maximum number of ns we can hold low to meet
596 * I2C specification.
597 *
598 * Note: max_low_ns should be (maximum data hold time * 2 - buffer)
599 * This is because the i2c host on Rockchip holds the data line
600 * for half the low time.
601 */
602 spec = rk3x_i2c_get_spec(t->bus_freq_hz);
603 min_high_ns = t->scl_rise_ns + spec->min_high_ns;
604
605 /*
606 * Timings for repeated start:
607 * - controller appears to drop SDA at .875x (7/8) programmed clk high.
608 * - controller appears to keep SCL high for 2x programmed clk high.
609 *
610 * We need to account for those rules in picking our "high" time so
611 * we meet tSU;STA and tHD;STA times.
612 */
613 min_high_ns = max(min_high_ns, DIV_ROUND_UP(
614 (t->scl_rise_ns + spec->min_setup_start_ns) * 1000, 875));
615 min_high_ns = max(min_high_ns, DIV_ROUND_UP(
616 (t->scl_rise_ns + spec->min_setup_start_ns + t->sda_fall_ns +
617 spec->min_high_ns), 2));
618
619 min_low_ns = t->scl_fall_ns + spec->min_low_ns;
620 max_low_ns = spec->max_data_hold_ns * 2 - data_hold_buffer_ns;
621 min_total_ns = min_low_ns + min_high_ns;
622
623 /* Adjust to avoid overflow */
624 clk_rate_khz = DIV_ROUND_UP(clk_rate, 1000);
625 scl_rate_khz = t->bus_freq_hz / 1000;
626
627 /*
628 * We need the total div to be >= this number
629 * so we don't clock too fast.
630 */
631 min_total_div = DIV_ROUND_UP(clk_rate_khz, scl_rate_khz * 8);
632
633 /* These are the min dividers needed for min hold times. */
634 min_low_div = DIV_ROUND_UP(clk_rate_khz * min_low_ns, 8 * 1000000);
635 min_high_div = DIV_ROUND_UP(clk_rate_khz * min_high_ns, 8 * 1000000);
636 min_div_for_hold = (min_low_div + min_high_div);
637
638 /*
639 * This is the maximum divider so we don't go over the maximum.
640 * We don't round up here (we round down) since this is a maximum.
641 */
642 max_low_div = clk_rate_khz * max_low_ns / (8 * 1000000);
643
644 if (min_low_div > max_low_div) {
645 WARN_ONCE(true,
646 "Conflicting, min_low_div %lu, max_low_div %lu\n",
647 min_low_div, max_low_div);
648 max_low_div = min_low_div;
649 }
650
651 if (min_div_for_hold > min_total_div) {
652 /*
653 * Time needed to meet hold requirements is important.
654 * Just use that.
655 */
656 t_calc->div_low = min_low_div;
657 t_calc->div_high = min_high_div;
658 } else {
659 /*
660 * We've got to distribute some time among the low and high
661 * so we don't run too fast.
662 */
663 extra_div = min_total_div - min_div_for_hold;
664
665 /*
666 * We'll try to split things up perfectly evenly,
667 * biasing slightly towards having a higher div
668 * for low (spend more time low).
669 */
670 ideal_low_div = DIV_ROUND_UP(clk_rate_khz * min_low_ns,
671 scl_rate_khz * 8 * min_total_ns);
672
673 /* Don't allow it to go over the maximum */
674 if (ideal_low_div > max_low_div)
675 ideal_low_div = max_low_div;
676
677 /*
678 * Handle when the ideal low div is going to take up
679 * more than we have.
680 */
681 if (ideal_low_div > min_low_div + extra_div)
682 ideal_low_div = min_low_div + extra_div;
683
684 /* Give low the "ideal" and give high whatever extra is left */
685 extra_low_div = ideal_low_div - min_low_div;
686 t_calc->div_low = ideal_low_div;
687 t_calc->div_high = min_high_div + (extra_div - extra_low_div);
688 }
689
690 /*
691 * Adjust to the fact that the hardware has an implicit "+1".
692 * NOTE: Above calculations always produce div_low > 0 and div_high > 0.
