openwrtv3/target/linux/ubicom32/files/drivers/spi/spi_ubicom32_gpio.c

268 lines
6.5 KiB
C
Raw Normal View History

/*
* drivers/spi_spi_ubicom32_gpio.c
* Ubicom32 GPIO based SPI driver
*
* (C) Copyright 2009, Ubicom, Inc.
*
* This file is part of the Ubicom32 Linux Kernel Port.
*
* The Ubicom32 Linux Kernel Port 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.
*
* The Ubicom32 Linux Kernel Port 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 the Ubicom32 Linux Kernel Port. If not,
* see <http://www.gnu.org/licenses/>.
*
* Ubicom32 implementation derived from (with many thanks):
* arch/m68knommu
* arch/blackfin
* arch/parisc
*/
#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/spi/spi.h>
#include <linux/spi/spi_bitbang.h>
#include <linux/gpio.h>
#include <asm/ubicom32-spi-gpio.h>
#define DRIVER_NAME "ubicom32-spi-gpio"
struct ubicom32_spi_gpio {
struct spi_bitbang bitbang;
struct ubicom32_spi_gpio_platform_data *pdata;
struct platform_device *dev;
};
/*
* The following 4 functions are used by EXPAND_BITBANG_TXRX to bitbang the data out.
*/
static inline void setsck(struct spi_device *dev, int on)
{
struct ubicom32_spi_gpio *usg = (struct ubicom32_spi_gpio *)spi_master_get_devdata(dev->master);
gpio_set_value(usg->pdata->pin_clk, on ? 1 : 0);
}
static inline void setmosi(struct spi_device *dev, int on)
{
struct ubicom32_spi_gpio *usg = (struct ubicom32_spi_gpio *)spi_master_get_devdata(dev->master);
gpio_set_value(usg->pdata->pin_mosi, on ? 1 : 0);
}
static inline u32 getmiso(struct spi_device *dev)
{
struct ubicom32_spi_gpio *usg = (struct ubicom32_spi_gpio *)spi_master_get_devdata(dev->master);
return gpio_get_value(usg->pdata->pin_miso) ? 1 : 0;
}
#define spidelay(x) ndelay(x)
#define EXPAND_BITBANG_TXRX
#include <linux/spi/spi_bitbang.h>
/*
* ubicom32_spi_gpio_txrx_mode0
*/
static u32 ubicom32_spi_gpio_txrx_mode0(struct spi_device *spi, unsigned nsecs, u32 word, u8 bits)
{
return bitbang_txrx_be_cpha0(spi, nsecs, 0, word, bits);
}
/*
* ubicom32_spi_gpio_txrx_mode1
*/
static u32 ubicom32_spi_gpio_txrx_mode1(struct spi_device *spi, unsigned nsecs, u32 word, u8 bits)
{
return bitbang_txrx_be_cpha1(spi, nsecs, 0, word, bits);
}
/*
* ubicom32_spi_gpio_txrx_mode2
*/
static u32 ubicom32_spi_gpio_txrx_mode2(struct spi_device *spi, unsigned nsecs, u32 word, u8 bits)
{
return bitbang_txrx_be_cpha0(spi, nsecs, 1, word, bits);
}
/*
* ubicom32_spi_gpio_txrx_mode3
*/
static u32 ubicom32_spi_gpio_txrx_mode3(struct spi_device *spi, unsigned nsecs, u32 word, u8 bits)
{
return bitbang_txrx_be_cpha1(spi, nsecs, 1, word, bits);
}
/*
* ubicom32_spi_gpio_chipselect
*/
static void ubicom32_spi_gpio_chipselect(struct spi_device *dev, int value)
{
struct ubicom32_spi_gpio_controller_data *cd = (struct ubicom32_spi_gpio_controller_data *)dev->controller_data;
unsigned int cs_polarity = dev->mode & SPI_CS_HIGH ? 1 : 0;
if (value == BITBANG_CS_ACTIVE) {
gpio_set_value(cd->pin_cs, cs_polarity);
return;
}
gpio_set_value(cd->pin_cs, !cs_polarity);
