summaryrefslogtreecommitdiff
path: root/drivers/spi/mxc_spi.c
blob: 95dd03f7b3ff5ab43d33a37a2a8c1f495e2ae82a (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
/*
 * Copyright (C) 2008, Guennadi Liakhovetski <lg@denx.de>
 *
 * SPDX-License-Identifier:	GPL-2.0+
 */

#include <common.h>
#include <malloc.h>
#include <spi.h>
#include <asm/errno.h>
#include <asm/io.h>
#include <asm/gpio.h>
#include <asm/arch/imx-regs.h>
#include <asm/arch/clock.h>

#ifdef CONFIG_MX27
/* i.MX27 has a completely wrong register layout and register definitions in the
 * datasheet, the correct one is in the Freescale's Linux driver */

#error "i.MX27 CSPI not supported due to drastic differences in register definitions" \
"See linux mxc_spi driver from Freescale for details."
#endif

static unsigned long spi_bases[] = {
	MXC_SPI_BASE_ADDRESSES
};

#define OUT	MXC_GPIO_DIRECTION_OUT

#define reg_read readl
#define reg_write(a, v) writel(v, a)

struct mxc_spi_slave {
	struct spi_slave slave;
	unsigned long	base;
	u32		ctrl_reg;
#if defined(MXC_ECSPI)
	u32		cfg_reg;
#endif
	int		gpio;
	int		ss_pol;
};

static inline struct mxc_spi_slave *to_mxc_spi_slave(struct spi_slave *slave)
{
	return container_of(slave, struct mxc_spi_slave, slave);
}

void spi_cs_activate(struct spi_slave *slave)
{
	struct mxc_spi_slave *mxcs = to_mxc_spi_slave(slave);
	if (mxcs->gpio > 0)
		gpio_set_value(mxcs->gpio, mxcs->ss_pol);
}

void spi_cs_deactivate(struct spi_slave *slave)
{
	struct mxc_spi_slave *mxcs = to_mxc_spi_slave(slave);
	if (mxcs->gpio > 0)
		gpio_set_value(mxcs->gpio,
			      !(mxcs->ss_pol));
}

u32 get_cspi_div(u32 div)
{
	int i;

	for (i = 0; i < 8; i++) {
		if (div <= (4 << i))
			return i;
	}
	return i;
}

#ifdef MXC_CSPI
static s32 spi_cfg_mxc(struct mxc_spi_slave *mxcs, unsigned int cs,
		unsigned int max_hz, unsigned int mode)
{
	unsigned int ctrl_reg;
	u32 clk_src;
	u32 div;

	clk_src = mxc_get_clock(MXC_CSPI_CLK);

	div = DIV_ROUND_UP(clk_src, max_hz);
	div = get_cspi_div(div);

	debug("clk %d Hz, div %d, real clk %d Hz\n",
		max_hz, div, clk_src / (4 << div));

	ctrl_reg = MXC_CSPICTRL_CHIPSELECT(cs) |
		MXC_CSPICTRL_BITCOUNT(MXC_CSPICTRL_MAXBITS) |
		MXC_CSPICTRL_DATARATE(div) |
		MXC_CSPICTRL_EN |
#ifdef CONFIG_MX35
		MXC_CSPICTRL_SSCTL |
#endif
		MXC_CSPICTRL_MODE;

	if (mode & SPI_CPHA)
		ctrl_reg |= MXC_CSPICTRL_PHA;
	if (mode & SPI_CPOL)
		ctrl_reg |= MXC_CSPICTRL_POL;
	if (mode & SPI_CS_HIGH)
		ctrl_reg |= MXC_CSPICTRL_SSPOL;
	mxcs->ctrl_reg = ctrl_reg;

	return 0;
}
#endif

#ifdef MXC_ECSPI
static s32 spi_cfg_mxc(struct mxc_spi_slave *mxcs, unsigned int cs,
		unsigned int max_hz, unsigned int mode)
{
	u32 clk_src = mxc_get_clock(MXC_CSPI_CLK);
	s32 reg_ctrl, reg_config;
	u32 ss_pol = 0, sclkpol = 0, sclkpha = 0, pre_div = 0, post_div = 0;
	struct cspi_regs *regs = (struct cspi_regs *)mxcs->base;

	if (max_hz == 0) {
		printf("Error: desired clock is 0\n");
		return -1;
	}

	/*
	 * Reset SPI and set all CSs to master mode, if toggling
	 * between slave and master mode we might see a glitch
	 * on the clock line
	 */
	reg_ctrl = MXC_CSPICTRL_MODE_MASK;
	reg_write(&regs->ctrl, reg_ctrl);
	reg_ctrl |=  MXC_CSPICTRL_EN;
	reg_write(&regs->ctrl, reg_ctrl);