693 */
694 t_calc->div_low--;
695 t_calc->div_high--;
696
697 /* Give the tuning value 0, that would not update con register */
698 t_calc->tuning = 0;
699 /* Maximum divider supported by hw is 0xffff */
700 if (t_calc->div_low > 0xffff) {
701 t_calc->div_low = 0xffff;
702 ret = -EINVAL;
703 }
704
705 if (t_calc->div_high > 0xffff) {
706 t_calc->div_high = 0xffff;
707 ret = -EINVAL;
708 }
709
710 return ret;
711 }
712
713 /**
714 * rk3x_i2c_v1_calc_timings - Calculate timing values for desired SCL frequency
715 * @clk_rate: I2C input clock rate
716 * @t: Known I2C timing information
717 * @t_calc: Caculated rk3x private timings that would be written into regs
718 *
719 * Return: %0 on success, -%EINVAL if the goal SCL rate is too slow. In that case
720 * a best-effort divider value is returned in divs. If the target rate is
721 * too high, we silently use the highest possible rate.
722 * The following formulas are v1's method to calculate timings.
723 *
724 * l = divl + 1;
725 * h = divh + 1;
726 * s = sda_update_config + 1;
727 * u = start_setup_config + 1;
728 * p = stop_setup_config + 1;
729 * T = Tclk_i2c;
730 *
731 * tHigh = 8 * h * T;
732 * tLow = 8 * l * T;
733 *
734 * tHD;sda = (l * s + 1) * T;
735 * tSU;sda = [(8 - s) * l + 1] * T;
736 * tI2C = 8 * (l + h) * T;
737 *
738 * tSU;sta = (8h * u + 1) * T;
739 * tHD;sta = [8h * (u + 1) - 1] * T;
740 * tSU;sto = (8h * p + 1) * T;
741 */
rk3x_i2c_v1_calc_timings(unsigned long clk_rate,struct i2c_timings * t,struct rk3x_i2c_calced_timings * t_calc)742 static int rk3x_i2c_v1_calc_timings(unsigned long clk_rate,
743 struct i2c_timings *t,
744 struct rk3x_i2c_calced_timings *t_calc)
745 {
746 unsigned long min_low_ns, min_high_ns;
747 unsigned long min_setup_start_ns, min_setup_data_ns;
748 unsigned long min_setup_stop_ns, max_hold_data_ns;
749
750 unsigned long clk_rate_khz, scl_rate_khz;
751
752 unsigned long min_low_div, min_high_div;
753
754 unsigned long min_div_for_hold, min_total_div;
755 unsigned long extra_div, extra_low_div;
756 unsigned long sda_update_cfg, stp_sta_cfg, stp_sto_cfg;
757
758 const struct i2c_spec_values *spec;
759 int ret = 0;
760
761 /* Support standard-mode, fast-mode and fast-mode plus */
762 if (WARN_ON(t->bus_freq_hz > I2C_MAX_FAST_MODE_PLUS_FREQ))
763 t->bus_freq_hz = I2C_MAX_FAST_MODE_PLUS_FREQ;
764
765 /* prevent scl_rate_khz from becoming 0 */
766 if (WARN_ON(t->bus_freq_hz < 1000))
767 t->bus_freq_hz = 1000;
768
769 /*
770 * min_low_ns: The minimum number of ns we need to hold low to
771 * meet I2C specification, should include fall time.
772 * min_high_ns: The minimum number of ns we need to hold high to
773 * meet I2C specification, should include rise time.
774 */
775 spec = rk3x_i2c_get_spec(t->bus_freq_hz);
776
777 /* calculate min-divh and min-divl */
778 clk_rate_khz = DIV_ROUND_UP(clk_rate, 1000);
779 scl_rate_khz = t->bus_freq_hz / 1000;
780 min_total_div = DIV_ROUND_UP(clk_rate_khz, scl_rate_khz * 8);
781
782 min_high_ns = t->scl_rise_ns + spec->min_high_ns;
783 min_high_div = DIV_ROUND_UP(clk_rate_khz * min_high_ns, 8 * 1000000);
784
785 min_low_ns = t->scl_fall_ns + spec->min_low_ns;
786 min_low_div = DIV_ROUND_UP(clk_rate_khz * min_low_ns, 8 * 1000000);
787
788 /*
789 * Final divh and divl must be greater than 0, otherwise the
790 * hardware would not output the i2c clk.
