2 * MPC512x PSC in SPI mode driver.
4 * Copyright (C) 2007,2008 Freescale Semiconductor Inc.
5 * Original port from 52xx driver:
6 * Hongjun Chen <hong-jun.chen@freescale.com>
8 * Fork of mpc52xx_psc_spi.c:
9 * Copyright (C) 2006 TOPTICA Photonics AG., Dragos Carp
11 * This program is free software; you can redistribute it and/or modify it
12 * under the terms of the GNU General Public License as published by the
13 * Free Software Foundation; either version 2 of the License, or (at your
14 * option) any later version.
17 #include <linux/module.h>
18 #include <linux/kernel.h>
19 #include <linux/init.h>
20 #include <linux/errno.h>
21 #include <linux/interrupt.h>
22 #include <linux/of_address.h>
23 #include <linux/of_irq.h>
24 #include <linux/of_platform.h>
25 #include <linux/completion.h>
27 #include <linux/delay.h>
28 #include <linux/clk.h>
29 #include <linux/spi/spi.h>
30 #include <linux/fsl_devices.h>
31 #include <linux/gpio.h>
32 #include <asm/mpc52xx_psc.h>
34 struct mpc512x_psc_spi
{
35 void (*cs_control
)(struct spi_device
*spi
, bool on
);
37 /* driver internal data */
38 struct mpc52xx_psc __iomem
*psc
;
39 struct mpc512x_psc_fifo __iomem
*fifo
;
46 struct completion txisrdone
;
49 /* controller state */
50 struct mpc512x_psc_spi_cs
{
55 /* set clock freq, clock ramp, bits per work
56 * if t is NULL then reset the values to the default values
58 static int mpc512x_psc_spi_transfer_setup(struct spi_device
*spi
,
59 struct spi_transfer
*t
)
61 struct mpc512x_psc_spi_cs
*cs
= spi
->controller_state
;
63 cs
->speed_hz
= (t
&& t
->speed_hz
)
64 ? t
->speed_hz
: spi
->max_speed_hz
;
65 cs
->bits_per_word
= (t
&& t
->bits_per_word
)
66 ? t
->bits_per_word
: spi
->bits_per_word
;
67 cs
->bits_per_word
= ((cs
->bits_per_word
+ 7) / 8) * 8;
71 static void mpc512x_psc_spi_activate_cs(struct spi_device
*spi
)
73 struct mpc512x_psc_spi_cs
*cs
= spi
->controller_state
;
74 struct mpc512x_psc_spi
*mps
= spi_master_get_devdata(spi
->master
);
75 struct mpc52xx_psc __iomem
*psc
= mps
->psc
;
81 sicr
= in_be32(&psc
->sicr
);
83 /* Set clock phase and polarity */
84 if (spi
->mode
& SPI_CPHA
)
89 if (spi
->mode
& SPI_CPOL
)
94 if (spi
->mode
& SPI_LSB_FIRST
)
98 out_be32(&psc
->sicr
, sicr
);
100 ccr
= in_be32(&psc
->ccr
);
102 speed
= cs
->speed_hz
;
104 speed
= 1000000; /* default 1MHz */
105 bclkdiv
= (mps
->mclk_rate
/ speed
) - 1;
107 ccr
|= (((bclkdiv
& 0xff) << 16) | (((bclkdiv
>> 8) & 0xff) << 8));
108 out_be32(&psc
->ccr
, ccr
);
109 mps
->bits_per_word
= cs
->bits_per_word
;
111 if (mps
->cs_control
&& gpio_is_valid(spi
->cs_gpio
))
112 mps
->cs_control(spi
, (spi
->mode
& SPI_CS_HIGH
) ? 1 : 0);
115 static void mpc512x_psc_spi_deactivate_cs(struct spi_device
*spi
)
117 struct mpc512x_psc_spi
*mps
= spi_master_get_devdata(spi
->master
);
119 if (mps
->cs_control
&& gpio_is_valid(spi
->cs_gpio
))
120 mps
->cs_control(spi
, (spi
->mode
& SPI_CS_HIGH
) ? 0 : 1);
124 /* extract and scale size field in txsz or rxsz */
125 #define MPC512x_PSC_FIFO_SZ(sz) ((sz & 0x7ff) << 2);
129 static int mpc512x_psc_spi_transfer_rxtx(struct spi_device
*spi
,
130 struct spi_transfer
*t
)
132 struct mpc512x_psc_spi
*mps
= spi_master_get_devdata(spi
->master
);
