target/linux/ar71xx/files/drivers/spi/ap83_spi.c

   1 /*
   2  * Atheros AP83 board specific SPI Controller driver
   3  *
   4  * Copyright (C) 2009 Gabor Juhos <juhosg@openwrt.org>
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2 as
   8  * published by the Free Software Foundation.
   9  *
  10  */
  11
  12 #include <linux/kernel.h>
  13 #include <linux/init.h>
  14 #include <linux/delay.h>
  15 #include <linux/spinlock.h>
  16 #include <linux/workqueue.h>
  17 #include <linux/platform_device.h>
  18 #include <linux/io.h>
  19 #include <linux/spi/spi.h>
  20 #include <linux/spi/spi_bitbang.h>
  21 #include <linux/bitops.h>
  22 #include <linux/gpio.h>
  23
  24 #include <asm/mach-ar71xx/ar71xx.h>
  25 #include <asm/mach-ar71xx/platform.h>
  26
  27 #define DRV_DESC        "Atheros AP83 board SPI Controller driver"
  28 #define DRV_VERSION     "0.1.0"
  29 #define DRV_NAME        "ap83-spi"
  30
  31 #define AP83_SPI_CLK_HIGH       (1 << 23)
  32 #define AP83_SPI_CLK_LOW        0
  33 #define AP83_SPI_MOSI_HIGH      (1 << 22)
  34 #define AP83_SPI_MOSI_LOW       0
  35
  36 #define AP83_SPI_GPIO_CS        1
  37 #define AP83_SPI_GPIO_MISO      3
  38
  39 struct ap83_spi {
  40         struct  spi_bitbang     bitbang;
  41         void __iomem            *base;
  42         u32                     addr;
  43
  44         struct platform_device  *pdev;
  45 };
  46
  47 static inline u32 ap83_spi_rr(struct ap83_spi *sp, u32 reg)
  48 {
  49         return __raw_readl(sp->base + reg);
  50 }
  51
  52 static inline struct ap83_spi *spidev_to_sp(struct spi_device *spi)
  53 {
  54         return spi_master_get_devdata(spi->master);
  55 }
  56
  57 static inline void setsck(struct spi_device *spi, int val)
  58 {
  59         struct ap83_spi *sp = spidev_to_sp(spi);
  60
  61         if (val)
  62                 sp->addr |= AP83_SPI_CLK_HIGH;
  63         else
  64                 sp->addr &= ~AP83_SPI_CLK_HIGH;
  65
  66         dev_dbg(&spi->dev, "addr=%08x,  SCK set to %s\n",
  67                 sp->addr, (val) ? "HIGH" : "LOW");
  68
  69         ap83_spi_rr(sp, sp->addr);
  70 }
  71
  72 static inline void setmosi(struct spi_device *spi, int val)
  73 {
  74         struct ap83_spi *sp = spidev_to_sp(spi);
  75
  76         if (val)
  77                 sp->addr |= AP83_SPI_MOSI_HIGH;
  78         else
  79                 sp->addr &= ~AP83_SPI_MOSI_HIGH;
  80
  81         dev_dbg(&spi->dev, "addr=%08x, MOSI set to %s\n",
  82                 sp->addr, (val) ? "HIGH" : "LOW");
  83
  84         ap83_spi_rr(sp, sp->addr);
  85 }
  86
  87 static inline u32 getmiso(struct spi_device *spi)
  88 {
  89         u32 ret;
  90
  91         ret = gpio_get_value(AP83_SPI_GPIO_MISO) ? 1 : 0;
  92         dev_dbg(&spi->dev, "get MISO: %d\n", ret);
  93
  94         return ret;
  95 }
  96
  97 static inline void do_spidelay(struct spi_device *spi, unsigned nsecs)
  98 {
  99         ndelay(nsecs);
 100 }
 101
 102 static void ap83_spi_chipselect(struct spi_device *spi, int on)
 103 {
 104         struct ap83_spi *sp = spidev_to_sp(spi);
 105
 106         dev_dbg(&spi->dev, "set CS to %d\n", (on) ? 0 : 1);
 107
 108         if (on) {
 109                 ar71xx_flash_acquire();
 110
 111                 sp->addr = 0;
 112                 ap83_spi_rr(sp, sp->addr);
 113
 114                 gpio_set_value(AP83_SPI_GPIO_CS, 0);
 115         } else {
 116                 gpio_set_value(AP83_SPI_GPIO_CS, 1);
 117                 ar71xx_flash_release();
 118         }
 119 }
 120
 121 #define spidelay(nsecs)                                                 \
 122         do {                                                            \
 123                 /* Steal the spi_device pointer from our caller.        \
 124                  * The bitbang-API should probably get fixed here... */ \
 125                 do_spidelay(spi, nsecs);                                \
 126         } while (0)
 127
 128 #define EXPAND_BITBANG_TXRX
 129 #include <linux/spi/spi_bitbang.h>
 130 #include "spi_bitbang_txrx.h"
 131
 132 static u32 ap83_spi_txrx_mode0(struct spi_device *spi,
 133                                unsigned nsecs, u32 word, u8 bits)
 134 {
 135         dev_dbg(&spi->dev, "TXRX0 word=%08x, bits=%u\n", word, bits);
 136         return bitbang_txrx_be_cpha0(spi, nsecs, 0, 0, word, bits);
 137 }
 138
 139 static u32 ap83_spi_txrx_mode1(struct spi_device *spi,
 140                                unsigned nsecs, u32 word, u8 bits)
 141 {
 142         dev_dbg(&spi->dev, "TXRX1 word=%08x, bits=%u\n", word, bits);
 143         return bitbang_txrx_be_cpha1(spi, nsecs, 0, 0, word, bits);
 144 }
 145
