1 /* 2 * i2c-versatile.c 3 * 4 * Copyright (C) 2006 ARM Ltd. 5 * written by Russell King, Deep Blue Solutions Ltd. 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 version 2 as 9 * published by the Free Software Foundation. 10 */ 11 #include <linux/kernel.h> 12 #include <linux/module.h> 13 #include <linux/i2c.h> 14 #include <linux/i2c-algo-bit.h> 15 #include <linux/init.h> 16 #include <linux/platform_device.h> 17 18 #include <asm/io.h> 19 20 #define I2C_CONTROL 0x00 21 #define I2C_CONTROLS 0x00 22 #define I2C_CONTROLC 0x04 23 #define SCL (1 << 0) 24 #define SDA (1 << 1) 25 26 struct i2c_versatile { 27 struct i2c_adapter adap; 28 struct i2c_algo_bit_data algo; 29 void __iomem *base; 30 }; 31 32 static void i2c_versatile_setsda(void *data, int state) 33 { 34 struct i2c_versatile *i2c = data; 35 36 writel(SDA, i2c->base + (state ? I2C_CONTROLS : I2C_CONTROLC)); 37 } 38 39 static void i2c_versatile_setscl(void *data, int state) 40 { 41 struct i2c_versatile *i2c = data; 42 43 writel(SCL, i2c->base + (state ? I2C_CONTROLS : I2C_CONTROLC)); 44 } 45 46 static int i2c_versatile_getsda(void *data) 47 { 48 struct i2c_versatile *i2c = data; 49 return !!(readl(i2c->base + I2C_CONTROL) & SDA); 50 } 51 52 static int i2c_versatile_getscl(void *data) 53 { 54 struct i2c_versatile *i2c = data; 55 return !!(readl(i2c->base + I2C_CONTROL) & SCL); 56 } 57 58 static struct i2c_algo_bit_data i2c_versatile_algo = { 59 .setsda = i2c_versatile_setsda, 60 .setscl = i2c_versatile_setscl, 61 .getsda = i2c_versatile_getsda, 62 .getscl = i2c_versatile_getscl, 63 .udelay = 30, 64 .timeout = HZ, 65 }; 66 67 static int i2c_versatile_probe(struct platform_device *dev) 68 { 69 struct i2c_versatile *i2c; 70 struct resource *r; 71 int ret; 72 73 r = platform_get_resource(dev, IORESOURCE_MEM, 0); 74 if (!r) { 75 ret = -EINVAL; 76 goto err_out; 77 } 78 79 if (!request_mem_region(r->start, r->end - r->start + 1, "versatile-i2c")) { 80 ret = -EBUSY; 81 goto err_out; 82 } 83 84 i2c = kzalloc(sizeof(struct i2c_versatile), GFP_KERNEL); 85 if (!i2c) { 86 ret = -ENOMEM; 87 goto err_release; 88 } 89 90 i2c->base = ioremap(r->start, r->end - r->start + 1); 91 if (!i2c->base) { 92 ret = -ENOMEM; 93 goto err_free; 94 } 95 96 writel(SCL | SDA, i2c->base + I2C_CONTROLS); 97 98 i2c->adap.owner = THIS_MODULE; 99 strlcpy(i2c->adap.name, "Versatile I2C adapter", sizeof(i2c->adap.name)); 100 i2c->adap.algo_data = &i2c->algo; 101 i2c->adap.dev.parent = &dev->dev; 102 i2c->algo = i2c_versatile_algo; 103 i2c->algo.data = i2c; 104 105 ret = i2c_bit_add_bus(&i2c->adap); 106 if (ret >= 0) { 107 platform_set_drvdata(dev, i2c); 108 return 0; 109 } 110 111 iounmap(i2c->base); 112 err_free: 113 kfree(i2c); 114 err_release: 115 release_mem_region(r->start, r->end - r->start + 1); 116 err_out: 117 return ret; 118 } 119 120 static int i2c_versatile_remove(struct platform_device *dev) 121 { 122 struct i2c_versatile *i2c = platform_get_drvdata(dev); 123 124 platform_set_drvdata(dev, NULL); 125 126 i2c_del_adapter(&i2c->adap); 127 return 0; 128 } 129 130 static struct platform_driver i2c_versatile_driver = { 131 .probe = i2c_versatile_probe, 132 .remove = i2c_versatile_remove, 133 .driver = { 134 .name = "versatile-i2c", 135 .owner = THIS_MODULE, 136 }, 137 }; 138 139 static int __init i2c_versatile_init(void) 140 { 141 return platform_driver_register(&i2c_versatile_driver); 142 } 143 144 static void __exit i2c_versatile_exit(void) 145 { 146 platform_driver_unregister(&i2c_versatile_driver); 147 } 148 149 module_init(i2c_versatile_init); 150 module_exit(i2c_versatile_exit); 151 152 MODULE_DESCRIPTION("ARM Versatile I2C bus driver"); 153 MODULE_LICENSE("GPL"); 154 MODULE_ALIAS("platform:versatile-i2c"); 155