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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * MPC52xx SPI bus driver.
4 *
5 * Copyright (C) 2008 Secret Lab Technologies Ltd.
6 *
7 * This is the driver for the MPC5200's dedicated SPI controller.
8 *
9 * Note: this driver does not support the MPC5200 PSC in SPI mode. For
10 * that driver see drivers/spi/mpc52xx_psc_spi.c
11 */
12
13#include <linux/module.h>
14#include <linux/errno.h>
15#include <linux/of_platform.h>
16#include <linux/interrupt.h>
17#include <linux/delay.h>
18#include <linux/spi/spi.h>
19#include <linux/io.h>
20#include <linux/of_gpio.h>
21#include <linux/slab.h>
22#include <asm/time.h>
23#include <asm/mpc52xx.h>
24
25MODULE_AUTHOR("Grant Likely <grant.likely@secretlab.ca>");
26MODULE_DESCRIPTION("MPC52xx SPI (non-PSC) Driver");
27MODULE_LICENSE("GPL");
28
29/* Register offsets */
30#define SPI_CTRL1 0x00
31#define SPI_CTRL1_SPIE (1 << 7)
32#define SPI_CTRL1_SPE (1 << 6)
33#define SPI_CTRL1_MSTR (1 << 4)
34#define SPI_CTRL1_CPOL (1 << 3)
35#define SPI_CTRL1_CPHA (1 << 2)
36#define SPI_CTRL1_SSOE (1 << 1)
37#define SPI_CTRL1_LSBFE (1 << 0)
38
39#define SPI_CTRL2 0x01
40#define SPI_BRR 0x04
41
42#define SPI_STATUS 0x05
43#define SPI_STATUS_SPIF (1 << 7)
44#define SPI_STATUS_WCOL (1 << 6)
45#define SPI_STATUS_MODF (1 << 4)
46
47#define SPI_DATA 0x09
48#define SPI_PORTDATA 0x0d
49#define SPI_DATADIR 0x10
50
51/* FSM state return values */
52#define FSM_STOP 0 /* Nothing more for the state machine to */
53 /* do. If something interesting happens */
54 /* then an IRQ will be received */
55#define FSM_POLL 1 /* need to poll for completion, an IRQ is */
56 /* not expected */
57#define FSM_CONTINUE 2 /* Keep iterating the state machine */
58
59/* Driver internal data */
60struct mpc52xx_spi {
61 struct spi_master *master;
62 void __iomem *regs;
63 int irq0; /* MODF irq */
64 int irq1; /* SPIF irq */
65 unsigned int ipb_freq;
66
67 /* Statistics; not used now, but will be reintroduced for debugfs */
68 int msg_count;
69 int wcol_count;
70 int wcol_ticks;
71 u32 wcol_tx_timestamp;
72 int modf_count;
73 int byte_count;
74
75 struct list_head queue; /* queue of pending messages */
76 spinlock_t lock;
77 struct work_struct work;
78
79 /* Details of current transfer (length, and buffer pointers) */
80 struct spi_message *message; /* current message */
81 struct spi_transfer *transfer; /* current transfer */
82 int (*state)(int irq, struct mpc52xx_spi *ms, u8 status, u8 data);
83 int len;
84 int timestamp;
85 u8 *rx_buf;
86 const u8 *tx_buf;
87 int cs_change;
88 int gpio_cs_count;
89 unsigned int *gpio_cs;
90};
91
92/*
93 * CS control function
94 */
95static void mpc52xx_spi_chipsel(struct mpc52xx_spi *ms, int value)
96{
97 int cs;
98
99 if (ms->gpio_cs_count > 0) {
100 cs = ms->message->spi->chip_select;
101 gpio_set_value(ms->gpio_cs[cs], value ? 0 : 1);
102 } else
103 out_8(ms->regs + SPI_PORTDATA, value ? 0 : 0x08);
104}
105
106/*
107 * Start a new transfer. This is called both by the idle state
108 * for the first transfer in a message, and by the wait state when the
109 * previous transfer in a message is complete.
