aboutsummaryrefslogtreecommitdiffstats
path: root/target/linux/ar71xx/files/drivers/spi/ap83_spi.c
blob: c93070d50a879fc8f3dd3c47553992b476dd1f45 (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
/*
 * Atheros AP83 board specific SPI Controller driver
 *
 * Copyright (C) 2009 Gabor Juhos <juhosg@openwrt.org>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 */

#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/delay.h>
#include <linux/spinlock.h>
#include <linux/workqueue.h>
#include <linux/platform_device.h>
#include <linux/io.h>
#include <linux/spi/spi.h>
#include <linux/spi/spi_bitbang.h>
#include <linux/bitops.h>
#include <linux/gpio.h>

#include <asm/mach-ar71xx/ar71xx.h>
#include <asm/mach-ar71xx/platform.h>

#define DRV_DESC	"Atheros AP83 board SPI Controller driver"
#define DRV_VERSION	"0.1.0"
#define DRV_NAME	"ap83-spi"

#define AP83_SPI_CLK_HIGH	(1 << 23)
#define AP83_SPI_CLK_LOW	0
#define AP83_SPI_MOSI_HIGH	(1 << 22)
#define AP83_SPI_MOSI_LOW	0

#define AP83_SPI_GPIO_CS	1
#define AP83_SPI_GPIO_MISO	3

struct ap83_spi {
	struct	spi_bitbang 	bitbang;
	void __iomem 		*base;
	u32			addr;

	struct platform_device	*pdev;
};

static inline u32 ap83_spi_rr(struct ap83_spi *sp, u32 reg)
{
	return __raw_readl(sp->base + reg);
}

static inline struct ap83_spi *spidev_to_sp(struct spi_device *spi)
{
	return spi_master_get_devdata(spi->master);
}

static inline void setsck(struct spi_device *spi, int val)
{
	struct ap83_spi *sp = spidev_to_sp(spi);

	if (val)
		sp->addr |= AP83_SPI_CLK_HIGH;
	else
		sp->addr &= ~AP83_SPI_CLK_HIGH;

	dev_dbg(&spi->dev, "addr=%08x,  SCK set to %s\n",
		sp->addr, (val) ? "HIGH" : "LOW");

	ap83_spi_rr(sp, sp->addr);
}

static inline void setmosi(struct spi_device *spi, int val)
{
	struct ap83_spi *sp = spidev_to_sp(spi);

	if (val)
		sp->addr |= AP83_SPI_MOSI_HIGH;
	else
		sp->addr &= ~AP83_SPI_MOSI_HIGH;

	dev_dbg(&spi->dev, "addr=%08x, MOSI set to %s\n",
		sp->addr, (val) ? "HIGH" : "LOW");

	ap83_spi_rr(sp, sp->addr);
}

static inline u32 getmiso(struct spi_device *spi)
{
	u32 ret;

	ret = gpio_get_value(AP83_SPI_GPIO_MISO) ? 1 : 0;
	dev_dbg(&spi->dev, "get MISO: %d\n", ret);

	return ret;
}

static inline void do_spidelay(struct spi_device *spi, unsigned nsecs)
{
	ndelay(nsecs);
}

static void ap83_spi_chipselect(struct spi_device *spi, int on)
{
	struct ap83_spi *sp = spidev_to_sp(spi);

	dev_dbg(&spi->dev, "set CS to %d\n", (on) ? 0 : 1);

	if (on) {
		ar71xx_flash_acquire();

		sp->addr = 0;
		ap83_spi_rr(sp, sp->addr);

		gpio_set_value(AP83_SPI_GPIO_CS, 0);
	} else {
		gpio_set_value(AP83_SPI_GPIO_CS, 1);
		ar71xx_flash_release();
	}
}

#define spidelay(nsecs)							\
	do {								\
		/* Steal the spi_device pointer from our caller.	\
		 * The bitbang-API should probably get fixed here... */	\
		do_spidelay(spi, nsecs);				\
	} while (0)

#define EXPAND_BITBANG_TXRX
#include <linux/spi/spi_bitbang.h>

static u32 ap83_spi_txrx_mode0(struct spi_device *spi,
			       unsigned nsecs, u32 word, u8 bits)
{
	dev_dbg(&spi->dev, "TXRX0 word=%08x, bits=%u\n", word, bits);
	return bitbang_txrx_be_cpha0(spi, nsecs, 0, word, bits);
}

static u32 ap83_spi_txrx_mode1(struct spi_device *spi,
			       unsigned nsecs, u32 word, u8 bits)
{
	dev_dbg(&spi->dev, "TXRX1 word=%08x, bits=%u\n", word, bits);
	return bitbang_txrx_be_cpha1(spi, nsecs, 0, word, bits);
}

