summaryrefslogtreecommitdiff
path: root/drivers/spi/spi-meson-spifc.c
blob: f7fe9b13d122db67389c055d9909a84d46c9f9bd (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
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
// SPDX-License-Identifier: GPL-2.0+
//
// Driver for Amlogic Meson SPI flash controller (SPIFC)
//
// Copyright (C) 2014 Beniamino Galvani <b.galvani@gmail.com>
//

#include <linux/clk.h>
#include <linux/delay.h>
#include <linux/device.h>
#include <linux/io.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/pm_runtime.h>
#include <linux/regmap.h>
#include <linux/spi/spi.h>
#include <linux/types.h>

/* register map */
#define REG_CMD			0x00
#define REG_ADDR		0x04
#define REG_CTRL		0x08
#define REG_CTRL1		0x0c
#define REG_STATUS		0x10
#define REG_CTRL2		0x14
#define REG_CLOCK		0x18
#define REG_USER		0x1c
#define REG_USER1		0x20
#define REG_USER2		0x24
#define REG_USER3		0x28
#define REG_USER4		0x2c
#define REG_SLAVE		0x30
#define REG_SLAVE1		0x34
#define REG_SLAVE2		0x38
#define REG_SLAVE3		0x3c
#define REG_C0			0x40
#define REG_B8			0x60
#define REG_MAX			0x7c

/* register fields */
#define CMD_USER		BIT(18)
#define CTRL_ENABLE_AHB		BIT(17)
#define CLOCK_SOURCE		BIT(31)
#define CLOCK_DIV_SHIFT		12
#define CLOCK_DIV_MASK		(0x3f << CLOCK_DIV_SHIFT)
#define CLOCK_CNT_HIGH_SHIFT	6
#define CLOCK_CNT_HIGH_MASK	(0x3f << CLOCK_CNT_HIGH_SHIFT)
#define CLOCK_CNT_LOW_SHIFT	0
#define CLOCK_CNT_LOW_MASK	(0x3f << CLOCK_CNT_LOW_SHIFT)
#define USER_DIN_EN_MS		BIT(0)
#define USER_CMP_MODE		BIT(2)
#define USER_UC_DOUT_SEL	BIT(27)
#define USER_UC_DIN_SEL		BIT(28)
#define USER_UC_MASK		((BIT(5) - 1) << 27)
#define USER1_BN_UC_DOUT_SHIFT	17
#define USER1_BN_UC_DOUT_MASK	(0xff << 16)
#define USER1_BN_UC_DIN_SHIFT	8
#define USER1_BN_UC_DIN_MASK	(0xff << 8)
#define USER4_CS_ACT		BIT(30)
#define SLAVE_TRST_DONE		BIT(4)
#define SLAVE_OP_MODE		BIT(30)
#define SLAVE_SW_RST		BIT(31)

#define SPIFC_BUFFER_SIZE	64

/**
 * struct meson_spifc
 * @master:	the SPI master
 * @regmap:	regmap for device registers
 * @clk:	input clock of the built-in baud rate generator
 * @device:	the device structure
 */
struct meson_spifc {
	struct spi_master *master;
	struct regmap *regmap;
	struct clk *clk;
	struct device *dev;
};

static const struct regmap_config spifc_regmap_config = {
	.reg_bits = 32,
	.val_bits = 32,
	.reg_stride = 4,
	.max_register = REG_MAX,
};

/**
 * meson_spifc_wait_ready() - wait for the current operation to terminate
 * @spifc:	the Meson SPI device
 * Return:	0 on success, a negative value on error
 */
static int meson_spifc_wait_ready(struct meson_spifc *spifc)
{
	unsigned long deadline = jiffies + msecs_to_jiffies(5);
	u32 data;

	do {
		regmap_read(spifc->regmap, REG_SLAVE, &data);
		if (data & SLAVE_TRST_DONE)
			return 0;
		cond_resched();
	} while (!time_after(jiffies, deadline));

	return -ETIMEDOUT;
}

/**
 * meson_spifc_drain_buffer() - copy data from device buffer to memory
 * @spifc:	the Meson SPI device
 * @buf:	the destination buffer
 * @len:	number of bytes to copy
 */
static void meson_spifc_drain_buffer(struct meson_spifc *spifc, u8 *buf,
				     int len)
{
	u32 data;
	int i = 0;

	while (i < len) {
		regmap_read(spifc->regmap, REG_C0 + i, &data);

		if (len - i >= 4) {
			*((u32 *)buf) = data;
			buf += 4;
		} else {
			memcpy(buf, &data, len - i);
			break;
		}
		i += 4;
	}
}