110 */
111static void mpc52xx_spi_start_transfer(struct mpc52xx_spi *ms)
112{
113 ms->rx_buf = ms->transfer->rx_buf;
114 ms->tx_buf = ms->transfer->tx_buf;
115 ms->len = ms->transfer->len;
116
117 /* Activate the chip select */
118 if (ms->cs_change)
119 mpc52xx_spi_chipsel(ms, 1);
120 ms->cs_change = ms->transfer->cs_change;
121
122 /* Write out the first byte */
123 ms->wcol_tx_timestamp = get_tbl();
124 if (ms->tx_buf)
125 out_8(ms->regs + SPI_DATA, *ms->tx_buf++);
126 else
127 out_8(ms->regs + SPI_DATA, 0);
128}
129
130/* Forward declaration of state handlers */
131static int mpc52xx_spi_fsmstate_transfer(int irq, struct mpc52xx_spi *ms,
132 u8 status, u8 data);
133static int mpc52xx_spi_fsmstate_wait(int irq, struct mpc52xx_spi *ms,
134 u8 status, u8 data);
135
136/*
137 * IDLE state
138 *
139 * No transfers are in progress; if another transfer is pending then retrieve
140 * it and kick it off. Otherwise, stop processing the state machine
141 */
142static int
143mpc52xx_spi_fsmstate_idle(int irq, struct mpc52xx_spi *ms, u8 status, u8 data)
144{
145 struct spi_device *spi;
146 int spr, sppr;
147 u8 ctrl1;
148
149 if (status && (irq != NO_IRQ))
150 dev_err(&ms->master->dev, "spurious irq, status=0x%.2x\n",
151 status);
152
153 /* Check if there is another transfer waiting. */
154 if (list_empty(&ms->queue))
155 return FSM_STOP;
156
157 /* get the head of the queue */
158 ms->message = list_first_entry(&ms->queue, struct spi_message, queue);
159 list_del_init(&ms->message->queue);
160
161 /* Setup the controller parameters */
162 ctrl1 = SPI_CTRL1_SPIE | SPI_CTRL1_SPE | SPI_CTRL1_MSTR;
163 spi = ms->message->spi;
164 if (spi->mode & SPI_CPHA)
165 ctrl1 |= SPI_CTRL1_CPHA;
166 if (spi->mode & SPI_CPOL)
167 ctrl1 |= SPI_CTRL1_CPOL;
168 if (spi->mode & SPI_LSB_FIRST)
169 ctrl1 |= SPI_CTRL1_LSBFE;
170 out_8(ms->regs + SPI_CTRL1, ctrl1);
171
172 /* Setup the controller speed */
173 /* minimum divider is '2'. Also, add '1' to force rounding the
174 * divider up. */
175 sppr = ((ms->ipb_freq / ms->message->spi->max_speed_hz) + 1) >> 1;
176 spr = 0;
177 if (sppr < 1)
178 sppr = 1;
179 while (((sppr - 1) & ~0x7) != 0) {
180 sppr = (sppr + 1) >> 1; /* add '1' to force rounding up */
181 spr++;
182 }
183 sppr--; /* sppr quantity in register is offset by 1 */
184 if (spr > 7) {
185 /* Don't overrun limits of SPI baudrate register */
186 spr = 7;
187 sppr = 7;
188 }
189 out_8(ms->regs + SPI_BRR, sppr << 4 | spr); /* Set speed */
190
191 ms->cs_change = 1;
192 ms->transfer = container_of(ms->message->transfers.next,
193 struct spi_transfer, transfer_list);
194
195 mpc52xx_spi_start_transfer(ms);
196 ms->state = mpc52xx_spi_fsmstate_transfer;
197
198 return FSM_CONTINUE;
199}
200
201/*
202 * TRANSFER state
203 *
204 * In the middle of a transfer. If the SPI core has completed processing
205 * a byte, then read out the received data and write out the next byte
206 * (unless this transfer is finished; in which case go on to the wait
207 * state)
208 */
209static int mpc52xx_spi_fsmstate_transfer(int irq, struct mpc52xx_spi *ms,
210 u8 status, u8 data)
211{
212 if (!status)
213 return ms->irq0 ? FSM_STOP : FSM_POLL;
214
215 if (status & SPI_STATUS_WCOL) {
216 /* The SPI controller is stoopid. At slower speeds, it may
217 * raise the SPIF flag before the state machine is actually
218 * finished, which causes a collision (internal to the state
219 * machine only). The manual recommends inserting a delay
220 * between receiving the interrupt and sending the next byte,
221 * but it can also be worked around simply by retrying the
222 * transfer which is what we do here. */
223 ms->wcol_count++;
224 ms->wcol_ticks += get_tbl() - ms->wcol_tx_timestamp;
225 ms->wcol_tx_timestamp = get_tbl();
226 data = 0;
227 if (ms->tx_buf)
228 data = *(ms->tx_buf - 1);
229 out_8(ms->regs + SPI_DATA, data); /* try again */
230 return FSM_CONTINUE;
231 } else if (status & SPI_STATUS_MODF) {
232 ms->modf_count++;
233 dev_err(&ms->master->dev, "mode fault\n");
234 mpc52xx_spi_chipsel(ms, 0);
235 ms->message->status = -EIO;
236 if (ms->message->complete)
237 ms->message->complete(ms->message->context);
238 ms->state = mpc52xx_spi_fsmstate_idle;
239 return FSM_CONTINUE;
240 }
241
242 /* Read data out of the spi device */
