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 void s3c2410_spigpio_chipselect(struct spi_device *dev, int value)
  77 {
  78         struct s3c2410_spigpio *sg = spidev_to_sg(dev);
  79
  80         if (sg->info && sg->info->chip_select)
  81                 (sg->info->chip_select)(sg->info, value);
  82 }
  83
  84 static int s3c2410_spigpio_probe(struct platform_device *dev)
  85 {
  86         struct spi_master       *master;
  87         struct s3c2410_spigpio  *sp;
  88         int ret;
  89         int i;
  90
  91         master = spi_alloc_master(&dev->dev, sizeof(struct s3c2410_spigpio));
  92         if (master == NULL) {
  93                 dev_err(&dev->dev, "failed to allocate spi master\n");
  94                 ret = -ENOMEM;
  95                 goto err;
  96         }
  97
  98         sp = spi_master_get_devdata(master);
  99
 100         platform_set_drvdata(dev, sp);
 101
 102         /* copy in the plkatform data */
 103         sp->info = dev->dev.platform_data;
 104
 105         /* setup spi bitbang adaptor */
 106         sp->bitbang.master = spi_master_get(master);
 107         sp->bitbang.chipselect = s3c2410_spigpio_chipselect;
 108
 109         sp->bitbang.txrx_word[SPI_MODE_0] = s3c2410_spigpio_txrx_mode0;
 110         sp->bitbang.txrx_word[SPI_MODE_1] = s3c2410_spigpio_txrx_mode1;
 111
 112         /* set state of spi pins */
 113         s3c2410_gpio_setpin(sp->info->pin_clk, 0);
 114         s3c2410_gpio_setpin(sp->info->pin_mosi, 0);
 115
 116         s3c2410_gpio_cfgpin(sp->info->pin_clk, S3C2410_GPIO_OUTPUT);
 117         s3c2410_gpio_cfgpin(sp->info->pin_mosi, S3C2410_GPIO_OUTPUT);
 118         s3c2410_gpio_cfgpin(sp->info->pin_miso, S3C2410_GPIO_INPUT);
 119
 120         ret = spi_bitbang_start(&sp->bitbang);
 121         if (ret)
 122                 goto err_no_bitbang;
 123
 124         /* register the chips to go with the board */
 125
 126         for (i = 0; i < sp->info->board_size; i++) {
 127                 dev_info(&dev->dev, "registering %p: %s\n",
 128                          &sp->info->board_info[i],
 129                          sp->info->board_info[i].modalias);
 130
 131                 sp->info->board_info[i].controller_data = sp;
 132                 spi_new_device(master, sp->info->board_info + i);
 133         }
 134
 135         return 0;
 136
 137  err_no_bitbang:
 138         spi_master_put(sp->bitbang.master);
 139  err:
 140         return ret;
 141
 142 }
 143
 144 static int s3c2410_spigpio_remove(struct platform_device *dev)
 145 {
 146         struct s3c2410_spigpio *sp = platform_get_drvdata(dev);
 147
 148         spi_bitbang_stop(&sp->bitbang);
 149         spi_master_put(sp->bitbang.master);
 150
 151         return 0;
 152 }
 153
 154 /* all gpio should be held over suspend/resume, so we should
 155  * not need to deal with this
 156 */
 157
 158 #define s3c2410_spigpio_suspend NULL
 159 #define s3c2410_spigpio_resume NULL
 160
 161
 162 static struct platform_driver s3c2410_spigpio_drv = {
 163         .probe          = s3c2410_spigpio_probe,
 164         .remove         = s3c2410_spigpio_remove,
 165         .suspend        = s3c2410_spigpio_suspend,
 166         .resume         = s3c2410_spigpio_resume,
 167         .driver         = {
 168                 .name   = "s3c24xx-spi-gpio",
 169                 .owner  = THIS_MODULE,
 170         },
 171 };
 172
 173 static int __init s3c2410_spigpio_init(void)
 174 {
 175         return platform_driver_register(&s3c2410_spigpio_drv);
 176 }
 177
 178 static void __exit s3c2410_spigpio_exit(void)
 179 {
 180         platform_driver_unregister(&s3c2410_spigpio_drv);
 181 }
 182
 183 module_init(s3c2410_spigpio_init);
 184 module_exit(s3c2410_spigpio_exit);
 185
 186 MODULE_DESCRIPTION("S3C24XX SPI Driver");
 187 MODULE_AUTHOR("Ben Dooks, <ben@simtec.co.uk>");
 188 MODULE_LICENSE("GPL");