summaryrefslogtreecommitdiff
path: root/target/linux/brcm63xx/files/drivers/spi/bcm63xx_spi.c
blob: bd75b8c7af76f94cd930fed6cdfbebb54a50accd (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
/*
 * Broadcom BCM63xx SPI controller support
 *
 * Copyright (C) 2009 Florian Fainelli <florian@openwrt.org>
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the
 * Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
 */

#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/clk.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/delay.h>
#include <linux/interrupt.h>
#include <linux/spi/spi.h>
#include <linux/spi/spi_bitbang.h>
#include <linux/gpio.h>
#include <linux/completion.h>
#include <linux/err.h>

#include <bcm63xx_io.h>
#include <bcm63xx_regs.h>
#include <bcm63xx_dev_spi.h>

#define PFX 		KBUILD_MODNAME
#define DRV_VER		"0.1.2"

struct bcm63xx_spi {
	/* bitbang has to be first */
        struct spi_bitbang	bitbang;
        struct completion	done;

        void __iomem		*regs;
        int			irq;

	/* Platform data */
        u32			speed_hz;
	unsigned		fifo_size;

	/* Data buffers */
	const unsigned char	*tx_ptr;
	unsigned char		*rx_ptr;
	int			remaining_bytes;

	struct clk		*clk;
	struct resource		*ioarea;
	struct platform_device	*pdev;
};

static void bcm63xx_spi_chipselect(struct spi_device *spi, int is_on)
{
	struct bcm63xx_spi *bs = spi_master_get_devdata(spi->master);
	u16 val;

	val = bcm_spi_readw(bs->regs, SPI_CMD);
	if (is_on == BITBANG_CS_INACTIVE)
		val |= SPI_CMD_NOOP;
	else if (is_on == BITBANG_CS_ACTIVE)
		val |= (1 << spi->chip_select << SPI_CMD_DEVICE_ID_SHIFT);
		
	bcm_spi_writew(val, bs->regs, SPI_CMD);
}

static int bcm63xx_spi_setup_transfer(struct spi_device *spi,
					struct spi_transfer *t)
{
	u8 bits_per_word;
	u8 clk_cfg;
	u32 hz;
	unsigned int div;

	struct bcm63xx_spi *bs = spi_master_get_devdata(spi->master);

	bits_per_word = (t) ? t->bits_per_word : spi->bits_per_word;
	hz = (t) ? t->speed_hz : spi->max_speed_hz;
	if (bits_per_word != 8) {
		dev_err(&spi->dev, "%s, unsupported bits_per_word=%d\n",
			__func__, bits_per_word);
		return -EINVAL;
        }

	if (spi->chip_select > spi->master->num_chipselect) {
		dev_err(&spi->dev, "%s, unsupported slave %d\n",
			__func__, spi->chip_select);
		return -EINVAL;
	}

	/* Check clock setting */
	div = (bs->speed_hz / hz);
	switch (div) {
	case 2:
		clk_cfg = SPI_CLK_25MHZ;
		break;
	case 4:
		clk_cfg = SPI_CLK_12_50MHZ;
		break;
	case 8:
		clk_cfg = SPI_CLK_6_250MHZ;
		break;
	case 16:
		clk_cfg = SPI_CLK_3_125MHZ;
		break;
	case 32:
		clk_cfg = SPI_CLK_1_563MHZ;
		break;
	case 128:
		clk_cfg = SPI_CLK_0_781MHZ;
		break;
	case 64:
	default:
		/* Set to slowest mode for compatibility */
		clk_cfg = SPI_CLK_0_781MHZ;
		break;
	}

	bcm_spi_writeb(clk_cfg, bs->regs, SPI_CLK_CFG);
	dev_dbg(&spi->dev, "Setting clock register to %d (hz %d, cmd %02x)\n",
								div, hz, clk_cfg);
	
	return 0;
}

/* the spi->mode bits understood by this driver: */
#define MODEBITS (SPI_CPOL | SPI_CPHA)

static int bcm63xx_spi_setup(struct spi_device *spi)
{
	struct spi_bitbang *bitbang;
	struct bcm63xx_spi *bs;
	int retval;

	bs = spi_master_get_devdata(spi->master);
	bitbang = &bs->bitbang;

	if (!spi->bits_per_word)
		spi->bits_per_word = 8;

	if (spi->mode & ~MODEBITS) {
		dev_err(&spi->dev, "%s, unsupported mode bits %x\n",
			__func__, spi->mode & ~MODEBITS);
		return -EINVAL;
	}

	retval = bcm63xx_spi_setup_transfer(spi, NULL);
	if (retval < 0) {
		dev_err(&spi->dev, "setup: unsupported mode bits %x\n",
			spi->mode & ~MODEBITS);
		return retval;
	}

	dev_dbg(&spi->dev, "%s, mode %d, %u bits/w, %u nsec/bit\n",
		__func__, spi->mode & MODEBITS, spi->bits_per_word, 0);

	return 0;
}

/* Fill the TX FIFO with as many bytes as possible */
static void bcm63xx_spi_fill_tx_fifo(struct bcm63xx_spi *bs)
{
        u8 tail;

