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 #include <linux/gpio.h>
  21
  22 #include <linux/spi/spi.h>
  23 #include <linux/spi/spi_bitbang.h>
  24
  25 #include <mach/regs-gpio.h>
  26 #include <mach/spi-gpio.h>
  27 #include <mach/hardware.h>
  28
  29 struct s3c2410_spigpio {
  30         struct spi_bitbang               bitbang;
  31
  32         struct s3c2410_spigpio_info     *info;
  33         struct platform_device          *dev;
  34 };
  35
  36 static inline struct s3c2410_spigpio *spidev_to_sg(struct spi_device *spi)
  37 {
  38         return spi_master_get_devdata(spi->master);
  39 }
  40
  41 static inline void setsck(struct spi_device *dev, int on)
  42 {
  43         struct s3c2410_spigpio *sg = spidev_to_sg(dev);
  44         s3c2410_gpio_setpin(sg->info->pin_clk, on ? 1 : 0);
  45 }
  46
  47 static inline void setmosi(struct spi_device *dev, int on)
  48 {
  49         struct s3c2410_spigpio *sg = spidev_to_sg(dev);
  50         s3c2410_gpio_setpin(sg->info->pin_mosi, on ? 1 : 0);
  51 }
  52
  53 static inline u32 getmiso(struct spi_device *dev)
  54 {
  55         struct s3c2410_spigpio *sg = spidev_to_sg(dev);
  56         return s3c2410_gpio_getpin(sg->info->pin_miso) ? 1 : 0;
  57 }
  58
  59 #define spidelay(x) ndelay(x)
  60
  61 #define EXPAND_BITBANG_TXRX
  62 #include <linux/spi/spi_bitbang.h>
  63
  64
  65 static u32 s3c2410_spigpio_txrx_mode0(struct spi_device *spi,
  66                                       unsigned nsecs, u32 word, u8 bits)
  67 {
  68         return bitbang_txrx_be_cpha0(spi, nsecs, 0, word, bits);
  69 }
  70
  71 static u32 s3c2410_spigpio_txrx_mode1(struct spi_device *spi,
  72                                       unsigned nsecs, u32 word, u8 bits)
  73 {
  74         return bitbang_txrx_be_cpha1(spi, nsecs, 0, word, bits);
  75 }
  76
  77 static u32 s3c2410_spigpio_txrx_mode2(struct spi_device *spi,
  78                                       unsigned nsecs, u32 word, u8 bits)
  79 {
  80         return bitbang_txrx_be_cpha0(spi, nsecs, 1, word, bits);
  81 }
  82
  83 static u32 s3c2410_spigpio_txrx_mode3(struct spi_device *spi,
  84                                       unsigned nsecs, u32 word, u8 bits)
  85 {
  86         return bitbang_txrx_be_cpha1(spi, nsecs, 1, word, bits);
  87 }
  88
  89
  90 static void s3c2410_spigpio_chipselect(struct spi_device *dev, int value)
  91 {
  92         struct s3c2410_spigpio *sg = spidev_to_sg(dev);
  93
  94         if (sg->info && sg->info->chip_select)
  95                 (sg->info->chip_select)(sg->info, value);
  96 }
  97
  98 static int s3c2410_spigpio_probe(struct platform_device *dev)
  99 {
 100         struct s3c2410_spigpio_info *info;
 101         struct spi_master       *master;
 102         struct s3c2410_spigpio  *sp;
 103         int ret;
 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.master->num_chipselect = info->num_chipselect;
 123         sp->bitbang.chipselect = s3c2410_spigpio_chipselect;
 124
 125         sp->bitbang.txrx_word[SPI_MODE_0] = s3c2410_spigpio_txrx_mode0;
 126         sp->bitbang.txrx_word[SPI_MODE_1] = s3c2410_spigpio_txrx_mode1;
 127         sp->bitbang.txrx_word[SPI_MODE_2] = s3c2410_spigpio_txrx_mode2;
 128         sp->bitbang.txrx_word[SPI_MODE_3] = s3c2410_spigpio_txrx_mode3;
 129
 130         /* set state of spi pins, always assume that the clock is
 131          * available, but do check the MOSI and MISO. */
 132         s3c2410_gpio_setpin(info->pin_clk, 0);
 133         s3c2410_gpio_cfgpin(info->pin_clk, S3C2410_GPIO_OUTPUT);
 134
 135         if (info->pin_mosi < S3C2410_GPH10) {
 136                 s3c2410_gpio_setpin(info->pin_mosi, 0);
 137                 s3c2410_gpio_cfgpin(info->pin_mosi, S3C2410_GPIO_OUTPUT);
 138         }
 139
 140         if (info->pin_miso != S3C2410_GPA0 && info->pin_miso < S3C2410_GPH10)
 141                 s3c2410_gpio_cfgpin(info->pin_miso, S3C2410_GPIO_INPUT);
 142
 143         ret = spi_bitbang_start(&sp->bitbang);
 144         if (ret)
 145                 goto err_no_bitbang;
 146
 147         return 0;
 148
 149  err_no_bitbang:
 150         spi_master_put(sp->bitbang.master);
 151  err:
 152         return ret;
 153
 154 }
 155
 156 static int s3c2410_spigpio_remove(struct platform_device *dev)
 157 {
 158         struct s3c2410_spigpio *sp = platform_get_drvdata(dev);
 159
 160         spi_bitbang_stop(&sp->bitbang);
 161         spi_master_put(sp->bitbang.master);
 162
 163         return 0;
 164 }
 165
 166 /* all gpio should be held over suspend/resume, so we should
 167  * not need to deal with this
 168 */
 169
 170 #define s3c2410_spigpio_suspend NULL
 171 #define s3c2410_spigpio_resume NULL
 172
 173 /* work with hotplug and coldplug */
 174 MODULE_ALIAS("platform:spi_s3c24xx_gpio");
 175
 176 static struct platform_driver s3c2410_spigpio_drv = {
 177         .probe          = s3c2410_spigpio_probe,
 178         .remove         = s3c2410_spigpio_remove,
 179         .suspend        = s3c2410_spigpio_suspend,
 180         .resume         = s3c2410_spigpio_resume,
 181         .driver         = {
 182                 .name   = "spi_s3c24xx_gpio",
 183                 .owner  = THIS_MODULE,
 184         },
 185 };
 186
 187 static int __init s3c2410_spigpio_init(void)
 188 {
 189         return platform_driver_register(&s3c2410_spigpio_drv);
 190 }
 191
 192 static void __exit s3c2410_spigpio_exit(void)
 193 {
 194         platform_driver_unregister(&s3c2410_spigpio_drv);
 195 }
 196
 197 module_init(s3c2410_spigpio_init);
 198 module_exit(s3c2410_spigpio_exit);
 199
 200 MODULE_DESCRIPTION("S3C24XX SPI Driver");
 201 MODULE_AUTHOR("Ben Dooks, <ben@simtec.co.uk>");
 202 MODULE_LICENSE("GPL");