2 * MPC512x PSC in SPI mode driver.
4 * Copyright (C) 2007,2008 Freescale Semiconductor Inc.
5 * Original port from 52xx driver:
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/errno.h>
20 #include <linux/interrupt.h>
21 #include <linux/of_address.h>
22 #include <linux/of_irq.h>
23 #include <linux/of_platform.h>
24 #include <linux/completion.h>
26 #include <linux/delay.h>
27 #include <linux/clk.h>
28 #include <linux/spi/spi.h>
29 #include <linux/fsl_devices.h>
30 #include <linux/gpio.h>
31 #include <asm/mpc52xx_psc.h>
39 * This macro abstracts the differences in the PSC register layout between
40 * MPC5121 (which uses a struct mpc52xx_psc) and MPC5125 (using mpc5125_psc).
42 #define psc_addr(mps, regname) ({ \
44 switch (mps->type) { \
45 case TYPE_MPC5121: { \
46 struct mpc52xx_psc __iomem *psc = mps->psc; \
47 __ret = &psc->regname; \
50 case TYPE_MPC5125: { \
51 struct mpc5125_psc __iomem *psc = mps->psc; \
52 __ret = &psc->regname; \
58 struct mpc512x_psc_spi {
59 void (*cs_control)(struct spi_device *spi, bool on);
61 /* driver internal data */
64 struct mpc512x_psc_fifo __iomem *fifo;
71 struct completion txisrdone;
74 /* controller state */
75 struct mpc512x_psc_spi_cs {
80 /* set clock freq, clock ramp, bits per work
81 * if t is NULL then reset the values to the default values
83 static int mpc512x_psc_spi_transfer_setup(struct spi_device *spi,
84 struct spi_transfer *t)
86 struct mpc512x_psc_spi_cs *cs = spi->controller_state;
88 cs->speed_hz = (t && t->speed_hz)
89 ? t->speed_hz : spi->max_speed_hz;
90 cs->bits_per_word = (t && t->bits_per_word)
91 ? t->bits_per_word : spi->bits_per_word;
92 cs->bits_per_word = ((cs->bits_per_word + 7) / 8) * 8;
96 static void mpc512x_psc_spi_activate_cs(struct spi_device *spi)
98 struct mpc512x_psc_spi_cs *cs = spi->controller_state;
99 struct mpc512x_psc_spi *mps = spi_master_get_devdata(spi->master);
105 sicr = in_be32(psc_addr(mps, sicr));
107 /* Set clock phase and polarity */
108 if (spi->mode & SPI_CPHA)
113 if (spi->mode & SPI_CPOL)
118 if (spi->mode & SPI_LSB_FIRST)
122 out_be32(psc_addr(mps, sicr), sicr);
124 ccr = in_be32(psc_addr(mps, ccr));
126 speed = cs->speed_hz;
128 speed = 1000000; /* default 1MHz */
129 bclkdiv = (mps->mclk_rate / speed) - 1;
131 ccr |= (((bclkdiv & 0xff) << 16) | (((bclkdiv >> 8) & 0xff) << 8));
132 out_be32(psc_addr(mps, ccr), ccr);
133 mps->bits_per_word = cs->bits_per_word;
135 if (mps->cs_control && gpio_is_valid(spi->cs_gpio))
136 mps->cs_control(spi, (spi->mode & SPI_CS_HIGH) ? 1 : 0);
139 static void mpc512x_psc_spi_deactivate_cs(struct spi_device *spi)
141 struct mpc512x_psc_spi *mps = spi_master_get_devdata(spi->master);
143 if (mps->cs_control && gpio_is_valid(spi->cs_gpio))
144 mps->cs_control(spi, (spi->mode & SPI_CS_HIGH) ? 0 : 1);
148 /* extract and scale size field in txsz or rxsz */
149 #define MPC512x_PSC_FIFO_SZ(sz) ((sz & 0x7ff) << 2);
153 static int mpc512x_psc_spi_transfer_rxtx(struct spi_device *spi,
154 struct spi_transfer *t)
156 struct mpc512x_psc_spi *mps = spi_master_get_devdata(spi->master);
157 struct mpc512x_psc_fifo __iomem *fifo = mps->fifo;
158 size_t tx_len = t->len;
159 size_t rx_len = t->len;
160 u8 *tx_buf = (u8 *)t->tx_buf;
161 u8 *rx_buf = (u8 *)t->rx_buf;
163 if (!tx_buf && !rx_buf && t->len)
166 while (rx_len || tx_len) {
174 * send the TX bytes in as large a chunk as possible
175 * but neither exceed the TX nor the RX FIFOs
177 fifosz = MPC512x_PSC_FIFO_SZ(in_be32(&fifo->txsz));
178 txcount = min(fifosz, tx_len);
179 fifosz = MPC512x_PSC_FIFO_SZ(in_be32(&fifo->rxsz));
