xref: /openbmc/linux/drivers/spi/spi-meson-spicc.c (revision 0ad53fe3)
1 /*
2  * Driver for Amlogic Meson SPI communication controller (SPICC)
3  *
4  * Copyright (C) BayLibre, SAS
5  * Author: Neil Armstrong <narmstrong@baylibre.com>
6  *
7  * SPDX-License-Identifier: GPL-2.0+
8  */
9 
10 #include <linux/bitfield.h>
11 #include <linux/clk.h>
12 #include <linux/clk-provider.h>
13 #include <linux/device.h>
14 #include <linux/io.h>
15 #include <linux/kernel.h>
16 #include <linux/module.h>
17 #include <linux/of.h>
18 #include <linux/of_device.h>
19 #include <linux/platform_device.h>
20 #include <linux/spi/spi.h>
21 #include <linux/types.h>
22 #include <linux/interrupt.h>
23 #include <linux/reset.h>
24 
25 /*
26  * The Meson SPICC controller could support DMA based transfers, but is not
27  * implemented by the vendor code, and while having the registers documentation
28  * it has never worked on the GXL Hardware.
29  * The PIO mode is the only mode implemented, and due to badly designed HW :
30  * - all transfers are cutted in 16 words burst because the FIFO hangs on
31  *   TX underflow, and there is no TX "Half-Empty" interrupt, so we go by
32  *   FIFO max size chunk only
33  * - CS management is dumb, and goes UP between every burst, so is really a
34  *   "Data Valid" signal than a Chip Select, GPIO link should be used instead
35  *   to have a CS go down over the full transfer
36  */
37 
38 #define SPICC_MAX_BURST	128
39 
40 /* Register Map */
41 #define SPICC_RXDATA	0x00
42 
43 #define SPICC_TXDATA	0x04
44 
45 #define SPICC_CONREG	0x08
46 #define SPICC_ENABLE		BIT(0)
47 #define SPICC_MODE_MASTER	BIT(1)
48 #define SPICC_XCH		BIT(2)
49 #define SPICC_SMC		BIT(3)
50 #define SPICC_POL		BIT(4)
51 #define SPICC_PHA		BIT(5)
52 #define SPICC_SSCTL		BIT(6)
53 #define SPICC_SSPOL		BIT(7)
54 #define SPICC_DRCTL_MASK	GENMASK(9, 8)
55 #define SPICC_DRCTL_IGNORE	0
56 #define SPICC_DRCTL_FALLING	1
57 #define SPICC_DRCTL_LOWLEVEL	2
58 #define SPICC_CS_MASK		GENMASK(13, 12)
59 #define SPICC_DATARATE_MASK	GENMASK(18, 16)
60 #define SPICC_DATARATE_DIV4	0
61 #define SPICC_DATARATE_DIV8	1
62 #define SPICC_DATARATE_DIV16	2
63 #define SPICC_DATARATE_DIV32	3
64 #define SPICC_BITLENGTH_MASK	GENMASK(24, 19)
65 #define SPICC_BURSTLENGTH_MASK	GENMASK(31, 25)
66 
67 #define SPICC_INTREG	0x0c
68 #define SPICC_TE_EN	BIT(0) /* TX FIFO Empty Interrupt */
69 #define SPICC_TH_EN	BIT(1) /* TX FIFO Half-Full Interrupt */
70 #define SPICC_TF_EN	BIT(2) /* TX FIFO Full Interrupt */
71 #define SPICC_RR_EN	BIT(3) /* RX FIFO Ready Interrupt */
72 #define SPICC_RH_EN	BIT(4) /* RX FIFO Half-Full Interrupt */
73 #define SPICC_RF_EN	BIT(5) /* RX FIFO Full Interrupt */
74 #define SPICC_RO_EN	BIT(6) /* RX FIFO Overflow Interrupt */
75 #define SPICC_TC_EN	BIT(7) /* Transfert Complete Interrupt */
76 
77 #define SPICC_DMAREG	0x10
78 #define SPICC_DMA_ENABLE		BIT(0)
79 #define SPICC_TXFIFO_THRESHOLD_MASK	GENMASK(5, 1)
80 #define SPICC_RXFIFO_THRESHOLD_MASK	GENMASK(10, 6)
81 #define SPICC_READ_BURST_MASK		GENMASK(14, 11)
82 #define SPICC_WRITE_BURST_MASK		GENMASK(18, 15)
83 #define SPICC_DMA_URGENT		BIT(19)
84 #define SPICC_DMA_THREADID_MASK		GENMASK(25, 20)
85 #define SPICC_DMA_BURSTNUM_MASK		GENMASK(31, 26)
86 
87 #define SPICC_STATREG	0x14
