Root/target/linux/ubicom32/files/drivers/spi/spi_ubicom32_gpio.c

1/*
2 * drivers/spi_spi_ubicom32_gpio.c
3 * Ubicom32 GPIO based SPI driver
4 *
5 * (C) Copyright 2009, Ubicom, Inc.
6 *
7 * This file is part of the Ubicom32 Linux Kernel Port.
8 *
9 * The Ubicom32 Linux Kernel Port is free software: you can redistribute
10 * it and/or modify it under the terms of the GNU General Public License
11 * as published by the Free Software Foundation, either version 2 of the
12 * License, or (at your option) any later version.
13 *
14 * The Ubicom32 Linux Kernel Port is distributed in the hope that it
15 * will be useful, but WITHOUT ANY WARRANTY; without even the implied
16 * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
17 * the GNU General Public License for more details.
18 *
19 * You should have received a copy of the GNU General Public License
20 * along with the Ubicom32 Linux Kernel Port. If not,
21 * see <http://www.gnu.org/licenses/>.
22 *
23 * Ubicom32 implementation derived from (with many thanks):
24 * arch/m68knommu
25 * arch/blackfin
26 * arch/parisc
27 */
28#include <linux/kernel.h>
29#include <linux/init.h>
30#include <linux/delay.h>
31#include <linux/spinlock.h>
32#include <linux/workqueue.h>
33#include <linux/platform_device.h>
34
35#include <linux/spi/spi.h>
36#include <linux/spi/spi_bitbang.h>
37
38#include <linux/gpio.h>
39
40#include <asm/ubicom32-spi-gpio.h>
41
42#define DRIVER_NAME "ubicom32-spi-gpio"
43
44struct ubicom32_spi_gpio {
45    struct spi_bitbang bitbang;
46
47    struct ubicom32_spi_gpio_platform_data *pdata;
48
49    struct platform_device *dev;
50};
51
52/*
53 * The following 4 functions are used by EXPAND_BITBANG_TXRX to bitbang the data out.
54 */
55static inline void setsck(struct spi_device *dev, int on)
56{
57    struct ubicom32_spi_gpio *usg = (struct ubicom32_spi_gpio *)spi_master_get_devdata(dev->master);
58    gpio_set_value(usg->pdata->pin_clk, on ? 1 : 0);
59}
60
61static inline void setmosi(struct spi_device *dev, int on)
62{
63    struct ubicom32_spi_gpio *usg = (struct ubicom32_spi_gpio *)spi_master_get_devdata(dev->master);
64    gpio_set_value(usg->pdata->pin_mosi, on ? 1 : 0);
65}
66
67static inline u32 getmiso(struct spi_device *dev)
68{
69    struct ubicom32_spi_gpio *usg = (struct ubicom32_spi_gpio *)spi_master_get_devdata(dev->master);
70    return gpio_get_value(usg->pdata->pin_miso) ? 1 : 0;
71}
72
73#define spidelay(x) ndelay(x)
74
75#define EXPAND_BITBANG_TXRX
76#include <linux/spi/spi_bitbang.h>
77
78/*
79 * ubicom32_spi_gpio_txrx_mode0
80 */
81static u32 ubicom32_spi_gpio_txrx_mode0(struct spi_device *spi, unsigned nsecs, u32 word, u8 bits)
82{
83    return bitbang_txrx_be_cpha0(spi, nsecs, 0, word, bits);
84}
85
86/*
87 * ubicom32_spi_gpio_txrx_mode1
88 */
89static u32 ubicom32_spi_gpio_txrx_mode1(struct spi_device *spi, unsigned nsecs, u32 word, u8 bits)
90{
91    return bitbang_txrx_be_cpha1(spi, nsecs, 0, word, bits);
92}
93
94/*
95 * ubicom32_spi_gpio_txrx_mode2
96 */
97static u32 ubicom32_spi_gpio_txrx_mode2(struct spi_device *spi, unsigned nsecs, u32 word, u8 bits)
98{
99    return bitbang_txrx_be_cpha0(spi, nsecs, 1, word, bits);
100}
101
102/*
103 * ubicom32_spi_gpio_txrx_mode3
104 */
105static u32 ubicom32_spi_gpio_txrx_mode3(struct spi_device *spi, unsigned nsecs, u32 word, u8 bits)
106{
107    return bitbang_txrx_be_cpha1(spi, nsecs, 1, word, bits);
108}
109
110/*
111 * ubicom32_spi_gpio_chipselect
112 */
113static void ubicom32_spi_gpio_chipselect(struct spi_device *dev, int value)
114{
115    struct ubicom32_spi_gpio_controller_data *cd = (struct ubicom32_spi_gpio_controller_data *)dev->controller_data;
116    unsigned int cs_polarity = dev->mode & SPI_CS_HIGH ? 1 : 0;
117
118    if (value == BITBANG_CS_ACTIVE) {
119        gpio_set_value(cd->pin_cs, cs_polarity);
120        return;
121    }
122    gpio_set_value(cd->pin_cs, !cs_polarity);
123}
124