133 struct mpc512x_psc_fifo __iomem
*fifo
= mps
->fifo
;
134 size_t tx_len
= t
->len
;
135 size_t rx_len
= t
->len
;
136 u8
*tx_buf
= (u8
*)t
->tx_buf
;
137 u8
*rx_buf
= (u8
*)t
->rx_buf
;
139 if (!tx_buf
&& !rx_buf
&& t
->len
)
142 while (rx_len
|| tx_len
) {
150 * send the TX bytes in as large a chunk as possible
151 * but neither exceed the TX nor the RX FIFOs
153 fifosz
= MPC512x_PSC_FIFO_SZ(in_be32(&fifo
->txsz
));
154 txcount
= min(fifosz
, tx_len
);
155 fifosz
= MPC512x_PSC_FIFO_SZ(in_be32(&fifo
->rxsz
));
156 fifosz
-= in_be32(&fifo
->rxcnt
) + 1;
157 txcount
= min(fifosz
, txcount
);
160 /* fill the TX FIFO */
161 while (txcount
-- > 0) {
162 data
= tx_buf
? *tx_buf
++ : 0;
163 if (tx_len
== EOFBYTE
&& t
->cs_change
)
164 setbits32(&fifo
->txcmd
,
165 MPC512x_PSC_FIFO_EOF
);
166 out_8(&fifo
->txdata_8
, data
);
170 /* have the ISR trigger when the TX FIFO is empty */
171 reinit_completion(&mps
->txisrdone
);
172 out_be32(&fifo
->txisr
, MPC512x_PSC_FIFO_EMPTY
);
173 out_be32(&fifo
->tximr
, MPC512x_PSC_FIFO_EMPTY
);
174 wait_for_completion(&mps
->txisrdone
);
178 * consume as much RX data as the FIFO holds, while we
179 * iterate over the transfer's TX data length
181 * only insist in draining all the remaining RX bytes
182 * when the TX bytes were exhausted (that's at the very
183 * end of this transfer, not when still iterating over
184 * the transfer's chunks)
190 * grab whatever was in the FIFO when we started
191 * looking, don't bother fetching what was added to
192 * the FIFO while we read from it -- we'll return
193 * here eventually and prefer sending out remaining
196 fifosz
= in_be32(&fifo
->rxcnt
);
197 rxcount
= min(fifosz
, rx_len
);
198 while (rxcount
-- > 0) {
199 data
= in_8(&fifo
->rxdata_8
);
206 * come back later if there still is TX data to send,
207 * bail out of the RX drain loop if all of the TX data
208 * was sent and all of the RX data was received (i.e.
209 * when the transmission has completed)
217 * TX data transmission has completed while RX data
218 * is still pending -- that's a transient situation
219 * which depends on wire speed and specific
220 * hardware implementation details (buffering) yet
221 * should resolve very quickly
223 * just yield for a moment to not hog the CPU for
224 * too long when running SPI at low speed
226 * the timeout range is rather arbitrary and tries
227 * to balance throughput against system load; the
228 * chosen values result in a minimal timeout of 50
229 * times 10us and thus work at speeds as low as
230 * some 20kbps, while the maximum timeout at the
231 * transfer's end could be 5ms _if_ nothing else
232 * ticks in the system _and_ RX data still wasn't
233 * received, which only occurs in situations that
234 * are exceptional; removing the unpredictability
235 * of the timeout either decreases throughput
236 * (longer timeouts), or puts more load on the
237 * system (fixed short timeouts) or requires the
238 * use of a timeout API instead of a counter and an
239 * unknown inner delay
241 usleep_range(10, 100);
243 } while (--rxtries
> 0);
244 if (!tx_len
&& rx_len
&& !rxtries
) {
246 * not enough RX bytes even after several retries
247 * and the resulting rather long timeout?