88 #define SPICC_TE	BIT(0) /* TX FIFO Empty Interrupt */
89 #define SPICC_TH	BIT(1) /* TX FIFO Half-Full Interrupt */
90 #define SPICC_TF	BIT(2) /* TX FIFO Full Interrupt */
91 #define SPICC_RR	BIT(3) /* RX FIFO Ready Interrupt */
92 #define SPICC_RH	BIT(4) /* RX FIFO Half-Full Interrupt */
93 #define SPICC_RF	BIT(5) /* RX FIFO Full Interrupt */
94 #define SPICC_RO	BIT(6) /* RX FIFO Overflow Interrupt */
95 #define SPICC_TC	BIT(7) /* Transfert Complete Interrupt */
96 
97 #define SPICC_PERIODREG	0x18
98 #define SPICC_PERIOD	GENMASK(14, 0)	/* Wait cycles */
99 
100 #define SPICC_TESTREG	0x1c
101 #define SPICC_TXCNT_MASK	GENMASK(4, 0)	/* TX FIFO Counter */
102 #define SPICC_RXCNT_MASK	GENMASK(9, 5)	/* RX FIFO Counter */
103 #define SPICC_SMSTATUS_MASK	GENMASK(12, 10)	/* State Machine Status */
104 #define SPICC_LBC_RO		BIT(13)	/* Loop Back Control Read-Only */
105 #define SPICC_LBC_W1		BIT(14) /* Loop Back Control Write-Only */
106 #define SPICC_SWAP_RO		BIT(14) /* RX FIFO Data Swap Read-Only */
107 #define SPICC_SWAP_W1		BIT(15) /* RX FIFO Data Swap Write-Only */
108 #define SPICC_DLYCTL_RO_MASK	GENMASK(20, 15) /* Delay Control Read-Only */
109 #define SPICC_MO_DELAY_MASK	GENMASK(17, 16) /* Master Output Delay */
110 #define SPICC_MO_NO_DELAY	0
111 #define SPICC_MO_DELAY_1_CYCLE	1
112 #define SPICC_MO_DELAY_2_CYCLE	2
113 #define SPICC_MO_DELAY_3_CYCLE	3
114 #define SPICC_MI_DELAY_MASK	GENMASK(19, 18) /* Master Input Delay */
115 #define SPICC_MI_NO_DELAY	0
116 #define SPICC_MI_DELAY_1_CYCLE	1
117 #define SPICC_MI_DELAY_2_CYCLE	2
118 #define SPICC_MI_DELAY_3_CYCLE	3
119 #define SPICC_MI_CAP_DELAY_MASK	GENMASK(21, 20) /* Master Capture Delay */
120 #define SPICC_CAP_AHEAD_2_CYCLE	0
121 #define SPICC_CAP_AHEAD_1_CYCLE	1
122 #define SPICC_CAP_NO_DELAY	2
123 #define SPICC_CAP_DELAY_1_CYCLE	3
124 #define SPICC_FIFORST_RO_MASK	GENMASK(22, 21) /* FIFO Softreset Read-Only */
125 #define SPICC_FIFORST_W1_MASK	GENMASK(23, 22) /* FIFO Softreset Write-Only */
126 
127 #define SPICC_DRADDR	0x20	/* Read Address of DMA */
128 
129 #define SPICC_DWADDR	0x24	/* Write Address of DMA */
130 
131 #define SPICC_ENH_CTL0	0x38	/* Enhanced Feature */
132 #define SPICC_ENH_CLK_CS_DELAY_MASK	GENMASK(15, 0)
133 #define SPICC_ENH_DATARATE_MASK		GENMASK(23, 16)
134 #define SPICC_ENH_DATARATE_EN		BIT(24)
135 #define SPICC_ENH_MOSI_OEN		BIT(25)
136 #define SPICC_ENH_CLK_OEN		BIT(26)
137 #define SPICC_ENH_CS_OEN		BIT(27)
138 #define SPICC_ENH_CLK_CS_DELAY_EN	BIT(28)
139 #define SPICC_ENH_MAIN_CLK_AO		BIT(29)
140 
141 #define writel_bits_relaxed(mask, val, addr) \
142 	writel_relaxed((readl_relaxed(addr) & ~(mask)) | (val), addr)
143 
144 struct meson_spicc_data {
145 	unsigned int			max_speed_hz;
146 	unsigned int			min_speed_hz;
147 	unsigned int			fifo_size;
148 	bool				has_oen;
149 	bool				has_enhance_clk_div;
150 	bool				has_pclk;
151 };
152 
153 struct meson_spicc_device {
154 	struct spi_master		*master;
155 	struct platform_device		*pdev;
156 	void __iomem			*base;
157 	struct clk			*core;
158 	struct clk			*pclk;
159 	struct clk			*clk;
160 	struct spi_message		*message;
161 	struct spi_transfer		*xfer;
162 	const struct meson_spicc_data	*data;
163 	u8				*tx_buf;
164 	u8				*rx_buf;
165 	unsigned int			bytes_per_word;
166 	unsigned long			tx_remain;
