1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Copyright (C) 2005 Simtec Electronics 4 * Ben Dooks <ben@simtec.co.uk> 5 * 6 * Simtec Generic I2C Controller 7 */ 8 9 #include <linux/kernel.h> 10 #include <linux/module.h> 11 #include <linux/delay.h> 12 #include <linux/platform_device.h> 13 #include <linux/slab.h> 14 #include <linux/io.h> 15 16 #include <linux/i2c.h> 17 #include <linux/i2c-algo-bit.h> 18 19 struct simtec_i2c_data { 20 struct resource *ioarea; 21 void __iomem *reg; 22 struct i2c_adapter adap; 23 struct i2c_algo_bit_data bit; 24 }; 25 26 #define CMD_SET_SDA (1<<2) 27 #define CMD_SET_SCL (1<<3) 28 29 #define STATE_SDA (1<<0) 30 #define STATE_SCL (1<<1) 31 32 /* i2c bit-bus functions */ 33 34 static void simtec_i2c_setsda(void *pw, int state) 35 { 36 struct simtec_i2c_data *pd = pw; 37 writeb(CMD_SET_SDA | (state ? STATE_SDA : 0), pd->reg); 38 } 39 40 static void simtec_i2c_setscl(void *pw, int state) 41 { 42 struct simtec_i2c_data *pd = pw; 43 writeb(CMD_SET_SCL | (state ? STATE_SCL : 0), pd->reg); 44 } 45 46 static int simtec_i2c_getsda(void *pw) 47 { 48 struct simtec_i2c_data *pd = pw; 49 return readb(pd->reg) & STATE_SDA ? 1 : 0; 50 } 51 52 static int simtec_i2c_getscl(void *pw) 53 { 54 struct simtec_i2c_data *pd = pw; 55 return readb(pd->reg) & STATE_SCL ? 1 : 0; 56 } 57 58 /* device registration */ 59 60 static int simtec_i2c_probe(struct platform_device *dev) 61 { 62 struct simtec_i2c_data *pd; 63 struct resource *res; 64 int size; 65 int ret; 66 67 pd = kzalloc(sizeof(struct simtec_i2c_data), GFP_KERNEL); 68 if (pd == NULL) 69 return -ENOMEM; 70 71 platform_set_drvdata(dev, pd); 72 73 res = platform_get_resource(dev, IORESOURCE_MEM, 0); 74 if (res == NULL) { 75 dev_err(&dev->dev, "cannot find IO resource\n"); 76 ret = -ENOENT; 77 goto err; 78 } 79 80 size = resource_size(res); 81 82 pd->ioarea = request_mem_region(res->start, size, dev->name); 83 if (pd->ioarea == NULL) { 84 dev_err(&dev->dev, "cannot request IO\n"); 85 ret = -ENXIO; 86 goto err; 87 } 88 89 pd->reg = ioremap(res->start, size); 90 if (pd->reg == NULL) { 91 dev_err(&dev->dev, "cannot map IO\n"); 92 ret = -ENXIO; 93 goto err_res; 94 } 95 96 /* setup the private data */ 97 98 pd->adap.owner = THIS_MODULE; 99 pd->adap.algo_data = &pd->bit; 100 pd->adap.dev.parent = &dev->dev; 101 102 strscpy(pd->adap.name, "Simtec I2C", sizeof(pd->adap.name)); 103 104 pd->bit.data = pd; 105 pd->bit.setsda = simtec_i2c_setsda; 106 pd->bit.setscl = simtec_i2c_setscl; 107 pd->bit.getsda = simtec_i2c_getsda; 108 pd->bit.getscl = simtec_i2c_getscl; 109 pd->bit.timeout = HZ; 110 pd->bit.udelay = 20; 111 112 ret = i2c_bit_add_bus(&pd->adap); 113 if (ret) 114 goto err_all; 115 116 return 0; 117 118 err_all: 119 iounmap(pd->reg); 120 121 err_res: 122 release_mem_region(pd->ioarea->start, size); 123 124 err: 125 kfree(pd); 126 return ret; 127 } 128 129 static void simtec_i2c_remove(struct platform_device *dev) 130 { 131 struct simtec_i2c_data *pd = platform_get_drvdata(dev); 132 133 i2c_del_adapter(&pd->adap); 134 135 iounmap(pd->reg); 136 release_mem_region(pd->ioarea->start, resource_size(pd->ioarea)); 137 kfree(pd); 138 } 139 140 /* device driver */ 141 142 static struct platform_driver simtec_i2c_driver = { 143 .driver = { 144 .name = "simtec-i2c", 145 }, 146 .probe = simtec_i2c_probe, 147 .remove_new = simtec_i2c_remove, 148 }; 149 150 module_platform_driver(simtec_i2c_driver); 151 152 MODULE_DESCRIPTION("Simtec Generic I2C Bus driver"); 153 MODULE_AUTHOR("Ben Dooks <ben@simtec.co.uk>"); 154 MODULE_LICENSE("GPL"); 155 MODULE_ALIAS("platform:simtec-i2c"); 156