diff options
Diffstat (limited to 'target/linux/ar71xx/files/drivers/spi/ar71xx_spi.c')
| -rw-r--r-- | target/linux/ar71xx/files/drivers/spi/ar71xx_spi.c | 240 |
1 files changed, 240 insertions, 0 deletions
diff --git a/target/linux/ar71xx/files/drivers/spi/ar71xx_spi.c b/target/linux/ar71xx/files/drivers/spi/ar71xx_spi.c new file mode 100644 index 000000000..98de435fd --- /dev/null +++ b/target/linux/ar71xx/files/drivers/spi/ar71xx_spi.c @@ -0,0 +1,240 @@ +/* + * Atheros AR71xx SPI Controller driver + * + * Copyright (C) 2008 Gabor Juhos <juhosg@openwrt.org> + * Copyright (C) 2008 Imre Kaloz <kaloz@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 <asm/mach-ar71xx/ar71xx.h> +#include <asm/mach-ar71xx/platform.h> + +#define DRV_DESC "Atheros AR71xx SPI Controller driver" +#define DRV_VERSION "0.2.2" +#define DRV_NAME "ar71xx-spi" + +#undef PER_BIT_READ + +struct ar71xx_spi { + struct spi_bitbang bitbang; + u32 ioc_base; + u32 reg_ctrl; + + void __iomem *base; + + struct platform_device *pdev; + u32 (*get_ioc_base)(u8 chip_select, int cs_high, + int is_on); +}; + +static inline u32 ar71xx_spi_rr(struct ar71xx_spi *sp, unsigned reg) +{ + return __raw_readl(sp->base + reg); +} + +static inline void ar71xx_spi_wr(struct ar71xx_spi *sp, unsigned reg, u32 val) +{ + __raw_writel(val, sp->base + reg); +} + +static inline struct ar71xx_spi *spidev_to_sp(struct spi_device *spi) +{ + return spi_master_get_devdata(spi->master); +} + +static u32 ar71xx_spi_get_ioc_base(u8 chip_select, int cs_high, int is_on) +{ + u32 ret; + + if (is_on == AR71XX_SPI_CS_INACTIVE) + ret = SPI_IOC_CS_ALL; + else + ret = SPI_IOC_CS_ALL & ~SPI_IOC_CS(chip_select); + + return ret; +} + +static void ar71xx_spi_chipselect(struct spi_device *spi, int value) +{ + struct ar71xx_spi *sp = spidev_to_sp(spi); + void __iomem *base = sp->base; + u32 ioc_base; + + switch (value) { + case BITBANG_CS_INACTIVE: + ioc_base = sp->get_ioc_base(spi->chip_select, + (spi->mode & SPI_CS_HIGH) != 0, + AR71XX_SPI_CS_INACTIVE); + + __raw_writel(ioc_base, base + SPI_REG_IOC); + __raw_writel(sp->reg_ctrl, base + SPI_REG_CTRL); + __raw_writel(0, base + SPI_REG_FS); + break; + + case BITBANG_CS_ACTIVE: + ioc_base = sp->get_ioc_base(spi->chip_select, + (spi->mode & SPI_CS_HIGH) != 0, + AR71XX_SPI_CS_ACTIVE); + + __raw_writel(SPI_FS_GPIO, base + SPI_REG_FS); + /* TODO: setup speed */ + __raw_writel(0x43, base + SPI_REG_CTRL); + __raw_writel(ioc_base, base + SPI_REG_IOC); + sp->ioc_base = ioc_base; + break; + } +} + +static u32 ar71xx_spi_txrx_mode0(struct spi_device *spi, unsigned nsecs, + u32 word, u8 bits) +{ + struct ar71xx_spi *sp = spidev_to_sp(spi); + void __iomem *base = sp->base; + u32 ioc = sp->ioc_base; + u32 ret; + + /* clock starts at inactive polarity */ + for (word <<= (32 - bits); likely(bits); bits--) { + u32 out; + + if (word & (1 << 31)) + out = ioc | SPI_IOC_DO; + else + out = ioc & ~SPI_IOC_DO; + + /* setup MSB (to slave) on trailing edge */ + __raw_writel(out, base + SPI_REG_IOC); + + __raw_writel(out | SPI_IOC_CLK, base + SPI_REG_IOC); + + word <<= 1; + +#ifdef PER_BIT_READ + /* sample MSB (from slave) on leading edge */ + ret = __raw_readl(base + SPI_REG_RDS); + __raw_writel(out, base + SPI_REG_IOC); +#endif + + } + +#ifndef PER_BIT_READ + ret = __raw_readl(base + SPI_REG_RDS); +#endif + return ret; +} + +static int ar71xx_spi_probe(struct platform_device *pdev) +{ + struct spi_master *master; + struct ar71xx_spi *sp; + struct ar71xx_spi_platform_data *pdata; + struct resource *r; + int ret; + + 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 = ar71xx_spi_chipselect; + sp->bitbang.txrx_word[SPI_MODE_0] = ar71xx_spi_txrx_mode0; + + sp->get_ioc_base = ar71xx_spi_get_ioc_base; + if (pdata) { + sp->bitbang.master->bus_num = pdata->bus_num; + sp->bitbang.master->num_chipselect = pdata->num_chipselect; + if (pdata->get_ioc_base) + sp->get_ioc_base = pdata->get_ioc_base; + } else { + sp->bitbang.master->bus_num = 0; + sp->bitbang.master->num_chipselect = 3; + } + + r = platform_get_resource(pdev, IORESOURCE_MEM, 0); + if (r == NULL) { + ret = -ENOENT; + goto err1; + } + + sp->base = ioremap_nocache(r->start, r->end - r->start + 1); + if (!sp->base) { + ret = -ENXIO; + goto err1; + } + + sp->reg_ctrl = ar71xx_spi_rr(sp, SPI_REG_IOC); + + ret = spi_bitbang_start(&sp->bitbang); + if (!ret) + return 0; + + iounmap(sp->base); +err1: + platform_set_drvdata(pdev, NULL); + spi_master_put(sp->bitbang.master); + + return ret; +} + +static int ar71xx_spi_remove(struct platform_device *pdev) +{ + struct ar71xx_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 ar71xx_spi_drv = { + .probe = ar71xx_spi_probe, + .remove = ar71xx_spi_remove, + .driver = { + .name = DRV_NAME, + .owner = THIS_MODULE, + }, +}; + +static int __init ar71xx_spi_init(void) +{ + printk(KERN_INFO DRV_DESC " version " DRV_VERSION "\n"); + return platform_driver_register(&ar71xx_spi_drv); +} +module_init(ar71xx_spi_init); + +static void __exit ar71xx_spi_exit(void) +{ + platform_driver_unregister(&ar71xx_spi_drv); +} +module_exit(ar71xx_spi_exit); + +MODULE_ALIAS("platform:" DRV_NAME); +MODULE_DESCRIPTION(DRV_DESC); +MODULE_VERSION(DRV_VERSION); +MODULE_AUTHOR("Gabor Juhos <juhosg@openwrt.org>"); +MODULE_AUTHOR("Imre Kaloz <kaloz@openwrt.org>"); +MODULE_LICENSE("GPL v2"); |