125/*
126 * ubicom32_spi_gpio_probe
127 */
128static int ubicom32_spi_gpio_probe(struct platform_device *dev)
129{
130    struct ubicom32_spi_gpio_platform_data *pdata;
131    struct spi_master *master;
132    struct ubicom32_spi_gpio *usg;
133    int ret;
134
135    master = spi_alloc_master(&dev->dev, sizeof(struct ubicom32_spi_gpio));
136    if (master == NULL) {
137        dev_err(&dev->dev, "failed to allocate spi master\n");
138        ret = -ENOMEM;
139        goto err;
140    }
141
142    usg = (struct ubicom32_spi_gpio *)spi_master_get_devdata(master);
143
144    platform_set_drvdata(dev, usg);
145
146    /*
147     * Copy in the platform data
148     */
149    pdata = dev->dev.platform_data;
150    usg->pdata = dev->dev.platform_data;
151
152    /*
153     * Request the GPIO lines
154     */
155    ret = gpio_request(pdata->pin_mosi, "spi-mosi");
156    if (ret) {
157        dev_err(&dev->dev, "Failed to allocate spi-mosi GPIO\n");
158        goto err;
159    }
160
161    ret = gpio_request(pdata->pin_miso, "spi-miso");
162    if (ret) {
163        dev_err(&dev->dev, "Failed to allocate spi-miso GPIO\n");
164        goto err_nomiso;
165    }
166
167    ret = gpio_request(pdata->pin_clk, "spi-clk");
168    if (ret) {
169        dev_err(&dev->dev, "Failed to allocate spi-clk GPIO\n");
170        goto err_noclk;
171    }
172
173    /*
174     * Setup spi-bitbang adaptor
175     */
176    usg->bitbang.flags |= SPI_CS_HIGH;
177    usg->bitbang.master = spi_master_get(master);
178    usg->bitbang.master->bus_num = pdata->bus_num;
179    usg->bitbang.master->num_chipselect = pdata->num_chipselect;
180    usg->bitbang.chipselect = ubicom32_spi_gpio_chipselect;
181
182    usg->bitbang.txrx_word[SPI_MODE_0] = ubicom32_spi_gpio_txrx_mode0;
183    usg->bitbang.txrx_word[SPI_MODE_1] = ubicom32_spi_gpio_txrx_mode1;
184    usg->bitbang.txrx_word[SPI_MODE_2] = ubicom32_spi_gpio_txrx_mode2;
185    usg->bitbang.txrx_word[SPI_MODE_3] = ubicom32_spi_gpio_txrx_mode3;
186
187    /*
188     * Setup the GPIO pins
189     */
190    gpio_direction_output(pdata->pin_clk, pdata->clk_default);
191    gpio_direction_output(pdata->pin_mosi, 0);
192    gpio_direction_input(pdata->pin_miso);
193
194    /*
195     * Ready to go
196     */
197    ret = spi_bitbang_start(&usg->bitbang);
198    if (ret) {
199        goto err_no_bitbang;
200    }
201
202    return 0;
203
204err_no_bitbang:
205    spi_master_put(usg->bitbang.master);
206
207    gpio_free(pdata->pin_clk);
208
209err_noclk:
210    gpio_free(pdata->pin_miso);
211
212err_nomiso:
213    gpio_free(pdata->pin_mosi);
214
215err:
216    return ret;
217}
218
219/*
220 * ubicom32_spi_gpio_remove
221 */
222static int ubicom32_spi_gpio_remove(struct platform_device *dev)
223{
224    struct ubicom32_spi_gpio *sp = platform_get_drvdata(dev);
225
226    spi_bitbang_stop(&sp->bitbang);
227    spi_master_put(sp->bitbang.master);
228
229    return 0;
230}
231
232/*
233 * Work with hotplug and coldplug
234 */
235MODULE_ALIAS("platform:ubicom32_spi_gpio");
236
237static struct platform_driver ubicom32_spi_gpio_drv = {
238    .probe = ubicom32_spi_gpio_probe,
239        .remove = ubicom32_spi_gpio_remove,
240        .driver = {
241        .name = DRIVER_NAME,
242        .owner = THIS_MODULE,
243        },
244};
245
246/*
247 * ubicom32_spi_gpio_init
248 */
249static int __init ubicom32_spi_gpio_init(void)
250{
251        return platform_driver_register(&ubicom32_spi_gpio_drv);
252}
253
254/*
255 * ubicom32_spi_gpio_exit
256 */
257static void __exit ubicom32_spi_gpio_exit(void)
258{
259        platform_driver_unregister(&ubicom32_spi_gpio_drv);
260}
261
262module_init(ubicom32_spi_gpio_init);
263module_exit(ubicom32_spi_gpio_exit);
264
265MODULE_DESCRIPTION("Ubicom32 SPI-GPIO Driver");
266MODULE_AUTHOR("Pat Tjin, <@ubicom.com>");
267MODULE_LICENSE("GPL");
268

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