167 	unsigned long			rx_remain;
168 	unsigned long			xfer_remain;
169 };
170 
171 static void meson_spicc_oen_enable(struct meson_spicc_device *spicc)
172 {
173 	u32 conf;
174 
175 	if (!spicc->data->has_oen)
176 		return;
177 
178 	conf = readl_relaxed(spicc->base + SPICC_ENH_CTL0) |
179 		SPICC_ENH_MOSI_OEN | SPICC_ENH_CLK_OEN | SPICC_ENH_CS_OEN;
180 
181 	writel_relaxed(conf, spicc->base + SPICC_ENH_CTL0);
182 }
183 
184 static inline bool meson_spicc_txfull(struct meson_spicc_device *spicc)
185 {
186 	return !!FIELD_GET(SPICC_TF,
187 			   readl_relaxed(spicc->base + SPICC_STATREG));
188 }
189 
190 static inline bool meson_spicc_rxready(struct meson_spicc_device *spicc)
191 {
192 	return FIELD_GET(SPICC_RH | SPICC_RR | SPICC_RF,
193 			 readl_relaxed(spicc->base + SPICC_STATREG));
194 }
195 
196 static inline u32 meson_spicc_pull_data(struct meson_spicc_device *spicc)
197 {
198 	unsigned int bytes = spicc->bytes_per_word;
199 	unsigned int byte_shift = 0;
200 	u32 data = 0;
201 	u8 byte;
202 
203 	while (bytes--) {
204 		byte = *spicc->tx_buf++;
205 		data |= (byte & 0xff) << byte_shift;
206 		byte_shift += 8;
207 	}
208 
209 	spicc->tx_remain--;
210 	return data;
211 }
212 
213 static inline void meson_spicc_push_data(struct meson_spicc_device *spicc,
214 					 u32 data)
215 {
216 	unsigned int bytes = spicc->bytes_per_word;
217 	unsigned int byte_shift = 0;
218 	u8 byte;
219 
220 	while (bytes--) {
221 		byte = (data >> byte_shift) & 0xff;
222 		*spicc->rx_buf++ = byte;
223 		byte_shift += 8;
224 	}
225 
226 	spicc->rx_remain--;
227 }
228 
229 static inline void meson_spicc_rx(struct meson_spicc_device *spicc)
230 {
231 	/* Empty RX FIFO */
232 	while (spicc->rx_remain &&
233 	       meson_spicc_rxready(spicc))
234 		meson_spicc_push_data(spicc,
235 				readl_relaxed(spicc->base + SPICC_RXDATA));
236 }
237 
238 static inline void meson_spicc_tx(struct meson_spicc_device *spicc)
239 {
240 	/* Fill Up TX FIFO */
241 	while (spicc->tx_remain &&
242 	       !meson_spicc_txfull(spicc))
243 		writel_relaxed(meson_spicc_pull_data(spicc),
244 			       spicc->base + SPICC_TXDATA);
245 }
246 
247 static inline void meson_spicc_setup_burst(struct meson_spicc_device *spicc)
248 {
249 
250 	unsigned int burst_len = min_t(unsigned int,
251 				       spicc->xfer_remain /
252 				       spicc->bytes_per_word,
253 				       spicc->data->fifo_size);
254 	/* Setup Xfer variables */
255 	spicc->tx_remain = burst_len;
256 	spicc->rx_remain = burst_len;
257 	spicc->xfer_remain -= burst_len * spicc->bytes_per_word;
258 
259 	/* Setup burst length */
260 	writel_bits_relaxed(SPICC_BURSTLENGTH_MASK,
261 			FIELD_PREP(SPICC_BURSTLENGTH_MASK,
262 				burst_len - 1),
263 			spicc->base + SPICC_CONREG);
264 
265 	/* Fill TX FIFO */
266 	meson_spicc_tx(spicc);
267 }
268 
269 static irqreturn_t meson_spicc_irq(int irq, void *data)
270 {
271 	struct meson_spicc_device *spicc = (void *) data;
272 
273 	writel_bits_relaxed(SPICC_TC, SPICC_TC, spicc->base + SPICC_STATREG);
274 
275 	/* Empty RX FIFO */
276 	meson_spicc_rx(spicc);
277 
278 	if (!spicc->xfer_remain) {
279 		/* Disable all IRQs */
280 		writel(0, spicc->base + SPICC_INTREG);
281 
282 		spi_finalize_current_transfer(spicc->master);
283 
284 		return IRQ_HANDLED;
285 	}
