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5314987d GP |
1 | /* |
2 | * Freescale i.MX7ULP LPSPI driver | |
3 | * | |
4 | * Copyright 2016 Freescale Semiconductor, Inc. | |
5 | * | |
6 | * This program is free software; you can redistribute it and/or modify | |
7 | * it under the terms of the GNU General Public License as published by | |
8 | * the Free Software Foundation; either version 2 of the License, or | |
9 | * (at your option) any later version. | |
10 | * | |
11 | * This program is distributed in the hope that it will be useful, | |
12 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
14 | * GNU General Public License for more details. | |
15 | * | |
16 | */ | |
17 | ||
18 | #include <linux/clk.h> | |
19 | #include <linux/completion.h> | |
20 | #include <linux/delay.h> | |
21 | #include <linux/err.h> | |
22 | #include <linux/interrupt.h> | |
23 | #include <linux/io.h> | |
24 | #include <linux/irq.h> | |
25 | #include <linux/kernel.h> | |
26 | #include <linux/module.h> | |
27 | #include <linux/of.h> | |
28 | #include <linux/of_device.h> | |
29 | #include <linux/platform_device.h> | |
30 | #include <linux/slab.h> | |
31 | #include <linux/spi/spi.h> | |
32 | #include <linux/spi/spi_bitbang.h> | |
33 | #include <linux/types.h> | |
34 | ||
35 | #define DRIVER_NAME "fsl_lpspi" | |
36 | ||
37 | /* i.MX7ULP LPSPI registers */ | |
38 | #define IMX7ULP_VERID 0x0 | |
39 | #define IMX7ULP_PARAM 0x4 | |
40 | #define IMX7ULP_CR 0x10 | |
41 | #define IMX7ULP_SR 0x14 | |
42 | #define IMX7ULP_IER 0x18 | |
43 | #define IMX7ULP_DER 0x1c | |
44 | #define IMX7ULP_CFGR0 0x20 | |
45 | #define IMX7ULP_CFGR1 0x24 | |
46 | #define IMX7ULP_DMR0 0x30 | |
47 | #define IMX7ULP_DMR1 0x34 | |
48 | #define IMX7ULP_CCR 0x40 | |
49 | #define IMX7ULP_FCR 0x58 | |
50 | #define IMX7ULP_FSR 0x5c | |
51 | #define IMX7ULP_TCR 0x60 | |
52 | #define IMX7ULP_TDR 0x64 | |
53 | #define IMX7ULP_RSR 0x70 | |
54 | #define IMX7ULP_RDR 0x74 | |
55 | ||
56 | /* General control register field define */ | |
57 | #define CR_RRF BIT(9) | |
58 | #define CR_RTF BIT(8) | |
59 | #define CR_RST BIT(1) | |
60 | #define CR_MEN BIT(0) | |
61 | #define SR_TCF BIT(10) | |
62 | #define SR_RDF BIT(1) | |
63 | #define SR_TDF BIT(0) | |
64 | #define IER_TCIE BIT(10) | |
65 | #define IER_RDIE BIT(1) | |
66 | #define IER_TDIE BIT(0) | |
67 | #define CFGR1_PCSCFG BIT(27) | |
68 | #define CFGR1_PCSPOL BIT(8) | |
69 | #define CFGR1_NOSTALL BIT(3) | |
70 | #define CFGR1_MASTER BIT(0) | |
71 | #define RSR_RXEMPTY BIT(1) | |
72 | #define TCR_CPOL BIT(31) | |
73 | #define TCR_CPHA BIT(30) | |
74 | #define TCR_CONT BIT(21) | |
75 | #define TCR_CONTC BIT(20) | |
76 | #define TCR_RXMSK BIT(19) | |
77 | #define TCR_TXMSK BIT(18) | |
78 | ||
79 | static int clkdivs[] = {1, 2, 4, 8, 16, 32, 64, 128}; | |
80 | ||
81 | struct lpspi_config { | |
82 | u8 bpw; | |
