2 * Atheros AR71xx SPI Controller driver
4 * Copyright (C) 2008 Gabor Juhos <juhosg@openwrt.org>
5 * Copyright (C) 2008 Imre Kaloz <kaloz@openwrt.org>
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License version 2 as
9 * published by the Free Software Foundation.
13 #include <linux/kernel.h>
14 #include <linux/init.h>
15 #include <linux/delay.h>
16 #include <linux/spinlock.h>
17 #include <linux/workqueue.h>
18 #include <linux/platform_device.h>
20 #include <linux/spi/spi.h>
21 #include <linux/spi/spi_bitbang.h>
22 #include <linux/bitops.h>
24 #include <asm/mach-ar71xx/ar71xx.h>
25 #include <asm/mach-ar71xx/platform.h>
27 #define DRV_DESC "Atheros AR71xx SPI Controller driver"
28 #define DRV_VERSION "0.2.2"
29 #define DRV_NAME "ar71xx-spi"
34 struct spi_bitbang bitbang;
40 struct platform_device *pdev;
41 u32 (*get_ioc_base)(u8 chip_select, int cs_high,
45 static inline u32 ar71xx_spi_rr(struct ar71xx_spi *sp, unsigned reg)
47 return __raw_readl(sp->base + reg);
50 static inline void ar71xx_spi_wr(struct ar71xx_spi *sp, unsigned reg, u32 val)
52 __raw_writel(val, sp->base + reg);
55 static inline struct ar71xx_spi *spidev_to_sp(struct spi_device *spi)
57 return spi_master_get_devdata(spi->master);
60 static u32 ar71xx_spi_get_ioc_base(u8 chip_select, int cs_high, int is_on)
64 if (is_on == AR71XX_SPI_CS_INACTIVE)
67 ret = SPI_IOC_CS_ALL & ~SPI_IOC_CS(chip_select);
72 static void ar71xx_spi_chipselect(struct spi_device *spi, int value)
74 struct ar71xx_spi *sp = spidev_to_sp(spi);
75 void __iomem *base = sp->base;
79 case BITBANG_CS_INACTIVE:
80 ioc_base = sp->get_ioc_base(spi->chip_select,
81 (spi->mode & SPI_CS_HIGH) != 0,
82 AR71XX_SPI_CS_INACTIVE);
84 __raw_writel(ioc_base, base + SPI_REG_IOC);
85 __raw_writel(sp->reg_ctrl, base + SPI_REG_CTRL);
86 __raw_writel(0, base + SPI_REG_FS);
89 case BITBANG_CS_ACTIVE:
90 ioc_base = sp->get_ioc_base(spi->chip_select,
91 (spi->mode & SPI_CS_HIGH) != 0,
92 AR71XX_SPI_CS_ACTIVE);
94 __raw_writel(SPI_FS_GPIO, base + SPI_REG_FS);
95 /* TODO: setup speed */
96 __raw_writel(0x43, base + SPI_REG_CTRL);
97 __raw_writel(ioc_base, base + SPI_REG_IOC);
98 sp->ioc_base = ioc_base;
103 static u32 ar71xx_spi_txrx_mode0(struct spi_device *spi, unsigned nsecs,
106 struct ar71xx_spi *sp = spidev_to_sp(spi);
107 void __iomem *base = sp->base;
108 u32 ioc = sp->ioc_base;
111 /* clock starts at inactive polarity */
112 for (word <<= (32 - bits); likely(bits); bits--) {
115 if (word & (1 << 31))
116 out = ioc | SPI_IOC_DO;
118 out = ioc & ~SPI_IOC_DO;
120 /* setup MSB (to slave) on trailing edge */
121 __raw_writel(out, base + SPI_REG_IOC);
123 __raw_writel(out | SPI_IOC_CLK, base + SPI_REG_IOC);
128 /* sample MSB (from slave) on leading edge */
129 ret = __raw_readl(base + SPI_REG_RDS);
130 __raw_writel(out, base + SPI_REG_IOC);
136 ret = __raw_readl(base + SPI_REG_RDS);
141 static int ar71xx_spi_probe(struct platform_device *pdev)
143 struct spi_master *master;
144 struct ar71xx_spi *sp;
145 struct ar71xx_spi_platform_data *pdata;
149 master = spi_alloc_master(&pdev->dev, sizeof(*sp));
150 if (master == NULL) {
151 dev_err(&pdev->dev, "failed to allocate spi master\n");
155 sp = spi_master_get_devdata(master);
156 platform_set_drvdata(pdev, sp);
158 pdata = pdev->dev.platform_data;
160 sp->bitbang.master = spi_master_get(master);
161 sp->bitbang.chipselect = ar71xx_spi_chipselect;
162 sp->bitbang.txrx_word[SPI_MODE_0] = ar71xx_spi_txrx_mode0;
164 sp->get_ioc_base = ar71xx_spi_get_ioc_base;
166 sp->bitbang.master->bus_num = pdata->bus_num;
167 sp->bitbang.master->num_chipselect = pdata->num_chipselect;
168 if (pdata->get_ioc_base)
169 sp->get_ioc_base = pdata->get_ioc_base;
171 sp->bitbang.master->bus_num = 0;
172 sp->bitbang.master->num_chipselect = 3;
175 r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
181 sp->base = ioremap_nocache(r->start, r->end - r->start + 1);
187 sp->reg_ctrl = ar71xx_spi_rr(sp, SPI_REG_IOC);
189 ret = spi_bitbang_start(&sp->bitbang);
195 platform_set_drvdata(pdev, NULL);
196 spi_master_put(sp->bitbang.master);
201 static int ar71xx_spi_remove(struct platform_device *pdev)
203 struct ar71xx_spi *sp = platform_get_drvdata(pdev);
205 spi_bitbang_stop(&sp->bitbang);
207 platform_set_drvdata(pdev, NULL);
208 spi_master_put(sp->bitbang.master);
213 static struct platform_driver ar71xx_spi_drv = {
214 .probe = ar71xx_spi_probe,
215 .remove = ar71xx_spi_remove,
218 .owner = THIS_MODULE,
222 static int __init ar71xx_spi_init(void)
224 printk(KERN_INFO DRV_DESC " version " DRV_VERSION "\n");
225 return platform_driver_register(&ar71xx_spi_drv);
227 module_init(ar71xx_spi_init);
229 static void __exit ar71xx_spi_exit(void)
231 platform_driver_unregister(&ar71xx_spi_drv);
233 module_exit(ar71xx_spi_exit);
235 MODULE_ALIAS("platform:" DRV_NAME);
236 MODULE_DESCRIPTION(DRV_DESC);
237 MODULE_VERSION(DRV_VERSION);
238 MODULE_AUTHOR("Gabor Juhos <juhosg@openwrt.org>");
239 MODULE_AUTHOR("Imre Kaloz <kaloz@openwrt.org>");
240 MODULE_LICENSE("GPL v2");