	if (clk_src > max_hz) {
		pre_div = (clk_src - 1) / max_hz;
		/* fls(1) = 1, fls(0x80000000) = 32, fls(16) = 5 */
		post_div = fls(pre_div);
		if (post_div > 4) {
			post_div -= 4;
			if (post_div >= 16) {
				printf("Error: no divider for the freq: %d\n",
					max_hz);
				return -1;
			}
			pre_div >>= post_div;
		} else {
			post_div = 0;
		}
	}

	debug("pre_div = %d, post_div=%d\n", pre_div, post_div);
	reg_ctrl = (reg_ctrl & ~MXC_CSPICTRL_SELCHAN(3)) |
		MXC_CSPICTRL_SELCHAN(cs);
	reg_ctrl = (reg_ctrl & ~MXC_CSPICTRL_PREDIV(0x0F)) |
		MXC_CSPICTRL_PREDIV(pre_div);
	reg_ctrl = (reg_ctrl & ~MXC_CSPICTRL_POSTDIV(0x0F)) |
		MXC_CSPICTRL_POSTDIV(post_div);

	/* We need to disable SPI before changing registers */
	reg_ctrl &= ~MXC_CSPICTRL_EN;

	if (mode & SPI_CS_HIGH)
		ss_pol = 1;

	if (mode & SPI_CPOL)
		sclkpol = 1;

	if (mode & SPI_CPHA)
		sclkpha = 1;

	reg_config = reg_read(&regs->cfg);

	/*
	 * Configuration register setup
	 * The MX51 supports different setup for each SS
	 */
	reg_config = (reg_config & ~(1 << (cs + MXC_CSPICON_SSPOL))) |
		(ss_pol << (cs + MXC_CSPICON_SSPOL));
	reg_config = (reg_config & ~(1 << (cs + MXC_CSPICON_POL))) |
		(sclkpol << (cs + MXC_CSPICON_POL));
	reg_config = (reg_config & ~(1 << (cs + MXC_CSPICON_PHA))) |
		(sclkpha << (cs + MXC_CSPICON_PHA));

	debug("reg_ctrl = 0x%x\n", reg_ctrl);
	reg_write(&regs->ctrl, reg_ctrl);
	debug("reg_config = 0x%x\n", reg_config);
	reg_write(&regs->cfg, reg_config);

	/* save config register and control register */
	mxcs->ctrl_reg = reg_ctrl;
	mxcs->cfg_reg = reg_config;

	/* clear interrupt reg */
	reg_write(&regs->intr, 0);
	reg_write(&regs->stat, MXC_CSPICTRL_TC | MXC_CSPICTRL_RXOVF);

	return 0;
}
#endif

int spi_xchg_single(struct spi_slave *slave, unsigned int bitlen,
	const u8 *dout, u8 *din, unsigned long flags)
{
	struct mxc_spi_slave *mxcs = to_mxc_spi_slave(slave);
	int nbytes = DIV_ROUND_UP(bitlen, 8);
	u32 data, cnt, i;
	struct cspi_regs *regs = (struct cspi_regs *)mxcs->base;

	debug("%s: bitlen %d dout 0x%x din 0x%x\n",
		__func__, bitlen, (u32)dout, (u32)din);

	mxcs->ctrl_reg = (mxcs->ctrl_reg &
		~MXC_CSPICTRL_BITCOUNT(MXC_CSPICTRL_MAXBITS)) |
		MXC_CSPICTRL_BITCOUNT(bitlen - 1);

	reg_write(&regs->ctrl, mxcs->ctrl_reg | MXC_CSPICTRL_EN);
#ifdef MXC_ECSPI
	reg_write(&regs->cfg, mxcs->cfg_reg);
#endif

	/* Clear interrupt register */
	reg_write(&regs->stat, MXC_CSPICTRL_TC | MXC_CSPICTRL_RXOVF);

	/*
	 * The SPI controller works only with words,
	 * check if less than a word is sent.
	 * Access to the FIFO is only 32 bit
	 */
	if (bitlen % 32) {
		data = 0;
		cnt = (bitlen % 32) / 8;
		if (dout) {
			for (i = 0; i < cnt; i++) {
				data = (data << 8) | (*dout++ & 0xFF);
			}
		}
		debug("Sending SPI 0x%x\n", data);

		reg_write(&regs->txdata, data);
		nbytes -= cnt;
	}

	data = 0;

	while (nbytes > 0) {
		data = 0;
		if (dout) {
			/* Buffer is not 32-bit aligned */
			if ((unsigned long)dout & 0x03) {
				data = 0;
				for (i = 0; i < 4; i++)
					data = (data << 8) | (*dout++ & 0xFF);
			} else {
				data = *(u32 *)dout;
				data = cpu_to_be32(data);
				dout += 4;
			}
		}
		debug("Sending SPI 0x%x\n", data);
		reg_write(&regs->txdata, data);
		nbytes -= 4;
	}

	/* FIFO is written, now starts the transfer setting the XCH bit */
	reg_write(&regs->ctrl, mxcs->ctrl_reg |
		MXC_CSPICTRL_EN | MXC_CSPICTRL_XCH);

	/* Wait until the TC (Transfer completed) bit is set */
	while ((reg_read(&regs->stat) & MXC_CSPICTRL_TC) == 0)
		;

