158 строки
3.1 KiB
C
158 строки
3.1 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* Copyright (C) 2005 Simtec Electronics
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* Ben Dooks <ben@simtec.co.uk>
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*
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* Simtec Generic I2C Controller
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*/
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/delay.h>
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#include <linux/platform_device.h>
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#include <linux/slab.h>
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#include <linux/io.h>
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#include <linux/i2c.h>
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#include <linux/i2c-algo-bit.h>
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struct simtec_i2c_data {
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struct resource *ioarea;
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void __iomem *reg;
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struct i2c_adapter adap;
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struct i2c_algo_bit_data bit;
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};
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#define CMD_SET_SDA (1<<2)
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#define CMD_SET_SCL (1<<3)
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#define STATE_SDA (1<<0)
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#define STATE_SCL (1<<1)
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/* i2c bit-bus functions */
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static void simtec_i2c_setsda(void *pw, int state)
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{
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struct simtec_i2c_data *pd = pw;
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writeb(CMD_SET_SDA | (state ? STATE_SDA : 0), pd->reg);
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}
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static void simtec_i2c_setscl(void *pw, int state)
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{
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struct simtec_i2c_data *pd = pw;
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writeb(CMD_SET_SCL | (state ? STATE_SCL : 0), pd->reg);
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}
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static int simtec_i2c_getsda(void *pw)
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{
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struct simtec_i2c_data *pd = pw;
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return readb(pd->reg) & STATE_SDA ? 1 : 0;
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}
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static int simtec_i2c_getscl(void *pw)
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{
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struct simtec_i2c_data *pd = pw;
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return readb(pd->reg) & STATE_SCL ? 1 : 0;
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}
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/* device registration */
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static int simtec_i2c_probe(struct platform_device *dev)
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{
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struct simtec_i2c_data *pd;
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struct resource *res;
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int size;
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int ret;
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pd = kzalloc(sizeof(struct simtec_i2c_data), GFP_KERNEL);
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if (pd == NULL)
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return -ENOMEM;
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platform_set_drvdata(dev, pd);
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res = platform_get_resource(dev, IORESOURCE_MEM, 0);
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if (res == NULL) {
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dev_err(&dev->dev, "cannot find IO resource\n");
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ret = -ENOENT;
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goto err;
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}
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size = resource_size(res);
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pd->ioarea = request_mem_region(res->start, size, dev->name);
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if (pd->ioarea == NULL) {
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dev_err(&dev->dev, "cannot request IO\n");
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ret = -ENXIO;
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goto err;
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}
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pd->reg = ioremap(res->start, size);
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if (pd->reg == NULL) {
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dev_err(&dev->dev, "cannot map IO\n");
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ret = -ENXIO;
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goto err_res;
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}
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/* setup the private data */
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pd->adap.owner = THIS_MODULE;
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pd->adap.algo_data = &pd->bit;
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pd->adap.dev.parent = &dev->dev;
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strlcpy(pd->adap.name, "Simtec I2C", sizeof(pd->adap.name));
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pd->bit.data = pd;
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pd->bit.setsda = simtec_i2c_setsda;
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pd->bit.setscl = simtec_i2c_setscl;
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pd->bit.getsda = simtec_i2c_getsda;
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pd->bit.getscl = simtec_i2c_getscl;
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pd->bit.timeout = HZ;
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pd->bit.udelay = 20;
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ret = i2c_bit_add_bus(&pd->adap);
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if (ret)
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goto err_all;
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return 0;
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err_all:
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iounmap(pd->reg);
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err_res:
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release_mem_region(pd->ioarea->start, size);
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err:
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kfree(pd);
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return ret;
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}
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static int simtec_i2c_remove(struct platform_device *dev)
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{
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struct simtec_i2c_data *pd = platform_get_drvdata(dev);
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i2c_del_adapter(&pd->adap);
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iounmap(pd->reg);
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release_mem_region(pd->ioarea->start, resource_size(pd->ioarea));
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kfree(pd);
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return 0;
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}
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/* device driver */
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static struct platform_driver simtec_i2c_driver = {
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.driver = {
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.name = "simtec-i2c",
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},
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.probe = simtec_i2c_probe,
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.remove = simtec_i2c_remove,
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};
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module_platform_driver(simtec_i2c_driver);
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MODULE_DESCRIPTION("Simtec Generic I2C Bus driver");
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MODULE_AUTHOR("Ben Dooks <ben@simtec.co.uk>");
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MODULE_LICENSE("GPL");
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MODULE_ALIAS("platform:simtec-i2c");
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