180 fifosz -= in_be32(&fifo->rxcnt) + 1;
181 txcount = min(fifosz, txcount);
184 /* fill the TX FIFO */
185 while (txcount-- > 0) {
186 data = tx_buf ? *tx_buf++ : 0;
187 if (tx_len == EOFBYTE && t->cs_change)
188 setbits32(&fifo->txcmd,
189 MPC512x_PSC_FIFO_EOF);
190 out_8(&fifo->txdata_8, data);
194 /* have the ISR trigger when the TX FIFO is empty */
195 reinit_completion(&mps->txisrdone);
196 out_be32(&fifo->txisr, MPC512x_PSC_FIFO_EMPTY);
197 out_be32(&fifo->tximr, MPC512x_PSC_FIFO_EMPTY);
198 wait_for_completion(&mps->txisrdone);
202 * consume as much RX data as the FIFO holds, while we
203 * iterate over the transfer's TX data length
205 * only insist in draining all the remaining RX bytes
206 * when the TX bytes were exhausted (that's at the very
207 * end of this transfer, not when still iterating over
208 * the transfer's chunks)
214 * grab whatever was in the FIFO when we started
215 * looking, don't bother fetching what was added to
216 * the FIFO while we read from it -- we'll return
217 * here eventually and prefer sending out remaining
220 fifosz = in_be32(&fifo->rxcnt);
221 rxcount = min(fifosz, rx_len);
222 while (rxcount-- > 0) {
223 data = in_8(&fifo->rxdata_8);
230 * come back later if there still is TX data to send,
231 * bail out of the RX drain loop if all of the TX data
232 * was sent and all of the RX data was received (i.e.
233 * when the transmission has completed)
241 * TX data transmission has completed while RX data
242 * is still pending -- that's a transient situation
243 * which depends on wire speed and specific
244 * hardware implementation details (buffering) yet
245 * should resolve very quickly
247 * just yield for a moment to not hog the CPU for
248 * too long when running SPI at low speed
250 * the timeout range is rather arbitrary and tries
251 * to balance throughput against system load; the
252 * chosen values result in a minimal timeout of 50
253 * times 10us and thus work at speeds as low as
254 * some 20kbps, while the maximum timeout at the
255 * transfer's end could be 5ms _if_ nothing else
256 * ticks in the system _and_ RX data still wasn't
257 * received, which only occurs in situations that
258 * are exceptional; removing the unpredictability
259 * of the timeout either decreases throughput
260 * (longer timeouts), or puts more load on the
261 * system (fixed short timeouts) or requires the
262 * use of a timeout API instead of a counter and an
263 * unknown inner delay
265 usleep_range(10, 100);
267 } while (--rxtries > 0);
268 if (!tx_len && rx_len && !rxtries) {
270 * not enough RX bytes even after several retries
271 * and the resulting rather long timeout?
273 rxcount = in_be32(&fifo->rxcnt);
275 "short xfer, missing %zd RX bytes, FIFO level %zd\n",
280 * drain and drop RX data which "should not be there" in
281 * the first place, for undisturbed transmission this turns
282 * into a NOP (except for the FIFO level fetch)
284 if (!tx_len && !rx_len) {
285 while (in_be32(&fifo->rxcnt))
286 in_8(&fifo->rxdata_8);
293 static int mpc512x_psc_spi_msg_xfer(struct spi_master *master,
294 struct spi_message *m)
296 struct spi_device *spi;
299 struct spi_transfer *t;
304 list_for_each_entry(t, &m->transfers, transfer_list) {
305 status = mpc512x_psc_spi_transfer_setup(spi, t);
310 mpc512x_psc_spi_activate_cs(spi);
311 cs_change = t->cs_change;
313 status = mpc512x_psc_spi_transfer_rxtx(spi, t);
316 m->actual_length += t->len;
319 udelay(t->delay_usecs);
322 mpc512x_psc_spi_deactivate_cs(spi);
327 m->complete(m->context);
329 if (status || !cs_change)