	/* Transfer completed, clear any pending request */
	reg_write(&regs->stat, MXC_CSPICTRL_TC | MXC_CSPICTRL_RXOVF);

	nbytes = DIV_ROUND_UP(bitlen, 8);

	cnt = nbytes % 32;

	if (bitlen % 32) {
		data = reg_read(&regs->rxdata);
		cnt = (bitlen % 32) / 8;
		data = cpu_to_be32(data) >> ((sizeof(data) - cnt) * 8);
		debug("SPI Rx unaligned: 0x%x\n", data);
		if (din) {
			memcpy(din, &data, cnt);
			din += cnt;
		}
		nbytes -= cnt;
	}

	while (nbytes > 0) {
		u32 tmp;
		tmp = reg_read(&regs->rxdata);
		data = cpu_to_be32(tmp);
		debug("SPI Rx: 0x%x 0x%x\n", tmp, data);
		cnt = min(nbytes, sizeof(data));
		if (din) {
			memcpy(din, &data, cnt);
			din += cnt;
		}
		nbytes -= cnt;
	}

	return 0;

}

int spi_xfer(struct spi_slave *slave, unsigned int bitlen, const void *dout,
		void *din, unsigned long flags)
{
	int n_bytes = DIV_ROUND_UP(bitlen, 8);
	int n_bits;
	int ret;
	u32 blk_size;
	u8 *p_outbuf = (u8 *)dout;
	u8 *p_inbuf = (u8 *)din;

	if (!slave)
		return -1;

	if (flags & SPI_XFER_BEGIN)
		spi_cs_activate(slave);

	while (n_bytes > 0) {
		if (n_bytes < MAX_SPI_BYTES)
			blk_size = n_bytes;
		else
			blk_size = MAX_SPI_BYTES;

		n_bits = blk_size * 8;

		ret = spi_xchg_single(slave, n_bits, p_outbuf, p_inbuf, 0);

		if (ret)
			return ret;
		if (dout)
			p_outbuf += blk_size;
		if (din)
			p_inbuf += blk_size;
		n_bytes -= blk_size;
	}

	if (flags & SPI_XFER_END) {
		spi_cs_deactivate(slave);
	}

	return 0;
}

void spi_init(void)
{
}

static int decode_cs(struct mxc_spi_slave *mxcs, unsigned int cs)
{
	int ret;

	/*
	 * Some SPI devices require active chip-select over multiple
	 * transactions, we achieve this using a GPIO. Still, the SPI
	 * controller has to be configured to use one of its own chipselects.
	 * To use this feature you have to call spi_setup_slave() with
	 * cs = internal_cs | (gpio << 8), and you have to use some unused
	 * on this SPI controller cs between 0 and 3.
	 */
	if (cs > 3) {
		mxcs->gpio = cs >> 8;
		cs &= 3;
		ret = gpio_direction_output(mxcs->gpio, !(mxcs->ss_pol));
		if (ret) {
			printf("mxc_spi: cannot setup gpio %d\n", mxcs->gpio);
			return -EINVAL;
		}
	} else {
		mxcs->gpio = -1;
	}

	return cs;
}

struct spi_slave *spi_setup_slave(unsigned int bus, unsigned int cs,
			unsigned int max_hz, unsigned int mode)
{
	struct mxc_spi_slave *mxcs;
	int ret;

	if (bus >= ARRAY_SIZE(spi_bases))
		return NULL;

	mxcs = spi_alloc_slave(struct mxc_spi_slave, bus, cs);
	if (!mxcs) {
		puts("mxc_spi: SPI Slave not allocated !\n");
		return NULL;
	}

	mxcs->ss_pol = (mode & SPI_CS_HIGH) ? 1 : 0;

	ret = decode_cs(mxcs, cs);
	if (ret < 0) {
		free(mxcs);
		return NULL;
	}

	cs = ret;

	mxcs->base = spi_bases[bus];

	ret = spi_cfg_mxc(mxcs, cs, max_hz, mode);
	if (ret) {
		printf("mxc_spi: cannot setup SPI controller\n");
		free(mxcs);
		return NULL;
	}
	return &mxcs->slave;
}

void spi_free_slave(struct spi_slave *slave)
{
	struct mxc_spi_slave *mxcs = to_mxc_spi_slave(slave);

	free(mxcs);
}

int spi_claim_bus(struct spi_slave *slave)
{
	struct mxc_spi_slave *mxcs = to_mxc_spi_slave(slave);
	struct cspi_regs *regs = (struct cspi_regs *)mxcs->base;

	reg_write(&regs->rxdata, 1);
	udelay(1);
	reg_write(&regs->ctrl, mxcs->ctrl_reg);
	reg_write(&regs->period, MXC_CSPIPERIOD_32KHZ);
	reg_write(&regs->intr, 0);

	return 0;
}

void spi_release_bus(struct spi_slave *slave)
{
	/* TODO: Shut the controller down */
}