static u32 ap83_spi_txrx_mode2(struct spi_device *spi,
			       unsigned nsecs, u32 word, u8 bits)
{
	dev_dbg(&spi->dev, "TXRX2 word=%08x, bits=%u\n", word, bits);
	return bitbang_txrx_be_cpha0(spi, nsecs, 1, word, bits);
}

static u32 ap83_spi_txrx_mode3(struct spi_device *spi,
			       unsigned nsecs, u32 word, u8 bits)
{
	dev_dbg(&spi->dev, "TXRX3 word=%08x, bits=%u\n", word, bits);
	return bitbang_txrx_be_cpha1(spi, nsecs, 1, word, bits);
}

static int ap83_spi_probe(struct platform_device *pdev)
{
	struct spi_master *master;
	struct ap83_spi *sp;
	struct ap83_spi_platform_data *pdata;
	struct resource	*r;
	int ret;

	ret = gpio_request(AP83_SPI_GPIO_MISO, "spi-miso");
	if (ret) {
		dev_err(&pdev->dev, "gpio request failed for MISO\n");
		return ret;
	}

	ret = gpio_request(AP83_SPI_GPIO_CS, "spi-cs");
	if (ret) {
		dev_err(&pdev->dev, "gpio request failed for CS\n");
		goto err_free_miso;
	}

	ret = gpio_direction_input(AP83_SPI_GPIO_MISO);
	if (ret) {
		dev_err(&pdev->dev, "unable to set direction of MISO\n");
		goto err_free_cs;
	}

	ret = gpio_direction_output(AP83_SPI_GPIO_CS, 0);
	if (ret) {
		dev_err(&pdev->dev, "unable to set direction of CS\n");
		goto err_free_cs;
	}

	master = spi_alloc_master(&pdev->dev, sizeof(*sp));
	if (master == NULL) {
		dev_err(&pdev->dev, "failed to allocate spi master\n");
		return -ENOMEM;
	}

	sp = spi_master_get_devdata(master);
	platform_set_drvdata(pdev, sp);

	pdata = pdev->dev.platform_data;

	sp->bitbang.master = spi_master_get(master);
	sp->bitbang.chipselect = ap83_spi_chipselect;
	sp->bitbang.txrx_word[SPI_MODE_0] = ap83_spi_txrx_mode0;
	sp->bitbang.txrx_word[SPI_MODE_1] = ap83_spi_txrx_mode1;
	sp->bitbang.txrx_word[SPI_MODE_2] = ap83_spi_txrx_mode2;
	sp->bitbang.txrx_word[SPI_MODE_3] = ap83_spi_txrx_mode3;

	sp->bitbang.master->bus_num = pdev->id;
	sp->bitbang.master->num_chipselect = 1;

	r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	if (r == NULL) {
		ret = -ENOENT;
		goto err_spi_put;
	}

	sp->base = ioremap_nocache(r->start, r->end - r->start + 1);
	if (!sp->base) {
		ret = -ENXIO;
		goto err_spi_put;
	}

	ret = spi_bitbang_start(&sp->bitbang);
	if (!ret)
		goto err_unmap;

	dev_info(&pdev->dev, "AP83 SPI adapter at %08x\n", r->start);

	return 0;

 err_unmap:
	iounmap(sp->base);
 err_spi_put:
	platform_set_drvdata(pdev, NULL);
	spi_master_put(sp->bitbang.master);

 err_free_cs:
	gpio_free(AP83_SPI_GPIO_CS);
 err_free_miso:
	gpio_free(AP83_SPI_GPIO_MISO);
	return ret;
}

static int ap83_spi_remove(struct platform_device *pdev)
{
	struct ap83_spi *sp = platform_get_drvdata(pdev);

	spi_bitbang_stop(&sp->bitbang);
	iounmap(sp->base);
	platform_set_drvdata(pdev, NULL);
	spi_master_put(sp->bitbang.master);

	return 0;
}

static struct platform_driver ap83_spi_drv = {
	.probe		= ap83_spi_probe,
	.remove		= ap83_spi_remove,
	.driver		= {
		.name	= DRV_NAME,
		.owner	= THIS_MODULE,
	},
};

static int __init ap83_spi_init(void)
{
	return platform_driver_register(&ap83_spi_drv);
}
module_init(ap83_spi_init);

static void __exit ap83_spi_exit(void)
{
	platform_driver_unregister(&ap83_spi_drv);
}
module_exit(ap83_spi_exit);

MODULE_ALIAS("platform:" DRV_NAME);
MODULE_DESCRIPTION(DRV_DESC);
MODULE_VERSION(DRV_VERSION);
MODULE_AUTHOR("Gabor Juhos <juhosg@openwrt.org>");
MODULE_LICENSE("GPL v2");