83 | u8 chip_select; | |
84 | u8 prescale; | |
85 | u16 mode; | |
86 | u32 speed_hz; | |
87 | }; | |
88 | ||
89 | struct fsl_lpspi_data { | |
90 | struct device *dev; | |
91 | void __iomem *base; | |
92 | struct clk *clk; | |
93 | ||
94 | void *rx_buf; | |
95 | const void *tx_buf; | |
96 | void (*tx)(struct fsl_lpspi_data *); | |
97 | void (*rx)(struct fsl_lpspi_data *); | |
98 | ||
99 | u32 remain; | |
100 | u8 txfifosize; | |
101 | u8 rxfifosize; | |
102 | ||
103 | struct lpspi_config config; | |
104 | struct completion xfer_done; | |
105 | }; | |
106 | ||
107 | static const struct of_device_id fsl_lpspi_dt_ids[] = { | |
108 | { .compatible = "fsl,imx7ulp-spi", }, | |
109 | { /* sentinel */ } | |
110 | }; | |
111 | MODULE_DEVICE_TABLE(of, fsl_lpspi_dt_ids); | |
112 | ||
113 | #define LPSPI_BUF_RX(type) \ | |
114 | static void fsl_lpspi_buf_rx_##type(struct fsl_lpspi_data *fsl_lpspi) \ | |
115 | { \ | |
116 | unsigned int val = readl(fsl_lpspi->base + IMX7ULP_RDR); \ | |
117 | \ | |
118 | if (fsl_lpspi->rx_buf) { \ | |
119 | *(type *)fsl_lpspi->rx_buf = val; \ | |
120 | fsl_lpspi->rx_buf += sizeof(type); \ | |
121 | } \ | |
122 | } | |
123 | ||
124 | #define LPSPI_BUF_TX(type) \ | |
125 | static void fsl_lpspi_buf_tx_##type(struct fsl_lpspi_data *fsl_lpspi) \ | |
126 | { \ | |
127 | type val = 0; \ | |
128 | \ | |
129 | if (fsl_lpspi->tx_buf) { \ | |
130 | val = *(type *)fsl_lpspi->tx_buf; \ | |
131 | fsl_lpspi->tx_buf += sizeof(type); \ | |
132 | } \ | |
133 | \ | |
134 | fsl_lpspi->remain -= sizeof(type); \ | |
135 | writel(val, fsl_lpspi->base + IMX7ULP_TDR); \ | |
136 | } | |
137 | ||
138 | LPSPI_BUF_RX(u8) | |
139 | LPSPI_BUF_TX(u8) | |
140 | LPSPI_BUF_RX(u16) | |
141 | LPSPI_BUF_TX(u16) | |
142 | LPSPI_BUF_RX(u32) | |
143 | LPSPI_BUF_TX(u32) | |
144 | ||
145 | static void fsl_lpspi_intctrl(struct fsl_lpspi_data *fsl_lpspi, | |
146 | unsigned int enable) | |
147 | { | |
148 | writel(enable, fsl_lpspi->base + IMX7ULP_IER); | |
149 | } | |
150 | ||
3ffa1a5d | 151 | static int lpspi_prepare_xfer_hardware(struct spi_master *master) |
5314987d GP |
152 | { |
153 | struct fsl_lpspi_data *fsl_lpspi = spi_master_get_devdata(master); | |
154 | ||
155 | return clk_prepare_enable(fsl_lpspi->clk); | |
156 | } | |
157 | ||
3ffa1a5d | 158 | static int lpspi_unprepare_xfer_hardware(struct spi_master *master) |
5314987d GP |
159 | { |
160 | struct fsl_lpspi_data *fsl_lpspi = spi_master_get_devdata(master); | |
161 | ||
162 | clk_disable_unprepare(fsl_lpspi->clk); | |
163 | ||
164 | return 0; | |
165 | } | |
166 | ||
167 | static int fsl_lpspi_txfifo_empty(struct fsl_lpspi_data *fsl_lpspi) | |
168 | { | |
169 | u32 txcnt; | |
170 | unsigned long orig_jiffies = jiffies; | |
171 | ||
172 | do { | |
173 | txcnt = readl(fsl_lpspi->base + IMX7ULP_FSR) & 0xff; | |
174 | ||
175 | if (time_after(jiffies, orig_jiffies + msecs_to_jiffies(500))) { | |
