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 struct resource *r; 68 int ret; 69 70 i2c = devm_kzalloc(&dev->dev, sizeof(struct i2c_versatile), GFP_KERNEL); 71 if (!i2c) 72 return -ENOMEM; 73 74 r = platform_get_resource(dev, IORESOURCE_MEM, 0); 75 i2c->base = devm_ioremap_resource(&dev->dev, r); 76 if (IS_ERR(i2c->base)) 77 return PTR_ERR(i2c->base); 78 79 writel(SCL | SDA, i2c->base + I2C_CONTROLS); 80 81 i2c->adap.owner = THIS_MODULE; 82 strscpy(i2c->adap.name, "Versatile I2C adapter", sizeof(i2c->adap.name)); 83 i2c->adap.algo_data = &i2c->algo; 84 i2c->adap.dev.parent = &dev->dev; 85 i2c->adap.dev.of_node = dev->dev.of_node; 86 i2c->algo = i2c_versatile_algo; 87 i2c->algo.data = i2c; 88 89 i2c->adap.nr = dev->id; 90 ret = i2c_bit_add_numbered_bus(&i2c->adap); 91 if (ret < 0) 92 return ret; 93 94 platform_set_drvdata(dev, i2c); 95 96 return 0; 97 } 98 99 static int i2c_versatile_remove(struct platform_device *dev) 100 { 101 struct i2c_versatile *i2c = platform_get_drvdata(dev); 102 103 i2c_del_adapter(&i2c->adap); 104 return 0; 105 } 106 107 static const struct of_device_id i2c_versatile_match[] = { 108 { .compatible = "arm,versatile-i2c", }, 109 {}, 110 }; 111 MODULE_DEVICE_TABLE(of, i2c_versatile_match); 112 113 static struct platform_driver i2c_versatile_driver = { 114 .probe = i2c_versatile_probe, 115 .remove = i2c_versatile_remove, 116 .driver = { 117 .name = "versatile-i2c", 118 .of_match_table = i2c_versatile_match, 119 }, 120 }; 121 122 static int __init i2c_versatile_init(void) 123 { 124 return platform_driver_register(&i2c_versatile_driver); 125 } 126 127 static void __exit i2c_versatile_exit(void) 128 { 129 platform_driver_unregister(&i2c_versatile_driver); 130 } 131 132 subsys_initcall(i2c_versatile_init); 133 module_exit(i2c_versatile_exit); 134 135 MODULE_DESCRIPTION("ARM Versatile I2C bus driver"); 136 MODULE_LICENSE("GPL"); 137 MODULE_ALIAS("platform:versatile-i2c"); 138