/**
 * meson_spifc_fill_buffer() - copy data from memory to device buffer
 * @spifc:	the Meson SPI device
 * @buf:	the source buffer
 * @len:	number of bytes to copy
 */
static void meson_spifc_fill_buffer(struct meson_spifc *spifc, const u8 *buf,
				    int len)
{
	u32 data;
	int i = 0;

	while (i < len) {
		if (len - i >= 4)
			data = *(u32 *)buf;
		else
			memcpy(&data, buf, len - i);

		regmap_write(spifc->regmap, REG_C0 + i, data);

		buf += 4;
		i += 4;
	}
}

/**
 * meson_spifc_setup_speed() - program the clock divider
 * @spifc:	the Meson SPI device
 * @speed:	desired speed in Hz
 */
static void meson_spifc_setup_speed(struct meson_spifc *spifc, u32 speed)
{
	unsigned long parent, value;
	int n;

	parent = clk_get_rate(spifc->clk);
	n = max_t(int, parent / speed - 1, 1);

	dev_dbg(spifc->dev, "parent %lu, speed %u, n %d\n", parent,
		speed, n);

	value = (n << CLOCK_DIV_SHIFT) & CLOCK_DIV_MASK;
	value |= (n << CLOCK_CNT_LOW_SHIFT) & CLOCK_CNT_LOW_MASK;
	value |= (((n + 1) / 2 - 1) << CLOCK_CNT_HIGH_SHIFT) &
		CLOCK_CNT_HIGH_MASK;

	regmap_write(spifc->regmap, REG_CLOCK, value);
}

/**
 * meson_spifc_txrx() - transfer a chunk of data
 * @spifc:	the Meson SPI device
 * @xfer:	the current SPI transfer
 * @offset:	offset of the data to transfer
 * @len:	length of the data to transfer
 * @last_xfer:	whether this is the last transfer of the message
 * @last_chunk:	whether this is the last chunk of the transfer
 * Return:	0 on success, a negative value on error
 */
static int meson_spifc_txrx(struct meson_spifc *spifc,
			    struct spi_transfer *xfer,
			    int offset, int len, bool last_xfer,
			    bool last_chunk)
{
	bool keep_cs = true;
	int ret;

	if (xfer->tx_buf)
		meson_spifc_fill_buffer(spifc, xfer->tx_buf + offset, len);

	/* enable DOUT stage */
	regmap_update_bits(spifc->regmap, REG_USER, USER_UC_MASK,
			   USER_UC_DOUT_SEL);
	regmap_write(spifc->regmap, REG_USER1,
		     (8 * len - 1) << USER1_BN_UC_DOUT_SHIFT);

	/* enable data input during DOUT */
	regmap_update_bits(spifc->regmap, REG_USER, USER_DIN_EN_MS,
			   USER_DIN_EN_MS);

	if (last_chunk) {
		if (last_xfer)
			keep_cs = xfer->cs_change;
		else
			keep_cs = !xfer->cs_change;
	}

	regmap_update_bits(spifc->regmap, REG_USER4, USER4_CS_ACT,
			   keep_cs ? USER4_CS_ACT : 0);

	/* clear transition done bit */
	regmap_update_bits(spifc->regmap, REG_SLAVE, SLAVE_TRST_DONE, 0);
	/* start transfer */
	regmap_update_bits(spifc->regmap, REG_CMD, CMD_USER, CMD_USER);

	ret = meson_spifc_wait_ready(spifc);

	if (!ret && xfer->rx_buf)
		meson_spifc_drain_buffer(spifc, xfer->rx_buf + offset, len);

	return ret;
}

/**
 * meson_spifc_transfer_one() - perform a single transfer
 * @master:	the SPI master
 * @spi:	the SPI device
 * @xfer:	the current SPI transfer
 * Return:	0 on success, a negative value on error
 */
static int meson_spifc_transfer_one(struct spi_master *master,
				    struct spi_device *spi,
				    struct spi_transfer *xfer)
{
	struct meson_spifc *spifc = spi_master_get_devdata(master);
	int len, done = 0, ret = 0;

	meson_spifc_setup_speed(spifc, xfer->speed_hz);

	regmap_update_bits(spifc->regmap, REG_CTRL, CTRL_ENABLE_AHB, 0);

	while (done < xfer->len && !ret) {
		len = min_t(int, xfer->len - done, SPIFC_BUFFER_SIZE);
		ret = meson_spifc_txrx(spifc, xfer, done, len,
				       spi_transfer_is_last(master, xfer),
				       done + len >= xfer->len);
		done += len;
	}

	regmap_update_bits(spifc->regmap, REG_CTRL, CTRL_ENABLE_AHB,
			   CTRL_ENABLE_AHB);

	return ret;
}

/**
 * meson_spifc_hw_init() - reset and initialize the SPI controller
 * @spifc:	the Meson SPI device
 */
static void meson_spifc_hw_init(struct meson_spifc *spifc)
{
	/* reset device */
	regmap_update_bits(spifc->regmap, REG_SLAVE, SLAVE_SW_RST,
			   SLAVE_SW_RST);
	/* disable compatible mode */
	regmap_update_bits(spifc->regmap, REG_USER, USER_CMP_MODE, 0);
	/* set master mode */
	regmap_update_bits(spifc->regmap, REG_SLAVE, SLAVE_OP_MODE, 0);
}

static int meson_spifc_probe(struct platform_device *pdev)
{
	struct spi_master *master;
	struct meson_spifc *spifc;
	struct resource *res;
	void __iomem *base;
	unsigned int rate;
	int ret = 0;

	master = spi_alloc_master(&pdev->dev, sizeof(struct meson_spifc));
	if (!master)
		return -ENOMEM;

	platform_set_drvdata(pdev, master);

	spifc = spi_master_get_devdata(master);
	spifc->dev = &pdev->dev;

