linux/drivers/spi/spi_s3c24xx_gpio.c
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   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
  29struct s3c2410_spigpio {
  30        struct spi_bitbang               bitbang;
  31
  32        struct s3c2410_spigpio_info     *info;
  33        struct platform_device          *dev;
  34};
  35
  36static inline struct s3c2410_spigpio *spidev_to_sg(struct spi_device *spi)
  37{
  38        return spi_master_get_devdata(spi->master);
  39}
  40
  41static 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
  47static 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
  53static 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#include "spi_bitbang_txrx.h"
  62
  63
  64static 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, 0, word, bits);
  68}
  69
  70static 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, 0, word, bits);
  74}
  75
  76static 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, 0, word, bits);
  80}
  81
  82static 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, 0, word, bits);
  86}
  87
  88
  89static 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
  97static 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.master->num_chipselect = info->num_chipselect;
 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        return 0;
 147
 148 err_no_bitbang:
 149        spi_master_put(sp->bitbang.master);
 150 err:
 151        return ret;
 152
 153}
 154
 155static int s3c2410_spigpio_remove(struct platform_device *dev)
 156{
 157        struct s3c2410_spigpio *sp = platform_get_drvdata(dev);
 158
 159        spi_bitbang_stop(&sp->bitbang);
 160        spi_master_put(sp->bitbang.master);
 161
 162        return 0;
 163}
 164
 165/* all gpio should be held over suspend/resume, so we should
 166 * not need to deal with this
 167*/
 168
 169#define s3c2410_spigpio_suspend NULL
 170#define s3c2410_spigpio_resume NULL
 171
 172/* work with hotplug and coldplug */
 173MODULE_ALIAS("platform:spi_s3c24xx_gpio");
 174
 175static struct platform_driver s3c2410_spigpio_drv = {
 176        .probe          = s3c2410_spigpio_probe,
 177        .remove         = s3c2410_spigpio_remove,
 178        .suspend        = s3c2410_spigpio_suspend,
 179        .resume         = s3c2410_spigpio_resume,
 180        .driver         = {
 181                .name   = "spi_s3c24xx_gpio",
 182                .owner  = THIS_MODULE,
 183        },
 184};
 185
 186static int __init s3c2410_spigpio_init(void)
 187{
 188        return platform_driver_register(&s3c2410_spigpio_drv);
 189}
 190
 191static void __exit s3c2410_spigpio_exit(void)
 192{
 193        platform_driver_unregister(&s3c2410_spigpio_drv);
 194}
 195
 196module_init(s3c2410_spigpio_init);
 197module_exit(s3c2410_spigpio_exit);
 198
 199MODULE_DESCRIPTION("S3C24XX SPI Driver");
 200MODULE_AUTHOR("Ben Dooks, <ben@simtec.co.uk>");
 201MODULE_LICENSE("GPL");
 202