drivers/spi/spi_s3c24xx_gpio.c

   1 /* linux/drivers/spi/spi_s3c24xx_gpio.c
   2  *
   3  * Copyright (c) 2006 Ben Dooks
   4  * Copyright (c) 2006 Simtec Electronics
   5  *
   6  * S3C24XX GPIO based SPI driver
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License version 2 as
  10  * published by the Free Software Foundation.
  11  *
  12 */
  13
  14 #include <linux/kernel.h>
  15 #include <linux/init.h>
  16 #include <linux/delay.h>
  17 #include <linux/spinlock.h>
  18 #include <linux/workqueue.h>
  19 #include <linux/platform_device.h>
  20
  21 #include <linux/spi/spi.h>
  22 #include <linux/spi/spi_bitbang.h>
  23
  24 #include <asm/arch/regs-gpio.h>
  25 #include <asm/arch/spi-gpio.h>
  26 #include <asm/hardware.h>
  27
  28 struct s3c2410_spigpio {
  29         struct spi_bitbang               bitbang;
  30
  31         struct s3c2410_spigpio_info     *info;
  32         struct platform_device          *dev;
  33 };
  34
  35 static inline struct s3c2410_spigpio *spidev_to_sg(struct spi_device *spi)
  36 {
  37         return spi->controller_data;
  38 }
  39
  40 static inline void setsck(struct spi_device *dev, int on)
  41 {
  42         struct s3c2410_spigpio *sg = spidev_to_sg(dev);
  43         s3c2410_gpio_setpin(sg->info->pin_clk, on ? 1 : 0);
  44 }
  45
  46 static inline void setmosi(struct spi_device *dev, int on)
  47 {
  48         struct s3c2410_spigpio *sg = spidev_to_sg(dev);
  49         s3c2410_gpio_setpin(sg->info->pin_mosi, on ? 1 : 0);
  50 }
  51
  52 static inline u32 getmiso(struct spi_device *dev)
  53 {
  54         struct s3c2410_spigpio *sg = spidev_to_sg(dev);
  55         return s3c2410_gpio_getpin(sg->info->pin_miso) ? 1 : 0;
  56 }
  57
  58 #define spidelay(x) ndelay(x)
  59
  60 #define EXPAND_BITBANG_TXRX
  61 #include <linux/spi/spi_bitbang.h>
  62
  63
  64 static u32 s3c2410_spigpio_txrx_mode0(struct spi_device *spi,
  65                                       unsigned nsecs, u32 word, u8 bits)
  66 {
  67         return bitbang_txrx_be_cpha0(spi, nsecs, 0, word, bits);
  68 }
  69
  70 static u32 s3c2410_spigpio_txrx_mode1(struct spi_device *spi,
  71                                       unsigned nsecs, u32 word, u8 bits)
  72 {
  73         return bitbang_txrx_be_cpha1(spi, nsecs, 0, word, bits);
  74 }
  75
  76 static u32 s3c2410_spigpio_txrx_mode2(struct spi_device *spi,
  77                                       unsigned nsecs, u32 word, u8 bits)
  78 {
  79         return bitbang_txrx_be_cpha0(spi, nsecs, 1, word, bits);
  80 }
  81
  82 static u32 s3c2410_spigpio_txrx_mode3(struct spi_device *spi,
  83                                       unsigned nsecs, u32 word, u8 bits)
  84 {
  85         return bitbang_txrx_be_cpha1(spi, nsecs, 1, word, bits);
  86 }
  87
  88
  89 static void s3c2410_spigpio_chipselect(struct spi_device *dev, int value)
  90 {
  91         struct s3c2410_spigpio *sg = spidev_to_sg(dev);
  92
  93         if (sg->info && sg->info->chip_select)
  94                 (sg->info->chip_select)(sg->info, value);
  95 }
  96
  97 static int s3c2410_spigpio_probe(struct platform_device *dev)
  98 {
  99         struct s3c2410_spigpio_info *info;
 100         struct spi_master       *master;
 101         struct s3c2410_spigpio  *sp;
 102         int ret;
 103         int i;
 104
 105         master = spi_alloc_master(&dev->dev, sizeof(struct s3c2410_spigpio));
 106         if (master == NULL) {
 107                 dev_err(&dev->dev, "failed to allocate spi master\n");
 108                 ret = -ENOMEM;
 109                 goto err;
