2 * Copyright (C) 2012 - 2014 Allwinner Tech
3 * Pan Nan <pannan@allwinnertech.com>
5 * Copyright (C) 2014 Maxime Ripard
6 * Maxime Ripard <maxime.ripard@free-electrons.com>
8 * This program is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU General Public License as
10 * published by the Free Software Foundation; either version 2 of
11 * the License, or (at your option) any later version.
14 #include <linux/clk.h>
15 #include <linux/delay.h>
16 #include <linux/device.h>
17 #include <linux/interrupt.h>
19 #include <linux/module.h>
20 #include <linux/of_device.h>
21 #include <linux/platform_device.h>
22 #include <linux/pm_runtime.h>
23 #include <linux/reset.h>
25 #include <linux/spi/spi.h>
27 #define SUN6I_FIFO_DEPTH 128
28 #define SUN8I_FIFO_DEPTH 64
30 #define SUN6I_GBL_CTL_REG 0x04
31 #define SUN6I_GBL_CTL_BUS_ENABLE BIT(0)
32 #define SUN6I_GBL_CTL_MASTER BIT(1)
33 #define SUN6I_GBL_CTL_TP BIT(7)
34 #define SUN6I_GBL_CTL_RST BIT(31)
36 #define SUN6I_TFR_CTL_REG 0x08
37 #define SUN6I_TFR_CTL_CPHA BIT(0)
38 #define SUN6I_TFR_CTL_CPOL BIT(1)
39 #define SUN6I_TFR_CTL_SPOL BIT(2)
40 #define SUN6I_TFR_CTL_CS_MASK 0x30
41 #define SUN6I_TFR_CTL_CS(cs) (((cs) << 4) & SUN6I_TFR_CTL_CS_MASK)
42 #define SUN6I_TFR_CTL_CS_MANUAL BIT(6)
43 #define SUN6I_TFR_CTL_CS_LEVEL BIT(7)
44 #define SUN6I_TFR_CTL_DHB BIT(8)
45 #define SUN6I_TFR_CTL_FBS BIT(12)
46 #define SUN6I_TFR_CTL_XCH BIT(31)
48 #define SUN6I_INT_CTL_REG 0x10
49 #define SUN6I_INT_CTL_RF_RDY BIT(0)
50 #define SUN6I_INT_CTL_TF_ERQ BIT(4)
51 #define SUN6I_INT_CTL_RF_OVF BIT(8)
52 #define SUN6I_INT_CTL_TC BIT(12)
54 #define SUN6I_INT_STA_REG 0x14
56 #define SUN6I_FIFO_CTL_REG 0x18
57 #define SUN6I_FIFO_CTL_RF_RDY_TRIG_LEVEL_MASK 0xff
58 #define SUN6I_FIFO_CTL_RF_RDY_TRIG_LEVEL_BITS 0
59 #define SUN6I_FIFO_CTL_RF_RST BIT(15)
60 #define SUN6I_FIFO_CTL_TF_ERQ_TRIG_LEVEL_MASK 0xff
61 #define SUN6I_FIFO_CTL_TF_ERQ_TRIG_LEVEL_BITS 16
62 #define SUN6I_FIFO_CTL_TF_RST BIT(31)
64 #define SUN6I_FIFO_STA_REG 0x1c
65 #define SUN6I_FIFO_STA_RF_CNT_MASK 0x7f
66 #define SUN6I_FIFO_STA_RF_CNT_BITS 0
67 #define SUN6I_FIFO_STA_TF_CNT_MASK 0x7f
68 #define SUN6I_FIFO_STA_TF_CNT_BITS 16
70 #define SUN6I_CLK_CTL_REG 0x24
71 #define SUN6I_CLK_CTL_CDR2_MASK 0xff
72 #define SUN6I_CLK_CTL_CDR2(div) (((div) & SUN6I_CLK_CTL_CDR2_MASK) << 0)
73 #define SUN6I_CLK_CTL_CDR1_MASK 0xf
74 #define SUN6I_CLK_CTL_CDR1(div) (((div) & SUN6I_CLK_CTL_CDR1_MASK) << 8)
75 #define SUN6I_CLK_CTL_DRS BIT(12)
77 #define SUN6I_MAX_XFER_SIZE 0xffffff
79 #define SUN6I_BURST_CNT_REG 0x30
80 #define SUN6I_BURST_CNT(cnt) ((cnt) & SUN6I_MAX_XFER_SIZE)
82 #define SUN6I_XMIT_CNT_REG 0x34
83 #define SUN6I_XMIT_CNT(cnt) ((cnt) & SUN6I_MAX_XFER_SIZE)
85 #define SUN6I_BURST_CTL_CNT_REG 0x38
86 #define SUN6I_BURST_CTL_CNT_STC(cnt) ((cnt) & SUN6I_MAX_XFER_SIZE)
88 #define SUN6I_TXDATA_REG 0x200
89 #define SUN6I_RXDATA_REG 0x300
92 struct spi_master *master;
93 void __iomem *base_addr;