176 | dev_dbg(fsl_lpspi->dev, "txfifo empty timeout\n"); | |
177 | return -ETIMEDOUT; | |
178 | } | |
14de3918 | 179 | cond_resched(); |
5314987d GP |
180 | |
181 | } while (txcnt); | |
182 | ||
183 | return 0; | |
184 | } | |
185 | ||
186 | static void fsl_lpspi_write_tx_fifo(struct fsl_lpspi_data *fsl_lpspi) | |
187 | { | |
188 | u8 txfifo_cnt; | |
189 | ||
190 | txfifo_cnt = readl(fsl_lpspi->base + IMX7ULP_FSR) & 0xff; | |
191 | ||
192 | while (txfifo_cnt < fsl_lpspi->txfifosize) { | |
193 | if (!fsl_lpspi->remain) | |
194 | break; | |
195 | fsl_lpspi->tx(fsl_lpspi); | |
196 | txfifo_cnt++; | |
197 | } | |
198 | ||
199 | if (!fsl_lpspi->remain && (txfifo_cnt < fsl_lpspi->txfifosize)) | |
200 | writel(0, fsl_lpspi->base + IMX7ULP_TDR); | |
201 | else | |
202 | fsl_lpspi_intctrl(fsl_lpspi, IER_TDIE); | |
203 | } | |
204 | ||
205 | static void fsl_lpspi_read_rx_fifo(struct fsl_lpspi_data *fsl_lpspi) | |
206 | { | |
207 | while (!(readl(fsl_lpspi->base + IMX7ULP_RSR) & RSR_RXEMPTY)) | |
208 | fsl_lpspi->rx(fsl_lpspi); | |
209 | } | |
210 | ||
211 | static void fsl_lpspi_set_cmd(struct fsl_lpspi_data *fsl_lpspi, | |
212 | bool is_first_xfer) | |
213 | { | |
214 | u32 temp = 0; | |
215 | ||
216 | temp |= fsl_lpspi->config.bpw - 1; | |
217 | temp |= fsl_lpspi->config.prescale << 27; | |
e3a49390 | 218 | temp |= (fsl_lpspi->config.mode & 0x3) << 30; |
5314987d GP |
219 | temp |= (fsl_lpspi->config.chip_select & 0x3) << 24; |
220 | ||
221 | /* | |
222 | * Set TCR_CONT will keep SS asserted after current transfer. | |
223 | * For the first transfer, clear TCR_CONTC to assert SS. | |
224 | * For subsequent transfer, set TCR_CONTC to keep SS asserted. | |
225 | */ | |
226 | temp |= TCR_CONT; | |
227 | if (is_first_xfer) | |
228 | temp &= ~TCR_CONTC; | |
229 | else | |
230 | temp |= TCR_CONTC; | |
231 | ||
232 | writel(temp, fsl_lpspi->base + IMX7ULP_TCR); | |
233 | ||
234 | dev_dbg(fsl_lpspi->dev, "TCR=0x%x\n", temp); | |
235 | } | |
236 | ||
237 | static void fsl_lpspi_set_watermark(struct fsl_lpspi_data *fsl_lpspi) | |
238 | { | |
239 | u8 txwatermark, rxwatermark; | |
240 | u32 temp; | |
241 | ||
242 | temp = readl(fsl_lpspi->base + IMX7ULP_PARAM); | |
243 | fsl_lpspi->txfifosize = 1 << (temp & 0x0f); | |
244 | fsl_lpspi->rxfifosize = 1 << ((temp >> 8) & 0x0f); | |
245 | rxwatermark = fsl_lpspi->txfifosize >> 1; | |
246 | txwatermark = fsl_lpspi->rxfifosize >> 1; | |
247 | temp = txwatermark | rxwatermark << 16; | |
248 | ||
249 | writel(temp, fsl_lpspi->base + IMX7ULP_FCR); | |
250 | ||
251 | dev_dbg(fsl_lpspi->dev, "FCR=0x%x\n", temp); | |
252 | } | |
253 | ||
254 | static int fsl_lpspi_set_bitrate(struct fsl_lpspi_data *fsl_lpspi) | |
255 | { | |
256 | struct lpspi_config config = fsl_lpspi->config; | |
257 | unsigned int perclk_rate, scldiv; | |
258 | u8 prescale; | |
259 | ||