 110         }
 111
 112         sp = spi_master_get_devdata(master);
 113
 114         platform_set_drvdata(dev, sp);
 115
 116         /* copy in the plkatform data */
 117         info = sp->info = dev->dev.platform_data;
 118
 119         /* setup spi bitbang adaptor */
 120         sp->bitbang.master = spi_master_get(master);
 121         sp->bitbang.master->bus_num = info->bus_num;
 122         sp->bitbang.chipselect = s3c2410_spigpio_chipselect;
 123
 124         sp->bitbang.txrx_word[SPI_MODE_0] = s3c2410_spigpio_txrx_mode0;
 125         sp->bitbang.txrx_word[SPI_MODE_1] = s3c2410_spigpio_txrx_mode1;
 126         sp->bitbang.txrx_word[SPI_MODE_2] = s3c2410_spigpio_txrx_mode2;
 127         sp->bitbang.txrx_word[SPI_MODE_3] = s3c2410_spigpio_txrx_mode3;
 128
 129         /* set state of spi pins, always assume that the clock is
 130          * available, but do check the MOSI and MISO. */
 131         s3c2410_gpio_setpin(info->pin_clk, 0);
 132         s3c2410_gpio_cfgpin(info->pin_clk, S3C2410_GPIO_OUTPUT);
 133
 134         if (info->pin_mosi < S3C2410_GPH10) {
 135                 s3c2410_gpio_setpin(info->pin_mosi, 0);
 136                 s3c2410_gpio_cfgpin(info->pin_mosi, S3C2410_GPIO_OUTPUT);
 137         }
 138
 139         if (info->pin_miso != S3C2410_GPA0 && info->pin_miso < S3C2410_GPH10)
 140                 s3c2410_gpio_cfgpin(info->pin_miso, S3C2410_GPIO_INPUT);
 141
 142         ret = spi_bitbang_start(&sp->bitbang);
 143         if (ret)
 144                 goto err_no_bitbang;
 145
 146         /* register the chips to go with the board */
 147
 148         for (i = 0; i < sp->info->board_size; i++) {
 149                 dev_info(&dev->dev, "registering %p: %s\n",
 150                          &sp->info->board_info[i],
 151                          sp->info->board_info[i].modalias);
 152
 153                 sp->info->board_info[i].controller_data = sp;
 154                 spi_new_device(master, sp->info->board_info + i);
 155         }
 156
 157         return 0;
 158
 159  err_no_bitbang:
 160         spi_master_put(sp->bitbang.master);
 161  err:
 162         return ret;
 163
 164 }
 165
 166 static int s3c2410_spigpio_remove(struct platform_device *dev)
 167 {
 168         struct s3c2410_spigpio *sp = platform_get_drvdata(dev);
 169
 170         spi_bitbang_stop(&sp->bitbang);
 171         spi_master_put(sp->bitbang.master);
 172
 173         return 0;
 174 }
 175
 176 /* all gpio should be held over suspend/resume, so we should
 177  * not need to deal with this
 178 */
 179
 180 #define s3c2410_spigpio_suspend NULL
 181 #define s3c2410_spigpio_resume NULL
 182
 183
 184 static struct platform_driver s3c2410_spigpio_drv = {
 185         .probe          = s3c2410_spigpio_probe,
 186         .remove         = s3c2410_spigpio_remove,
 187         .suspend        = s3c2410_spigpio_suspend,
 188         .resume         = s3c2410_spigpio_resume,
 189         .driver         = {
 190                 .name   = "spi_s3c24xx_gpio",
 191                 .owner  = THIS_MODULE,
 192         },
 193 };
 194
 195 static int __init s3c2410_spigpio_init(void)
 196 {
 197         return platform_driver_register(&s3c2410_spigpio_drv);
 198 }
 199
 200 static void __exit s3c2410_spigpio_exit(void)
 201 {
 202         platform_driver_unregister(&s3c2410_spigpio_drv);
 203 }
 204
 205 module_init(s3c2410_spigpio_init);
 206 module_exit(s3c2410_spigpio_exit);
 207
 208 MODULE_DESCRIPTION("S3C24XX SPI Driver");
 209 MODULE_AUTHOR("Ben Dooks, <ben@simtec.co.uk>");
 210 MODULE_LICENSE("GPL");