791 */
792 min_high_div = (min_high_div < 1) ? 2 : min_high_div;
793 min_low_div = (min_low_div < 1) ? 2 : min_low_div;
794
795 /* These are the min dividers needed for min hold times. */
796 min_div_for_hold = (min_low_div + min_high_div);
797
798 /*
799 * This is the maximum divider so we don't go over the maximum.
800 * We don't round up here (we round down) since this is a maximum.
801 */
802 if (min_div_for_hold >= min_total_div) {
803 /*
804 * Time needed to meet hold requirements is important.
805 * Just use that.
806 */
807 t_calc->div_low = min_low_div;
808 t_calc->div_high = min_high_div;
809 } else {
810 /*
811 * We've got to distribute some time among the low and high
812 * so we don't run too fast.
813 * We'll try to split things up by the scale of min_low_div and
814 * min_high_div, biasing slightly towards having a higher div
815 * for low (spend more time low).
816 */
817 extra_div = min_total_div - min_div_for_hold;
818 extra_low_div = DIV_ROUND_UP(min_low_div * extra_div,
819 min_div_for_hold);
820
821 t_calc->div_low = min_low_div + extra_low_div;
822 t_calc->div_high = min_high_div + (extra_div - extra_low_div);
823 }
824
825 /*
826 * calculate sda data hold count by the rules, data_upd_st:3
827 * is a appropriate value to reduce calculated times.
828 */
829 for (sda_update_cfg = 3; sda_update_cfg > 0; sda_update_cfg--) {
830 max_hold_data_ns = DIV_ROUND_UP((sda_update_cfg
831 * (t_calc->div_low) + 1)
832 * 1000000, clk_rate_khz);
833 min_setup_data_ns = DIV_ROUND_UP(((8 - sda_update_cfg)
834 * (t_calc->div_low) + 1)
835 * 1000000, clk_rate_khz);
836 if ((max_hold_data_ns < spec->max_data_hold_ns) &&
837 (min_setup_data_ns > spec->min_data_setup_ns))
838 break;
839 }
840
841 /* calculate setup start config */
842 min_setup_start_ns = t->scl_rise_ns + spec->min_setup_start_ns;
843 stp_sta_cfg = DIV_ROUND_UP(clk_rate_khz * min_setup_start_ns
844 - 1000000, 8 * 1000000 * (t_calc->div_high));
845
846 /* calculate setup stop config */
847 min_setup_stop_ns = t->scl_rise_ns + spec->min_setup_stop_ns;
848 stp_sto_cfg = DIV_ROUND_UP(clk_rate_khz * min_setup_stop_ns
849 - 1000000, 8 * 1000000 * (t_calc->div_high));
850
851 t_calc->tuning = REG_CON_SDA_CFG(--sda_update_cfg) |
852 REG_CON_STA_CFG(--stp_sta_cfg) |
853 REG_CON_STO_CFG(--stp_sto_cfg);
854
855 t_calc->div_low--;
856 t_calc->div_high--;
857
858 /* Maximum divider supported by hw is 0xffff */
859 if (t_calc->div_low > 0xffff) {
860 t_calc->div_low = 0xffff;
861 ret = -EINVAL;
862 }
863
864 if (t_calc->div_high > 0xffff) {
865 t_calc->div_high = 0xffff;
866 ret = -EINVAL;
867 }
868
869 return ret;
870 }
871
rk3x_i2c_adapt_div(struct rk3x_i2c * i2c,unsigned long clk_rate)872 static void rk3x_i2c_adapt_div(struct rk3x_i2c *i2c, unsigned long clk_rate)
873 {
874 struct i2c_timings *t = &i2c->t;
875 struct rk3x_i2c_calced_timings calc;
876 u64 t_low_ns, t_high_ns;
877 unsigned long flags;
878 u32 val;
879 int ret;
880
881 ret = i2c->soc_data->calc_timings(clk_rate, t, &calc);
882 WARN_ONCE(ret != 0, "Could not reach SCL freq %u", t->bus_freq_hz);
883
884 clk_enable(i2c->pclk);
885
886 spin_lock_irqsave(&i2c->lock, flags);
887 val = i2c_readl(i2c, REG_CON);
888 val &= ~REG_CON_TUNING_MASK;
889 val |= calc.tuning;
890 i2c_writel(i2c, val, REG_CON);
891 i2c_writel(i2c, (calc.div_high << 16) | (calc.div_low & 0xffff),
892 REG_CLKDIV);
893 spin_unlock_irqrestore(&i2c->lock, flags);
894
895 clk_disable(i2c->pclk);
896
897 t_low_ns = div_u64(((u64)calc.div_low + 1) * 8 * 1000000000, clk_rate);
898 t_high_ns = div_u64(((u64)calc.div_high + 1) * 8 * 1000000000,
899 clk_rate);
900 dev_dbg(i2c->dev,
901 "CLK %lukhz, Req %uns, Act low %lluns high %lluns\n",
902 clk_rate / 1000,
903 1000000000 / t->bus_freq_hz,
904 t_low_ns, t_high_ns);
905 }
906
907 /**
908 * rk3x_i2c_clk_notifier_cb - Clock rate change callback
909 * @nb: Pointer to notifier block
910 * @event: Notification reason
911 * @data: Pointer to notification data object
912 *
913 * The callback checks whether a valid bus frequency can be generated after the
914 * change. If so, the change is acknowledged, otherwise the change is aborted.