249 rxcount
= in_be32(&fifo
->rxcnt
);
251 "short xfer, missing %zd RX bytes, FIFO level %zd\n",
256 * drain and drop RX data which "should not be there" in
257 * the first place, for undisturbed transmission this turns
258 * into a NOP (except for the FIFO level fetch)
260 if (!tx_len
&& !rx_len
) {
261 while (in_be32(&fifo
->rxcnt
))
262 in_8(&fifo
->rxdata_8
);
269 static int mpc512x_psc_spi_msg_xfer(struct spi_master
*master
,
270 struct spi_message
*m
)
272 struct spi_device
*spi
;
275 struct spi_transfer
*t
;
280 list_for_each_entry(t
, &m
->transfers
, transfer_list
) {
281 if (t
->bits_per_word
|| t
->speed_hz
) {
282 status
= mpc512x_psc_spi_transfer_setup(spi
, t
);
288 mpc512x_psc_spi_activate_cs(spi
);
289 cs_change
= t
->cs_change
;
291 status
= mpc512x_psc_spi_transfer_rxtx(spi
, t
);
294 m
->actual_length
+= t
->len
;
297 udelay(t
->delay_usecs
);
300 mpc512x_psc_spi_deactivate_cs(spi
);
304 m
->complete(m
->context
);
306 if (status
|| !cs_change
)
307 mpc512x_psc_spi_deactivate_cs(spi
);
309 mpc512x_psc_spi_transfer_setup(spi
, NULL
);
311 spi_finalize_current_message(master
);
315 static int mpc512x_psc_spi_prep_xfer_hw(struct spi_master
*master
)
317 struct mpc512x_psc_spi
*mps
= spi_master_get_devdata(master
);
318 struct mpc52xx_psc __iomem
*psc
= mps
->psc
;
320 dev_dbg(&master
->dev
, "%s()\n", __func__
);
324 out_8(&psc
->mode
, 0x0);
326 /* enable transmitter/receiver */
327 out_8(&psc
->command
, MPC52xx_PSC_TX_ENABLE
| MPC52xx_PSC_RX_ENABLE
);
332 static int mpc512x_psc_spi_unprep_xfer_hw(struct spi_master
*master
)
334 struct mpc512x_psc_spi
*mps
= spi_master_get_devdata(master
);
335 struct mpc52xx_psc __iomem
*psc
= mps
->psc
;
336 struct mpc512x_psc_fifo __iomem
*fifo
= mps
->fifo
;
338 dev_dbg(&master
->dev
, "%s()\n", __func__
);
340 /* disable transmitter/receiver and fifo interrupt */
341 out_8(&psc
->command
, MPC52xx_PSC_TX_DISABLE
| MPC52xx_PSC_RX_DISABLE
);
342 out_be32(&fifo
->tximr
, 0);
347 static int mpc512x_psc_spi_setup(struct spi_device
*spi
)
349 struct mpc512x_psc_spi_cs
*cs
= spi
->controller_state
;
352 if (spi
->bits_per_word
% 8)
356 cs
= kzalloc(sizeof *cs
, GFP_KERNEL
);
360 if (gpio_is_valid(spi
->cs_gpio
)) {
361 ret
= gpio_request(spi
->cs_gpio
, dev_name(&spi
->dev
));
363 dev_err(&spi
->dev
, "can't get CS gpio: %d\n",
368 gpio_direction_output(spi
->cs_gpio
,
369 spi
->mode
& SPI_CS_HIGH
? 0 : 1);
372 spi
->controller_state
= cs
;
375 cs
->bits_per_word
= spi
->bits_per_word
;
376 cs
->speed_hz
= spi
->max_speed_hz
;
381 static void mpc512x_psc_spi_cleanup(struct spi_device
*spi
)
383 if (gpio_is_valid(spi
->cs_gpio
))
384 gpio_free(spi
->cs_gpio
);
385 kfree(spi
->controller_state
);
388 static int mpc512x_psc_spi_port_config(struct spi_master
*master
,
389 struct mpc512x_psc_spi
*mps
)
391 struct mpc52xx_psc __iomem
*psc
= mps
