1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * i2c-versatile.c 4 * 5 * Copyright (C) 2006 ARM Ltd. 6 * written by Russell King, Deep Blue Solutions Ltd. 7 */ 8 #include <linux/kernel.h> 9 #include <linux/module.h> 10 #include <linux/i2c.h> 11 #include <linux/i2c-algo-bit.h> 12 #include <linux/init.h> 13 #include <linux/platform_device.h> 14 #include <linux/slab.h> 15 #include <linux/io.h> 16 17 #define I2C_CONTROL 0x00 18 #define I2C_CONTROLS 0x00 19 #define I2C_CONTROLC 0x04 20 #define SCL (1 << 0) 21 #define SDA (1 << 1) 22 23 struct i2c_versatile { 24 struct i2c_adapter adap; 25 struct i2c_algo_bit_data algo; 26 void __iomem *base; 27 }; 28 29 static void i2c_versatile_setsda(void *data, int state) 30 { 31 struct i2c_versatile *i2c = data; 32 33 writel(SDA, i2c->base + (state ? I2C_CONTROLS : I2C_CONTROLC)); 34 } 35 36 static void i2c_versatile_setscl(void *data, int state) 37 { 38 struct i2c_versatile *i2c = data; 39 40 writel(SCL, i2c->base + (state ? I2C_CONTROLS : I2C_CONTROLC)); 41 } 42 43 static int i2c_versatile_getsda(void *data) 44 { 45 struct i2c_versatile *i2c = data; 46 return !!(readl(i2c->base + I2C_CONTROL) & SDA); 47 } 48 49 static int i2c_versatile_getscl(void *data) 50 { 51 struct i2c_versatile *i2c = data; 52 return !!(readl(i2c->base + I2C_CONTROL) & SCL); 53 } 54 55 static const struct i2c_algo_bit_data i2c_versatile_algo = { 56 .setsda = i2c_versatile_setsda, 57 .setscl = i2c_versatile_setscl, 58 .getsda = i2c_versatile_getsda, 59 .getscl = i2c_versatile_getscl, 60 .udelay = 30, 61 .timeout = HZ, 62 }; 63 64 static int i2c_versatile_probe(struct platform_device *dev) 65 { 66 struct i2c_versatile *i2c; 67 int ret; 68 69 i2c = devm_kzalloc(&dev->dev, sizeof(struct i2c_versatile), GFP_KERNEL); 70 if (!i2c) 71 return -ENOMEM; 72 73 i2c->base = devm_platform_get_and_ioremap_resource(dev, 0, NULL); 74 if (IS_ERR(i2c->base)) 75 return PTR_ERR(i2c->base); 76 77 writel(SCL | SDA, i2c->base + I2C_CONTROLS); 78 79 i2c->adap.owner = THIS_MODULE; 80 strscpy(i2c->adap.name, "Versatile I2C adapter", sizeof(i2c->adap.name)); 81 i2c->adap.algo_data = &i2c->algo; 82 i2c->adap.dev.parent = &dev->dev; 83 i2c->adap.dev.of_node = dev->dev.of_node; 84 i2c->algo = i2c_versatile_algo; 85 i2c->algo.data = i2c; 86 87 i2c->adap.nr = dev->id; 88 ret = i2c_bit_add_numbered_bus(&i2c->adap); 89 if (ret < 0) 90 return ret; 91 92 platform_set_drvdata(dev, i2c); 93 94 return 0; 95 } 96 97 static void i2c_versatile_remove(struct platform_device *dev) 98 { 99 struct i2c_versatile *i2c = platform_get_drvdata(dev); 100 101 i2c_del_adapter(&i2c->adap); 102 } 103 104 static const struct of_device_id i2c_versatile_match[] = { 105 { .compatible = "arm,versatile-i2c", }, 106 {}, 107 }; 108 MODULE_DEVICE_TABLE(of, i2c_versatile_match); 109 110 static struct platform_driver i2c_versatile_driver = { 111 .probe = i2c_versatile_probe, 112 .remove = i2c_versatile_remove, 113 .driver = { 114 .name = "versatile-i2c", 115 .of_match_table = i2c_versatile_match, 116 }, 117 }; 118 119 static int __init i2c_versatile_init(void) 120 { 121 return platform_driver_register(&i2c_versatile_driver); 122 } 123 124 static void __exit i2c_versatile_exit(void) 125 { 126 platform_driver_unregister(&i2c_versatile_driver); 127 } 128 129 subsys_initcall(i2c_versatile_init); 130 module_exit(i2c_versatile_exit); 131 132 MODULE_DESCRIPTION("ARM Versatile I2C bus driver"); 133 MODULE_LICENSE("GPL"); 134 MODULE_ALIAS("platform:versatile-i2c"); 135