260 | perclk_rate = clk_get_rate(fsl_lpspi->clk); | |
261 | for (prescale = 0; prescale < 8; prescale++) { | |
262 | scldiv = perclk_rate / | |
263 | (clkdivs[prescale] * config.speed_hz) - 2; | |
264 | if (scldiv < 256) { | |
265 | fsl_lpspi->config.prescale = prescale; | |
266 | break; | |
267 | } | |
268 | } | |
269 | ||
270 | if (prescale == 8 && scldiv >= 256) | |
271 | return -EINVAL; | |
272 | ||
273 | writel(scldiv, fsl_lpspi->base + IMX7ULP_CCR); | |
274 | ||
275 | dev_dbg(fsl_lpspi->dev, "perclk=%d, speed=%d, prescale =%d, scldiv=%d\n", | |
276 | perclk_rate, config.speed_hz, prescale, scldiv); | |
277 | ||
278 | return 0; | |
279 | } | |
280 | ||
281 | static int fsl_lpspi_config(struct fsl_lpspi_data *fsl_lpspi) | |
282 | { | |
283 | u32 temp; | |
284 | int ret; | |
285 | ||
286 | temp = CR_RST; | |
287 | writel(temp, fsl_lpspi->base + IMX7ULP_CR); | |
288 | writel(0, fsl_lpspi->base + IMX7ULP_CR); | |
289 | ||
290 | ret = fsl_lpspi_set_bitrate(fsl_lpspi); | |
291 | if (ret) | |
292 | return ret; | |
293 | ||
294 | fsl_lpspi_set_watermark(fsl_lpspi); | |
295 | ||
296 | temp = CFGR1_PCSCFG | CFGR1_MASTER | CFGR1_NOSTALL; | |
297 | if (fsl_lpspi->config.mode & SPI_CS_HIGH) | |
298 | temp |= CFGR1_PCSPOL; | |
299 | writel(temp, fsl_lpspi->base + IMX7ULP_CFGR1); | |
300 | ||
301 | temp = readl(fsl_lpspi->base + IMX7ULP_CR); | |
302 | temp |= CR_RRF | CR_RTF | CR_MEN; | |
303 | writel(temp, fsl_lpspi->base + IMX7ULP_CR); | |
304 | ||
305 | return 0; | |
306 | } | |
307 | ||
308 | static void fsl_lpspi_setup_transfer(struct spi_device *spi, | |
309 | struct spi_transfer *t) | |
310 | { | |
311 | struct fsl_lpspi_data *fsl_lpspi = spi_master_get_devdata(spi->master); | |
312 | ||
313 | fsl_lpspi->config.mode = spi->mode; | |
314 | fsl_lpspi->config.bpw = t ? t->bits_per_word : spi->bits_per_word; | |
315 | fsl_lpspi->config.speed_hz = t ? t->speed_hz : spi->max_speed_hz; | |
316 | fsl_lpspi->config.chip_select = spi->chip_select; | |
317 | ||
318 | if (!fsl_lpspi->config.speed_hz) | |
319 | fsl_lpspi->config.speed_hz = spi->max_speed_hz; | |
320 | if (!fsl_lpspi->config.bpw) | |
321 | fsl_lpspi->config.bpw = spi->bits_per_word; | |
322 | ||
323 | /* Initialize the functions for transfer */ | |
324 | if (fsl_lpspi->config.bpw <= 8) { | |
325 | fsl_lpspi->rx = fsl_lpspi_buf_rx_u8; | |
326 | fsl_lpspi->tx = fsl_lpspi_buf_tx_u8; | |
327 | } else if (fsl_lpspi->config.bpw <= 16) { | |
328 | fsl_lpspi->rx = fsl_lpspi_buf_rx_u16; | |
329 | fsl_lpspi->tx = fsl_lpspi_buf_tx_u16; | |
330 | } else { | |
331 | fsl_lpspi->rx = fsl_lpspi_buf_rx_u32; | |
332 | fsl_lpspi->tx = fsl_lpspi_buf_tx_u32; | |
333 | } | |
334 | ||
335 | fsl_lpspi_config(fsl_lpspi); | |
336 | } | |
337 | ||
338 | static int fsl_lpspi_transfer_one(struct spi_master *master, | |
339 | struct spi_device *spi, | |
340 | struct spi_transfer *t) | |