286 
287 	/* Setup burst */
288 	meson_spicc_setup_burst(spicc);
289 
290 	/* Start burst */
291 	writel_bits_relaxed(SPICC_XCH, SPICC_XCH, spicc->base + SPICC_CONREG);
292 
293 	return IRQ_HANDLED;
294 }
295 
296 static void meson_spicc_auto_io_delay(struct meson_spicc_device *spicc)
297 {
298 	u32 div, hz;
299 	u32 mi_delay, cap_delay;
300 	u32 conf;
301 
302 	if (spicc->data->has_enhance_clk_div) {
303 		div = FIELD_GET(SPICC_ENH_DATARATE_MASK,
304 				readl_relaxed(spicc->base + SPICC_ENH_CTL0));
305 		div++;
306 		div <<= 1;
307 	} else {
308 		div = FIELD_GET(SPICC_DATARATE_MASK,
309 				readl_relaxed(spicc->base + SPICC_CONREG));
310 		div += 2;
311 		div = 1 << div;
312 	}
313 
314 	mi_delay = SPICC_MI_NO_DELAY;
315 	cap_delay = SPICC_CAP_AHEAD_2_CYCLE;
316 	hz = clk_get_rate(spicc->clk);
317 
318 	if (hz >= 100000000)
319 		cap_delay = SPICC_CAP_DELAY_1_CYCLE;
320 	else if (hz >= 80000000)
321 		cap_delay = SPICC_CAP_NO_DELAY;
322 	else if (hz >= 40000000)
323 		cap_delay = SPICC_CAP_AHEAD_1_CYCLE;
324 	else if (div >= 16)
325 		mi_delay = SPICC_MI_DELAY_3_CYCLE;
326 	else if (div >= 8)
327 		mi_delay = SPICC_MI_DELAY_2_CYCLE;
328 	else if (div >= 6)
329 		mi_delay = SPICC_MI_DELAY_1_CYCLE;
330 
331 	conf = readl_relaxed(spicc->base + SPICC_TESTREG);
332 	conf &= ~(SPICC_MO_DELAY_MASK | SPICC_MI_DELAY_MASK
333 		  | SPICC_MI_CAP_DELAY_MASK);
334 	conf |= FIELD_PREP(SPICC_MI_DELAY_MASK, mi_delay);
335 	conf |= FIELD_PREP(SPICC_MI_CAP_DELAY_MASK, cap_delay);
336 	writel_relaxed(conf, spicc->base + SPICC_TESTREG);
337 }
338 
339 static void meson_spicc_setup_xfer(struct meson_spicc_device *spicc,
340 				   struct spi_transfer *xfer)
341 {
342 	u32 conf, conf_orig;
343 
344 	/* Read original configuration */
345 	conf = conf_orig = readl_relaxed(spicc->base + SPICC_CONREG);
346 
347 	/* Setup word width */
348 	conf &= ~SPICC_BITLENGTH_MASK;
349 	conf |= FIELD_PREP(SPICC_BITLENGTH_MASK,
350 			   (spicc->bytes_per_word << 3) - 1);
351 
352 	/* Ignore if unchanged */
353 	if (conf != conf_orig)
354 		writel_relaxed(conf, spicc->base + SPICC_CONREG);
355 
356 	clk_set_rate(spicc->clk, xfer->speed_hz);
357 
358 	meson_spicc_auto_io_delay(spicc);
359 
360 	writel_relaxed(0, spicc->base + SPICC_DMAREG);
361 }
362 
363 static void meson_spicc_reset_fifo(struct meson_spicc_device *spicc)
364 {
365 	if (spicc->data->has_oen)
366 		writel_bits_relaxed(SPICC_ENH_MAIN_CLK_AO,
367 				    SPICC_ENH_MAIN_CLK_AO,
368 				    spicc->base + SPICC_ENH_CTL0);
369 
370 	writel_bits_relaxed(SPICC_FIFORST_W1_MASK, SPICC_FIFORST_W1_MASK,
371 			    spicc->base + SPICC_TESTREG);
372 
373 	while (meson_spicc_rxready(spicc))
374 		readl_relaxed(spicc->base + SPICC_RXDATA);
375 
376 	if (spicc->data->has_oen)
377 		writel_bits_relaxed(SPICC_ENH_MAIN_CLK_AO, 0,
378 				    spicc->base + SPICC_ENH_CTL0);
379 }
380 
381 static int meson_spicc_transfer_one(struct spi_master *master,
382 				    struct spi_device *spi,
383 				    struct spi_transfer *xfer)
384 {
385 	struct meson_spicc_device *spicc = spi_master_get_devdata(master);
386 
387 	/* Store current transfer */
388 	spicc->xfer = xfer;
389 
390 	/* Setup transfer parameters */
391 	spicc->tx_buf = (u8 *)xfer->tx_buf;
392 	spicc->rx_buf = (u8 *)xfer->rx_buf;
