| 1 | /* |
| 2 | * SH SCI SPI interface |
| 3 | * |
| 4 | * Copyright (c) 2008 Magnus Damm |
| 5 | * |
| 6 | * Based on S3C24XX GPIO based SPI driver, which is: |
| 7 | * Copyright (c) 2006 Ben Dooks |
| 8 | * Copyright (c) 2006 Simtec Electronics |
| 9 | * |
| 10 | * This program is free software; you can redistribute it and/or modify |
| 11 | * it under the terms of the GNU General Public License version 2 as |
| 12 | * published by the Free Software Foundation. |
| 13 | * |
| 14 | */ |
| 15 | |
| 16 | #include <linux/kernel.h> |
| 17 | #include <linux/delay.h> |
| 18 | #include <linux/spinlock.h> |
| 19 | #include <linux/platform_device.h> |
| 20 | |
| 21 | #include <linux/spi/spi.h> |
| 22 | #include <linux/spi/spi_bitbang.h> |
| 23 | #include <linux/module.h> |
| 24 | |
| 25 | #include <asm/spi.h> |
| 26 | #include <asm/io.h> |
| 27 | |
| 28 | struct sh_sci_spi { |
| 29 | struct spi_bitbang bitbang; |
| 30 | |
| 31 | void __iomem *membase; |
| 32 | unsigned char val; |
| 33 | struct sh_spi_info *info; |
| 34 | struct platform_device *dev; |
| 35 | }; |
| 36 | |
| 37 | #define SCSPTR(sp) (sp->membase + 0x1c) |
| 38 | #define PIN_SCK (1 << 2) |
| 39 | #define PIN_TXD (1 << 0) |
| 40 | #define PIN_RXD PIN_TXD |
| 41 | #define PIN_INIT ((1 << 1) | (1 << 3) | PIN_SCK | PIN_TXD) |
| 42 | |
| 43 | static inline void setbits(struct sh_sci_spi *sp, int bits, int on) |
| 44 | { |
| 45 | /* |
| 46 | * We are the only user of SCSPTR so no locking is required. |
| 47 | * Reading bit 2 and 0 in SCSPTR gives pin state as input. |
| 48 | * Writing the same bits sets the output value. |
| 49 | * This makes regular read-modify-write difficult so we |
| 50 | * use sp->val to keep track of the latest register value. |
| 51 | */ |
| 52 | |
| 53 | if (on) |
| 54 | sp->val |= bits; |
| 55 | else |
| 56 | sp->val &= ~bits; |
| 57 | |
| 58 | iowrite8(sp->val, SCSPTR(sp)); |
| 59 | } |
| 60 | |
| 61 | static inline void setsck(struct spi_device *dev, int on) |
| 62 | { |
| 63 | setbits(spi_master_get_devdata(dev->master), PIN_SCK, on); |
| 64 | } |
| 65 | |
| 66 | static inline void setmosi(struct spi_device *dev, int on) |
| 67 | { |
| 68 | setbits(spi_master_get_devdata(dev->master), PIN_TXD, on); |
| 69 | } |
| 70 | |
| 71 | static inline u32 getmiso(struct spi_device *dev) |
| 72 | { |
| 73 | struct sh_sci_spi *sp = spi_master_get_devdata(dev->master); |
| 74 | |
| 75 | return (ioread8(SCSPTR(sp)) & PIN_RXD) ? 1 : 0; |
| 76 | } |
| 77 | |
| 78 | #define spidelay(x) ndelay(x) |
| 79 | |
| 80 | #include "spi-bitbang-txrx.h" |
| 81 | |
| 82 | static u32 sh_sci_spi_txrx_mode0(struct spi_device *spi, |
| 83 | unsigned nsecs, u32 word, u8 bits) |
| 84 | { |
| 85 | return bitbang_txrx_be_cpha0(spi, nsecs, 0, 0, word, bits); |
| 86 | } |
| 87 | |
| 88 | static u32 sh_sci_spi_txrx_mode1(struct spi_device *spi, |
| 89 | unsigned nsecs, u32 word, u8 bits) |
| 90 | { |
| 91 | return bitbang_txrx_be_cpha1(spi, nsecs, 0, 0, word, bits); |
| 92 | } |
| 93 | |
| 94 | static u32 sh_sci_spi_txrx_mode2(struct spi_device *spi, |
| 95 | unsigned nsecs, u32 word, u8 bits) |
| 96 | { |
| 97 | return bitbang_txrx_be_cpha0(spi, nsecs, 1, 0, word, bits); |
| 98 | } |
| 99 | |
| 100 | static u32 sh_sci_spi_txrx_mode3(struct spi_device *spi, |
