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
 104         master = spi_alloc_master(&dev->dev, sizeof(struct s3c2410_spigpio));
 105         if (master == NULL) {
 106                 dev_err(&dev->dev, "failed to allocate spi master\n");
 107                 ret = -ENOMEM;
 108                 goto err;
 109         }
 110
 111         sp = spi_master_get_devdata(master);
 112
 113         platform_set_drvdata(dev, sp);
 114
 115         /* copy in the plkatform data */
 116         info = sp->info = dev->dev.platform_data;
 117
 118         /* setup spi bitbang adaptor */
 119         sp->bitbang.master = spi_master_get(master);
 120         sp->bitbang.master->bus_num = info->bus_num;
 121         sp->bitbang.chipselect = s3c2410_spigpio_chipselect;
 122
 123         sp->bitbang.txrx_word[SPI_MODE_0] = s3c2410_spigpio_txrx_mode0;
 124         sp->bitbang.txrx_word[SPI_MODE_1] = s3c2410_spigpio_txrx_mode1;
 125         sp->bitbang.txrx_word[SPI_MODE_2] = s3c2410_spigpio_txrx_mode2;
 126         sp->bitbang.txrx_word[SPI_MODE_3] = s3c2410_spigpio_txrx_mode3;
 127
 128         /* set state of spi pins, always assume that the clock is
 129          * available, but do check the MOSI and MISO. */
 130         s3c2410_gpio_setpin(info->pin_clk, 0);
 131         s3c2410_gpio_cfgpin(info->pin_clk, S3C2410_GPIO_OUTPUT);
 132
 133         if (info->pin_mosi < S3C2410_GPH10) {
 134                 s3c2410_gpio_setpin(info->pin_mosi, 0);
 135                 s3c2410_gpio_cfgpin(info->pin_mosi, S3C2410_GPIO_OUTPUT);
 136         }
 137
 138         if (info->pin_miso != S3C2410_GPA0 && info->pin_miso < S3C2410_GPH10)
 139                 s3c2410_gpio_cfgpin(info->pin_miso, S3C2410_GPIO_INPUT);
 140
 141         ret = spi_bitbang_start(&sp->bitbang);
 142         if (ret)
 143                 goto err_no_bitbang;
 144
 145         return 0;
 146
 147  err_no_bitbang:
 148         spi_master_put(sp->bitbang.master);
 149  err:
 150         return ret;
 151
 152 }
 153
 154 static int s3c2410_spigpio_remove(struct platform_device *dev)
 155 {
 156         struct s3c2410_spigpio *sp = platform_get_drvdata(dev);
 157
 158         spi_bitbang_stop(&sp->bitbang);
 159         spi_master_put(sp->bitbang.master);
 160
 161         return 0;
 162 }
 163
 164 /* all gpio should be held over suspend/resume, so we should
 165  * not need to deal with this
 166 */
 167
 168 #define s3c2410_spigpio_suspend NULL
 169 #define s3c2410_spigpio_resume NULL
 170
 171
 172 static struct platform_driver s3c2410_spigpio_drv = {
 173         .probe          = s3c2410_spigpio_probe,
 174         .remove         = s3c2410_spigpio_remove,
 175         .suspend        = s3c2410_spigpio_suspend,
 176         .resume         = s3c2410_spigpio_resume,
 177         .driver         = {
 178                 .name   = "spi_s3c24xx_gpio",
 179                 .owner  = THIS_MODULE,
 180         },
 181 };
 182
 183 static int __init s3c2410_spigpio_init(void)
 184 {
 185         return platform_driver_register(&s3c2410_spigpio_drv);
 186 }
 187
 188 static void __exit s3c2410_spigpio_exit(void)
 189 {
 190         platform_driver_unregister(&s3c2410_spigpio_drv);
 191 }
 192
 193 module_init(s3c2410_spigpio_init);
 194 module_exit(s3c2410_spigpio_exit);
 195
 196 MODULE_DESCRIPTION("S3C24XX SPI Driver");
 197 MODULE_AUTHOR("Ben Dooks, <ben@simtec.co.uk>");
 198 MODULE_LICENSE("GPL");