393 	spicc->xfer_remain = xfer->len;
394 
395 	/* Pre-calculate word size */
396 	spicc->bytes_per_word =
397 	   DIV_ROUND_UP(spicc->xfer->bits_per_word, 8);
398 
399 	if (xfer->len % spicc->bytes_per_word)
400 		return -EINVAL;
401 
402 	/* Setup transfer parameters */
403 	meson_spicc_setup_xfer(spicc, xfer);
404 
405 	meson_spicc_reset_fifo(spicc);
406 
407 	/* Setup burst */
408 	meson_spicc_setup_burst(spicc);
409 
410 	/* Start burst */
411 	writel_bits_relaxed(SPICC_XCH, SPICC_XCH, spicc->base + SPICC_CONREG);
412 
413 	/* Enable interrupts */
414 	writel_relaxed(SPICC_TC_EN, spicc->base + SPICC_INTREG);
415 
416 	return 1;
417 }
418 
419 static int meson_spicc_prepare_message(struct spi_master *master,
420 				       struct spi_message *message)
421 {
422 	struct meson_spicc_device *spicc = spi_master_get_devdata(master);
423 	struct spi_device *spi = message->spi;
424 	u32 conf = 0;
425 
426 	/* Store current message */
427 	spicc->message = message;
428 
429 	/* Enable Master */
430 	conf |= SPICC_ENABLE;
431 	conf |= SPICC_MODE_MASTER;
432 
433 	/* SMC = 0 */
434 
435 	/* Setup transfer mode */
436 	if (spi->mode & SPI_CPOL)
437 		conf |= SPICC_POL;
438 	else
439 		conf &= ~SPICC_POL;
440 
441 	if (spi->mode & SPI_CPHA)
442 		conf |= SPICC_PHA;
443 	else
444 		conf &= ~SPICC_PHA;
445 
446 	/* SSCTL = 0 */
447 
448 	if (spi->mode & SPI_CS_HIGH)
449 		conf |= SPICC_SSPOL;
450 	else
451 		conf &= ~SPICC_SSPOL;
452 
453 	if (spi->mode & SPI_READY)
454 		conf |= FIELD_PREP(SPICC_DRCTL_MASK, SPICC_DRCTL_LOWLEVEL);
455 	else
456 		conf |= FIELD_PREP(SPICC_DRCTL_MASK, SPICC_DRCTL_IGNORE);
457 
458 	/* Select CS */
459 	conf |= FIELD_PREP(SPICC_CS_MASK, spi->chip_select);
460 
461 	/* Default Clock rate core/4 */
462 
463 	/* Default 8bit word */
464 	conf |= FIELD_PREP(SPICC_BITLENGTH_MASK, 8 - 1);
465 
466 	writel_relaxed(conf, spicc->base + SPICC_CONREG);
467 
468 	/* Setup no wait cycles by default */
469 	writel_relaxed(0, spicc->base + SPICC_PERIODREG);
470 
471 	writel_bits_relaxed(SPICC_LBC_W1, 0, spicc->base + SPICC_TESTREG);
472 
473 	return 0;
474 }
475 
476 static int meson_spicc_unprepare_transfer(struct spi_master *master)
477 {
478 	struct meson_spicc_device *spicc = spi_master_get_devdata(master);
479 
480 	/* Disable all IRQs */
481 	writel(0, spicc->base + SPICC_INTREG);
482 
483 	device_reset_optional(&spicc->pdev->dev);
484 
485 	return 0;
486 }
487 
488 static int meson_spicc_setup(struct spi_device *spi)
489 {
490 	if (!spi->controller_state)
491 		spi->controller_state = spi_master_get_devdata(spi->master);
492 
493 	return 0;
494 }
495 
496 static void meson_spicc_cleanup(struct spi_device *spi)
497 {
498 	spi->controller_state = NULL;
499 }
500 
501 /*
502  * The Clock Mux
503  *            x-----------------x   x------------x    x------\
504  *        |---| pow2 fixed div  |---| pow2 div   |----|      |
505  *        |   x-----------------x   x------------x    |      |
506  * src ---|                                           | mux  |-- out
507  *        |   x-----------------x   x------------x    |      |
508  *        |---| enh fixed div   |---| enh div    |0---|      |
509  *            x-----------------x   x------------x    x------/
510  *
511  * Clk path for GX series:
512  *    src -> pow2 fixed div -> pow2 div -> out
513  *
514  * Clk path for AXG series:
515  *    src -> pow2 fixed div -> pow2 div -> mux -> out
516  *    src -> enh fixed div -> enh div -> mux -> out
517  *
518  * Clk path for G12A series:
519  *    pclk -> pow2 fixed div -> pow2 div -> mux -> out
520  *    pclk -> enh fixed div -> enh div -> mux -> out
521  */
522 
523 static int meson_spicc_clk_init(struct meson_spicc_device *spicc)
524 {
525 	struct device *dev = &spicc->pdev->dev;
526 	struct clk_fixed_factor *pow2_fixed_div, *enh_fixed_div;
527 	struct clk_divider *pow2_div, *enh_div;
528 	struct clk_mux *mux;
529 	struct clk_init_data init;
530 	struct clk *clk;
531 	struct clk_parent_data parent_data[2];
532 	char name[64];
533 
534 	memset(&init, 0, sizeof(init));
535 	memset(&parent_data, 0, sizeof(parent_data));
536 
537 	init.parent_data = parent_data;
538 
539 	/* algorithm for pow2 div: rate = freq / 4 / (2 ^ N) */
540 
541 	pow2_fixed_div = devm_kzalloc(dev, sizeof(*pow2_fixed_div), GFP_KERNEL);
542 	if (!pow2_fixed_div)
543 		return -ENOMEM;
544 
545 	snprintf(name, sizeof(name), "%s#pow2_fixed_div", dev_name(dev));
546 	init.name = name;
547 	init.ops = &clk_fixed_factor_ops;
548 	init.flags = 0;
549 	if (spicc->data->has_pclk)
550 		parent_data[0].hw = __clk_get_hw(spicc->pclk);
551 	else
552 		parent_data[0].hw = __clk_get_hw(spicc->core);
553 	init.num_parents = 1;
554 
555 	pow2_fixed_div->mult = 1,
556 	pow2_fixed_div->div = 4,
557 	pow2_fixed_div->hw.init = &init;
558 
559 	clk = devm_clk_register(dev, &pow2_fixed_div->hw);
560 	if (WARN_ON(IS_ERR(clk)))
561 		return PTR_ERR(clk);
562 
563 	pow2_div = devm_kzalloc(dev, sizeof(*pow2_div), GFP_KERNEL);
564 	if (!pow2_div)
565 		return -ENOMEM;
566 
567 	snprintf(name, sizeof(name), "%s#pow2_div", dev_name(dev));
568 	init.name = name;
569 	init.ops = &clk_divider_ops;
570 	init.flags = CLK_SET_RATE_PARENT;
571 	parent_data[0].hw = &pow2_fixed_div->hw;
572 	init.num_parents = 1;
573 
574 	pow2_div->shift = 16,
575 	pow2_div->width = 3,
576 	pow2_div->flags = CLK_DIVIDER_POWER_OF_TWO,
577 	pow2_div->reg = spicc->base + SPICC_CONREG;
578 	pow2_div->hw.init = &init;
579 
580 	clk = devm_clk_register(dev, &pow2_div->hw);
581 	if (WARN_ON(IS_ERR(clk)))
582 		return PTR_ERR(clk);
583 
584 	if (!spicc->data->has_enhance_clk_div) {
585 		spicc->clk = clk;
586 		return 0;
587 	}
588 
589 	/* algorithm for enh div: rate = freq / 2 / (N + 1) */
590 
591 	enh_fixed_div = devm_kzalloc(dev, sizeof(*enh_fixed_div), GFP_KERNEL);
592 	if (!enh_fixed_div)
593 		return -ENOMEM;
594 
595 	snprintf(name, sizeof(name), "%s#enh_fixed_div", dev_name(dev));
596 	init.name = name;
597 	init.ops = &clk_fixed_factor_ops;
598 	init.flags = 0;
599 	if (spicc->data->has_pclk)
600 		parent_data[0].hw = __clk_get_hw(spicc->pclk);
601 	else
602 		parent_data[0].hw = __clk_get_hw(spicc->core);
603 	init.num_parents = 1;
604 
605 	enh_fixed_div->mult = 1,
606 	enh_fixed_div->div = 2,
607 	enh_fixed_div->hw.init = &init;
608 
609 	clk = devm_clk_register(dev, &enh_fixed_div->hw);
610 	if (WARN_ON(IS_ERR(clk)))
611 		return PTR_ERR(clk);
612 
613 	enh_div = devm_kzalloc(dev, sizeof(*enh_div), GFP_KERNEL);
614 	if (!enh_div)
615 		return -ENOMEM;
616 
617 	snprintf(name, sizeof(name), "%s#enh_div", dev_name(dev));