243 ms->byte_count++;
244 if (ms->rx_buf)
245 *ms->rx_buf++ = data;
246
247 /* Is the transfer complete? */
248 ms->len--;
249 if (ms->len == 0) {
250 ms->timestamp = get_tbl();
251 ms->timestamp += ms->transfer->delay_usecs * tb_ticks_per_usec;
252 ms->state = mpc52xx_spi_fsmstate_wait;
253 return FSM_CONTINUE;
254 }
255
256 /* Write out the next byte */
257 ms->wcol_tx_timestamp = get_tbl();
258 if (ms->tx_buf)
259 out_8(ms->regs + SPI_DATA, *ms->tx_buf++);
260 else
261 out_8(ms->regs + SPI_DATA, 0);
262
263 return FSM_CONTINUE;
264}
265
266/*
267 * WAIT state
268 *
269 * A transfer has completed; need to wait for the delay period to complete
270 * before starting the next transfer
271 */
272static int
273mpc52xx_spi_fsmstate_wait(int irq, struct mpc52xx_spi *ms, u8 status, u8 data)
274{
275 if (status && irq)
276 dev_err(&ms->master->dev, "spurious irq, status=0x%.2x\n",
277 status);
278
279 if (((int)get_tbl()) - ms->timestamp < 0)
280 return FSM_POLL;
281
282 ms->message->actual_length += ms->transfer->len;
283
284 /* Check if there is another transfer in this message. If there
285 * aren't then deactivate CS, notify sender, and drop back to idle
286 * to start the next message. */
287 if (ms->transfer->transfer_list.next == &ms->message->transfers) {
288 ms->msg_count++;
289 mpc52xx_spi_chipsel(ms, 0);
290 ms->message->status = 0;
291 if (ms->message->complete)
292 ms->message->complete(ms->message->context);
293 ms->state = mpc52xx_spi_fsmstate_idle;
294 return FSM_CONTINUE;
295 }
296
297 /* There is another transfer; kick it off */
298
299 if (ms->cs_change)
300 mpc52xx_spi_chipsel(ms, 0);
301
302 ms->transfer = container_of(ms->transfer->transfer_list.next,
303 struct spi_transfer, transfer_list);
304 mpc52xx_spi_start_transfer(ms);
305 ms->state = mpc52xx_spi_fsmstate_transfer;
306 return FSM_CONTINUE;
307}
308
309/**
310 * mpc52xx_spi_fsm_process - Finite State Machine iteration function
311 * @irq: irq number that triggered the FSM or 0 for polling
312 * @ms: pointer to mpc52xx_spi driver data
313 */
314static void mpc52xx_spi_fsm_process(int irq, struct mpc52xx_spi *ms)
315{
316 int rc = FSM_CONTINUE;
317 u8 status, data;
318
319 while (rc == FSM_CONTINUE) {
320 /* Interrupt cleared by read of STATUS followed by
321 * read of DATA registers */
322 status = in_8(ms->regs + SPI_STATUS);
323 data = in_8(ms->regs + SPI_DATA);
324 rc = ms->state(irq, ms, status, data);
325 }
326
327 if (rc == FSM_POLL)
328 schedule_work(&ms->work);
329}
330
331/**
332 * mpc52xx_spi_irq - IRQ handler
333 */
334static irqreturn_t mpc52xx_spi_irq(int irq, void *_ms)
335{
336 struct mpc52xx_spi *ms = _ms;
337 spin_lock(&ms->lock);
338 mpc52xx_spi_fsm_process(irq, ms);
339 spin_unlock(&ms->lock);
340 return IRQ_HANDLED;
341}
342
343/**
344 * mpc52xx_spi_wq - Workqueue function for polling the state machine
345 */
346static void mpc52xx_spi_wq(struct work_struct *work)
347{
348 struct mpc52xx_spi *ms = container_of(work, struct mpc52xx_spi, work);
349 unsigned long flags;
350
351 spin_lock_irqsave(&ms->lock, flags);
352 mpc52xx_spi_fsm_process(0, ms);
353 spin_unlock_irqrestore(&ms->lock, flags);
354}
355
356/*
357 * spi_master ops
358 */
359
360static int mpc52xx_spi_transfer(struct spi_device *spi, struct spi_message *m)
361{
362 struct mpc52xx_spi *ms = spi_master_get_devdata(spi->master);
363 unsigned long flags;
364
365 m->actual_length = 0;
366 m->status = -EINPROGRESS;
367
368 spin_lock_irqsave(&ms->lock, flags);
369 list_add_tail(&m->queue, &ms->queue);
370 spin_unlock_irqrestore(&ms->lock, flags);
371 schedule_work(&ms->work);
372
373 return 0;
374}
375
376/*
377 * OF Platform Bus Binding
378 */
379static int mpc52xx_spi_probe(struct platform_device *op)
380{
381 struct spi_master *master;
382 struct mpc52xx_spi *ms;
383 void __iomem *regs;
384 u8 ctrl1;
385 int rc, i = 0;
386 int gpio_cs;
387
388 /* MMIO registers */
389 dev_dbg(&op->dev, "probing mpc5200 SPI device\n");
390 regs = of_iomap(op->dev.of_node, 0);
391 if (!regs)
392 return -ENODEV;
393
394 /* initialize the device */
395 ctrl1 = SPI_CTRL1_SPIE | SPI_CTRL1_SPE | SPI_CTRL1_MSTR;
396 out_8(regs + SPI_CTRL1, ctrl1);
397 out_8(regs + SPI_CTRL2, 0x0);
398 out_8(regs + SPI_DATADIR, 0xe); /* Set output pins */