 146 static u32 ap83_spi_txrx_mode2(struct spi_device *spi,
 147                                unsigned nsecs, u32 word, u8 bits)
 148 {
 149         dev_dbg(&spi->dev, "TXRX2 word=%08x, bits=%u\n", word, bits);
 150         return bitbang_txrx_be_cpha0(spi, nsecs, 1, 0, word, bits);
 151 }
 152
 153 static u32 ap83_spi_txrx_mode3(struct spi_device *spi,
 154                                unsigned nsecs, u32 word, u8 bits)
 155 {
 156         dev_dbg(&spi->dev, "TXRX3 word=%08x, bits=%u\n", word, bits);
 157         return bitbang_txrx_be_cpha1(spi, nsecs, 1, 0, word, bits);
 158 }
 159
 160 static int ap83_spi_probe(struct platform_device *pdev)
 161 {
 162         struct spi_master *master;
 163         struct ap83_spi *sp;
 164         struct ap83_spi_platform_data *pdata;
 165         struct resource *r;
 166         int ret;
 167
 168         ret = gpio_request(AP83_SPI_GPIO_MISO, "spi-miso");
 169         if (ret) {
 170                 dev_err(&pdev->dev, "gpio request failed for MISO\n");
 171                 return ret;
 172         }
 173
 174         ret = gpio_request(AP83_SPI_GPIO_CS, "spi-cs");
 175         if (ret) {
 176                 dev_err(&pdev->dev, "gpio request failed for CS\n");
 177                 goto err_free_miso;
 178         }
 179
 180         ret = gpio_direction_input(AP83_SPI_GPIO_MISO);
 181         if (ret) {
 182                 dev_err(&pdev->dev, "unable to set direction of MISO\n");
 183                 goto err_free_cs;
 184         }
 185
 186         ret = gpio_direction_output(AP83_SPI_GPIO_CS, 0);
 187         if (ret) {
 188                 dev_err(&pdev->dev, "unable to set direction of CS\n");
 189                 goto err_free_cs;
 190         }
 191
 192         master = spi_alloc_master(&pdev->dev, sizeof(*sp));
 193         if (master == NULL) {
 194                 dev_err(&pdev->dev, "failed to allocate spi master\n");
 195                 return -ENOMEM;
 196         }
 197
 198         sp = spi_master_get_devdata(master);
 199         platform_set_drvdata(pdev, sp);
 200
 201         pdata = pdev->dev.platform_data;
 202
 203         sp->bitbang.master = spi_master_get(master);
 204         sp->bitbang.chipselect = ap83_spi_chipselect;
 205         sp->bitbang.txrx_word[SPI_MODE_0] = ap83_spi_txrx_mode0;
 206         sp->bitbang.txrx_word[SPI_MODE_1] = ap83_spi_txrx_mode1;
 207         sp->bitbang.txrx_word[SPI_MODE_2] = ap83_spi_txrx_mode2;
 208         sp->bitbang.txrx_word[SPI_MODE_3] = ap83_spi_txrx_mode3;
 209
 210         sp->bitbang.master->bus_num = pdev->id;
 211         sp->bitbang.master->num_chipselect = 1;
 212
 213         r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 214         if (r == NULL) {
 215                 ret = -ENOENT;
 216                 goto err_spi_put;
 217         }
 218
 219         sp->base = ioremap_nocache(r->start, r->end - r->start + 1);
 220         if (!sp->base) {
 221                 ret = -ENXIO;
 222                 goto err_spi_put;
 223         }
 224
 225         ret = spi_bitbang_start(&sp->bitbang);
 226         if (!ret)
 227                 goto err_unmap;
 228
 229         dev_info(&pdev->dev, "AP83 SPI adapter at %08x\n", r->start);
 230
 231         return 0;
 232
 233  err_unmap:
 234         iounmap(sp->base);
 235  err_spi_put:
 236         platform_set_drvdata(pdev, NULL);
 237         spi_master_put(sp->bitbang.master);
 238
 239  err_free_cs:
 240         gpio_free(AP83_SPI_GPIO_CS);
 241  err_free_miso:
 242         gpio_free(AP83_SPI_GPIO_MISO);
 243         return ret;
 244 }
 245
 246 static int ap83_spi_remove(struct platform_device *pdev)
 247 {
 248         struct ap83_spi *sp = platform_get_drvdata(pdev);
 249
 250         spi_bitbang_stop(&sp->bitbang);
 251         iounmap(sp->base);
 252         platform_set_drvdata(pdev, NULL);
 253         spi_master_put(sp->bitbang.master);
 254
 255         return 0;
 256 }
 257
 258 static struct platform_driver ap83_spi_drv = {
 259         .probe          = ap83_spi_probe,
 260         .remove         = ap83_spi_remove,
 261         .driver         = {
 262                 .name   = DRV_NAME,
 263                 .owner  = THIS_MODULE,
 264         },
 265 };
 266
 267 static int __init ap83_spi_init(void)
 268 {
 269         return platform_driver_register(&ap83_spi_drv);
 270 }
 271 module_init(ap83_spi_init);
 272
 273 static void __exit ap83_spi_exit(void)
 274 {
 275         platform_driver_unregister(&ap83_spi_drv);
 276 }
 277 module_exit(ap83_spi_exit);
 278
 279 MODULE_ALIAS("platform:" DRV_NAME);
 280 MODULE_DESCRIPTION(DRV_DESC);
 281 MODULE_VERSION(DRV_VERSION);
 282 MODULE_AUTHOR("Gabor Juhos <juhosg@openwrt.org>");
 283 MODULE_LICENSE("GPL v2");