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/init.h> 24 #include <linux/delay.h> 25 #include <linux/platform_device.h> 26 #include <linux/slab.h> 27 #include <linux/io.h> 28 29 #include <linux/i2c.h> 30 #include <linux/i2c-algo-bit.h> 31 32 struct simtec_i2c_data { 33 struct resource *ioarea; 34 void __iomem *reg; 35 struct i2c_adapter adap; 36 struct i2c_algo_bit_data bit; 37 }; 38 39 #define CMD_SET_SDA (1<<2) 40 #define CMD_SET_SCL (1<<3) 41 42 #define STATE_SDA (1<<0) 43 #define STATE_SCL (1<<1) 44 45 /* i2c bit-bus functions */ 46 47 static void simtec_i2c_setsda(void *pw, int state) 48 { 49 struct simtec_i2c_data *pd = pw; 50 writeb(CMD_SET_SDA | (state ? STATE_SDA : 0), pd->reg); 51 } 52 53 static void simtec_i2c_setscl(void *pw, int state) 54 { 55 struct simtec_i2c_data *pd = pw; 56 writeb(CMD_SET_SCL | (state ? STATE_SCL : 0), pd->reg); 57 } 58 59 static int simtec_i2c_getsda(void *pw) 60 { 61 struct simtec_i2c_data *pd = pw; 62 return readb(pd->reg) & STATE_SDA ? 1 : 0; 63 } 64 65 static int simtec_i2c_getscl(void *pw) 66 { 67 struct simtec_i2c_data *pd = pw; 68 return readb(pd->reg) & STATE_SCL ? 1 : 0; 69 } 70 71 /* device registration */ 72 73 static int simtec_i2c_probe(struct platform_device *dev) 74 { 75 struct simtec_i2c_data *pd; 76 struct resource *res; 77 int size; 78 int ret; 79 80 pd = kzalloc(sizeof(struct simtec_i2c_data), GFP_KERNEL); 81 if (pd == NULL) { 82 dev_err(&dev->dev, "cannot allocate private data\n"); 83 return -ENOMEM; 84 } 85 86 platform_set_drvdata(dev, pd); 87 88 res = platform_get_resource(dev, IORESOURCE_MEM, 0); 89 if (res == NULL) { 90 dev_err(&dev->dev, "cannot find IO resource\n"); 91 ret = -ENOENT; 92 goto err; 93 } 94 95 size = resource_size(res); 96 97 pd->ioarea = request_mem_region(res->start, size, dev->name); 98 if (pd->ioarea == NULL) { 99 dev_err(&dev->dev, "cannot request IO\n"); 100 ret = -ENXIO; 101 goto err; 102 } 103 104 pd->reg = ioremap(res->start, size); 105 if (pd->reg == NULL) { 106 dev_err(&dev->dev, "cannot map IO\n"); 107 ret = -ENXIO; 108 goto err_res; 109 } 110 111 /* setup the private data */ 112 113 pd->adap.owner = THIS_MODULE; 114 pd->adap.algo_data = &pd->bit; 115 pd->adap.dev.parent = &dev->dev; 116 117 strlcpy(pd->adap.name, "Simtec I2C", sizeof(pd->adap.name)); 118 119 pd->bit.data = pd; 120 pd->bit.setsda = simtec_i2c_setsda; 121 pd->bit.setscl = simtec_i2c_setscl; 122 pd->bit.getsda = simtec_i2c_getsda; 123 pd->bit.getscl = simtec_i2c_getscl; 124 pd->bit.timeout = HZ; 125 pd->bit.udelay = 20; 126 127 ret = i2c_bit_add_bus(&pd->adap); 128 if (ret) 129 goto err_all; 130 131 return 0; 132 133 err_all: 134 iounmap(pd->reg); 135 136 err_res: 137 release_resource(pd->ioarea); 138 kfree(pd->ioarea); 139 140 err: 141 kfree(pd); 142 return ret; 143 } 144 145 static int simtec_i2c_remove(struct platform_device *dev) 146 { 147 struct simtec_i2c_data *pd = platform_get_drvdata(dev); 148 149 i2c_del_adapter(&pd->adap); 150 151 iounmap(pd->reg); 152 release_resource(pd->ioarea); 153 kfree(pd->ioarea); 154 kfree(pd); 155 156 return 0; 157 } 158 159 /* device driver */ 160 161 static struct platform_driver simtec_i2c_driver = { 162 .driver = { 163 .name = "simtec-i2c", 164 .owner = THIS_MODULE, 165 }, 166 .probe = simtec_i2c_probe, 167 .remove = simtec_i2c_remove, 168 }; 169 170 module_platform_driver(simtec_i2c_driver); 171 172 MODULE_DESCRIPTION("Simtec Generic I2C Bus driver"); 173 MODULE_AUTHOR("Ben Dooks <ben@simtec.co.uk>"); 174 MODULE_LICENSE("GPL"); 175 MODULE_ALIAS("platform:simtec-i2c"); 176