96 struct reset_control *rstc;
98 struct completion done;
103 unsigned long fifo_depth;
106 static inline u32 sun6i_spi_read(struct sun6i_spi *sspi, u32 reg)
108 return readl(sspi->base_addr + reg);
111 static inline void sun6i_spi_write(struct sun6i_spi *sspi, u32 reg, u32 value)
113 writel(value, sspi->base_addr + reg);
116 static inline u32 sun6i_spi_get_tx_fifo_count(struct sun6i_spi *sspi)
118 u32 reg = sun6i_spi_read(sspi, SUN6I_FIFO_STA_REG);
120 reg >>= SUN6I_FIFO_STA_TF_CNT_BITS;
122 return reg & SUN6I_FIFO_STA_TF_CNT_MASK;
125 static inline void sun6i_spi_enable_interrupt(struct sun6i_spi *sspi, u32 mask)
127 u32 reg = sun6i_spi_read(sspi, SUN6I_INT_CTL_REG);
130 sun6i_spi_write(sspi, SUN6I_INT_CTL_REG, reg);
133 static inline void sun6i_spi_disable_interrupt(struct sun6i_spi *sspi, u32 mask)
135 u32 reg = sun6i_spi_read(sspi, SUN6I_INT_CTL_REG);
138 sun6i_spi_write(sspi, SUN6I_INT_CTL_REG, reg);
141 static inline void sun6i_spi_drain_fifo(struct sun6i_spi *sspi, int len)
146 /* See how much data is available */
147 reg = sun6i_spi_read(sspi, SUN6I_FIFO_STA_REG);
148 reg &= SUN6I_FIFO_STA_RF_CNT_MASK;
149 cnt = reg >> SUN6I_FIFO_STA_RF_CNT_BITS;
155 byte = readb(sspi->base_addr + SUN6I_RXDATA_REG);
157 *sspi->rx_buf++ = byte;
161 static inline void sun6i_spi_fill_fifo(struct sun6i_spi *sspi, int len)
166 /* See how much data we can fit */
167 cnt = sspi->fifo_depth - sun6i_spi_get_tx_fifo_count(sspi);
169 len = min3(len, (int)cnt, sspi->len);
172 byte = sspi->tx_buf ? *sspi->tx_buf++ : 0;
173 writeb(byte, sspi->base_addr + SUN6I_TXDATA_REG);
178 static void sun6i_spi_set_cs(struct spi_device *spi, bool enable)
180 struct sun6i_spi *sspi = spi_master_get_devdata(spi->master);
183 reg = sun6i_spi_read(sspi, SUN6I_TFR_CTL_REG);
184 reg &= ~SUN6I_TFR_CTL_CS_MASK;
185 reg |= SUN6I_TFR_CTL_CS(spi->chip_select);
188 reg |= SUN6I_TFR_CTL_CS_LEVEL;
190 reg &= ~SUN6I_TFR_CTL_CS_LEVEL;
192 sun6i_spi_write(sspi, SUN6I_TFR_CTL_REG, reg);
195 static size_t sun6i_spi_max_transfer_size(struct spi_device *spi)
197 return SUN6I_MAX_XFER_SIZE - 1;
200 static int sun6i_spi_transfer_one(struct spi_master *master,
201 struct spi_device *spi,
202 struct spi_transfer *tfr)
204 struct sun6i_spi *sspi = spi_master_get_devdata(master);
205 unsigned int mclk_rate, div, timeout;
206 unsigned int start, end, tx_time;
207 unsigned int trig_level;
208 unsigned int tx_len = 0;
212 if (tfr->len > SUN6I_MAX_XFER_SIZE)
215 reinit_completion(&sspi->done);
216 sspi->tx_buf = tfr->tx_buf;
217 sspi->rx_buf = tfr->rx_buf;
218 sspi->len = tfr->len;
220 /* Clear pending interrupts */
221 sun6i_spi_write(sspi, SUN6I_INT_STA_REG, ~0);
224 sun6i_spi_write(sspi, SUN6I_FIFO_CTL_REG,
225 SUN6I_FIFO_CTL_RF_RST | SUN6I_FIFO_CTL_TF_RST);
228 * Setup FIFO interrupt trigger level
229 * Here we choose 3/4 of the full fifo depth, as it's the hardcoded
230 * value used in old generation of Allwinner SPI controller.
