Root/target/linux/ar71xx/files/drivers/spi/ap83_spi.c

1/*
2 * Atheros AP83 board specific SPI Controller driver
3 *
4 * Copyright (C) 2009 Gabor Juhos <juhosg@openwrt.org>
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation.
9 *
10 */
11
12#include <linux/kernel.h>
13#include <linux/init.h>
14#include <linux/delay.h>
15#include <linux/spinlock.h>
16#include <linux/workqueue.h>
17#include <linux/platform_device.h>
18#include <linux/io.h>
19#include <linux/spi/spi.h>
20#include <linux/spi/spi_bitbang.h>
21#include <linux/bitops.h>
22#include <linux/gpio.h>
23
24#include <asm/mach-ar71xx/ar71xx.h>
25#include <asm/mach-ar71xx/platform.h>
26
27#define DRV_DESC "Atheros AP83 board SPI Controller driver"
28#define DRV_VERSION "0.1.0"
29#define DRV_NAME "ap83-spi"
30
31#define AP83_SPI_CLK_HIGH (1 << 23)
32#define AP83_SPI_CLK_LOW 0
33#define AP83_SPI_MOSI_HIGH (1 << 22)
34#define AP83_SPI_MOSI_LOW 0
35
36#define AP83_SPI_GPIO_CS 1
37#define AP83_SPI_GPIO_MISO 3
38
39struct ap83_spi {
40    struct spi_bitbang bitbang;
41    void __iomem *base;
42    u32 addr;
43
44    struct platform_device *pdev;
45};
46
47static inline u32 ap83_spi_rr(struct ap83_spi *sp, u32 reg)
48{
49    return __raw_readl(sp->base + reg);
50}
51
52static inline struct ap83_spi *spidev_to_sp(struct spi_device *spi)
53{
54    return spi_master_get_devdata(spi->master);
55}
56
57static inline void setsck(struct spi_device *spi, int val)
58{
59    struct ap83_spi *sp = spidev_to_sp(spi);
60
61    if (val)
62        sp->addr |= AP83_SPI_CLK_HIGH;
63    else
64        sp->addr &= ~AP83_SPI_CLK_HIGH;
65
66    dev_dbg(&spi->dev, "addr=%08x, SCK set to %s\n",
67        sp->addr, (val) ? "HIGH" : "LOW");
68
69    ap83_spi_rr(sp, sp->addr);
70}
71
72static inline void setmosi(struct spi_device *spi, int val)
73{
74    struct ap83_spi *sp = spidev_to_sp(spi);
75
76    if (val)
77        sp->addr |= AP83_SPI_MOSI_HIGH;
78    else
79        sp->addr &= ~AP83_SPI_MOSI_HIGH;
80
81    dev_dbg(&spi->dev, "addr=%08x, MOSI set to %s\n",
82        sp->addr, (val) ? "HIGH" : "LOW");
83
84    ap83_spi_rr(sp, sp->addr);
85}
86
87static inline u32 getmiso(struct spi_device *spi)
88{
89    u32 ret;
90
91    ret = gpio_get_value(AP83_SPI_GPIO_MISO) ? 1 : 0;
92    dev_dbg(&spi->dev, "get MISO: %d\n", ret);
93
94    return ret;
95}
96
97static inline void do_spidelay(struct spi_device *spi, unsigned nsecs)
98{
99    ndelay(nsecs);
100}
101
102static void ap83_spi_chipselect(struct spi_device *spi, int on)
103{
104    struct ap83_spi *sp = spidev_to_sp(spi);
105
106    dev_dbg(&spi->dev, "set CS to %d\n", (on) ? 0 : 1);
107
108    if (on) {
109        ar71xx_flash_acquire();
110
111        sp->addr = 0;
112        ap83_spi_rr(sp, sp->addr);
113
114        gpio_set_value(AP83_SPI_GPIO_CS, 0);
115    } else {
116        gpio_set_value(AP83_SPI_GPIO_CS, 1);
117        ar71xx_flash_release();
118    }
119}
120
121#define spidelay(nsecs) \
122    do { \
123        /* Steal the spi_device pointer from our caller. \
124         * The bitbang-API should probably get fixed here... */ \
125        do_spidelay(spi, nsecs); \
126    } while (0)
127
128#define EXPAND_BITBANG_TXRX
129#include <linux/spi/spi_bitbang.h>
130
131static u32 ap83_spi_txrx_mode0(struct spi_device *spi,
132                   unsigned nsecs, u32 word, u8 bits)
133{
134    dev_dbg(&spi->dev, "TXRX0 word=%08x, bits=%u\n", word, bits);
135    return bitbang_txrx_be_cpha0(spi, nsecs, 0, word, bits);
136}
137
138static u32 ap83_spi_txrx_mode1(struct spi_device *spi,
139                   unsigned nsecs, u32 word, u8 bits)
140{
141    dev_dbg(&spi->dev, "TXRX1 word=%08x, bits=%u\n", word, bits);
142    return bitbang_txrx_be_cpha1(spi, nsecs, 0, word, bits);
143}
144
145static u32 ap83_spi_txrx_mode2(struct spi_device *spi,
146                   unsigned nsecs, u32 word, u8 bits)
147{
148    dev_dbg(&spi->dev, "TXRX2 word=%08x, bits=%u\n", word, bits);
149    return bitbang_txrx_be_cpha0(spi, nsecs, 1, word, bits);
150}
151