341 | { | |
342 | struct fsl_lpspi_data *fsl_lpspi = spi_master_get_devdata(master); | |
343 | int ret; | |
344 | ||
345 | fsl_lpspi->tx_buf = t->tx_buf; | |
346 | fsl_lpspi->rx_buf = t->rx_buf; | |
347 | fsl_lpspi->remain = t->len; | |
348 | ||
349 | reinit_completion(&fsl_lpspi->xfer_done); | |
350 | fsl_lpspi_write_tx_fifo(fsl_lpspi); | |
d2ad0a62 GP |
351 | |
352 | ret = wait_for_completion_timeout(&fsl_lpspi->xfer_done, HZ); | |
353 | if (!ret) { | |
354 | dev_dbg(fsl_lpspi->dev, "wait for completion timeout\n"); | |
355 | return -ETIMEDOUT; | |
356 | } | |
5314987d GP |
357 | |
358 | ret = fsl_lpspi_txfifo_empty(fsl_lpspi); | |
359 | fsl_lpspi_read_rx_fifo(fsl_lpspi); | |
360 | ||
361 | return ret; | |
362 | } | |
363 | ||
364 | static int fsl_lpspi_transfer_one_msg(struct spi_master *master, | |
365 | struct spi_message *msg) | |
366 | { | |
367 | struct fsl_lpspi_data *fsl_lpspi = spi_master_get_devdata(master); | |
368 | struct spi_device *spi = msg->spi; | |
369 | struct spi_transfer *xfer; | |
370 | bool is_first_xfer = true; | |
371 | u32 temp; | |
372 | int ret; | |
373 | ||
374 | msg->status = 0; | |
375 | msg->actual_length = 0; | |
376 | ||
377 | list_for_each_entry(xfer, &msg->transfers, transfer_list) { | |
378 | fsl_lpspi_setup_transfer(spi, xfer); | |
379 | fsl_lpspi_set_cmd(fsl_lpspi, is_first_xfer); | |
380 | ||
381 | is_first_xfer = false; | |
382 | ||
383 | ret = fsl_lpspi_transfer_one(master, spi, xfer); | |
384 | if (ret < 0) | |
385 | goto complete; | |
386 | ||
387 | msg->actual_length += xfer->len; | |
388 | } | |
389 | ||
390 | complete: | |
391 | /* de-assert SS, then finalize current message */ | |
392 | temp = readl(fsl_lpspi->base + IMX7ULP_TCR); | |
393 | temp &= ~TCR_CONTC; | |
394 | writel(temp, fsl_lpspi->base + IMX7ULP_TCR); | |
395 | ||
396 | msg->status = ret; | |
397 | spi_finalize_current_message(master); | |
398 | ||
399 | return ret; | |
400 | } | |
401 | ||
402 | static irqreturn_t fsl_lpspi_isr(int irq, void *dev_id) | |
403 | { | |
404 | struct fsl_lpspi_data *fsl_lpspi = dev_id; | |
405 | u32 temp; | |
406 | ||
407 | fsl_lpspi_intctrl(fsl_lpspi, 0); | |
408 | temp = readl(fsl_lpspi->base + IMX7ULP_SR); | |
409 | ||
410 | fsl_lpspi_read_rx_fifo(fsl_lpspi); | |
411 | ||
412 | if (temp & SR_TDF) { | |
413 | fsl_lpspi_write_tx_fifo(fsl_lpspi); | |
414 | ||
415 | if (!fsl_lpspi->remain) | |
416 | complete(&fsl_lpspi->xfer_done); | |
417 | ||
418 | return IRQ_HANDLED; | |
419 | } | |
420 | ||
421 | return IRQ_NONE; | |
422 | } | |
423 | ||
424 | static int fsl_lpspi_probe(struct platform_device *pdev) | |
425 | { | |
426 | struct fsl_lpspi_data *fsl_lpspi; | |
427 | struct spi_master *master; | |
428 | struct resource *res; | |
429 | int ret, irq; | |
430 | ||
431 | master = spi_alloc_master(&pdev->dev, sizeof(struct fsl_lpspi_data)); | |
432 | if (!master) | |
