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/*
* 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");
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