Kyle Swenson | 8d8f654 | 2021-03-15 11:02:55 -0600 | [diff] [blame^] | 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 | |
| 17 | #include <linux/kernel.h> |
| 18 | #include <linux/module.h> |
| 19 | #include <linux/delay.h> |
| 20 | #include <linux/platform_device.h> |
| 21 | #include <linux/slab.h> |
| 22 | #include <linux/io.h> |
| 23 | |
| 24 | #include <linux/i2c.h> |
| 25 | #include <linux/i2c-algo-bit.h> |
| 26 | |
| 27 | struct simtec_i2c_data { |
| 28 | struct resource *ioarea; |
| 29 | void __iomem *reg; |
| 30 | struct i2c_adapter adap; |
| 31 | struct i2c_algo_bit_data bit; |
| 32 | }; |
| 33 | |
| 34 | #define CMD_SET_SDA (1<<2) |
| 35 | #define CMD_SET_SCL (1<<3) |
| 36 | |
| 37 | #define STATE_SDA (1<<0) |
| 38 | #define STATE_SCL (1<<1) |
| 39 | |
| 40 | /* i2c bit-bus functions */ |
| 41 | |
| 42 | static void simtec_i2c_setsda(void *pw, int state) |
| 43 | { |
| 44 | struct simtec_i2c_data *pd = pw; |
| 45 | writeb(CMD_SET_SDA | (state ? STATE_SDA : 0), pd->reg); |
| 46 | } |
| 47 | |
| 48 | static void simtec_i2c_setscl(void *pw, int state) |
| 49 | { |
| 50 | struct simtec_i2c_data *pd = pw; |
| 51 | writeb(CMD_SET_SCL | (state ? STATE_SCL : 0), pd->reg); |
| 52 | } |
| 53 | |
| 54 | static int simtec_i2c_getsda(void *pw) |
| 55 | { |
| 56 | struct simtec_i2c_data *pd = pw; |
| 57 | return readb(pd->reg) & STATE_SDA ? 1 : 0; |
| 58 | } |
| 59 | |
| 60 | static int simtec_i2c_getscl(void *pw) |
| 61 | { |
| 62 | struct simtec_i2c_data *pd = pw; |
| 63 | return readb(pd->reg) & STATE_SCL ? 1 : 0; |
| 64 | } |
| 65 | |
| 66 | /* device registration */ |
| 67 | |
| 68 | static int simtec_i2c_probe(struct platform_device *dev) |
| 69 | { |
| 70 | struct simtec_i2c_data *pd; |
| 71 | struct resource *res; |
| 72 | int size; |
| 73 | int ret; |
| 74 | |
| 75 | pd = kzalloc(sizeof(struct simtec_i2c_data), GFP_KERNEL); |
| 76 | if (pd == NULL) |
| 77 | return -ENOMEM; |
| 78 | |
| 79 | platform_set_drvdata(dev, pd); |
| 80 | |
| 81 | res = platform_get_resource(dev, IORESOURCE_MEM, 0); |
| 82 | if (res == NULL) { |
| 83 | dev_err(&dev->dev, "cannot find IO resource\n"); |
| 84 | ret = -ENOENT; |
| 85 | goto err; |
| 86 | } |
| 87 | |
| 88 | size = resource_size(res); |
| 89 | |
| 90 | pd->ioarea = request_mem_region(res->start, size, dev->name); |
| 91 | if (pd->ioarea == NULL) { |
| 92 | dev_err(&dev->dev, "cannot request IO\n"); |
| 93 | ret = -ENXIO; |
| 94 | goto err; |
| 95 | } |
| 96 | |
| 97 | pd->reg = ioremap(res->start, size); |
| 98 | if (pd->reg == NULL) { |
| 99 | dev_err(&dev->dev, "cannot map IO\n"); |
| 100 | ret = -ENXIO; |
| 101 | goto err_res; |
| 102 | } |
| 103 | |
| 104 | /* setup the private data */ |
| 105 | |
| 106 | pd->adap.owner = THIS_MODULE; |
| 107 | pd->adap.algo_data = &pd->bit; |
| 108 | pd->adap.dev.parent = &dev->dev; |
| 109 | |
| 110 | strlcpy(pd->adap.name, "Simtec I2C", sizeof(pd->adap.name)); |
| 111 | |
| 112 | pd->bit.data = pd; |
| 113 | pd->bit.setsda = simtec_i2c_setsda; |
| 114 | pd->bit.setscl = simtec_i2c_setscl; |
| 115 | pd->bit.getsda = simtec_i2c_getsda; |
| 116 | pd->bit.getscl = simtec_i2c_getscl; |
| 117 | pd->bit.timeout = HZ; |
| 118 | pd->bit.udelay = 20; |
| 119 | |
| 120 | ret = i2c_bit_add_bus(&pd->adap); |
| 121 | if (ret) |
| 122 | goto err_all; |
| 123 | |
| 124 | return 0; |
| 125 | |
| 126 | err_all: |
| 127 | iounmap(pd->reg); |
| 128 | |
| 129 | err_res: |
| 130 | release_resource(pd->ioarea); |
| 131 | kfree(pd->ioarea); |
| 132 | |
| 133 | err: |
| 134 | kfree(pd); |
| 135 | return ret; |
| 136 | } |
| 137 | |
| 138 | static int simtec_i2c_remove(struct platform_device *dev) |
| 139 | { |
| 140 | struct simtec_i2c_data *pd = platform_get_drvdata(dev); |
| 141 | |
| 142 | i2c_del_adapter(&pd->adap); |
| 143 | |
| 144 | iounmap(pd->reg); |
| 145 | release_resource(pd->ioarea); |
| 146 | kfree(pd->ioarea); |
| 147 | kfree(pd); |
| 148 | |
| 149 | return 0; |
| 150 | } |
| 151 | |
| 152 | /* device driver */ |
| 153 | |
| 154 | static struct platform_driver simtec_i2c_driver = { |
| 155 | .driver = { |
| 156 | .name = "simtec-i2c", |
| 157 | }, |
| 158 | .probe = simtec_i2c_probe, |
| 159 | .remove = simtec_i2c_remove, |
| 160 | }; |
| 161 | |
| 162 | module_platform_driver(simtec_i2c_driver); |
| 163 | |
| 164 | MODULE_DESCRIPTION("Simtec Generic I2C Bus driver"); |
| 165 | MODULE_AUTHOR("Ben Dooks <ben@simtec.co.uk>"); |
| 166 | MODULE_LICENSE("GPL"); |
| 167 | MODULE_ALIAS("platform:simtec-i2c"); |