915 * New dividers are written to the HW in the pre- or post change notification
916 * depending on the scaling direction.
917 *
918 * Code adapted from i2c-cadence.c.
919 *
920 * Return: NOTIFY_STOP if the rate change should be aborted, NOTIFY_OK
921 * to acknowledge the change, NOTIFY_DONE if the notification is
922 * considered irrelevant.
923 */
rk3x_i2c_clk_notifier_cb(struct notifier_block * nb,unsigned long event,void * data)924 static int rk3x_i2c_clk_notifier_cb(struct notifier_block *nb, unsigned long
925 event, void *data)
926 {
927 struct clk_notifier_data *ndata = data;
928 struct rk3x_i2c *i2c = container_of(nb, struct rk3x_i2c, clk_rate_nb);
929 struct rk3x_i2c_calced_timings calc;
930
931 switch (event) {
932 case PRE_RATE_CHANGE:
933 /*
934 * Try the calculation (but don't store the result) ahead of
935 * time to see if we need to block the clock change. Timings
936 * shouldn't actually take effect until rk3x_i2c_adapt_div().
937 */
938 if (i2c->soc_data->calc_timings(ndata->new_rate, &i2c->t,
939 &calc) != 0)
940 return NOTIFY_STOP;
941
942 /* scale up */
943 if (ndata->new_rate > ndata->old_rate)
944 rk3x_i2c_adapt_div(i2c, ndata->new_rate);
945
946 return NOTIFY_OK;
947 case POST_RATE_CHANGE:
948 /* scale down */
949 if (ndata->new_rate < ndata->old_rate)
950 rk3x_i2c_adapt_div(i2c, ndata->new_rate);
951 return NOTIFY_OK;
952 case ABORT_RATE_CHANGE:
953 /* scale up */
954 if (ndata->new_rate > ndata->old_rate)
955 rk3x_i2c_adapt_div(i2c, ndata->old_rate);
956 return NOTIFY_OK;
957 default:
958 return NOTIFY_DONE;
959 }
960 }
961
962 /**
963 * rk3x_i2c_setup - Setup I2C registers for an I2C operation specified by msgs, num.
964 * @i2c: target controller data
965 * @msgs: I2C msgs to process
966 * @num: Number of msgs
967 *
968 * Must be called with i2c->lock held.
969 *
970 * Return: Number of I2C msgs processed or negative in case of error
971 */
rk3x_i2c_setup(struct rk3x_i2c * i2c,struct i2c_msg * msgs,int num)972 static int rk3x_i2c_setup(struct rk3x_i2c *i2c, struct i2c_msg *msgs, int num)
973 {
974 u32 addr = (msgs[0].addr & 0x7f) << 1;
975 int ret = 0;
976
977 /*
978 * The I2C adapter can issue a small (len < 4) write packet before
979 * reading. This speeds up SMBus-style register reads.
980 * The MRXADDR/MRXRADDR hold the slave address and the slave register
981 * address in this case.