399 out_8(regs + SPI_PORTDATA, 0x8); /* Deassert /SS signal */
400
401 /* Clear the status register and re-read it to check for a MODF
402 * failure. This driver cannot currently handle multiple masters
403 * on the SPI bus. This fault will also occur if the SPI signals
404 * are not connected to any pins (port_config setting) */
405 in_8(regs + SPI_STATUS);
406 out_8(regs + SPI_CTRL1, ctrl1);
407
408 in_8(regs + SPI_DATA);
409 if (in_8(regs + SPI_STATUS) & SPI_STATUS_MODF) {
410 dev_err(&op->dev, "mode fault; is port_config correct?\n");
411 rc = -EIO;
412 goto err_init;
413 }
414
415 dev_dbg(&op->dev, "allocating spi_master struct\n");
416 master = spi_alloc_master(&op->dev, sizeof *ms);
417 if (!master) {
418 rc = -ENOMEM;
419 goto err_alloc;
420 }
421
422 master->transfer = mpc52xx_spi_transfer;
423 master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_LSB_FIRST;
424 master->bits_per_word_mask = SPI_BPW_MASK(8);
425 master->dev.of_node = op->dev.of_node;
426
427 platform_set_drvdata(op, master);
428
429 ms = spi_master_get_devdata(master);
430 ms->master = master;
431 ms->regs = regs;
432 ms->irq0 = irq_of_parse_and_map(op->dev.of_node, 0);
433 ms->irq1 = irq_of_parse_and_map(op->dev.of_node, 1);
434 ms->state = mpc52xx_spi_fsmstate_idle;
435 ms->ipb_freq = mpc5xxx_get_bus_frequency(op->dev.of_node);
436 ms->gpio_cs_count = of_gpio_count(op->dev.of_node);
437 if (ms->gpio_cs_count > 0) {
438 master->num_chipselect = ms->gpio_cs_count;
439 ms->gpio_cs = kmalloc_array(ms->gpio_cs_count,
440 sizeof(*ms->gpio_cs),
441 GFP_KERNEL);
442 if (!ms->gpio_cs) {
443 rc = -ENOMEM;
444 goto err_alloc_gpio;
445 }
446
447 for (i = 0; i < ms->gpio_cs_count; i++) {
448 gpio_cs = of_get_gpio(op->dev.of_node, i);
449 if (!gpio_is_valid(gpio_cs)) {
450 dev_err(&op->dev,
451 "could not parse the gpio field in oftree\n");
452 rc = -ENODEV;
453 goto err_gpio;
454 }
455
456 rc = gpio_request(gpio_cs, dev_name(&op->dev));
457 if (rc) {
458 dev_err(&op->dev,
459 "can't request spi cs gpio #%d on gpio line %d\n",
460 i, gpio_cs);
461 goto err_gpio;
462 }
463
464 gpio_direction_output(gpio_cs, 1);
465 ms->gpio_cs[i] = gpio_cs;
466 }
467 }
468
469 spin_lock_init(&ms->lock);
470 INIT_LIST_HEAD(&ms->queue);
471 INIT_WORK(&ms->work, mpc52xx_spi_wq);
472
473 /* Decide if interrupts can be used */
474 if (ms->irq0 && ms->irq1) {
475 rc = request_irq(ms->irq0, mpc52xx_spi_irq, 0,
476 "mpc5200-spi-modf", ms);
477 rc |= request_irq(ms->irq1, mpc52xx_spi_irq, 0,
478 "mpc5200-spi-spif", ms);
479 if (rc) {
480 free_irq(ms->irq0, ms);
481 free_irq(ms->irq1, ms);
482 ms->irq0 = ms->irq1 = 0;
483 }
484 } else {
485 /* operate in polled mode */
486 ms->irq0 = ms->irq1 = 0;
487 }
488
489 if (!ms->irq0)
490 dev_info(&op->dev, "using polled mode\n");
491
492 dev_dbg(&op->dev, "registering spi_master struct\n");
493 rc = spi_register_master(master);
494 if (rc)
495 goto err_register;
496
497 dev_info(&ms->master->dev, "registered MPC5200 SPI bus\n");
498
499 return rc;
500
501 err_register:
502 dev_err(&ms->master->dev, "initialization failed\n");
503 err_gpio:
504 while (i-- > 0)
505 gpio_free(ms->gpio_cs[i]);
506
507 kfree(ms->gpio_cs);
508 err_alloc_gpio:
509 spi_master_put(master);
510 err_alloc:
511 err_init:
512 iounmap(regs);
513 return rc;
514}
515
516static int mpc52xx_spi_remove(struct platform_device *op)
517{
518 struct spi_master *master = spi_master_get(platform_get_drvdata(op));
519 struct mpc52xx_spi *ms = spi_master_get_devdata(master);
520 int i;
521
522 free_irq(ms->irq0, ms);
523 free_irq(ms->irq1, ms);
524
525 for (i = 0; i < ms->gpio_cs_count; i++)
526 gpio_free(ms->gpio_cs[i]);
527
528 kfree(ms->gpio_cs);
529 spi_unregister_master(master);
530 iounmap(ms->regs);
531 spi_master_put(master);
532
533 return 0;
534}
535
536static const struct of_device_id mpc52xx_spi_match[] = {
537 { .compatible = "fsl,mpc5200-spi", },
538 {}
539};
540MODULE_DEVICE_TABLE(of, mpc52xx_spi_match);
541
542static struct platform_driver mpc52xx_spi_of_driver = {
543 .driver = {
544 .name = "mpc52xx-spi",
545 .of_match_table = mpc52xx_spi_match,
546 },
547 .probe = mpc52xx_spi_probe,
548 .remove = mpc52xx_spi_remove,
549};
550module_platform_driver(mpc52xx_spi_of_driver);
1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * MPC52xx SPI bus driver.