330 mpc512x_psc_spi_deactivate_cs(spi);
332 mpc512x_psc_spi_transfer_setup(spi, NULL);
334 spi_finalize_current_message(master);
338 static int mpc512x_psc_spi_prep_xfer_hw(struct spi_master *master)
340 struct mpc512x_psc_spi *mps = spi_master_get_devdata(master);
342 dev_dbg(&master->dev, "%s()\n", __func__);
345 in_8(psc_addr(mps, mr2));
346 out_8(psc_addr(mps, mr2), 0x0);
348 /* enable transmitter/receiver */
349 out_8(psc_addr(mps, command), MPC52xx_PSC_TX_ENABLE | MPC52xx_PSC_RX_ENABLE);
354 static int mpc512x_psc_spi_unprep_xfer_hw(struct spi_master *master)
356 struct mpc512x_psc_spi *mps = spi_master_get_devdata(master);
357 struct mpc512x_psc_fifo __iomem *fifo = mps->fifo;
359 dev_dbg(&master->dev, "%s()\n", __func__);
361 /* disable transmitter/receiver and fifo interrupt */
362 out_8(psc_addr(mps, command), MPC52xx_PSC_TX_DISABLE | MPC52xx_PSC_RX_DISABLE);
363 out_be32(&fifo->tximr, 0);
368 static int mpc512x_psc_spi_setup(struct spi_device *spi)
370 struct mpc512x_psc_spi_cs *cs = spi->controller_state;
373 if (spi->bits_per_word % 8)
377 cs = kzalloc(sizeof *cs, GFP_KERNEL);
381 if (gpio_is_valid(spi->cs_gpio)) {
382 ret = gpio_request(spi->cs_gpio, dev_name(&spi->dev));
384 dev_err(&spi->dev, "can't get CS gpio: %d\n",
389 gpio_direction_output(spi->cs_gpio,
390 spi->mode & SPI_CS_HIGH ? 0 : 1);
393 spi->controller_state = cs;
396 cs->bits_per_word = spi->bits_per_word;
397 cs->speed_hz = spi->max_speed_hz;
402 static void mpc512x_psc_spi_cleanup(struct spi_device *spi)
404 if (gpio_is_valid(spi->cs_gpio))
405 gpio_free(spi->cs_gpio);
406 kfree(spi->controller_state);
409 static int mpc512x_psc_spi_port_config(struct spi_master *master,
410 struct mpc512x_psc_spi *mps)
412 struct mpc512x_psc_fifo __iomem *fifo = mps->fifo;
418 /* Reset the PSC into a known state */
419 out_8(psc_addr(mps, command), MPC52xx_PSC_RST_RX);
420 out_8(psc_addr(mps, command), MPC52xx_PSC_RST_TX);
421 out_8(psc_addr(mps, command), MPC52xx_PSC_TX_DISABLE | MPC52xx_PSC_RX_DISABLE);
423 /* Disable psc interrupts all useful interrupts are in fifo */
424 out_be16(psc_addr(mps, isr_imr.imr), 0);
426 /* Disable fifo interrupts, will be enabled later */
427 out_be32(&fifo->tximr, 0);
428 out_be32(&fifo->rximr, 0);
430 /* Setup fifo slice address and size */
431 /*out_be32(&fifo->txsz, 0x0fe00004);*/
432 /*out_be32(&fifo->rxsz, 0x0ff00004);*/
434 sicr = 0x01000000 | /* SIM = 0001 -- 8 bit */
435 0x00800000 | /* GenClk = 1 -- internal clk */
436 0x00008000 | /* SPI = 1 */
437 0x00004000 | /* MSTR = 1 -- SPI master */
438 0x00000800; /* UseEOF = 1 -- SS low until EOF */
440 out_be32(psc_addr(mps, sicr), sicr);
442 ccr = in_be32(psc_addr(mps, ccr));
444 speed = 1000000; /* default 1MHz */
445 bclkdiv = (mps->mclk_rate / speed) - 1;
446 ccr |= (((bclkdiv & 0xff) << 16) | (((bclkdiv >> 8) & 0xff) << 8));
447 out_be32(psc_addr(mps, ccr), ccr);
449 /* Set 2ms DTL delay */
450 out_8(psc_addr(mps, ctur), 0x00);
451 out_8(psc_addr(mps, ctlr), 0x82);
453 /* we don't use the alarms */
454 out_be32(&fifo->rxalarm, 0xfff);
455 out_be32(&fifo->txalarm, 0);
457 /* Enable FIFO slices for Rx/Tx */
458 out_be32(&fifo->rxcmd,
459 MPC512x_PSC_FIFO_ENABLE_SLICE | MPC512x_PSC_FIFO_ENABLE_DMA);
460 out_be32(&fifo->txcmd,
461 MPC512x_PSC_FIFO_ENABLE_SLICE | MPC512x_PSC_FIFO_ENABLE_DMA);
463 mps->bits_per_word = 8;
468 static irqreturn_t mpc512x_psc_spi_isr(int irq, void *dev_id)
470 struct mpc512x_psc_spi *mps = (struct mpc512x_psc_spi *)dev_id;
471 struct mpc512x_psc_fifo __iomem *fifo = mps->fifo;
473 /* clear interrupt and wake up the rx/tx routine */