| 101 | unsigned nsecs, u32 word, u8 bits) |
| 102 | { |
| 103 | return bitbang_txrx_be_cpha1(spi, nsecs, 1, 0, word, bits); |
| 104 | } |
| 105 | |
| 106 | static void sh_sci_spi_chipselect(struct spi_device *dev, int value) |
| 107 | { |
| 108 | struct sh_sci_spi *sp = spi_master_get_devdata(dev->master); |
| 109 | |
| 110 | if (sp->info->chip_select) |
| 111 | (sp->info->chip_select)(sp->info, dev->chip_select, value); |
| 112 | } |
| 113 | |
| 114 | static int sh_sci_spi_probe(struct platform_device *dev) |
| 115 | { |
| 116 | struct resource *r; |
| 117 | struct spi_master *master; |
| 118 | struct sh_sci_spi *sp; |
| 119 | int ret; |
| 120 | |
| 121 | master = spi_alloc_master(&dev->dev, sizeof(struct sh_sci_spi)); |
| 122 | if (master == NULL) { |
| 123 | dev_err(&dev->dev, "failed to allocate spi master\n"); |
| 124 | ret = -ENOMEM; |
| 125 | goto err0; |
| 126 | } |
| 127 | |
| 128 | sp = spi_master_get_devdata(master); |
| 129 | |
| 130 | platform_set_drvdata(dev, sp); |
| 131 | sp->info = dev_get_platdata(&dev->dev); |
| 132 | if (!sp->info) { |
| 133 | dev_err(&dev->dev, "platform data is missing\n"); |
| 134 | ret = -ENOENT; |
| 135 | goto err1; |
| 136 | } |
| 137 | |
| 138 | /* setup spi bitbang adaptor */ |
| 139 | sp->bitbang.master = master; |
| 140 | sp->bitbang.master->bus_num = sp->info->bus_num; |
| 141 | sp->bitbang.master->num_chipselect = sp->info->num_chipselect; |
| 142 | sp->bitbang.chipselect = sh_sci_spi_chipselect; |
| 143 | |
| 144 | sp->bitbang.txrx_word[SPI_MODE_0] = sh_sci_spi_txrx_mode0; |
| 145 | sp->bitbang.txrx_word[SPI_MODE_1] = sh_sci_spi_txrx_mode1; |
| 146 | sp->bitbang.txrx_word[SPI_MODE_2] = sh_sci_spi_txrx_mode2; |
| 147 | sp->bitbang.txrx_word[SPI_MODE_3] = sh_sci_spi_txrx_mode3; |
| 148 | |
| 149 | r = platform_get_resource(dev, IORESOURCE_MEM, 0); |
| 150 | if (r == NULL) { |
| 151 | ret = -ENOENT; |
| 152 | goto err1; |
| 153 | } |
| 154 | sp->membase = ioremap(r->start, resource_size(r)); |
| 155 | if (!sp->membase) { |
| 156 | ret = -ENXIO; |
| 157 | goto err1; |
| 158 | } |
| 159 | sp->val = ioread8(SCSPTR(sp)); |
| 160 | setbits(sp, PIN_INIT, 1); |
| 161 | |
| 162 | ret = spi_bitbang_start(&sp->bitbang); |
| 163 | if (!ret) |
| 164 | return 0; |
| 165 | |
| 166 | setbits(sp, PIN_INIT, 0); |
| 167 | iounmap(sp->membase); |
| 168 | err1: |
| 169 | spi_master_put(sp->bitbang.master); |
| 170 | err0: |
| 171 | return ret; |
| 172 | } |
| 173 | |
| 174 | static int sh_sci_spi_remove(struct platform_device *dev) |
| 175 | { |
| 176 | struct sh_sci_spi *sp = platform_get_drvdata(dev); |
| 177 | |
| 178 | spi_bitbang_stop(&sp->bitbang); |
| 179 | setbits(sp, PIN_INIT, 0); |
| 180 | iounmap(sp->membase); |
| 181 | spi_master_put(sp->bitbang.master); |
| 182 | return 0; |
| 183 | } |
| 184 | |
| 185 | static struct platform_driver sh_sci_spi_drv = { |
| 186 | .probe = sh_sci_spi_probe, |
| 187 | .remove = sh_sci_spi_remove, |
| 188 | .driver = { |
| 189 | .name = "spi_sh_sci", |
| 190 | }, |
| 191 | }; |
| 192 | module_platform_driver(sh_sci_spi_drv); |
| 193 | |
| 194 | MODULE_DESCRIPTION("SH SCI SPI Driver"); |
| 195 | MODULE_AUTHOR("Magnus Damm <damm@opensource.se>"); |
| 196 | MODULE_LICENSE("GPL"); |
| 197 | MODULE_ALIAS("platform:spi_sh_sci"); |