4 *
5 * Copyright (C) 2008 Secret Lab Technologies Ltd.
6 *
7 * This is the driver for the MPC5200's dedicated SPI controller.
8 *
9 * Note: this driver does not support the MPC5200 PSC in SPI mode. For
10 * that driver see drivers/spi/mpc52xx_psc_spi.c
11 */
12
13#include <linux/module.h>
14#include <linux/err.h>
15#include <linux/errno.h>
16#include <linux/of_platform.h>
17#include <linux/interrupt.h>
18#include <linux/delay.h>
19#include <linux/gpio/consumer.h>
20#include <linux/spi/spi.h>
21#include <linux/io.h>
22#include <linux/slab.h>
23#include <linux/of_address.h>
24#include <linux/of_irq.h>
25#include <linux/platform_device.h>
26
27#include <asm/time.h>
28#include <asm/mpc52xx.h>
29
30MODULE_AUTHOR("Grant Likely <grant.likely@secretlab.ca>");
31MODULE_DESCRIPTION("MPC52xx SPI (non-PSC) Driver");
32MODULE_LICENSE("GPL");
33
34/* Register offsets */
35#define SPI_CTRL1 0x00
36#define SPI_CTRL1_SPIE (1 << 7)
37#define SPI_CTRL1_SPE (1 << 6)
38#define SPI_CTRL1_MSTR (1 << 4)
39#define SPI_CTRL1_CPOL (1 << 3)
40#define SPI_CTRL1_CPHA (1 << 2)
41#define SPI_CTRL1_SSOE (1 << 1)
42#define SPI_CTRL1_LSBFE (1 << 0)
43
44#define SPI_CTRL2 0x01
45#define SPI_BRR 0x04
46
47#define SPI_STATUS 0x05
48#define SPI_STATUS_SPIF (1 << 7)
49#define SPI_STATUS_WCOL (1 << 6)
50#define SPI_STATUS_MODF (1 << 4)
51
52#define SPI_DATA 0x09
53#define SPI_PORTDATA 0x0d
54#define SPI_DATADIR 0x10
55
56/* FSM state return values */
57#define FSM_STOP 0 /* Nothing more for the state machine to */
58 /* do. If something interesting happens */
59 /* then an IRQ will be received */
60#define FSM_POLL 1 /* need to poll for completion, an IRQ is */
61 /* not expected */
62#define FSM_CONTINUE 2 /* Keep iterating the state machine */
63
64/* Driver internal data */
65struct mpc52xx_spi {
66 struct spi_controller *host;
67 void __iomem *regs;
68 int irq0; /* MODF irq */
69 int irq1; /* SPIF irq */
70 unsigned int ipb_freq;
71
72 /* Statistics; not used now, but will be reintroduced for debugfs */
73 int msg_count;
74 int wcol_count;
75 int wcol_ticks;
76 u32 wcol_tx_timestamp;
77 int modf_count;
78 int byte_count;
79
80 struct list_head queue; /* queue of pending messages */
81 spinlock_t lock;
82 struct work_struct work;
83
84 /* Details of current transfer (length, and buffer pointers) */
85 struct spi_message *message; /* current message */
86 struct spi_transfer *transfer; /* current transfer */
87 int (*state)(int irq, struct mpc52xx_spi *ms, u8 status, u8 data);
88 int len;
89 int timestamp;
90 u8 *rx_buf;
91 const u8 *tx_buf;
92 int cs_change;
93 int gpio_cs_count;
94 struct gpio_desc **gpio_cs;
95};
96
97/*
98 * CS control function
99 */
100static void mpc52xx_spi_chipsel(struct mpc52xx_spi *ms, int value)
101{
102 int cs;
103
104 if (ms->gpio_cs_count > 0) {
105 cs = spi_get_chipselect(ms->message->spi, 0);
106 gpiod_set_value(ms->gpio_cs[cs], value);
107 } else {
108 out_8(ms->regs + SPI_PORTDATA, value ? 0 : 0x08);
109 }
110}
111
112/*
113 * Start a new transfer. This is called both by the idle state
114 * for the first transfer in a message, and by the wait state when the
115 * previous transfer in a message is complete.