233 trig_level = sspi->fifo_depth / 4 * 3;
234 sun6i_spi_write(sspi, SUN6I_FIFO_CTL_REG,
235 (trig_level << SUN6I_FIFO_CTL_RF_RDY_TRIG_LEVEL_BITS) |
236 (trig_level << SUN6I_FIFO_CTL_TF_ERQ_TRIG_LEVEL_BITS));
239 * Setup the transfer control register: Chip Select,
242 reg = sun6i_spi_read(sspi, SUN6I_TFR_CTL_REG);
244 if (spi->mode & SPI_CPOL)
245 reg |= SUN6I_TFR_CTL_CPOL;
247 reg &= ~SUN6I_TFR_CTL_CPOL;
249 if (spi->mode & SPI_CPHA)
250 reg |= SUN6I_TFR_CTL_CPHA;
252 reg &= ~SUN6I_TFR_CTL_CPHA;
254 if (spi->mode & SPI_LSB_FIRST)
255 reg |= SUN6I_TFR_CTL_FBS;
257 reg &= ~SUN6I_TFR_CTL_FBS;
260 * If it's a TX only transfer, we don't want to fill the RX
261 * FIFO with bogus data
264 reg &= ~SUN6I_TFR_CTL_DHB;
266 reg |= SUN6I_TFR_CTL_DHB;
268 /* We want to control the chip select manually */
269 reg |= SUN6I_TFR_CTL_CS_MANUAL;
271 sun6i_spi_write(sspi, SUN6I_TFR_CTL_REG, reg);
273 /* Ensure that we have a parent clock fast enough */
274 mclk_rate = clk_get_rate(sspi->mclk);
275 if (mclk_rate < (2 * tfr->speed_hz)) {
276 clk_set_rate(sspi->mclk, 2 * tfr->speed_hz);
277 mclk_rate = clk_get_rate(sspi->mclk);
281 * Setup clock divider.
283 * We have two choices there. Either we can use the clock
284 * divide rate 1, which is calculated thanks to this formula:
285 * SPI_CLK = MOD_CLK / (2 ^ cdr)
286 * Or we can use CDR2, which is calculated with the formula:
287 * SPI_CLK = MOD_CLK / (2 * (cdr + 1))
288 * Wether we use the former or the latter is set through the
291 * First try CDR2, and if we can't reach the expected
292 * frequency, fall back to CDR1.
294 div = mclk_rate / (2 * tfr->speed_hz);
295 if (div <= (SUN6I_CLK_CTL_CDR2_MASK + 1)) {
299 reg = SUN6I_CLK_CTL_CDR2(div) | SUN6I_CLK_CTL_DRS;
301 div = ilog2(mclk_rate) - ilog2(tfr->speed_hz);
302 reg = SUN6I_CLK_CTL_CDR1(div);
305 sun6i_spi_write(sspi, SUN6I_CLK_CTL_REG, reg);
307 /* Setup the transfer now... */
311 /* Setup the counters */
312 sun6i_spi_write(sspi, SUN6I_BURST_CNT_REG, SUN6I_BURST_CNT(tfr->len));
313 sun6i_spi_write(sspi, SUN6I_XMIT_CNT_REG, SUN6I_XMIT_CNT(tx_len));
314 sun6i_spi_write(sspi, SUN6I_BURST_CTL_CNT_REG,
315 SUN6I_BURST_CTL_CNT_STC(tx_len));
317 /* Fill the TX FIFO */
318 sun6i_spi_fill_fifo(sspi, sspi->fifo_depth);
320 /* Enable the interrupts */
321 sun6i_spi_write(sspi, SUN6I_INT_CTL_REG, SUN6I_INT_CTL_TC);
322 sun6i_spi_enable_interrupt(sspi, SUN6I_INT_CTL_TC |
323 SUN6I_INT_CTL_RF_RDY);
324 if (tx_len > sspi->fifo_depth)
325 sun6i_spi_enable_interrupt(sspi, SUN6I_INT_CTL_TF_ERQ);
327 /* Start the transfer */
328 reg = sun6i_spi_read(sspi, SUN6I_TFR_CTL_REG);
329 sun6i_spi_write(sspi, SUN6I_TFR_CTL_REG, reg | SUN6I_TFR_CTL_XCH);
331 tx_time = max(tfr->len * 8 * 2 / (tfr->speed_hz / 1000), 100U);
333 timeout = wait_for_completion_timeout(&sspi->done,
334 msecs_to_jiffies(tx_time));
337 dev_warn(&master->dev,