474 if (in_be32(&fifo->txisr) &
475 in_be32(&fifo->tximr) & MPC512x_PSC_FIFO_EMPTY) {
476 out_be32(&fifo->txisr, MPC512x_PSC_FIFO_EMPTY);
477 out_be32(&fifo->tximr, 0);
478 complete(&mps->txisrdone);
484 static void mpc512x_spi_cs_control(struct spi_device *spi, bool onoff)
486 gpio_set_value(spi->cs_gpio, onoff);
489 static int mpc512x_psc_spi_do_probe(struct device *dev, u32 regaddr,
490 u32 size, unsigned int irq)
492 struct fsl_spi_platform_data *pdata = dev_get_platdata(dev);
493 struct mpc512x_psc_spi *mps;
494 struct spi_master *master;
499 master = spi_alloc_master(dev, sizeof *mps);
503 dev_set_drvdata(dev, master);
504 mps = spi_master_get_devdata(master);
505 mps->type = (int)of_device_get_match_data(dev);
509 mps->cs_control = mpc512x_spi_cs_control;
511 mps->cs_control = pdata->cs_control;
512 master->bus_num = pdata->bus_num;
513 master->num_chipselect = pdata->max_chipselect;
516 master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH | SPI_LSB_FIRST;
517 master->setup = mpc512x_psc_spi_setup;
518 master->prepare_transfer_hardware = mpc512x_psc_spi_prep_xfer_hw;
519 master->transfer_one_message = mpc512x_psc_spi_msg_xfer;
520 master->unprepare_transfer_hardware = mpc512x_psc_spi_unprep_xfer_hw;
521 master->cleanup = mpc512x_psc_spi_cleanup;
522 master->dev.of_node = dev->of_node;
524 tempp = devm_ioremap(dev, regaddr, size);
526 dev_err(dev, "could not ioremap I/O port range\n");
532 (struct mpc512x_psc_fifo *)(tempp + sizeof(struct mpc52xx_psc));
533 ret = devm_request_irq(dev, mps->irq, mpc512x_psc_spi_isr, IRQF_SHARED,
534 "mpc512x-psc-spi", mps);
537 init_completion(&mps->txisrdone);
539 clk = devm_clk_get(dev, "mclk");
544 ret = clk_prepare_enable(clk);
548 mps->mclk_rate = clk_get_rate(clk);
550 clk = devm_clk_get(dev, "ipg");
553 goto free_mclk_clock;
555 ret = clk_prepare_enable(clk);
557 goto free_mclk_clock;
560 ret = mpc512x_psc_spi_port_config(master, mps);
564 ret = devm_spi_register_master(dev, master);
571 clk_disable_unprepare(mps->clk_ipg);
573 clk_disable_unprepare(mps->clk_mclk);
575 spi_master_put(master);
580 static int mpc512x_psc_spi_do_remove(struct device *dev)
582 struct spi_master *master = dev_get_drvdata(dev);
583 struct mpc512x_psc_spi *mps = spi_master_get_devdata(master);
585 clk_disable_unprepare(mps->clk_mclk);
586 clk_disable_unprepare(mps->clk_ipg);
591 static int mpc512x_psc_spi_of_probe(struct platform_device *op)
593 const u32 *regaddr_p;
594 u64 regaddr64, size64;
596 regaddr_p = of_get_address(op->dev.of_node, 0, &size64, NULL);
598 dev_err(&op->dev, "Invalid PSC address\n");
601 regaddr64 = of_translate_address(op->dev.of_node, regaddr_p);
603 return mpc512x_psc_spi_do_probe(&op->dev, (u32) regaddr64, (u32) size64,
604 irq_of_parse_and_map(op->dev.of_node, 0));
607 static int mpc512x_psc_spi_of_remove(struct platform_device *op)
609 return mpc512x_psc_spi_do_remove(&op->dev);
612 static const struct of_device_id mpc512x_psc_spi_of_match[] = {
613 { .compatible = "fsl,mpc5121-psc-spi", .data = (void *)TYPE_MPC5121 },
614 { .compatible = "fsl,mpc5125-psc-spi", .data = (void *)TYPE_MPC5125 },
618 MODULE_DEVICE_TABLE(of, mpc512x_psc_spi_of_match);
620 static struct platform_driver mpc512x_psc_spi_of_driver = {
621 .probe = mpc512x_psc_spi_of_probe,
622 .remove = mpc512x_psc_spi_of_remove,
624 .name = "mpc512x-psc-spi",
625 .of_match_table = mpc512x_psc_spi_of_match,
628 module_platform_driver(mpc512x_psc_spi_of_driver);
630 MODULE_AUTHOR("John Rigby");
631 MODULE_DESCRIPTION("MPC512x PSC SPI Driver");
632 MODULE_LICENSE("GPL");