116 */
117static void mpc52xx_spi_start_transfer(struct mpc52xx_spi *ms)
118{
119 ms->rx_buf = ms->transfer->rx_buf;
120 ms->tx_buf = ms->transfer->tx_buf;
121 ms->len = ms->transfer->len;
122
123 /* Activate the chip select */
124 if (ms->cs_change)
125 mpc52xx_spi_chipsel(ms, 1);
126 ms->cs_change = ms->transfer->cs_change;
127
128 /* Write out the first byte */
129 ms->wcol_tx_timestamp = mftb();
130 if (ms->tx_buf)
131 out_8(ms->regs + SPI_DATA, *ms->tx_buf++);
132 else
133 out_8(ms->regs + SPI_DATA, 0);
134}
135
136/* Forward declaration of state handlers */
137static int mpc52xx_spi_fsmstate_transfer(int irq, struct mpc52xx_spi *ms,
138 u8 status, u8 data);
139static int mpc52xx_spi_fsmstate_wait(int irq, struct mpc52xx_spi *ms,
140 u8 status, u8 data);
141
142/*
143 * IDLE state
144 *
145 * No transfers are in progress; if another transfer is pending then retrieve
146 * it and kick it off. Otherwise, stop processing the state machine
147 */
148static int
149mpc52xx_spi_fsmstate_idle(int irq, struct mpc52xx_spi *ms, u8 status, u8 data)
150{
151 struct spi_device *spi;
152 int spr, sppr;
153 u8 ctrl1;
154
155 if (status && irq)
156 dev_err(&ms->host->dev, "spurious irq, status=0x%.2x\n",
157 status);
158
159 /* Check if there is another transfer waiting. */
160 if (list_empty(&ms->queue))
161 return FSM_STOP;
162
163 /* get the head of the queue */
164 ms->message = list_first_entry(&ms->queue, struct spi_message, queue);
165 list_del_init(&ms->message->queue);
166
167 /* Setup the controller parameters */
168 ctrl1 = SPI_CTRL1_SPIE | SPI_CTRL1_SPE | SPI_CTRL1_MSTR;
169 spi = ms->message->spi;
170 if (spi->mode & SPI_CPHA)
171 ctrl1 |= SPI_CTRL1_CPHA;
172 if (spi->mode & SPI_CPOL)
173 ctrl1 |= SPI_CTRL1_CPOL;
174 if (spi->mode & SPI_LSB_FIRST)
175 ctrl1 |= SPI_CTRL1_LSBFE;
176 out_8(ms->regs + SPI_CTRL1, ctrl1);
177
178 /* Setup the controller speed */
179 /* minimum divider is '2'. Also, add '1' to force rounding the
180 * divider up. */
181 sppr = ((ms->ipb_freq / ms->message->spi->max_speed_hz) + 1) >> 1;
182 spr = 0;
183 if (sppr < 1)
184 sppr = 1;
185 while (((sppr - 1) & ~0x7) != 0) {
186 sppr = (sppr + 1) >> 1; /* add '1' to force rounding up */
187 spr++;
188 }
189 sppr--; /* sppr quantity in register is offset by 1 */
190 if (spr > 7) {
191 /* Don't overrun limits of SPI baudrate register */
192 spr = 7;
193 sppr = 7;
194 }
195 out_8(ms->regs + SPI_BRR, sppr << 4 | spr); /* Set speed */
196
197 ms->cs_change = 1;
198 ms->transfer = container_of(ms->message->transfers.next,
199 struct spi_transfer, transfer_list);
200
201 mpc52xx_spi_start_transfer(ms);
202 ms->state = mpc52xx_spi_fsmstate_transfer;
203
204 return FSM_CONTINUE;
205}
206
207/*
208 * TRANSFER state
209 *
210 * In the middle of a transfer. If the SPI core has completed processing
211 * a byte, then read out the received data and write out the next byte
212 * (unless this transfer is finished; in which case go on to the wait
213 * state)
214 */
215static int mpc52xx_spi_fsmstate_transfer(int irq, struct mpc52xx_spi *ms,
216 u8 status, u8 data)
217{
218 if (!status)
219 return ms->irq0 ? FSM_STOP : FSM_POLL;
220
221 if (status & SPI_STATUS_WCOL) {
222 /* The SPI controller is stoopid. At slower speeds, it may
223 * raise the SPIF flag before the state machine is actually
224 * finished, which causes a collision (internal to the state
225 * machine only). The manual recommends inserting a delay
226 * between receiving the interrupt and sending the next byte,
227 * but it can also be worked around simply by retrying the
228 * transfer which is what we do here. */
229 ms->wcol_count++;
230 ms->wcol_ticks += mftb() - ms->wcol_tx_timestamp;
231 ms->wcol_tx_timestamp = mftb();
232 data = 0;
233 if (ms->tx_buf)
234 data = *(ms->tx_buf - 1);
235 out_8(ms->regs + SPI_DATA, data); /* try again */
236 return FSM_CONTINUE;
237 } else if (status & SPI_STATUS_MODF) {
238 ms->modf_count++;
239 dev_err(&ms->host->dev, "mode fault\n");
240 mpc52xx_spi_chipsel(ms, 0);
241 ms->message->status = -EIO;
242 if (ms->message->complete)
243 ms->message->complete(ms->message->context);
244 ms->state = mpc52xx_spi_fsmstate_idle;
245 return FSM_CONTINUE;