982 */
983
984 if (num >= 2 && msgs[0].len < 4 &&
985 !(msgs[0].flags & I2C_M_RD) && (msgs[1].flags & I2C_M_RD)) {
986 u32 reg_addr = 0;
987 int i;
988
989 dev_dbg(i2c->dev, "Combined write/read from addr 0x%x\n",
990 addr >> 1);
991
992 /* Fill MRXRADDR with the register address(es) */
993 for (i = 0; i < msgs[0].len; ++i) {
994 reg_addr |= msgs[0].buf[i] << (i * 8);
995 reg_addr |= REG_MRXADDR_VALID(i);
996 }
997
998 /* msgs[0] is handled by hw. */
999 i2c->msg = &msgs[1];
1000
1001 i2c->mode = REG_CON_MOD_REGISTER_TX;
1002
1003 i2c_writel(i2c, addr | REG_MRXADDR_VALID(0), REG_MRXADDR);
1004 i2c_writel(i2c, reg_addr, REG_MRXRADDR);
1005
1006 ret = 2;
1007 } else {
1008 /*
1009 * We'll have to do it the boring way and process the msgs
1010 * one-by-one.
1011 */
1012
1013 if (msgs[0].flags & I2C_M_RD) {
1014 addr |= 1; /* set read bit */
1015
1016 /*
1017 * We have to transmit the slave addr first. Use
1018 * MOD_REGISTER_TX for that purpose.
1019 */
1020 i2c->mode = REG_CON_MOD_REGISTER_TX;
1021 i2c_writel(i2c, addr | REG_MRXADDR_VALID(0),
1022 REG_MRXADDR);
1023 i2c_writel(i2c, 0, REG_MRXRADDR);
1024 } else {
1025 i2c->mode = REG_CON_MOD_TX;
1026 }
1027
1028 i2c->msg = &msgs[0];
1029
1030 ret = 1;
1031 }
1032
1033 i2c->addr = msgs[0].addr;
1034 i2c->busy = true;
1035 i2c->state = STATE_START;
1036 i2c->processed = 0;
1037 i2c->error = 0;
1038
1039 rk3x_i2c_clean_ipd(i2c);
1040
1041 return ret;
1042 }
1043
rk3x_i2c_wait_xfer_poll(struct rk3x_i2c * i2c)1044 static int rk3x_i2c_wait_xfer_poll(struct rk3x_i2c *i2c)
1045 {
1046 ktime_t timeout = ktime_add_ms(ktime_get(), WAIT_TIMEOUT);
1047
1048 while (READ_ONCE(i2c->busy) &&
1049 ktime_compare(ktime_get(), timeout) < 0) {
1050 udelay(5);
1051 rk3x_i2c_irq(0, i2c);
1052 }
1053
1054 return !i2c->busy;
1055 }
1056
rk3x_i2c_xfer_common(struct i2c_adapter * adap,struct i2c_msg * msgs,int num,bool polling)1057 static int rk3x_i2c_xfer_common(struct i2c_adapter *adap,
1058 struct i2c_msg *msgs, int num, bool polling)
1059 {
1060 struct rk3x_i2c *i2c = (struct rk3x_i2c *)adap->algo_data;
1061 unsigned long timeout, flags;
1062 u32 val;
1063 int ret = 0;
1064 int i;
1065
1066 spin_lock_irqsave(&i2c->lock, flags);
1067
1068 clk_enable(i2c->clk);
1069 clk_enable(i2c->pclk);
1070
1071 i2c->is_last_msg = false;
1072
1073 /*
1074 * Process msgs. We can handle more than one message at once (see
1075 * rk3x_i2c_setup()).