152static u32 ap83_spi_txrx_mode3(struct spi_device *spi,
153                   unsigned nsecs, u32 word, u8 bits)
154{
155    dev_dbg(&spi->dev, "TXRX3 word=%08x, bits=%u\n", word, bits);
156    return bitbang_txrx_be_cpha1(spi, nsecs, 1, word, bits);
157}
158
159static int ap83_spi_probe(struct platform_device *pdev)
160{
161    struct spi_master *master;
162    struct ap83_spi *sp;
163    struct ap83_spi_platform_data *pdata;
164    struct resource *r;
165    int ret;
166
167    ret = gpio_request(AP83_SPI_GPIO_MISO, "spi-miso");
168    if (ret) {
169        dev_err(&pdev->dev, "gpio request failed for MISO\n");
170        return ret;
171    }
172
173    ret = gpio_request(AP83_SPI_GPIO_CS, "spi-cs");
174    if (ret) {
175        dev_err(&pdev->dev, "gpio request failed for CS\n");
176        goto err_free_miso;
177    }
178
179    ret = gpio_direction_input(AP83_SPI_GPIO_MISO);
180    if (ret) {
181        dev_err(&pdev->dev, "unable to set direction of MISO\n");
182        goto err_free_cs;
183    }
184
185    ret = gpio_direction_output(AP83_SPI_GPIO_CS, 0);
186    if (ret) {
187        dev_err(&pdev->dev, "unable to set direction of CS\n");
188        goto err_free_cs;
189    }
190
191    master = spi_alloc_master(&pdev->dev, sizeof(*sp));
192    if (master == NULL) {
193        dev_err(&pdev->dev, "failed to allocate spi master\n");
194        return -ENOMEM;
195    }
196
197    sp = spi_master_get_devdata(master);
198    platform_set_drvdata(pdev, sp);
199
200    pdata = pdev->dev.platform_data;
201
202    sp->bitbang.master = spi_master_get(master);
203    sp->bitbang.chipselect = ap83_spi_chipselect;
204    sp->bitbang.txrx_word[SPI_MODE_0] = ap83_spi_txrx_mode0;
205    sp->bitbang.txrx_word[SPI_MODE_1] = ap83_spi_txrx_mode1;
206    sp->bitbang.txrx_word[SPI_MODE_2] = ap83_spi_txrx_mode2;
207    sp->bitbang.txrx_word[SPI_MODE_3] = ap83_spi_txrx_mode3;
208
209    sp->bitbang.master->bus_num = pdev->id;
210    sp->bitbang.master->num_chipselect = 1;
211
212    r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
213    if (r == NULL) {
214        ret = -ENOENT;
215        goto err_spi_put;
216    }
217
218    sp->base = ioremap_nocache(r->start, r->end - r->start + 1);
219    if (!sp->base) {
220        ret = -ENXIO;
221        goto err_spi_put;
222    }
223
224    ret = spi_bitbang_start(&sp->bitbang);
225    if (!ret)
226        goto err_unmap;
227
228    dev_info(&pdev->dev, "AP83 SPI adapter at %08x\n", r->start);
229
230    return 0;
231
232 err_unmap:
233    iounmap(sp->base);
234 err_spi_put:
235    platform_set_drvdata(pdev, NULL);
236    spi_master_put(sp->bitbang.master);
237
238 err_free_cs:
239    gpio_free(AP83_SPI_GPIO_CS);
240 err_free_miso:
241    gpio_free(AP83_SPI_GPIO_MISO);
242    return ret;
243}
244
245static int ap83_spi_remove(struct platform_device *pdev)
246{
247    struct ap83_spi *sp = platform_get_drvdata(pdev);
248
249    spi_bitbang_stop(&sp->bitbang);
250    iounmap(sp->base);
251    platform_set_drvdata(pdev, NULL);
252    spi_master_put(sp->bitbang.master);
253
254    return 0;
255}
256
257static struct platform_driver ap83_spi_drv = {
258    .probe = ap83_spi_probe,
259    .remove = ap83_spi_remove,
260    .driver = {
261        .name = DRV_NAME,
262        .owner = THIS_MODULE,
263    },
264};
265
266static int __init ap83_spi_init(void)
267{
268    return platform_driver_register(&ap83_spi_drv);
269}
270module_init(ap83_spi_init);
271
272static void __exit ap83_spi_exit(void)
273{
274    platform_driver_unregister(&ap83_spi_drv);
275}
276module_exit(ap83_spi_exit);
277
278MODULE_ALIAS("platform:" DRV_NAME);
279MODULE_DESCRIPTION(DRV_DESC);
280MODULE_VERSION(DRV_VERSION);
281MODULE_AUTHOR("Gabor Juhos <juhosg@openwrt.org>");
282MODULE_LICENSE("GPL v2");
283

Archive Download this file

Branches:
backfire
history
master
release_2010-11-17
release_2010-12-14
release_2011-02-23
release_2011-05-28
release_2011-08-27
release_2011-11-13
release_2012-03-18
release_2012-04-09
release_2012-10-11
uclibc_nptl



interactive