618 	init.name = name;
619 	init.ops = &clk_divider_ops;
620 	init.flags = CLK_SET_RATE_PARENT;
621 	parent_data[0].hw = &enh_fixed_div->hw;
622 	init.num_parents = 1;
623 
624 	enh_div->shift	= 16,
625 	enh_div->width	= 8,
626 	enh_div->reg = spicc->base + SPICC_ENH_CTL0;
627 	enh_div->hw.init = &init;
628 
629 	clk = devm_clk_register(dev, &enh_div->hw);
630 	if (WARN_ON(IS_ERR(clk)))
631 		return PTR_ERR(clk);
632 
633 	mux = devm_kzalloc(dev, sizeof(*mux), GFP_KERNEL);
634 	if (!mux)
635 		return -ENOMEM;
636 
637 	snprintf(name, sizeof(name), "%s#sel", dev_name(dev));
638 	init.name = name;
639 	init.ops = &clk_mux_ops;
640 	parent_data[0].hw = &pow2_div->hw;
641 	parent_data[1].hw = &enh_div->hw;
642 	init.num_parents = 2;
643 	init.flags = CLK_SET_RATE_PARENT;
644 
645 	mux->mask = 0x1,
646 	mux->shift = 24,
647 	mux->reg = spicc->base + SPICC_ENH_CTL0;
648 	mux->hw.init = &init;
649 
650 	spicc->clk = devm_clk_register(dev, &mux->hw);
651 	if (WARN_ON(IS_ERR(spicc->clk)))
652 		return PTR_ERR(spicc->clk);
653 
654 	return 0;
655 }
656 
657 static int meson_spicc_probe(struct platform_device *pdev)
658 {
659 	struct spi_master *master;
660 	struct meson_spicc_device *spicc;
661 	int ret, irq;
662 
663 	master = spi_alloc_master(&pdev->dev, sizeof(*spicc));
664 	if (!master) {
665 		dev_err(&pdev->dev, "master allocation failed\n");
666 		return -ENOMEM;
667 	}
668 	spicc = spi_master_get_devdata(master);
669 	spicc->master = master;
670 
671 	spicc->data = of_device_get_match_data(&pdev->dev);
672 	if (!spicc->data) {
673 		dev_err(&pdev->dev, "failed to get match data\n");
674 		ret = -EINVAL;
675 		goto out_master;
676 	}
677 
678 	spicc->pdev = pdev;
679 	platform_set_drvdata(pdev, spicc);
680 
681 	spicc->base = devm_platform_ioremap_resource(pdev, 0);
682 	if (IS_ERR(spicc->base)) {
683 		dev_err(&pdev->dev, "io resource mapping failed\n");
684 		ret = PTR_ERR(spicc->base);
685 		goto out_master;
686 	}
687 
688 	/* Set master mode and enable controller */
689 	writel_relaxed(SPICC_ENABLE | SPICC_MODE_MASTER,
690 		       spicc->base + SPICC_CONREG);
691 
692 	/* Disable all IRQs */
693 	writel_relaxed(0, spicc->base + SPICC_INTREG);
694 
695 	irq = platform_get_irq(pdev, 0);
696 	ret = devm_request_irq(&pdev->dev, irq, meson_spicc_irq,
697 			       0, NULL, spicc);
698 	if (ret) {
699 		dev_err(&pdev->dev, "irq request failed\n");
700 		goto out_master;
701 	}
702 
703 	spicc->core = devm_clk_get(&pdev->dev, "core");
704 	if (IS_ERR(spicc->core)) {
705 		dev_err(&pdev->dev, "core clock request failed\n");
706 		ret = PTR_ERR(spicc->core);
707 		goto out_master;
708 	}
709 
710 	if (spicc->data->has_pclk) {
711 		spicc->pclk = devm_clk_get(&pdev->dev, "pclk");
712 		if (IS_ERR(spicc->pclk)) {
713 			dev_err(&pdev->dev, "pclk clock request failed\n");
714 			ret = PTR_ERR(spicc->pclk);
715 			goto out_master;
716 		}
717 	}
718 
719 	ret = clk_prepare_enable(spicc->core);
720 	if (ret) {
721 		dev_err(&pdev->dev, "core clock enable failed\n");
722 		goto out_master;
723 	}
724 
725 	ret = clk_prepare_enable(spicc->pclk);
726 	if (ret) {
727 		dev_err(&pdev->dev, "pclk clock enable failed\n");
728 		goto out_core_clk;
729 	}
730 
731 	device_reset_optional(&pdev->dev);
732 