->psc
;
392 struct mpc512x_psc_fifo __iomem
*fifo
= mps
->fifo
;
398 /* Reset the PSC into a known state */
399 out_8(&psc
->command
, MPC52xx_PSC_RST_RX
);
400 out_8(&psc
->command
, MPC52xx_PSC_RST_TX
);
401 out_8(&psc
->command
, MPC52xx_PSC_TX_DISABLE
| MPC52xx_PSC_RX_DISABLE
);
403 /* Disable psc interrupts all useful interrupts are in fifo */
404 out_be16(&psc
->isr_imr
.imr
, 0);
406 /* Disable fifo interrupts, will be enabled later */
407 out_be32(&fifo
->tximr
, 0);
408 out_be32(&fifo
->rximr
, 0);
410 /* Setup fifo slice address and size */
411 /*out_be32(&fifo->txsz, 0x0fe00004);*/
412 /*out_be32(&fifo->rxsz, 0x0ff00004);*/
414 sicr
= 0x01000000 | /* SIM = 0001 -- 8 bit */
415 0x00800000 | /* GenClk = 1 -- internal clk */
416 0x00008000 | /* SPI = 1 */
417 0x00004000 | /* MSTR = 1 -- SPI master */
418 0x00000800; /* UseEOF = 1 -- SS low until EOF */
420 out_be32(&psc
->sicr
, sicr
);
422 ccr
= in_be32(&psc
->ccr
);
424 speed
= 1000000; /* default 1MHz */
425 bclkdiv
= (mps
->mclk_rate
/ speed
) - 1;
426 ccr
|= (((bclkdiv
& 0xff) << 16) | (((bclkdiv
>> 8) & 0xff) << 8));
427 out_be32(&psc
->ccr
, ccr
);
429 /* Set 2ms DTL delay */
430 out_8(&psc
->ctur
, 0x00);
431 out_8(&psc
->ctlr
, 0x82);
433 /* we don't use the alarms */
434 out_be32(&fifo
->rxalarm
, 0xfff);
435 out_be32(&fifo
->txalarm
, 0);
437 /* Enable FIFO slices for Rx/Tx */
438 out_be32(&fifo
->rxcmd
,
439 MPC512x_PSC_FIFO_ENABLE_SLICE
| MPC512x_PSC_FIFO_ENABLE_DMA
);
440 out_be32(&fifo
->txcmd
,
441 MPC512x_PSC_FIFO_ENABLE_SLICE
| MPC512x_PSC_FIFO_ENABLE_DMA
);
443 mps
->bits_per_word
= 8;
448 static irqreturn_t
mpc512x_psc_spi_isr(int irq
, void *dev_id
)
450 struct mpc512x_psc_spi
*mps
= (struct mpc512x_psc_spi
*)dev_id
;
451 struct mpc512x_psc_fifo __iomem
*fifo
= mps
->fifo
;
453 /* clear interrupt and wake up the rx/tx routine */
454 if (in_be32(&fifo
->txisr
) &
455 in_be32(&fifo
->tximr
) & MPC512x_PSC_FIFO_EMPTY
) {
456 out_be32(&fifo
->txisr
, MPC512x_PSC_FIFO_EMPTY
);
457 out_be32(&fifo
->tximr
, 0);
458 complete(&mps
->txisrdone
);
464 static void mpc512x_spi_cs_control(struct spi_device
*spi
, bool onoff
)
466 gpio_set_value(spi
->cs_gpio
, onoff
);
469 /* bus_num is used only for the case dev->platform_data == NULL */
470 static int mpc512x_psc_spi_do_probe(struct device
*dev
, u32 regaddr
,
471 u32 size
, unsigned int irq
,
474 struct fsl_spi_platform_data
*pdata
= dev_get_platdata(dev
);
475 struct mpc512x_psc_spi
*mps
;
476 struct spi_master
*master
;
481 master
= spi_alloc_master(dev
, sizeof *mps
);
485 dev_set_drvdata(dev
, master
);
486 mps
= spi_master_get_devdata(master
);
490 mps
->cs_control
= mpc512x_spi_cs_control
;
491 master
->bus_num
= bus_num
;
493 mps
->cs_control
= pdata
->cs_control
;
494 master
->bus_num
= pdata
->bus_num
;
495 master
->num_chipselect
= pdata
->max_chipselect