338 "%s: timeout transferring %u bytes@%iHz for %i(%i)ms",
339 dev_name(&spi->dev), tfr->len, tfr->speed_hz,
340 jiffies_to_msecs(end - start), tx_time);
346 sun6i_spi_write(sspi, SUN6I_INT_CTL_REG, 0);
351 static irqreturn_t sun6i_spi_handler(int irq, void *dev_id)
353 struct sun6i_spi *sspi = dev_id;
354 u32 status = sun6i_spi_read(sspi, SUN6I_INT_STA_REG);
356 /* Transfer complete */
357 if (status & SUN6I_INT_CTL_TC) {
358 sun6i_spi_write(sspi, SUN6I_INT_STA_REG, SUN6I_INT_CTL_TC);
359 sun6i_spi_drain_fifo(sspi, sspi->fifo_depth);
360 complete(&sspi->done);
364 /* Receive FIFO 3/4 full */
365 if (status & SUN6I_INT_CTL_RF_RDY) {
366 sun6i_spi_drain_fifo(sspi, SUN6I_FIFO_DEPTH);
367 /* Only clear the interrupt _after_ draining the FIFO */
368 sun6i_spi_write(sspi, SUN6I_INT_STA_REG, SUN6I_INT_CTL_RF_RDY);
372 /* Transmit FIFO 3/4 empty */
373 if (status & SUN6I_INT_CTL_TF_ERQ) {
374 sun6i_spi_fill_fifo(sspi, SUN6I_FIFO_DEPTH);
377 /* nothing left to transmit */
378 sun6i_spi_disable_interrupt(sspi, SUN6I_INT_CTL_TF_ERQ);
380 /* Only clear the interrupt _after_ re-seeding the FIFO */
381 sun6i_spi_write(sspi, SUN6I_INT_STA_REG, SUN6I_INT_CTL_TF_ERQ);
389 static int sun6i_spi_runtime_resume(struct device *dev)
391 struct spi_master *master = dev_get_drvdata(dev);
392 struct sun6i_spi *sspi = spi_master_get_devdata(master);
395 ret = clk_prepare_enable(sspi->hclk);
397 dev_err(dev, "Couldn't enable AHB clock\n");
401 ret = clk_prepare_enable(sspi->mclk);
403 dev_err(dev, "Couldn't enable module clock\n");
407 ret = reset_control_deassert(sspi->rstc);
409 dev_err(dev, "Couldn't deassert the device from reset\n");
413 sun6i_spi_write(sspi, SUN6I_GBL_CTL_REG,
414 SUN6I_GBL_CTL_BUS_ENABLE | SUN6I_GBL_CTL_MASTER | SUN6I_GBL_CTL_TP);
419 clk_disable_unprepare(sspi->mclk);
421 clk_disable_unprepare(sspi->hclk);
426 static int sun6i_spi_runtime_suspend(struct device *dev)
428 struct spi_master *master = dev_get_drvdata(dev);
429 struct sun6i_spi *sspi = spi_master_get_devdata(master);
431 reset_control_assert(sspi->rstc);
432 clk_disable_unprepare(sspi->mclk);
433 clk_disable_unprepare(sspi->hclk);
438 static int sun6i_spi_probe(struct platform_device *pdev)
440 struct spi_master *master;
441 struct sun6i_spi *sspi;
442 struct resource *res;
445 master = spi_alloc_master(&pdev->dev, sizeof(struct sun6i_spi));
447 dev_err(&pdev->dev, "Unable to allocate SPI Master\n");
451 platform_set_drvdata(pdev, master);
452 sspi = spi_master_get_devdata(master);
454 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
455 sspi->base_addr = devm_ioremap_resource(&pdev->dev, res);
456 if (IS_ERR(sspi->base_addr)) {
457 ret = PTR_ERR(sspi->base_addr);
458 goto err_free_master;
461 irq = platform_get_irq(pdev, 0);
463 dev_err(&pdev->dev, "No spi IRQ specified\n");
465 goto err_free_master;
468 ret = devm_request_irq(&pdev->dev, irq, sun6i_spi_handler,