246 }
247
248 /* Read data out of the spi device */
249 ms->byte_count++;
250 if (ms->rx_buf)
251 *ms->rx_buf++ = data;
252
253 /* Is the transfer complete? */
254 ms->len--;
255 if (ms->len == 0) {
256 ms->timestamp = mftb();
257 if (ms->transfer->delay.unit == SPI_DELAY_UNIT_USECS)
258 ms->timestamp += ms->transfer->delay.value *
259 tb_ticks_per_usec;
260 ms->state = mpc52xx_spi_fsmstate_wait;
261 return FSM_CONTINUE;
262 }
263
264 /* Write out the next byte */
265 ms->wcol_tx_timestamp = mftb();
266 if (ms->tx_buf)
267 out_8(ms->regs + SPI_DATA, *ms->tx_buf++);
268 else
269 out_8(ms->regs + SPI_DATA, 0);
270
271 return FSM_CONTINUE;
272}
273
274/*
275 * WAIT state
276 *
277 * A transfer has completed; need to wait for the delay period to complete
278 * before starting the next transfer
279 */
280static int
281mpc52xx_spi_fsmstate_wait(int irq, struct mpc52xx_spi *ms, u8 status, u8 data)
282{
283 if (status && irq)
284 dev_err(&ms->host->dev, "spurious irq, status=0x%.2x\n",
285 status);
286
287 if (((int)mftb()) - ms->timestamp < 0)
288 return FSM_POLL;
289
290 ms->message->actual_length += ms->transfer->len;
291
292 /* Check if there is another transfer in this message. If there
293 * aren't then deactivate CS, notify sender, and drop back to idle
294 * to start the next message. */
295 if (ms->transfer->transfer_list.next == &ms->message->transfers) {
296 ms->msg_count++;
297 mpc52xx_spi_chipsel(ms, 0);
298 ms->message->status = 0;
299 if (ms->message->complete)
300 ms->message->complete(ms->message->context);
301 ms->state = mpc52xx_spi_fsmstate_idle;
302 return FSM_CONTINUE;
303 }
304
305 /* There is another transfer; kick it off */
306
307 if (ms->cs_change)
308 mpc52xx_spi_chipsel(ms, 0);
309
310 ms->transfer = container_of(ms->transfer->transfer_list.next,
311 struct spi_transfer, transfer_list);
312 mpc52xx_spi_start_transfer(ms);
313 ms->state = mpc52xx_spi_fsmstate_transfer;
314 return FSM_CONTINUE;
315}
316
317/**
318 * mpc52xx_spi_fsm_process - Finite State Machine iteration function
319 * @irq: irq number that triggered the FSM or 0 for polling
320 * @ms: pointer to mpc52xx_spi driver data
321 */
322static void mpc52xx_spi_fsm_process(int irq, struct mpc52xx_spi *ms)
323{
324 int rc = FSM_CONTINUE;
325 u8 status, data;
326
327 while (rc == FSM_CONTINUE) {
328 /* Interrupt cleared by read of STATUS followed by
329 * read of DATA registers */
330 status = in_8(ms->regs + SPI_STATUS);
331 data = in_8(ms->regs + SPI_DATA);
332 rc = ms->state(irq, ms, status, data);
333 }
334
335 if (rc == FSM_POLL)
336 schedule_work(&ms->work);
337}
338
339/**
340 * mpc52xx_spi_irq - IRQ handler
341 */
342static irqreturn_t mpc52xx_spi_irq(int irq, void *_ms)
343{
344 struct mpc52xx_spi *ms = _ms;
345 spin_lock(&ms->lock);
346 mpc52xx_spi_fsm_process(irq, ms);
347 spin_unlock(&ms->lock);
348 return IRQ_HANDLED;
349}
350
351/**
352 * mpc52xx_spi_wq - Workqueue function for polling the state machine
353 */
354static void mpc52xx_spi_wq(struct work_struct *work)
355{
356 struct mpc52xx_spi *ms = container_of(work, struct mpc52xx_spi, work);
357 unsigned long flags;
358
359 spin_lock_irqsave(&ms->lock, flags);
360 mpc52xx_spi_fsm_process(0, ms);
361 spin_unlock_irqrestore(&ms->lock, flags);
362}
363
364/*
365 * spi_controller ops
366 */
367
368static int mpc52xx_spi_transfer(struct spi_device *spi, struct spi_message *m)
369{
370 struct mpc52xx_spi *ms = spi_controller_get_devdata(spi->controller);
371 unsigned long flags;
372
373 m->actual_length = 0;
374 m->status = -EINPROGRESS;
375
376 spin_lock_irqsave(&ms->lock, flags);
377 list_add_tail(&m->queue, &ms->queue);
378 spin_unlock_irqrestore(&ms->lock, flags);
379 schedule_work(&ms->work);
380
381 return 0;
382}
383
384/*
385 * OF Platform Bus Binding
386 */
387static int mpc52xx_spi_probe(struct platform_device *op)
388{
389 struct spi_controller *host;
390 struct mpc52xx_spi *ms;
391 struct gpio_desc *gpio_cs;
392 void __iomem *regs;
393 u8 ctrl1;
394 int rc, i = 0;
395
396 /* MMIO registers */
397 dev_dbg(&op->dev, "probing mpc5200 SPI device\n");
398 regs = of_iomap(op->dev.of_node, 0);
399 if (!regs)
400 return -ENODEV;
401
402 /* initialize the device */
