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/platform_device.h>
  19
  20 #include <linux/spi/spi.h>
  21 #include <linux/spi/spi_bitbang.h>
  22
  23 #include <asm/arch/regs-gpio.h>
  24 #include <asm/arch/spi-gpio.h>
  25 #include <asm/arch/hardware.h>
  26
  27 struct s3c2410_spigpio {
  28         struct spi_bitbang               bitbang;
  29
  30         struct s3c2410_spigpio_info     *info;
  31         struct platform_device          *dev;
  32 };
  33
  34 static inline struct s3c2410_spigpio *spidev_to_sg(struct spi_device *spi)
  35 {
  36         return spi->controller_data;
  37 }
  38
  39 static inline void setsck(struct spi_device *dev, int on)
  40 {
  41         struct s3c2410_spigpio *sg = spidev_to_sg(dev);
  42         s3c2410_gpio_setpin(sg->info->pin_clk, on ? 1 : 0);
  43 }
  44
  45 static inline void setmosi(struct spi_device *dev, int on)
  46 {
  47         struct s3c2410_spigpio *sg = spidev_to_sg(dev);
  48         s3c2410_gpio_setpin(sg->info->pin_mosi, on ? 1 : 0);
  49 }
  50
  51 static inline u32 getmiso(struct spi_device *dev)
  52 {
  53         struct s3c2410_spigpio *sg = spidev_to_sg(dev);
  54         return s3c2410_gpio_getpin(sg->info->pin_miso) ? 1 : 0;
  55 }
  56
  57 #define spidelay(x) ndelay(x)
  58
  59 #define EXPAND_BITBANG_TXRX
  60 #include <linux/spi/spi_bitbang.h>
  61
  62
  63 static u32 s3c2410_spigpio_txrx_mode0(struct spi_device *spi,
  64                                       unsigned nsecs, u32 word, u8 bits)
  65 {
  66         return bitbang_txrx_be_cpha0(spi, nsecs, 0, word, bits);
  67 }
  68
  69 static u32 s3c2410_spigpio_txrx_mode1(struct spi_device *spi,
  70                                       unsigned nsecs, u32 word, u8 bits)
  71 {
  72         return bitbang_txrx_be_cpha1(spi, nsecs, 0, word, bits);
  73 }
  74
  75 static void s3c2410_spigpio_chipselect(struct spi_device *dev, int value)
  76 {
  77         struct s3c2410_spigpio *sg = spidev_to_sg(dev);
  78
  79         if (sg->info && sg->info->chip_select)
  80                 (sg->info->chip_select)(sg->info, value);
  81 }
  82
  83 static int s3c2410_spigpio_probe(struct platform_device *dev)
  84 {
  85         struct spi_master       *master;
  86         struct s3c2410_spigpio  *sp;
  87         int ret;
  88         int i;
  89
  90         master = spi_alloc_master(&dev->dev, sizeof(struct s3c2410_spigpio));
  91         if (master == NULL) {
  92                 dev_err(&dev->dev, "failed to allocate spi master\n");
  93                 ret = -ENOMEM;
  94                 goto err;
  95         }
  96
  97         sp = spi_master_get_devdata(master);
  98
  99         platform_set_drvdata(dev, sp);
 100
 101         /* copy in the plkatform data */
 102         sp->info = dev->dev.platform_data;
 103
 104         /* setup spi bitbang adaptor */
 105         sp->bitbang.master = spi_master_get(master);
 106         sp->bitbang.chipselect = s3c2410_spigpio_chipselect;
 107
 108         sp->bitbang.txrx_word[SPI_MODE_0] = s3c2410_spigpio_txrx_mode0;
 109         sp->bitbang.txrx_word[SPI_MODE_1] = s3c2410_spigpio_txrx_mode1;
 110
 111         /* set state of spi pins */
 112         s3c2410_gpio_setpin(sp->info->pin_clk, 0);
 113         s3c2410_gpio_setpin(sp->info->pin_mosi, 0);
 114
 115         s3c2410_gpio_cfgpin(sp->info->pin_clk, S3C2410_GPIO_OUTPUT);
 116         s3c2410_gpio_cfgpin(sp->info->pin_mosi, S3C2410_GPIO_OUTPUT);
 117         s3c2410_gpio_cfgpin(sp->info->pin_miso, S3C2410_GPIO_INPUT);
 118
 119         ret = spi_bitbang_start(&sp->bitbang);
 120         if (ret)
 121                 goto err_no_bitbang;
 122
 123         /* register the chips to go with the board */
 124
 125         for (i = 0; i < sp->info->board_size; i++) {
 126                 dev_info(&dev->dev, "registering %p: %s\n",
 127                          &sp->info->board_info[i],
 128                          sp->info->board_info[i].modalias);
 129
 130                 sp->info->board_info[i].controller_data = sp;
 131                 spi_new_device(master, sp->info->board_info + i);
 132         }
 133
 134         return 0;
 135
 136  err_no_bitbang:
 137         spi_master_put(sp->bitbang.master);
 138  err:
 139         return ret;
 140
 141 }
 142
 143 static int s3c2410_spigpio_remove(struct platform_device *dev)
 144 {
 145         struct s3c2410_spigpio *sp = platform_get_drvdata(dev);
 146
 147         spi_bitbang_stop(&sp->bitbang);
 148         spi_master_put(sp->bitbang.master);
 149
 150         return 0;
 151 }
 152
 153 /* all gpio should be held over suspend/resume, so we should
 154  * not need to deal with this
 155 */
 156
 157 #define s3c2410_spigpio_suspend NULL
 158 #define s3c2410_spigpio_resume NULL
 159
 160
 161 static struct platform_driver s3c2410_spigpio_drv = {
 162         .probe          = s3c2410_spigpio_probe,
 163         .remove         = s3c2410_spigpio_remove,
 164         .suspend        = s3c2410_spigpio_suspend,
 165         .resume         = s3c2410_spigpio_resume,
 166         .driver         = {
 167                 .name   = "s3c24xx-spi-gpio",
 168                 .owner  = THIS_MODULE,
 169         },
 170 };
 171
 172 static int __init s3c2410_spigpio_init(void)
 173 {
 174         return platform_driver_register(&s3c2410_spigpio_drv);
 175 }
 176
 177 static void __exit s3c2410_spigpio_exit(void)
 178 {
 179         platform_driver_unregister(&s3c2410_spigpio_drv);
 180 }
 181
 182 module_init(s3c2410_spigpio_init);
 183 module_exit(s3c2410_spigpio_exit);
 184
 185 MODULE_DESCRIPTION("S3C24XX SPI Driver");
 186 MODULE_AUTHOR("Ben Dooks, <ben@simtec.co.uk>");
 187 MODULE_LICENSE("GPL");