2 * Atheros AR71xx SPI Controller driver
4 * Copyright (C) 2008-2009 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 "0.2.4"
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);
83 __raw_writel(ioc_base, base + SPI_REG_IOC);
86 case BITBANG_CS_ACTIVE:
87 ioc_base = sp->get_ioc_base(spi->chip_select,
88 (spi->mode & SPI_CS_HIGH) != 0,
89 AR71XX_SPI_CS_ACTIVE);
91 __raw_writel(ioc_base, base + SPI_REG_IOC);
92 sp->ioc_base = ioc_base;
97 static void ar71xx_spi_setup_regs(struct spi_device *spi)
99 struct ar71xx_spi *sp = spidev_to_sp(spi);
101 /* enable GPIO mode */
102 ar71xx_spi_wr(sp, SPI_REG_FS, SPI_FS_GPIO);
104 /* save CTRL register */
105 sp->reg_ctrl = ar71xx_spi_rr(sp, SPI_REG_CTRL);
107 /* TODO: setup speed? */
108 ar71xx_spi_wr(sp, SPI_REG_CTRL, 0x43);
111 static void ar71xx_spi_restore_regs(struct spi_device *spi)
113 struct ar71xx_spi *sp = spidev_to_sp(spi);
115 /* restore CTRL register */
116 ar71xx_spi_wr(sp, SPI_REG_CTRL, sp->reg_ctrl);
117 /* disable GPIO mode */
118 ar71xx_spi_wr(sp, SPI_REG_FS, 0);
121 static int ar71xx_spi_setup(struct spi_device *spi)
125 if (spi->bits_per_word > 32)
128 if (!spi->controller_state)
129 ar71xx_spi_setup_regs(spi);
131 status = spi_bitbang_setup(spi);
132 if (status && !spi->controller_state)
133 ar71xx_spi_restore_regs(spi);
138 static void ar71xx_spi_cleanup(struct spi_device *spi)
140 ar71xx_spi_restore_regs(spi);
141 spi_bitbang_cleanup(spi);
144 static u32 ar71xx_spi_txrx_mode0(struct spi_device *spi, unsigned nsecs,
147 struct ar71xx_spi *sp = spidev_to_sp(spi);
148 void __iomem *base = sp->base;
149 u32 ioc = sp->ioc_base;
152 /* clock starts at inactive polarity */
153 for (word <<= (32 - bits); likely(bits); bits--) {
156 if (word & (1 << 31))
157 out = ioc | SPI_IOC_DO;
159 out = ioc & ~SPI_IOC_DO;
161 /* setup MSB (to slave) on trailing edge */
162 __raw_writel(out, base + SPI_REG_IOC);
164 __raw_writel(out | SPI_IOC_CLK, base + SPI_REG_IOC);
169 /* sample MSB (from slave) on leading edge */
170 ret = __raw_readl(base + SPI_REG_RDS);
171 __raw_writel(out, base + SPI_REG_IOC);
177 ret = __raw_readl(base + SPI_REG_RDS);
182 static int ar71xx_spi_probe(struct platform_device *pdev)
184 struct spi_master *master;
185 struct ar71xx_spi *sp;
186 struct ar71xx_spi_platform_data *pdata;
190 master = spi_alloc_master(&pdev->dev, sizeof(*sp));
191 if (master == NULL) {
192 dev_err(&pdev->dev, "failed to allocate spi master\n");
196 sp = spi_master_get_devdata(master);
197 platform_set_drvdata(pdev, sp);
199 pdata = pdev->dev.platform_data;
201 master->setup = ar71xx_spi_setup;
202 master->cleanup = ar71xx_spi_cleanup;
204 sp->bitbang.master = spi_master_get(master);
205 sp->bitbang.chipselect = ar71xx_spi_chipselect;
206 sp->bitbang.txrx_word[SPI_MODE_0] = ar71xx_spi_txrx_mode0;
207 sp->bitbang.setup_transfer = spi_bitbang_setup_transfer;
209 sp->get_ioc_base = ar71xx_spi_get_ioc_base;
211 sp->bitbang.master->bus_num = pdata->bus_num;
212 sp->bitbang.master->num_chipselect = pdata->num_chipselect;
213 if (pdata->get_ioc_base)
214 sp->get_ioc_base = pdata->get_ioc_base;
216 sp->bitbang.master->bus_num = 0;
217 sp->bitbang.master->num_chipselect = 3;
220 r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
226 sp->base = ioremap_nocache(r->start, r->end - r->start + 1);
232 ret = spi_bitbang_start(&sp->bitbang);
238 platform_set_drvdata(pdev, NULL);
239 spi_master_put(sp->bitbang.master);
244 static int ar71xx_spi_remove(struct platform_device *pdev)
246 struct ar71xx_spi *sp = platform_get_drvdata(pdev);
248 spi_bitbang_stop(&sp->bitbang);
250 platform_set_drvdata(pdev, NULL);
251 spi_master_put(sp->bitbang.master);
256 static struct platform_driver ar71xx_spi_drv = {
257 .probe = ar71xx_spi_probe,
258 .remove = ar71xx_spi_remove,
261 .owner = THIS_MODULE,
265 static int __init ar71xx_spi_init(void)
267 printk(KERN_INFO DRV_DESC " version " DRV_VERSION "\n");
268 return platform_driver_register(&ar71xx_spi_drv);
270 module_init(ar71xx_spi_init);
272 static void __exit ar71xx_spi_exit(void)
274 platform_driver_unregister(&ar71xx_spi_drv);
276 module_exit(ar71xx_spi_exit);
278 MODULE_ALIAS("platform:" DRV_NAME);
279 MODULE_DESCRIPTION(DRV_DESC);
280 MODULE_VERSION(DRV_VERSION);
281 MODULE_AUTHOR("Gabor Juhos <juhosg@openwrt.org>");
282 MODULE_AUTHOR("Imre Kaloz <kaloz@openwrt.org>");
283 MODULE_LICENSE("GPL v2");