733 	master->num_chipselect = 4;
734 	master->dev.of_node = pdev->dev.of_node;
735 	master->mode_bits = SPI_CPHA | SPI_CPOL | SPI_CS_HIGH;
736 	master->bits_per_word_mask = SPI_BPW_MASK(32) |
737 				     SPI_BPW_MASK(24) |
738 				     SPI_BPW_MASK(16) |
739 				     SPI_BPW_MASK(8);
740 	master->flags = (SPI_MASTER_MUST_RX | SPI_MASTER_MUST_TX);
741 	master->min_speed_hz = spicc->data->min_speed_hz;
742 	master->max_speed_hz = spicc->data->max_speed_hz;
743 	master->setup = meson_spicc_setup;
744 	master->cleanup = meson_spicc_cleanup;
745 	master->prepare_message = meson_spicc_prepare_message;
746 	master->unprepare_transfer_hardware = meson_spicc_unprepare_transfer;
747 	master->transfer_one = meson_spicc_transfer_one;
748 	master->use_gpio_descriptors = true;
749 
750 	meson_spicc_oen_enable(spicc);
751 
752 	ret = meson_spicc_clk_init(spicc);
753 	if (ret) {
754 		dev_err(&pdev->dev, "clock registration failed\n");
755 		goto out_clk;
756 	}
757 
758 	ret = devm_spi_register_master(&pdev->dev, master);
759 	if (ret) {
760 		dev_err(&pdev->dev, "spi master registration failed\n");
761 		goto out_clk;
762 	}
763 
764 	return 0;
765 
766 out_clk:
767 	clk_disable_unprepare(spicc->pclk);
768 
769 out_core_clk:
770 	clk_disable_unprepare(spicc->core);
771 
772 out_master:
773 	spi_master_put(master);
774 
775 	return ret;
776 }
777 
778 static int meson_spicc_remove(struct platform_device *pdev)
779 {
780 	struct meson_spicc_device *spicc = platform_get_drvdata(pdev);
781 
782 	/* Disable SPI */
783 	writel(0, spicc->base + SPICC_CONREG);
784 
785 	clk_disable_unprepare(spicc->core);
786 	clk_disable_unprepare(spicc->pclk);
787 
788 	spi_master_put(spicc->master);
789 
790 	return 0;
791 }
792 
793 static const struct meson_spicc_data meson_spicc_gx_data = {
794 	.max_speed_hz		= 30000000,
795 	.min_speed_hz		= 325000,
796 	.fifo_size		= 16,
797 };
798 
799 static const struct meson_spicc_data meson_spicc_axg_data = {
800 	.max_speed_hz		= 80000000,
801 	.min_speed_hz		= 325000,
802 	.fifo_size		= 16,
803 	.has_oen		= true,
804 	.has_enhance_clk_div	= true,
805 };
806 
807 static const struct meson_spicc_data meson_spicc_g12a_data = {
808 	.max_speed_hz		= 166666666,
809 	.min_speed_hz		= 50000,
810 	.fifo_size		= 15,
811 	.has_oen		= true,
812 	.has_enhance_clk_div	= true,
813 	.has_pclk		= true,
814 };
815 
816 static const struct of_device_id meson_spicc_of_match[] = {
817 	{
818 		.compatible	= "amlogic,meson-gx-spicc",
819 		.data		= &meson_spicc_gx_data,
820 	},
821 	{
822 		.compatible = "amlogic,meson-axg-spicc",
823 		.data		= &meson_spicc_axg_data,
824 	},
825 	{
826 		.compatible = "amlogic,meson-g12a-spicc",
827 		.data		= &meson_spicc_g12a_data,
828 	},
829 	{ /* sentinel */ }
830 };
831 MODULE_DEVICE_TABLE(of, meson_spicc_of_match);
832 
833 static struct platform_driver meson_spicc_driver = {
834 	.probe   = meson_spicc_probe,
835 	.remove  = meson_spicc_remove,
836 	.driver  = {
837 		.name = "meson-spicc",
838 		.of_match_table = of_match_ptr(meson_spicc_of_match),
839 	},
840 };
841 
842 module_platform_driver(meson_spicc_driver);
843 
844 MODULE_DESCRIPTION("Meson SPI Communication Controller driver");
845 MODULE_AUTHOR("Neil Armstrong <narmstrong@baylibre.com>");
846 MODULE_LICENSE("GPL");
847