diff options
Diffstat (limited to 'kernel/drivers/spi/spi-sh-sci.c')
| -rw-r--r-- | kernel/drivers/spi/spi-sh-sci.c | 197 |
1 files changed, 197 insertions, 0 deletions
diff --git a/kernel/drivers/spi/spi-sh-sci.c b/kernel/drivers/spi/spi-sh-sci.c new file mode 100644 index 000000000..a9beeeed8 --- /dev/null +++ b/kernel/drivers/spi/spi-sh-sci.c @@ -0,0 +1,197 @@ +/* + * SH SCI SPI interface + * + * Copyright (c) 2008 Magnus Damm + * + * Based on S3C24XX GPIO based SPI driver, which is: + * Copyright (c) 2006 Ben Dooks + * Copyright (c) 2006 Simtec Electronics + * + * 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/delay.h> +#include <linux/spinlock.h> +#include <linux/platform_device.h> + +#include <linux/spi/spi.h> +#include <linux/spi/spi_bitbang.h> +#include <linux/module.h> + +#include <asm/spi.h> +#include <asm/io.h> + +struct sh_sci_spi { + struct spi_bitbang bitbang; + + void __iomem *membase; + unsigned char val; + struct sh_spi_info *info; + struct platform_device *dev; +}; + +#define SCSPTR(sp) (sp->membase + 0x1c) +#define PIN_SCK (1 << 2) +#define PIN_TXD (1 << 0) +#define PIN_RXD PIN_TXD +#define PIN_INIT ((1 << 1) | (1 << 3) | PIN_SCK | PIN_TXD) + +static inline void setbits(struct sh_sci_spi *sp, int bits, int on) +{ + /* + * We are the only user of SCSPTR so no locking is required. + * Reading bit 2 and 0 in SCSPTR gives pin state as input. + * Writing the same bits sets the output value. + * This makes regular read-modify-write difficult so we + * use sp->val to keep track of the latest register value. + */ + + if (on) + sp->val |= bits; + else + sp->val &= ~bits; + + iowrite8(sp->val, SCSPTR(sp)); +} + +static inline void setsck(struct spi_device *dev, int on) +{ + setbits(spi_master_get_devdata(dev->master), PIN_SCK, on); +} + +static inline void setmosi(struct spi_device *dev, int on) +{ + setbits(spi_master_get_devdata(dev->master), PIN_TXD, on); +} + +static inline u32 getmiso(struct spi_device *dev) +{ + struct sh_sci_spi *sp = spi_master_get_devdata(dev->master); + + return (ioread8(SCSPTR(sp)) & PIN_RXD) ? 1 : 0; +} + +#define spidelay(x) ndelay(x) + +#include "spi-bitbang-txrx.h" + +static u32 sh_sci_spi_txrx_mode0(struct spi_device *spi, + unsigned nsecs, u32 word, u8 bits) +{ + return bitbang_txrx_be_cpha0(spi, nsecs, 0, 0, word, bits); +} + +static u32 sh_sci_spi_txrx_mode1(struct spi_device *spi, + unsigned nsecs, u32 word, u8 bits) +{ + return bitbang_txrx_be_cpha1(spi, nsecs, 0, 0, word, bits); +} + +static u32 sh_sci_spi_txrx_mode2(struct spi_device *spi, + unsigned nsecs, u32 word, u8 bits) +{ + return bitbang_txrx_be_cpha0(spi, nsecs, 1, 0, word, bits); +} + +static u32 sh_sci_spi_txrx_mode3(struct spi_device *spi, + unsigned nsecs, u32 word, u8 bits) +{ + return bitbang_txrx_be_cpha1(spi, nsecs, 1, 0, word, bits); +} + +static void sh_sci_spi_chipselect(struct spi_device *dev, int value) +{ + struct sh_sci_spi *sp = spi_master_get_devdata(dev->master); + + if (sp->info->chip_select) + (sp->info->chip_select)(sp->info, dev->chip_select, value); +} + +static int sh_sci_spi_probe(struct platform_device *dev) +{ + struct resource *r; + struct spi_master *master; + struct sh_sci_spi *sp; + int ret; + + master = spi_alloc_master(&dev->dev, sizeof(struct sh_sci_spi)); + if (master == NULL) { + dev_err(&dev->dev, "failed to allocate spi master\n"); + ret = -ENOMEM; + goto err0; + } + + sp = spi_master_get_devdata(master); + + platform_set_drvdata(dev, sp); + sp->info = dev_get_platdata(&dev->dev); + if (!sp->info) { + dev_err(&dev->dev, "platform data is missing\n"); + ret = -ENOENT; + goto err1; + } + + /* setup spi bitbang adaptor */ + sp->bitbang.master = master; + sp->bitbang.master->bus_num = sp->info->bus_num; + sp->bitbang.master->num_chipselect = sp->info->num_chipselect; + sp->bitbang.chipselect = sh_sci_spi_chipselect; + + sp->bitbang.txrx_word[SPI_MODE_0] = sh_sci_spi_txrx_mode0; + sp->bitbang.txrx_word[SPI_MODE_1] = sh_sci_spi_txrx_mode1; + sp->bitbang.txrx_word[SPI_MODE_2] = sh_sci_spi_txrx_mode2; + sp->bitbang.txrx_word[SPI_MODE_3] = sh_sci_spi_txrx_mode3; + + r = platform_get_resource(dev, IORESOURCE_MEM, 0); + if (r == NULL) { + ret = -ENOENT; + goto err1; + } + sp->membase = ioremap(r->start, resource_size(r)); + if (!sp->membase) { + ret = -ENXIO; + goto err1; + } + sp->val = ioread8(SCSPTR(sp)); + setbits(sp, PIN_INIT, 1); + + ret = spi_bitbang_start(&sp->bitbang); + if (!ret) + return 0; + + setbits(sp, PIN_INIT, 0); + iounmap(sp->membase); + err1: + spi_master_put(sp->bitbang.master); + err0: + return ret; +} + +static int sh_sci_spi_remove(struct platform_device *dev) +{ + struct sh_sci_spi *sp = platform_get_drvdata(dev); + + spi_bitbang_stop(&sp->bitbang); + setbits(sp, PIN_INIT, 0); + iounmap(sp->membase); + spi_master_put(sp->bitbang.master); + return 0; +} + +static struct platform_driver sh_sci_spi_drv = { + .probe = sh_sci_spi_probe, + .remove = sh_sci_spi_remove, + .driver = { + .name = "spi_sh_sci", + }, +}; +module_platform_driver(sh_sci_spi_drv); + +MODULE_DESCRIPTION("SH SCI SPI Driver"); +MODULE_AUTHOR("Magnus Damm <damm@opensource.se>"); +MODULE_LICENSE("GPL"); +MODULE_ALIAS("platform:spi_sh_sci"); |