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 dev_err(&dev->dev, "cannot allocate private data\n"); 82 return -ENOMEM; 83 } 84 85 platform_set_drvdata(dev, pd); 86 87 res = platform_get_resource(dev, IORESOURCE_MEM, 0); 88 if (res == NULL) { 89 dev_err(&dev->dev, "cannot find IO resource\n"); 90 ret = -ENOENT; 91 goto err; 92 } 93 94 size = resource_size(res); 95 96 pd->ioarea = request_mem_region(res->start, size, dev->name); 97 if (pd->ioarea == NULL) { 98 dev_err(&dev->dev, "cannot request IO\n"); 99 ret = -ENXIO; 100 goto err; 101 } 102 103 pd->reg = ioremap(res->start, size); 104 if (pd->reg == NULL) { 105 dev_err(&dev->dev, "cannot map IO\n"); 106 ret = -ENXIO; 107 goto err_res; 108 } 109 110 /* setup the private data */ 111 112 pd->adap.owner = THIS_MODULE; 113 pd->adap.algo_data = &pd->bit; 114 pd->adap.dev.parent = &dev->dev; 115 116 strlcpy(pd->adap.name, "Simtec I2C", sizeof(pd->adap.name)); 117 118 pd->bit.data = pd; 119 pd->bit.setsda = simtec_i2c_setsda; 120 pd->bit.setscl = simtec_i2c_setscl; 121 pd->bit.getsda = simtec_i2c_getsda; 122 pd->bit.getscl = simtec_i2c_getscl; 123 pd->bit.timeout = HZ; 124 pd->bit.udelay = 20; 125 126 ret = i2c_bit_add_bus(&pd->adap); 127 if (ret) 128 goto err_all; 129 130 return 0; 131 132 err_all: 133 iounmap(pd->reg); 134 135 err_res: 136 release_resource(pd->ioarea); 137 kfree(pd->ioarea); 138 139 err: 140 kfree(pd); 141 return ret; 142 } 143 144 static int simtec_i2c_remove(struct platform_device *dev) 145 { 146 struct simtec_i2c_data *pd = platform_get_drvdata(dev); 147 148 i2c_del_adapter(&pd->adap); 149 150 iounmap(pd->reg); 151 release_resource(pd->ioarea); 152 kfree(pd->ioarea); 153 kfree(pd); 154 155 return 0; 156 } 157 158 /* device driver */ 159 160 static struct platform_driver simtec_i2c_driver = { 161 .driver = { 162 .name = "simtec-i2c", 163 .owner = THIS_MODULE, 164 }, 165 .probe = simtec_i2c_probe, 166 .remove = simtec_i2c_remove, 167 }; 168 169 module_platform_driver(simtec_i2c_driver); 170 171 MODULE_DESCRIPTION("Simtec Generic I2C Bus driver"); 172 MODULE_AUTHOR("Ben Dooks <ben@simtec.co.uk>"); 173 MODULE_LICENSE("GPL"); 174 MODULE_ALIAS("platform:simtec-i2c"); 175