1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * SH SCI SPI interface 4 * 5 * Copyright (c) 2008 Magnus Damm 6 * 7 * Based on S3C24XX GPIO based SPI driver, which is: 8 * Copyright (c) 2006 Ben Dooks 9 * Copyright (c) 2006 Simtec Electronics 10 */ 11 12 #include <linux/kernel.h> 13 #include <linux/delay.h> 14 #include <linux/spinlock.h> 15 #include <linux/platform_device.h> 16 17 #include <linux/spi/spi.h> 18 #include <linux/spi/spi_bitbang.h> 19 #include <linux/module.h> 20 21 #include <asm/spi.h> 22 #include <asm/io.h> 23 24 struct sh_sci_spi { 25 struct spi_bitbang bitbang; 26 27 void __iomem *membase; 28 unsigned char val; 29 struct sh_spi_info *info; 30 struct platform_device *dev; 31 }; 32 33 #define SCSPTR(sp) (sp->membase + 0x1c) 34 #define PIN_SCK (1 << 2) 35 #define PIN_TXD (1 << 0) 36 #define PIN_RXD PIN_TXD 37 #define PIN_INIT ((1 << 1) | (1 << 3) | PIN_SCK | PIN_TXD) 38 39 static inline void setbits(struct sh_sci_spi *sp, int bits, int on) 40 { 41 /* 42 * We are the only user of SCSPTR so no locking is required. 43 * Reading bit 2 and 0 in SCSPTR gives pin state as input. 44 * Writing the same bits sets the output value. 45 * This makes regular read-modify-write difficult so we 46 * use sp->val to keep track of the latest register value. 47 */ 48 49 if (on) 50 sp->val |= bits; 51 else 52 sp->val &= ~bits; 53 54 iowrite8(sp->val, SCSPTR(sp)); 55 } 56 57 static inline void setsck(struct spi_device *dev, int on) 58 { 59 setbits(spi_master_get_devdata(dev->master), PIN_SCK, on); 60 } 61 62 static inline void setmosi(struct spi_device *dev, int on) 63 { 64 setbits(spi_master_get_devdata(dev->master), PIN_TXD, on); 65 } 66 67 static inline u32 getmiso(struct spi_device *dev) 68 { 69 struct sh_sci_spi *sp = spi_master_get_devdata(dev->master); 70 71 return (ioread8(SCSPTR(sp)) & PIN_RXD) ? 1 : 0; 72 } 73 74 #define spidelay(x) ndelay(x) 75 76 #include "spi-bitbang-txrx.h" 77 78 static u32 sh_sci_spi_txrx_mode0(struct spi_device *spi, 79 unsigned nsecs, u32 word, u8 bits, 80 unsigned flags) 81 { 82 return bitbang_txrx_be_cpha0(spi, nsecs, 0, flags, word, bits); 83 } 84 85 static u32 sh_sci_spi_txrx_mode1(struct spi_device *spi, 86 unsigned nsecs, u32 word, u8 bits, 87 unsigned flags) 88 { 89 return bitbang_txrx_be_cpha1(spi, nsecs, 0, flags, word, bits); 90 } 91 92 static u32 sh_sci_spi_txrx_mode2(struct spi_device *spi, 93 unsigned nsecs, u32 word, u8 bits, 94 unsigned flags) 95 { 96 return bitbang_txrx_be_cpha0(spi, nsecs, 1, flags, word, bits); 97 } 98 99 static u32 sh_sci_spi_txrx_mode3(struct spi_device *spi, 100 unsigned nsecs, u32 word, u8 bits, 101 unsigned flags) 102 { 103 return bitbang_txrx_be_cpha1(spi, nsecs, 1, flags, 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"); 198