	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	base = devm_ioremap_resource(spifc->dev, res);
	if (IS_ERR(base)) {
		ret = PTR_ERR(base);
		goto out_err;
	}

	spifc->regmap = devm_regmap_init_mmio(spifc->dev, base,
					      &spifc_regmap_config);
	if (IS_ERR(spifc->regmap)) {
		ret = PTR_ERR(spifc->regmap);
		goto out_err;
	}

	spifc->clk = devm_clk_get(spifc->dev, NULL);
	if (IS_ERR(spifc->clk)) {
		dev_err(spifc->dev, "missing clock\n");
		ret = PTR_ERR(spifc->clk);
		goto out_err;
	}

	ret = clk_prepare_enable(spifc->clk);
	if (ret) {
		dev_err(spifc->dev, "can't prepare clock\n");
		goto out_err;
	}

	rate = clk_get_rate(spifc->clk);

	master->num_chipselect = 1;
	master->dev.of_node = pdev->dev.of_node;
	master->bits_per_word_mask = SPI_BPW_MASK(8);
	master->auto_runtime_pm = true;
	master->transfer_one = meson_spifc_transfer_one;
	master->min_speed_hz = rate >> 6;
	master->max_speed_hz = rate >> 1;

	meson_spifc_hw_init(spifc);

	pm_runtime_set_active(spifc->dev);
	pm_runtime_enable(spifc->dev);

	ret = devm_spi_register_master(spifc->dev, master);
	if (ret) {
		dev_err(spifc->dev, "failed to register spi master\n");
		goto out_clk;
	}

	return 0;
out_clk:
	clk_disable_unprepare(spifc->clk);
out_err:
	spi_master_put(master);
	return ret;
}

static int meson_spifc_remove(struct platform_device *pdev)
{
	struct spi_master *master = platform_get_drvdata(pdev);
	struct meson_spifc *spifc = spi_master_get_devdata(master);

	pm_runtime_get_sync(&pdev->dev);
	clk_disable_unprepare(spifc->clk);
	pm_runtime_disable(&pdev->dev);

	return 0;
}

#ifdef CONFIG_PM_SLEEP
static int meson_spifc_suspend(struct device *dev)
{
	struct spi_master *master = dev_get_drvdata(dev);
	struct meson_spifc *spifc = spi_master_get_devdata(master);
	int ret;

	ret = spi_master_suspend(master);
	if (ret)
		return ret;

	if (!pm_runtime_suspended(dev))
		clk_disable_unprepare(spifc->clk);

	return 0;
}

static int meson_spifc_resume(struct device *dev)
{
	struct spi_master *master = dev_get_drvdata(dev);
	struct meson_spifc *spifc = spi_master_get_devdata(master);
	int ret;

	if (!pm_runtime_suspended(dev)) {
		ret = clk_prepare_enable(spifc->clk);
		if (ret)
			return ret;
	}

	meson_spifc_hw_init(spifc);

	ret = spi_master_resume(master);
	if (ret)
		clk_disable_unprepare(spifc->clk);

	return ret;
}
#endif /* CONFIG_PM_SLEEP */

#ifdef CONFIG_PM
static int meson_spifc_runtime_suspend(struct device *dev)
{
	struct spi_master *master = dev_get_drvdata(dev);
	struct meson_spifc *spifc = spi_master_get_devdata(master);

	clk_disable_unprepare(spifc->clk);

	return 0;
}

static int meson_spifc_runtime_resume(struct device *dev)
{
	struct spi_master *master = dev_get_drvdata(dev);
	struct meson_spifc *spifc = spi_master_get_devdata(master);

	return clk_prepare_enable(spifc->clk);
}
#endif /* CONFIG_PM */

static const struct dev_pm_ops meson_spifc_pm_ops = {
	SET_SYSTEM_SLEEP_PM_OPS(meson_spifc_suspend, meson_spifc_resume)
	SET_RUNTIME_PM_OPS(meson_spifc_runtime_suspend,
			   meson_spifc_runtime_resume,
			   NULL)
};

static const struct of_device_id meson_spifc_dt_match[] = {
	{ .compatible = "amlogic,meson6-spifc", },
	{ .compatible = "amlogic,meson-gxbb-spifc", },
	{ },
};
MODULE_DEVICE_TABLE(of, meson_spifc_dt_match);

static struct platform_driver meson_spifc_driver = {
	.probe	= meson_spifc_probe,
	.remove	= meson_spifc_remove,
	.driver	= {
		.name		= "meson-spifc",
		.of_match_table	= of_match_ptr(meson_spifc_dt_match),
		.pm		= &meson_spifc_pm_ops,
	},
};

module_platform_driver(meson_spifc_driver);

MODULE_AUTHOR("Beniamino Galvani <b.galvani@gmail.com>");
MODULE_DESCRIPTION("Amlogic Meson SPIFC driver");
MODULE_LICENSE("GPL v2");