2 * drivers/spi_spi_ubicom32_gpio.c
3 * Ubicom32 GPIO based SPI driver
5 * (C) Copyright 2009, Ubicom, Inc.
7 * This file is part of the Ubicom32 Linux Kernel Port.
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.
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.
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/>.
23 * Ubicom32 implementation derived from (with many thanks):
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>
35 #include <linux/spi/spi.h>
36 #include <linux/spi/spi_bitbang.h>
38 #include <linux/gpio.h>
40 #include <asm/ubicom32-spi-gpio.h>
42 #define DRIVER_NAME "ubicom32-spi-gpio"
44 struct ubicom32_spi_gpio {
45 struct spi_bitbang bitbang;
47 struct ubicom32_spi_gpio_platform_data *pdata;
49 struct platform_device *dev;
53 * The following 4 functions are used by EXPAND_BITBANG_TXRX to bitbang the data out.
55 static inline void setsck(struct spi_device *dev, int on)
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);
61 static inline void setmosi(struct spi_device *dev, int on)
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);
67 static inline u32 getmiso(struct spi_device *dev)
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;
73 #define spidelay(x) ndelay(x)
75 #define EXPAND_BITBANG_TXRX
76 #include <linux/spi/spi_bitbang.h>
79 * ubicom32_spi_gpio_txrx_mode0
81 static u32 ubicom32_spi_gpio_txrx_mode0(struct spi_device *spi, unsigned nsecs, u32 word, u8 bits)
83 return bitbang_txrx_be_cpha0(spi, nsecs, 0, word, bits);
87 * ubicom32_spi_gpio_txrx_mode1
89 static u32 ubicom32_spi_gpio_txrx_mode1(struct spi_device *spi, unsigned nsecs, u32 word, u8 bits)
91 return bitbang_txrx_be_cpha1(spi, nsecs, 0, word, bits);
95 * ubicom32_spi_gpio_txrx_mode2
97 static u32 ubicom32_spi_gpio_txrx_mode2(struct spi_device *spi, unsigned nsecs, u32 word, u8 bits)
99 return bitbang_txrx_be_cpha0(spi, nsecs, 1, word, bits);
103 * ubicom32_spi_gpio_txrx_mode3
105 static u32 ubicom32_spi_gpio_txrx_mode3(struct spi_device *spi, unsigned nsecs, u32 word, u8 bits)
107 return bitbang_txrx_be_cpha1(spi, nsecs, 1, word, bits);
111 * ubicom32_spi_gpio_chipselect
113 static void ubicom32_spi_gpio_chipselect(struct spi_device *dev, int value)
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;
118 if (value == BITBANG_CS_ACTIVE) {
119 gpio_set_value(cd->pin_cs, cs_polarity);
122 gpio_set_value(cd->pin_cs, !cs_polarity);
126 * ubicom32_spi_gpio_probe
128 static int ubicom32_spi_gpio_probe(struct platform_device *dev)
130 struct ubicom32_spi_gpio_platform_data *pdata;
131 struct spi_master *master;
132 struct ubicom32_spi_gpio *usg;
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");
142 usg = (struct ubicom32_spi_gpio *)spi_master_get_devdata(master);
144 platform_set_drvdata(dev, usg);
147 * Copy in the platform data
149 pdata = dev->dev.platform_data;
150 usg->pdata = dev->dev.platform_data;
153 * Request the GPIO lines
155 ret = gpio_request(pdata->pin_mosi, "spi-mosi");
157 dev_err(&dev->dev, "Failed to allocate spi-mosi GPIO\n");
161 ret = gpio_request(pdata->pin_miso, "spi-miso");
163 dev_err(&dev->dev, "Failed to allocate spi-miso GPIO\n");
167 ret = gpio_request(pdata->pin_clk, "spi-clk");
169 dev_err(&dev->dev, "Failed to allocate spi-clk GPIO\n");
174 * Setup spi-bitbang adaptor
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;
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;
188 * Setup the GPIO pins
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);
197 ret = spi_bitbang_start(&usg->bitbang);
205 spi_master_put(usg->bitbang.master);
207 gpio_free(pdata->pin_clk);
210 gpio_free(pdata->pin_miso);
213 gpio_free(pdata->pin_mosi);
220 * ubicom32_spi_gpio_remove
222 static int ubicom32_spi_gpio_remove(struct platform_device *dev)
224 struct ubicom32_spi_gpio *sp = platform_get_drvdata(dev);
226 spi_bitbang_stop(&sp->bitbang);
227 spi_master_put(sp->bitbang.master);
233 * Work with hotplug and coldplug
235 MODULE_ALIAS("platform:ubicom32_spi_gpio");
237 static struct platform_driver ubicom32_spi_gpio_drv = {
238 .probe = ubicom32_spi_gpio_probe,
239 .remove = ubicom32_spi_gpio_remove,
242 .owner = THIS_MODULE,
247 * ubicom32_spi_gpio_init
249 static int __init ubicom32_spi_gpio_init(void)
251 return platform_driver_register(&ubicom32_spi_gpio_drv);
255 * ubicom32_spi_gpio_exit
257 static void __exit ubicom32_spi_gpio_exit(void)
259 platform_driver_unregister(&ubicom32_spi_gpio_drv);
262 module_init(ubicom32_spi_gpio_init);
263 module_exit(ubicom32_spi_gpio_exit);
265 MODULE_DESCRIPTION("Ubicom32 SPI-GPIO Driver");
266 MODULE_AUTHOR("Pat Tjin, <@ubicom.com>");
267 MODULE_LICENSE("GPL");