}
/*
* ubicom32_spi_gpio_probe
*/
static int ubicom32_spi_gpio_probe(struct platform_device *dev)
{
struct ubicom32_spi_gpio_platform_data *pdata;
struct spi_master *master;
struct ubicom32_spi_gpio *usg;
int ret;
master = spi_alloc_master(&dev->dev, sizeof(struct ubicom32_spi_gpio));
if (master == NULL) {
dev_err(&dev->dev, "failed to allocate spi master\n");
ret = -ENOMEM;
goto err;
}
usg = (struct ubicom32_spi_gpio *)spi_master_get_devdata(master);
platform_set_drvdata(dev, usg);
/*
* Copy in the platform data
*/
pdata = dev->dev.platform_data;
usg->pdata = dev->dev.platform_data;
/*
* Request the GPIO lines
*/
ret = gpio_request(pdata->pin_mosi, "spi-mosi");
if (ret) {
dev_err(&dev->dev, "Failed to allocate spi-mosi GPIO\n");
goto err;
}
ret = gpio_request(pdata->pin_miso, "spi-miso");
if (ret) {
dev_err(&dev->dev, "Failed to allocate spi-miso GPIO\n");
goto err_nomiso;
}
ret = gpio_request(pdata->pin_clk, "spi-clk");
if (ret) {
dev_err(&dev->dev, "Failed to allocate spi-clk GPIO\n");
goto err_noclk;
}
/*
* Setup spi-bitbang adaptor
*/
usg->bitbang.flags |= SPI_CS_HIGH;
usg->bitbang.master = spi_master_get(master);
usg->bitbang.master->bus_num = pdata->bus_num;
usg->bitbang.master->num_chipselect = pdata->num_chipselect;
usg->bitbang.chipselect = ubicom32_spi_gpio_chipselect;
usg->bitbang.txrx_word[SPI_MODE_0] = ubicom32_spi_gpio_txrx_mode0;
usg->bitbang.txrx_word[SPI_MODE_1] = ubicom32_spi_gpio_txrx_mode1;
usg->bitbang.txrx_word[SPI_MODE_2] = ubicom32_spi_gpio_txrx_mode2;
usg->bitbang.txrx_word[SPI_MODE_3] = ubicom32_spi_gpio_txrx_mode3;
/*
* Setup the GPIO pins
*/
gpio_direction_output(pdata->pin_clk, pdata->clk_default);
gpio_direction_output(pdata->pin_mosi, 0);
gpio_direction_input(pdata->pin_miso);
/*
* Ready to go
*/
ret = spi_bitbang_start(&usg->bitbang);
if (ret) {
goto err_no_bitbang;
}
return 0;
err_no_bitbang:
spi_master_put(usg->bitbang.master);
gpio_free(pdata->pin_clk);
err_noclk:
gpio_free(pdata->pin_miso);
err_nomiso:
gpio_free(pdata->pin_mosi);
err:
return ret;
}
/*
* ubicom32_spi_gpio_remove
*/
static int ubicom32_spi_gpio_remove(struct platform_device *dev)
{
struct ubicom32_spi_gpio *sp = platform_get_drvdata(dev);
spi_bitbang_stop(&sp->bitbang);
spi_master_put(sp->bitbang.master);
return 0;
}
/*
* Work with hotplug and coldplug
*/
MODULE_ALIAS("platform:ubicom32_spi_gpio");
static struct platform_driver ubicom32_spi_gpio_drv = {
.probe = ubicom32_spi_gpio_probe,
.remove = ubicom32_spi_gpio_remove,
.driver = {
.name = DRIVER_NAME,
.owner = THIS_MODULE,
},
};
/*
* ubicom32_spi_gpio_init
*/
static int __init ubicom32_spi_gpio_init(void)
{
return platform_driver_register(&ubicom32_spi_gpio_drv);
}
/*
* ubicom32_spi_gpio_exit
*/
static void __exit ubicom32_spi_gpio_exit(void)
{
platform_driver_unregister(&ubicom32_spi_gpio_drv);
}
module_init(ubicom32_spi_gpio_init);
module_exit(ubicom32_spi_gpio_exit);
MODULE_DESCRIPTION("Ubicom32 SPI-GPIO Driver");
MODULE_AUTHOR("Pat Tjin, <@ubicom.com>");
MODULE_LICENSE("GPL");