;
498 master
->mode_bits
= SPI_CPOL
| SPI_CPHA
| SPI_CS_HIGH
| SPI_LSB_FIRST
;
499 master
->setup
= mpc512x_psc_spi_setup
;
500 master
->prepare_transfer_hardware
= mpc512x_psc_spi_prep_xfer_hw
;
501 master
->transfer_one_message
= mpc512x_psc_spi_msg_xfer
;
502 master
->unprepare_transfer_hardware
= mpc512x_psc_spi_unprep_xfer_hw
;
503 master
->cleanup
= mpc512x_psc_spi_cleanup
;
504 master
->dev
.of_node
= dev
->of_node
;
506 tempp
= devm_ioremap(dev
, regaddr
, size
);
508 dev_err(dev
, "could not ioremap I/O port range\n");
514 (struct mpc512x_psc_fifo
*)(tempp
+ sizeof(struct mpc52xx_psc
));
515 ret
= devm_request_irq(dev
, mps
->irq
, mpc512x_psc_spi_isr
, IRQF_SHARED
,
516 "mpc512x-psc-spi", mps
);
519 init_completion(&mps
->txisrdone
);
521 clk
= devm_clk_get(dev
, "mclk");
526 ret
= clk_prepare_enable(clk
);
530 mps
->mclk_rate
= clk_get_rate(clk
);
532 clk
= devm_clk_get(dev
, "ipg");
535 goto free_mclk_clock
;
537 ret
= clk_prepare_enable(clk
);
539 goto free_mclk_clock
;
542 ret
= mpc512x_psc_spi_port_config(master
, mps
);
546 ret
= devm_spi_register_master(dev
, master
);
553 clk_disable_unprepare(mps
->clk_ipg
);
555 clk_disable_unprepare(mps
->clk_mclk
);
557 spi_master_put(master
);
562 static int mpc512x_psc_spi_do_remove(struct device
*dev
)
564 struct spi_master
*master
= dev_get_drvdata(dev
);
565 struct mpc512x_psc_spi
*mps
= spi_master_get_devdata(master
);
567 clk_disable_unprepare(mps
->clk_mclk
);
568 clk_disable_unprepare(mps
->clk_ipg
);
573 static int mpc512x_psc_spi_of_probe(struct platform_device
*op
)
575 const u32
*regaddr_p
;
576 u64 regaddr64
, size64
;
579 regaddr_p
= of_get_address(op
->dev
.of_node
, 0, &size64
, NULL
);
581 dev_err(&op
->dev
, "Invalid PSC address\n");
584 regaddr64
= of_translate_address(op
->dev
.of_node
, regaddr_p
);
586 /* get PSC id (0..11, used by port_config) */
587 id
= of_alias_get_id(op
->dev
.of_node
, "spi");
589 dev_err(&op
->dev
, "no alias id for %s\n",
590 op
->dev
.of_node
->full_name
);
594 return mpc512x_psc_spi_do_probe(&op
->dev
, (u32
) regaddr64
, (u32
) size64
,
595 irq_of_parse_and_map(op
->dev
.of_node
, 0), id
);
598 static int mpc512x_psc_spi_of_remove(struct platform_device
*op
)
600 return mpc512x_psc_spi_do_remove(&op
->dev
);
603 static struct of_device_id mpc512x_psc_spi_of_match
[] = {
604 { .compatible
= "fsl,mpc5121-psc-spi", },
608 MODULE_DEVICE_TABLE(of
, mpc512x_psc_spi_of_match
);
610 static struct platform_driver mpc512x_psc_spi_of_driver
= {
611 .probe
= mpc512x_psc_spi_of_probe
,
612 .remove
= mpc512x_psc_spi_of_remove
,
614 .name
= "mpc512x-psc-spi",
615 .owner
= THIS_MODULE
,
616 .of_match_table
= mpc512x_psc_spi_of_match
,
619 module_platform_driver(mpc512x_psc_spi_of_driver
);
621 MODULE_AUTHOR("John Rigby");
622 MODULE_DESCRIPTION("MPC512x PSC SPI Driver");
623 MODULE_LICENSE("GPL");