1076 */
1077 for (i = 0; i < num; i += ret) {
1078 ret = rk3x_i2c_setup(i2c, msgs + i, num - i);
1079
1080 if (ret < 0) {
1081 dev_err(i2c->dev, "rk3x_i2c_setup() failed\n");
1082 break;
1083 }
1084
1085 if (i + ret >= num)
1086 i2c->is_last_msg = true;
1087
1088 spin_unlock_irqrestore(&i2c->lock, flags);
1089
1090 rk3x_i2c_start(i2c);
1091
1092 if (!polling) {
1093 timeout = wait_event_timeout(i2c->wait, !i2c->busy,
1094 msecs_to_jiffies(WAIT_TIMEOUT));
1095 } else {
1096 timeout = rk3x_i2c_wait_xfer_poll(i2c);
1097 }
1098
1099 spin_lock_irqsave(&i2c->lock, flags);
1100
1101 if (timeout == 0) {
1102 dev_err(i2c->dev, "timeout, ipd: 0x%02x, state: %d\n",
1103 i2c_readl(i2c, REG_IPD), i2c->state);
1104
1105 /* Force a STOP condition without interrupt */
1106 i2c_writel(i2c, 0, REG_IEN);
1107 val = i2c_readl(i2c, REG_CON) & REG_CON_TUNING_MASK;
1108 val |= REG_CON_EN | REG_CON_STOP;
1109 i2c_writel(i2c, val, REG_CON);
1110
1111 i2c->state = STATE_IDLE;
1112
1113 ret = -ETIMEDOUT;
1114 break;
1115 }
1116
1117 if (i2c->error) {
1118 ret = i2c->error;
1119 break;
1120 }
1121 }
1122
1123 clk_disable(i2c->pclk);
1124 clk_disable(i2c->clk);
1125
1126 spin_unlock_irqrestore(&i2c->lock, flags);
1127
1128 return ret < 0 ? ret : num;
1129 }
1130
rk3x_i2c_xfer(struct i2c_adapter * adap,struct i2c_msg * msgs,int num)1131 static int rk3x_i2c_xfer(struct i2c_adapter *adap,
1132 struct i2c_msg *msgs, int num)
1133 {
1134 return rk3x_i2c_xfer_common(adap, msgs, num, false);
1135 }
1136
rk3x_i2c_xfer_polling(struct i2c_adapter * adap,struct i2c_msg * msgs,int num)1137 static int rk3x_i2c_xfer_polling(struct i2c_adapter *adap,
1138 struct i2c_msg *msgs, int num)
1139 {
1140 return rk3x_i2c_xfer_common(adap, msgs, num, true);
1141 }
1142
rk3x_i2c_resume(struct device * dev)1143 static __maybe_unused int rk3x_i2c_resume(struct device *dev)
1144 {
1145 struct rk3x_i2c *i2c = dev_get_drvdata(dev);
1146
1147 rk3x_i2c_adapt_div(i2c, clk_get_rate(i2c->clk));
1148
1149 return 0;
1150 }
1151
rk3x_i2c_func(struct i2c_adapter * adap)1152 static u32 rk3x_i2c_func(struct i2c_adapter *adap)
1153 {
1154 return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | I2C_FUNC_PROTOCOL_MANGLING;
1155 }
1156
1157 static const struct i2c_algorithm rk3x_i2c_algorithm = {
1158 .master_xfer = rk3x_i2c_xfer,
1159 .master_xfer_atomic = rk3x_i2c_xfer_polling,
1160 .functionality = rk3x_i2c_func,
1161 };
1162
1163 static const struct rk3x_i2c_soc_data rv1108_soc_data = {
1164 .grf_offset = -1,
1165 .calc_timings = rk3x_i2c_v1_calc_timings,
1166 };
1167
1168 static const struct rk3x_i2c_soc_data rv1126_soc_data = {
1169 .grf_offset = 0x118,
1170 .calc_timings = rk3x_i2c_v1_calc_timings,
1171 };
1172
1173 static const struct rk3x_i2c_soc_data rk3066_soc_data = {
1174 .grf_offset = 0x154,