433 | return -ENOMEM; | |
434 | ||
435 | platform_set_drvdata(pdev, master); | |
436 | ||
437 | master->bits_per_word_mask = SPI_BPW_RANGE_MASK(8, 32); | |
438 | master->bus_num = pdev->id; | |
439 | ||
440 | fsl_lpspi = spi_master_get_devdata(master); | |
441 | fsl_lpspi->dev = &pdev->dev; | |
442 | ||
443 | master->transfer_one_message = fsl_lpspi_transfer_one_msg; | |
3ffa1a5d GP |
444 | master->prepare_transfer_hardware = lpspi_prepare_xfer_hardware; |
445 | master->unprepare_transfer_hardware = lpspi_unprepare_xfer_hardware; | |
5314987d GP |
446 | master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH; |
447 | master->flags = SPI_MASTER_MUST_RX | SPI_MASTER_MUST_TX; | |
448 | master->dev.of_node = pdev->dev.of_node; | |
449 | master->bus_num = pdev->id; | |
450 | ||
451 | init_completion(&fsl_lpspi->xfer_done); | |
452 | ||
453 | res = platform_get_resource(pdev, IORESOURCE_MEM, 0); | |
454 | fsl_lpspi->base = devm_ioremap_resource(&pdev->dev, res); | |
455 | if (IS_ERR(fsl_lpspi->base)) { | |
456 | ret = PTR_ERR(fsl_lpspi->base); | |
457 | goto out_master_put; | |
458 | } | |
459 | ||
460 | irq = platform_get_irq(pdev, 0); | |
461 | if (irq < 0) { | |
462 | ret = irq; | |
463 | goto out_master_put; | |
464 | } | |
465 | ||
466 | ret = devm_request_irq(&pdev->dev, irq, fsl_lpspi_isr, 0, | |
467 | dev_name(&pdev->dev), fsl_lpspi); | |
468 | if (ret) { | |
469 | dev_err(&pdev->dev, "can't get irq%d: %d\n", irq, ret); | |
470 | goto out_master_put; | |
471 | } | |
472 | ||
473 | fsl_lpspi->clk = devm_clk_get(&pdev->dev, "ipg"); | |
474 | if (IS_ERR(fsl_lpspi->clk)) { | |
475 | ret = PTR_ERR(fsl_lpspi->clk); | |
476 | goto out_master_put; | |
477 | } | |
478 | ||
479 | ret = devm_spi_register_master(&pdev->dev, master); | |
480 | if (ret < 0) { | |
481 | dev_err(&pdev->dev, "spi_register_master error.\n"); | |
482 | goto out_master_put; | |
483 | } | |
484 | ||
485 | return 0; | |
486 | ||
487 | out_master_put: | |
488 | spi_master_put(master); | |
489 | ||
490 | return ret; | |
491 | } | |
492 | ||
493 | static int fsl_lpspi_remove(struct platform_device *pdev) | |
494 | { | |
495 | struct spi_master *master = platform_get_drvdata(pdev); | |
496 | struct fsl_lpspi_data *fsl_lpspi = spi_master_get_devdata(master); | |
497 | ||
498 | clk_disable_unprepare(fsl_lpspi->clk); | |
499 | ||
500 | return 0; | |
501 | } | |
502 | ||
503 | static struct platform_driver fsl_lpspi_driver = { | |
504 | .driver = { | |
505 | .name = DRIVER_NAME, | |
506 | .of_match_table = fsl_lpspi_dt_ids, | |
507 | }, | |
508 | .probe = fsl_lpspi_probe, | |
509 | .remove = fsl_lpspi_remove, | |
510 | }; | |
511 | module_platform_driver(fsl_lpspi_driver); | |
512 | ||
513 | MODULE_DESCRIPTION("LPSPI Master Controller driver"); | |
514 | MODULE_AUTHOR("Gao Pan <pandy.gao@nxp.com>"); | |
515 | MODULE_LICENSE("GPL v2"); |