403 ctrl1 = SPI_CTRL1_SPIE | SPI_CTRL1_SPE | SPI_CTRL1_MSTR;
404 out_8(regs + SPI_CTRL1, ctrl1);
405 out_8(regs + SPI_CTRL2, 0x0);
406 out_8(regs + SPI_DATADIR, 0xe); /* Set output pins */
407 out_8(regs + SPI_PORTDATA, 0x8); /* Deassert /SS signal */
408
409 /* Clear the status register and re-read it to check for a MODF
410 * failure. This driver cannot currently handle multiple hosts
411 * on the SPI bus. This fault will also occur if the SPI signals
412 * are not connected to any pins (port_config setting) */
413 in_8(regs + SPI_STATUS);
414 out_8(regs + SPI_CTRL1, ctrl1);
415
416 in_8(regs + SPI_DATA);
417 if (in_8(regs + SPI_STATUS) & SPI_STATUS_MODF) {
418 dev_err(&op->dev, "mode fault; is port_config correct?\n");
419 rc = -EIO;
420 goto err_init;
421 }
422
423 dev_dbg(&op->dev, "allocating spi_controller struct\n");
424 host = spi_alloc_host(&op->dev, sizeof(*ms));
425 if (!host) {
426 rc = -ENOMEM;
427 goto err_alloc;
428 }
429
430 host->transfer = mpc52xx_spi_transfer;
431 host->mode_bits = SPI_CPOL | SPI_CPHA | SPI_LSB_FIRST;
432 host->bits_per_word_mask = SPI_BPW_MASK(8);
433 host->dev.of_node = op->dev.of_node;
434
435 platform_set_drvdata(op, host);
436
437 ms = spi_controller_get_devdata(host);
438 ms->host = host;
439 ms->regs = regs;
440 ms->irq0 = irq_of_parse_and_map(op->dev.of_node, 0);
441 ms->irq1 = irq_of_parse_and_map(op->dev.of_node, 1);
442 ms->state = mpc52xx_spi_fsmstate_idle;
443 ms->ipb_freq = mpc5xxx_get_bus_frequency(&op->dev);
444 ms->gpio_cs_count = gpiod_count(&op->dev, NULL);
445 if (ms->gpio_cs_count > 0) {
446 host->num_chipselect = ms->gpio_cs_count;
447 ms->gpio_cs = kmalloc_array(ms->gpio_cs_count,
448 sizeof(*ms->gpio_cs),
449 GFP_KERNEL);
450 if (!ms->gpio_cs) {
451 rc = -ENOMEM;
452 goto err_alloc_gpio;
453 }
454
455 for (i = 0; i < ms->gpio_cs_count; i++) {
456 gpio_cs = gpiod_get_index(&op->dev,
457 NULL, i, GPIOD_OUT_LOW);
458 rc = PTR_ERR_OR_ZERO(gpio_cs);
459 if (rc) {
460 dev_err(&op->dev,
461 "failed to get spi cs gpio #%d: %d\n",
462 i, rc);
463 goto err_gpio;
464 }
465
466 ms->gpio_cs[i] = gpio_cs;
467 }
468 }
469
470 spin_lock_init(&ms->lock);
471 INIT_LIST_HEAD(&ms->queue);
472 INIT_WORK(&ms->work, mpc52xx_spi_wq);
473
474 /* Decide if interrupts can be used */
475 if (ms->irq0 && ms->irq1) {
476 rc = request_irq(ms->irq0, mpc52xx_spi_irq, 0,
477 "mpc5200-spi-modf", ms);
478 rc |= request_irq(ms->irq1, mpc52xx_spi_irq, 0,
479 "mpc5200-spi-spif", ms);
480 if (rc) {
481 free_irq(ms->irq0, ms);
482 free_irq(ms->irq1, ms);
483 ms->irq0 = ms->irq1 = 0;
484 }
485 } else {
486 /* operate in polled mode */
487 ms->irq0 = ms->irq1 = 0;
488 }
489
490 if (!ms->irq0)
491 dev_info(&op->dev, "using polled mode\n");
492
493 dev_dbg(&op->dev, "registering spi_controller struct\n");
494 rc = spi_register_controller(host);
495 if (rc)
496 goto err_register;
497
498 dev_info(&ms->host->dev, "registered MPC5200 SPI bus\n");
499
500 return rc;
501
502 err_register:
503 dev_err(&ms->host->dev, "initialization failed\n");
504 err_gpio:
505 while (i-- > 0)
506 gpiod_put(ms->gpio_cs[i]);
507
508 kfree(ms->gpio_cs);
509 err_alloc_gpio:
510 spi_controller_put(host);
511 err_alloc:
512 err_init:
513 iounmap(regs);
514 return rc;
515}
516
517static void mpc52xx_spi_remove(struct platform_device *op)
518{
519 struct spi_controller *host = spi_controller_get(platform_get_drvdata(op));
520 struct mpc52xx_spi *ms = spi_controller_get_devdata(host);
521 int i;
522
523 cancel_work_sync(&ms->work);
524 free_irq(ms->irq0, ms);
525 free_irq(ms->irq1, ms);
526
527 for (i = 0; i < ms->gpio_cs_count; i++)
528 gpiod_put(ms->gpio_cs[i]);
529
530 kfree(ms->gpio_cs);
531 spi_unregister_controller(host);
532 iounmap(ms->regs);
533 spi_controller_put(host);
534}
535
536static const struct of_device_id mpc52xx_spi_match[] = {
537 { .compatible = "fsl,mpc5200-spi", },
538 {}
539};
540MODULE_DEVICE_TABLE(of, mpc52xx_spi_match);
541
542static struct platform_driver mpc52xx_spi_of_driver = {
543 .driver = {
544 .name = "mpc52xx-spi",
545 .of_match_table = mpc52xx_spi_match,
546 },
547 .probe = mpc52xx_spi_probe,
548 .remove = mpc52xx_spi_remove,
549};
550module_platform_driver(mpc52xx_spi_of_driver);