        /* Fill the Tx FIFO with as many bytes as possible */
	tail = bcm_spi_readb(bs->regs, SPI_MSG_TAIL);
        while ((tail < bs->fifo_size) && (bs->remaining_bytes > 0)) {
                if (bs->tx_ptr)
                        bcm_spi_writeb(*bs->tx_ptr++, bs->regs, SPI_MSG_DATA);
		else
			bcm_spi_writeb(0, bs->regs, SPI_MSG_DATA); 
                bs->remaining_bytes--;
		tail = bcm_spi_readb(bs->regs, SPI_MSG_TAIL);
        }
}

static int bcm63xx_txrx_bufs(struct spi_device *spi, struct spi_transfer *t)
{
	struct bcm63xx_spi *bs = spi_master_get_devdata(spi->master);
	u8 msg_ctl;
	u16 cmd;

	dev_dbg(&spi->dev, "txrx: tx %p, rx %p, len %d\n",
				t->tx_buf, t->rx_buf, t->len);

	/* Transmitter is inhibited */
	bs->tx_ptr = t->tx_buf;
	bs->rx_ptr = t->rx_buf;
	bs->remaining_bytes = t->len;
	init_completion(&bs->done);

	bcm63xx_spi_fill_tx_fifo(bs);

	/* Enable the command done interrupt which
	 * we use to determine completion of a command */
	bcm_spi_writeb(SPI_INTR_CMD_DONE, bs->regs, SPI_INT_MASK);
	
	/* Fill in the Message control register */
	msg_ctl = bcm_spi_readb(bs->regs, SPI_MSG_CTL);
	msg_ctl |= (t->len << SPI_BYTE_CNT_SHIFT);
	msg_ctl |= (SPI_FD_RW << SPI_MSG_TYPE_SHIFT);
	bcm_spi_writeb(msg_ctl, bs->regs, SPI_MSG_CTL);
	
	/* Issue the transfer */
	cmd = bcm_spi_readb(bs->regs, SPI_CMD);
	cmd |= SPI_CMD_START_IMMEDIATE;
	cmd |= (0 << SPI_CMD_PREPEND_BYTE_CNT_SHIFT);
	bcm_spi_writeb(cmd, bs->regs, SPI_CMD);

	wait_for_completion(&bs->done);	

	/* Disable the CMD_DONE interrupt */
	bcm_spi_writeb(~(SPI_INTR_CMD_DONE), bs->regs, SPI_INT_MASK);

	return t->len - bs->remaining_bytes;
}

/* This driver supports single master mode only. Hence 
 * CMD_DONE is the only interrupt we care about
 */
static irqreturn_t bcm63xx_spi_interrupt(int irq, void *dev_id)
{
	struct spi_master *master = (struct spi_master *)dev_id;
	struct bcm63xx_spi *bs = spi_master_get_devdata(master);
	u8 intr;
	u16 cmd;

	/* Read interupts and clear them immediately */
	intr = bcm_spi_readb(bs->regs, SPI_INT_STATUS);
	bcm_spi_writeb(SPI_INTR_CLEAR_ALL, bs->regs, SPI_INT_STATUS);

	/* A tansfer completed */
	if (intr & SPI_INTR_CMD_DONE) {
		u8 rx_empty;
	
		rx_empty = bcm_spi_readb(bs->regs, SPI_ST);
		/* Read out all the data */
		while ((rx_empty & SPI_RX_EMPTY) == 0) {
			u8 data;
		
			data = bcm_spi_readb(bs->regs, SPI_RX_DATA);
			if (bs->rx_ptr)
				*bs->rx_ptr++ = data;

			rx_empty = bcm_spi_readb(bs->regs, SPI_RX_EMPTY);
		}

		/* See if there is more data to send */
		if (bs->remaining_bytes > 0) {
			bcm63xx_spi_fill_tx_fifo(bs);

			/* Start the transfer */
			cmd = bcm_spi_readb(bs->regs, SPI_CMD);
			cmd |= SPI_CMD_START_IMMEDIATE;
			cmd |= (0 << SPI_CMD_PREPEND_BYTE_CNT_SHIFT);
			bcm_spi_writeb(cmd, bs->regs, SPI_CMD);
		} else
			complete(&bs->done);
	}

	return IRQ_HANDLED;
}


static int __init bcm63xx_spi_probe(struct platform_device *pdev)
{
	struct resource *r;
	struct bcm63xx_spi_pdata *pdata = pdev->dev.platform_data;
	int irq;
	struct spi_master *master;
	struct clk *clk;
	struct bcm63xx_spi *bs;
	int ret;

	r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	if (!r) {
		ret = -ENXIO;
		goto out;
	}

