1 /* 2 * Copyright (C) 2005 Simtec Electronics 3 * Ben Dooks <ben@simtec.co.uk> 4 * 5 * Simtec Generic I2C Controller 6 * 7 * This program is free software; you can redistribute it and/or modify 8 * it under the terms of the GNU General Public License as published by 9 * the Free Software Foundation; either version 2 of the License 10 * 11 * This program is distributed in the hope that it will be useful, 12 * but WITHOUT ANY WARRANTY; without even the implied warranty of 13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 14 * GNU General Public License for more details. 15 * 16 * You should have received a copy of the GNU General Public License 17 * along with this program; if not, write to the Free Software 18 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA 19 */ 20 21 #include <linux/kernel.h> 22 #include <linux/module.h> 23 #include <linux/delay.h> 24 #include <linux/platform_device.h> 25 #include <linux/slab.h> 26 #include <linux/io.h> 27 28 #include <linux/i2c.h> 29 #include <linux/i2c-algo-bit.h> 30 31 struct simtec_i2c_data { 32 struct resource *ioarea; 33 void __iomem *reg; 34 struct i2c_adapter adap; 35 struct i2c_algo_bit_data bit; 36 }; 37 38 #define CMD_SET_SDA (1<<2) 39 #define CMD_SET_SCL (1<<3) 40 41 #define STATE_SDA (1<<0) 42 #define STATE_SCL (1<<1) 43 44 /* i2c bit-bus functions */ 45 46 static void simtec_i2c_setsda(void *pw, int state) 47 { 48 struct simtec_i2c_data *pd = pw; 49 writeb(CMD_SET_SDA | (state ? STATE_SDA : 0), pd->reg); 50 } 51 52 static void simtec_i2c_setscl(void *pw, int state) 53 { 54 struct simtec_i2c_data *pd = pw; 55 writeb(CMD_SET_SCL | (state ? STATE_SCL : 0), pd->reg); 56 } 57 58 static int simtec_i2c_getsda(void *pw) 59 { 60 struct simtec_i2c_data *pd = pw; 61 return readb(pd->reg) & STATE_SDA ? 1 : 0; 62 } 63 64 static int simtec_i2c_getscl(void *pw) 65 { 66 struct simtec_i2c_data *pd = pw; 67 return readb(pd->reg) & STATE_SCL ? 1 : 0; 68 } 69 70 /* device registration */ 71 72 static int simtec_i2c_probe(struct platform_device *dev) 73 { 74 struct simtec_i2c_data *pd; 75 struct resource *res; 76 int size; 77 int ret; 78 79 pd = kzalloc(sizeof(struct simtec_i2c_data), GFP_KERNEL); 80 if (pd == NULL) 81 return -ENOMEM; 82 83 platform_set_drvdata(dev, pd); 84 85 res = platform_get_resource(dev, IORESOURCE_MEM, 0); 86 if (res == NULL) { 87 dev_err(&dev->dev, "cannot find IO resource\n"); 88 ret = -ENOENT; 89 goto err; 90 } 91 92 size = resource_size(res); 93 94 pd->ioarea = request_mem_region(res->start, size, dev->name); 95 if (pd->ioarea == NULL) { 96 dev_err(&dev->dev, "cannot request IO\n"); 97 ret = -ENXIO; 98 goto err; 99 } 100 101 pd->reg = ioremap(res->start, size); 102 if (pd->reg == NULL) { 103 dev_err(&dev->dev, "cannot map IO\n"); 104 ret = -ENXIO; 105 goto err_res; 106 } 107 108 /* setup the private data */ 109 110 pd->adap.owner = THIS_MODULE; 111 pd->adap.algo_data = &pd->bit; 112 pd->adap.dev.parent = &dev->dev; 113 114 strlcpy(pd->adap.name, "Simtec I2C", sizeof(pd->adap.name)); 115 116 pd->bit.data = pd; 117 pd->bit.setsda = simtec_i2c_setsda; 118 pd->bit.setscl = simtec_i2c_setscl; 119 pd->bit.getsda = simtec_i2c_getsda; 120 pd->bit.getscl = simtec_i2c_getscl; 121 pd->bit.timeout = HZ; 122 pd->bit.udelay = 20; 123 124 ret = i2c_bit_add_bus(&pd->adap); 125 if (ret) 126 goto err_all; 127 128 return 0; 129 130 err_all: 131 iounmap(pd->reg); 132 133 err_res: 134 release_resource(pd->ioarea); 135 kfree(pd->ioarea); 136 137 err: 138 kfree(pd); 139 return ret; 140 } 141 142 static int simtec_i2c_remove(struct platform_device *dev) 143 { 144 struct simtec_i2c_data *pd = platform_get_drvdata(dev); 145 146 i2c_del_adapter(&pd->adap); 147 148 iounmap(pd->reg); 149 release_resource(pd->ioarea); 150 kfree(pd->ioarea); 151 kfree(pd); 152 153 return 0; 154 } 155 156 /* device driver */ 157 158 static struct platform_driver simtec_i2c_driver = { 159 .driver = { 160 .name = "simtec-i2c", 161 .owner = THIS_MODULE, 162 }, 163 .probe = simtec_i2c_probe, 164 .remove = simtec_i2c_remove, 165 }; 166 167 module_platform_driver(simtec_i2c_driver); 168 169 MODULE_DESCRIPTION("Simtec Generic I2C Bus driver"); 170 MODULE_AUTHOR("Ben Dooks <ben@simtec.co.uk>"); 171 MODULE_LICENSE("GPL"); 172 MODULE_ALIAS("platform:simtec-i2c"); 173