1175 .calc_timings = rk3x_i2c_v0_calc_timings,
1176 };
1177
1178 static const struct rk3x_i2c_soc_data rk3188_soc_data = {
1179 .grf_offset = 0x0a4,
1180 .calc_timings = rk3x_i2c_v0_calc_timings,
1181 };
1182
1183 static const struct rk3x_i2c_soc_data rk3228_soc_data = {
1184 .grf_offset = -1,
1185 .calc_timings = rk3x_i2c_v0_calc_timings,
1186 };
1187
1188 static const struct rk3x_i2c_soc_data rk3288_soc_data = {
1189 .grf_offset = -1,
1190 .calc_timings = rk3x_i2c_v0_calc_timings,
1191 };
1192
1193 static const struct rk3x_i2c_soc_data rk3399_soc_data = {
1194 .grf_offset = -1,
1195 .calc_timings = rk3x_i2c_v1_calc_timings,
1196 };
1197
1198 static const struct of_device_id rk3x_i2c_match[] = {
1199 {
1200 .compatible = "rockchip,rv1108-i2c",
1201 .data = &rv1108_soc_data
1202 },
1203 {
1204 .compatible = "rockchip,rv1126-i2c",
1205 .data = &rv1126_soc_data
1206 },
1207 {
1208 .compatible = "rockchip,rk3066-i2c",
1209 .data = &rk3066_soc_data
1210 },
1211 {
1212 .compatible = "rockchip,rk3188-i2c",
1213 .data = &rk3188_soc_data
1214 },
1215 {
1216 .compatible = "rockchip,rk3228-i2c",
1217 .data = &rk3228_soc_data
1218 },
1219 {
1220 .compatible = "rockchip,rk3288-i2c",
1221 .data = &rk3288_soc_data
1222 },
1223 {
1224 .compatible = "rockchip,rk3399-i2c",
1225 .data = &rk3399_soc_data
1226 },
1227 {},
1228 };
1229 MODULE_DEVICE_TABLE(of, rk3x_i2c_match);
1230
rk3x_i2c_probe(struct platform_device * pdev)1231 static int rk3x_i2c_probe(struct platform_device *pdev)
1232 {
1233 struct device_node *np = pdev->dev.of_node;
1234 const struct of_device_id *match;
1235 struct rk3x_i2c *i2c;
1236 int ret = 0;
1237 int bus_nr;
1238 u32 value;
1239 int irq;
1240 unsigned long clk_rate;
1241
1242 i2c = devm_kzalloc(&pdev->dev, sizeof(struct rk3x_i2c), GFP_KERNEL);
1243 if (!i2c)
1244 return -ENOMEM;
1245
1246 match = of_match_node(rk3x_i2c_match, np);
1247 i2c->soc_data = match->data;
1248
1249 /* use common interface to get I2C timing properties */
1250 i2c_parse_fw_timings(&pdev->dev, &i2c->t, true);
1251
1252 strscpy(i2c->adap.name, "rk3x-i2c", sizeof(i2c->adap.name));
1253 i2c->adap.owner = THIS_MODULE;
1254 i2c->adap.algo = &rk3x_i2c_algorithm;
1255 i2c->adap.retries = 3;
1256 i2c->adap.dev.of_node = np;
1257 i2c->adap.algo_data = i2c;
1258 i2c->adap.dev.parent = &pdev->dev;
1259
1260 i2c->dev = &pdev->dev;
1261
1262 spin_lock_init(&i2c->lock);
1263 init_waitqueue_head(&i2c->wait);
1264
1265 i2c->regs = devm_platform_ioremap_resource(pdev, 0);
1266 if (IS_ERR(i2c->regs))
1267 return PTR_ERR(i2c->regs);
1268
1269 /* Try to set the I2C adapter number from dt */
1270 bus_nr = of_alias_get_id(np, "i2c");
1271
1272 /*
1273 * Switch to new interface if the SoC also offers the old one.
1274 * The control bit is located in the GRF register space.