	irq = platform_get_irq(pdev, 0);
	if (irq < 0) {
		ret = -ENXIO;
		goto out;
	}

	clk = clk_get(&pdev->dev, "spi");
	if (IS_ERR(clk)) {
		dev_err(&pdev->dev, "No clock for device\n");
		ret = -ENODEV;
		goto out;
	}
	
	master = spi_alloc_master(&pdev->dev, sizeof(struct bcm63xx_spi));
	if (!master) {
		ret = -ENOMEM;
		goto out_free;
	}

	bs = spi_master_get_devdata(master);
	bs->bitbang.master = spi_master_get(master);
	bs->bitbang.chipselect = bcm63xx_spi_chipselect;
	bs->bitbang.setup_transfer = bcm63xx_spi_setup_transfer;
	bs->bitbang.txrx_bufs = bcm63xx_txrx_bufs;
	bs->bitbang.master->setup = bcm63xx_spi_setup;
	init_completion(&bs->done);
	
	platform_set_drvdata(pdev, master);
        bs->pdev = pdev;

	if (!request_mem_region(r->start,
			r->end - r->start, PFX)) {
		ret = -ENXIO;
		goto out_free;
	}

        bs->regs = ioremap_nocache(r->start, r->end - r->start);
	if (!bs->regs) {
		printk(KERN_ERR PFX " unable to ioremap regs\n");
		ret = -ENOMEM;
		goto out_free;
	}
	bs->irq = irq;
	bs->clk = clk;
	bs->fifo_size = pdata->fifo_size;

	ret = request_irq(irq, bcm63xx_spi_interrupt, 0,
				pdev->name, master);
	if (ret) {
		printk(KERN_ERR PFX " unable to request irq\n");
		goto out_unmap;
	}

	master->bus_num = pdata->bus_num;
	master->num_chipselect = pdata->num_chipselect;
	bs->speed_hz = pdata->speed_hz;
	
	/* Initialize hardware */
	clk_enable(bs->clk);
	bcm_spi_writew(SPI_CMD_HARD_RESET, bs->regs, SPI_CMD);
	bcm_spi_writeb(SPI_INTR_CLEAR_ALL, bs->regs, SPI_INT_MASK);
	
	dev_info(&pdev->dev, " at 0x%08x (irq %d, FIFOs size %d) v%s\n",
				r->start, irq, bs->fifo_size, DRV_VER);

	ret = spi_bitbang_start(&bs->bitbang);
	if (ret) {
		dev_err(&pdev->dev, "spi_bitbang_start FAILED\n");
		goto out_reset_hw;
	}

	return ret;

out_reset_hw:
	clk_disable(clk);
	free_irq(irq, master);
out_unmap:
	iounmap(bs->regs);
out_free:
	clk_put(clk);
	spi_master_put(master);
out:
	return ret;
}

static int __exit bcm63xx_spi_remove(struct platform_device *pdev)
{
	struct spi_master	*master = platform_get_drvdata(pdev);
	struct bcm63xx_spi	*bs = spi_master_get_devdata(master);

	spi_bitbang_stop(&bs->bitbang);
	clk_disable(bs->clk);
	clk_put(bs->clk);
	free_irq(bs->irq, master);
	iounmap(bs->regs);
	platform_set_drvdata(pdev, 0);
	spi_master_put(bs->bitbang.master);

	return 0;
}

#ifdef CONFIG_PM
static int bcm63xx_spi_suspend(struct platform_device *pdev, pm_message_t mesg)
{
	struct spi_master	*master = platform_get_drvdata(pdev);
	struct bcm63xx_spi	*bs = spi_master_get_devdata(master);

        clk_disable(bs->clk);
        
	return 0;
}

static int bcm63xx_spi_resume(struct platform_device *pdev)
{
	struct bcm63xx_spi	*bs = spi_master_get_devdata(master);
	struct bcm63xx_spi	*bs = spi_master_get_devdata(master);

	clk_enable(bs->clk);

	return 0;
}
#else
#define bcm63xx_spi_suspend	NULL
#define bcm63xx_spi_resume	NULL
#endif

static struct platform_driver bcm63xx_spi_driver = {
	.driver = {
		.name	= "bcm63xx-spi",
		.owner	= THIS_MODULE,
	},
	.probe		= bcm63xx_spi_probe,
	.remove		= bcm63xx_spi_remove,
	.suspend	= bcm63xx_spi_suspend,
	.resume		= bcm63xx_spi_resume,
};


static int __init bcm63xx_spi_init(void)
{
	return platform_driver_register(&bcm63xx_spi_driver);
}

static void __exit bcm63xx_spi_exit(void)
{
	platform_driver_unregister(&bcm63xx_spi_driver);
}

module_init(bcm63xx_spi_init);
module_exit(bcm63xx_spi_exit);

MODULE_ALIAS("platform:bcm63xx_spi");
MODULE_AUTHOR("Florian Fainelli <florian@openwrt.org>");
MODULE_DESCRIPTION("Broadcom BCM63xx SPI Controller driver");
MODULE_LICENSE("GPL");
MODULE_VERSION(DRV_VER);