469 0, "sun6i-spi", sspi);
471 dev_err(&pdev->dev, "Cannot request IRQ\n");
472 goto err_free_master;
475 sspi->master = master;
476 sspi->fifo_depth = (unsigned long)of_device_get_match_data(&pdev->dev);
478 master->max_speed_hz = 100 * 1000 * 1000;
479 master->min_speed_hz = 3 * 1000;
480 master->set_cs = sun6i_spi_set_cs;
481 master->transfer_one = sun6i_spi_transfer_one;
482 master->num_chipselect = 4;
483 master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH | SPI_LSB_FIRST;
484 master->bits_per_word_mask = SPI_BPW_MASK(8);
485 master->dev.of_node = pdev->dev.of_node;
486 master->auto_runtime_pm = true;
487 master->max_transfer_size = sun6i_spi_max_transfer_size;
489 sspi->hclk = devm_clk_get(&pdev->dev, "ahb");
490 if (IS_ERR(sspi->hclk)) {
491 dev_err(&pdev->dev, "Unable to acquire AHB clock\n");
492 ret = PTR_ERR(sspi->hclk);
493 goto err_free_master;
496 sspi->mclk = devm_clk_get(&pdev->dev, "mod");
497 if (IS_ERR(sspi->mclk)) {
498 dev_err(&pdev->dev, "Unable to acquire module clock\n");
499 ret = PTR_ERR(sspi->mclk);
500 goto err_free_master;
503 init_completion(&sspi->done);
505 sspi->rstc = devm_reset_control_get_exclusive(&pdev->dev, NULL);
506 if (IS_ERR(sspi->rstc)) {
507 dev_err(&pdev->dev, "Couldn't get reset controller\n");
508 ret = PTR_ERR(sspi->rstc);
509 goto err_free_master;
513 * This wake-up/shutdown pattern is to be able to have the
514 * device woken up, even if runtime_pm is disabled
516 ret = sun6i_spi_runtime_resume(&pdev->dev);
518 dev_err(&pdev->dev, "Couldn't resume the device\n");
519 goto err_free_master;
522 pm_runtime_set_active(&pdev->dev);
523 pm_runtime_enable(&pdev->dev);
524 pm_runtime_idle(&pdev->dev);
526 ret = devm_spi_register_master(&pdev->dev, master);
528 dev_err(&pdev->dev, "cannot register SPI master\n");
535 pm_runtime_disable(&pdev->dev);
536 sun6i_spi_runtime_suspend(&pdev->dev);
538 spi_master_put(master);
542 static int sun6i_spi_remove(struct platform_device *pdev)
544 pm_runtime_force_suspend(&pdev->dev);
549 static const struct of_device_id sun6i_spi_match[] = {
550 { .compatible = "allwinner,sun6i-a31-spi", .data = (void *)SUN6I_FIFO_DEPTH },
551 { .compatible = "allwinner,sun8i-h3-spi", .data = (void *)SUN8I_FIFO_DEPTH },
554 MODULE_DEVICE_TABLE(of, sun6i_spi_match);
556 static const struct dev_pm_ops sun6i_spi_pm_ops = {
557 .runtime_resume = sun6i_spi_runtime_resume,
558 .runtime_suspend = sun6i_spi_runtime_suspend,
561 static struct platform_driver sun6i_spi_driver = {
562 .probe = sun6i_spi_probe,
563 .remove = sun6i_spi_remove,
566 .of_match_table = sun6i_spi_match,
567 .pm = &sun6i_spi_pm_ops,
570 module_platform_driver(sun6i_spi_driver);
572 MODULE_AUTHOR("Pan Nan <pannan@allwinnertech.com>");
573 MODULE_AUTHOR("Maxime Ripard <maxime.ripard@free-electrons.com>");
574 MODULE_DESCRIPTION("Allwinner A31 SPI controller driver");
575 MODULE_LICENSE("GPL");