1275 */
1276 if (i2c->soc_data->grf_offset >= 0) {
1277 struct regmap *grf;
1278
1279 grf = syscon_regmap_lookup_by_phandle(np, "rockchip,grf");
1280 if (IS_ERR(grf)) {
1281 dev_err(&pdev->dev,
1282 "rk3x-i2c needs 'rockchip,grf' property\n");
1283 return PTR_ERR(grf);
1284 }
1285
1286 if (bus_nr < 0) {
1287 dev_err(&pdev->dev, "rk3x-i2c needs i2cX alias");
1288 return -EINVAL;
1289 }
1290
1291 /* 27+i: write mask, 11+i: value */
1292 value = BIT(27 + bus_nr) | BIT(11 + bus_nr);
1293
1294 ret = regmap_write(grf, i2c->soc_data->grf_offset, value);
1295 if (ret != 0) {
1296 dev_err(i2c->dev, "Could not write to GRF: %d\n", ret);
1297 return ret;
1298 }
1299 }
1300
1301 /* IRQ setup */
1302 irq = platform_get_irq(pdev, 0);
1303 if (irq < 0)
1304 return irq;
1305
1306 ret = devm_request_irq(&pdev->dev, irq, rk3x_i2c_irq,
1307 0, dev_name(&pdev->dev), i2c);
1308 if (ret < 0) {
1309 dev_err(&pdev->dev, "cannot request IRQ\n");
1310 return ret;
1311 }
1312
1313 platform_set_drvdata(pdev, i2c);
1314
1315 if (i2c->soc_data->calc_timings == rk3x_i2c_v0_calc_timings) {
1316 /* Only one clock to use for bus clock and peripheral clock */
1317 i2c->clk = devm_clk_get(&pdev->dev, NULL);
1318 i2c->pclk = i2c->clk;
1319 } else {
1320 i2c->clk = devm_clk_get(&pdev->dev, "i2c");
1321 i2c->pclk = devm_clk_get(&pdev->dev, "pclk");
1322 }
1323
1324 if (IS_ERR(i2c->clk))
1325 return dev_err_probe(&pdev->dev, PTR_ERR(i2c->clk),
1326 "Can't get bus clk\n");
1327
1328 if (IS_ERR(i2c->pclk))
1329 return dev_err_probe(&pdev->dev, PTR_ERR(i2c->pclk),
1330 "Can't get periph clk\n");
1331
1332 ret = clk_prepare(i2c->clk);
1333 if (ret < 0) {
1334 dev_err(&pdev->dev, "Can't prepare bus clk: %d\n", ret);
1335 return ret;
1336 }
1337 ret = clk_prepare(i2c->pclk);
1338 if (ret < 0) {
1339 dev_err(&pdev->dev, "Can't prepare periph clock: %d\n", ret);
1340 goto err_clk;
1341 }
1342
1343 i2c->clk_rate_nb.notifier_call = rk3x_i2c_clk_notifier_cb;
1344 ret = clk_notifier_register(i2c->clk, &i2c->clk_rate_nb);
1345 if (ret != 0) {
1346 dev_err(&pdev->dev, "Unable to register clock notifier\n");
1347 goto err_pclk;
1348 }
1349
1350 ret = clk_enable(i2c->clk);
1351 if (ret < 0) {
1352 dev_err(&pdev->dev, "Can't enable bus clk: %d\n", ret);
1353 goto err_clk_notifier;
1354 }
1355
1356 clk_rate = clk_get_rate(i2c->clk);
1357 rk3x_i2c_adapt_div(i2c, clk_rate);
1358 clk_disable(i2c->clk);
1359
1360 ret = i2c_add_adapter(&i2c->adap);
1361 if (ret < 0)
1362 goto err_clk_notifier;
1363
1364 return 0;
1365
1366 err_clk_notifier:
1367 clk_notifier_unregister(i2c->clk, &i2c->clk_rate_nb);
1368 err_pclk:
1369 clk_unprepare(i2c->pclk);
1370 err_clk:
1371 clk_unprepare(i2c->clk);
1372 return ret;
1373 }
1374
rk3x_i2c_remove(struct platform_device * pdev)1375 static void rk3x_i2c_remove(struct platform_device *pdev)
1376 {
1377 struct rk3x_i2c *i2c = platform_get_drvdata(pdev);
1378
1379 i2c_del_adapter(&i2c->adap);
1380
1381 clk_notifier_unregister(i2c->clk, &i2c->clk_rate_nb);
1382 clk_unprepare(i2c->pclk);
1383 clk_unprepare(i2c->clk);
1384 }
1385
1386 static SIMPLE_DEV_PM_OPS(rk3x_i2c_pm_ops, NULL, rk3x_i2c_resume);
1387
1388 static struct platform_driver rk3x_i2c_driver = {
1389 .probe = rk3x_i2c_probe,
1390 .remove_new = rk3x_i2c_remove,
1391 .driver = {
1392 .name = "rk3x-i2c",
1393 .of_match_table = rk3x_i2c_match,
1394 .pm = &rk3x_i2c_pm_ops,
1395 },
1396 };
1397
1398 module_platform_driver(rk3x_i2c_driver);
1399
1400 MODULE_DESCRIPTION("Rockchip RK3xxx I2C Bus driver");
1401 MODULE_AUTHOR("Max Schwarz <max.schwarz@online.de>");
1402 MODULE_LICENSE("GPL v2");
1403
