161 lines
3.5 KiB
C
161 lines
3.5 KiB
C
/*
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* i2c-versatile.c
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*
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* Copyright (C) 2006 ARM Ltd.
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* written by Russell King, Deep Blue Solutions Ltd.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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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/i2c.h>
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#include <linux/i2c-algo-bit.h>
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#include <linux/init.h>
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#include <linux/platform_device.h>
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#include <asm/io.h>
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#define I2C_CONTROL 0x00
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#define I2C_CONTROLS 0x00
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#define I2C_CONTROLC 0x04
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#define SCL (1 << 0)
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#define SDA (1 << 1)
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struct i2c_versatile {
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struct i2c_adapter adap;
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struct i2c_algo_bit_data algo;
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void __iomem *base;
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};
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static void i2c_versatile_setsda(void *data, int state)
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{
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struct i2c_versatile *i2c = data;
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writel(SDA, i2c->base + (state ? I2C_CONTROLS : I2C_CONTROLC));
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}
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static void i2c_versatile_setscl(void *data, int state)
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{
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struct i2c_versatile *i2c = data;
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writel(SCL, i2c->base + (state ? I2C_CONTROLS : I2C_CONTROLC));
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}
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static int i2c_versatile_getsda(void *data)
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{
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struct i2c_versatile *i2c = data;
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return !!(readl(i2c->base + I2C_CONTROL) & SDA);
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}
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static int i2c_versatile_getscl(void *data)
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{
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struct i2c_versatile *i2c = data;
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return !!(readl(i2c->base + I2C_CONTROL) & SCL);
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}
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static struct i2c_algo_bit_data i2c_versatile_algo = {
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.setsda = i2c_versatile_setsda,
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.setscl = i2c_versatile_setscl,
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.getsda = i2c_versatile_getsda,
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.getscl = i2c_versatile_getscl,
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.udelay = 30,
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.timeout = HZ,
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};
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static int i2c_versatile_probe(struct platform_device *dev)
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{
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struct i2c_versatile *i2c;
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struct resource *r;
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int ret;
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r = platform_get_resource(dev, IORESOURCE_MEM, 0);
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if (!r) {
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ret = -EINVAL;
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goto err_out;
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}
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if (!request_mem_region(r->start, r->end - r->start + 1, "versatile-i2c")) {
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ret = -EBUSY;
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goto err_out;
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}
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i2c = kzalloc(sizeof(struct i2c_versatile), GFP_KERNEL);
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if (!i2c) {
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ret = -ENOMEM;
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goto err_release;
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}
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i2c->base = ioremap(r->start, r->end - r->start + 1);
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if (!i2c->base) {
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ret = -ENOMEM;
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goto err_free;
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}
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writel(SCL | SDA, i2c->base + I2C_CONTROLS);
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i2c->adap.owner = THIS_MODULE;
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strlcpy(i2c->adap.name, "Versatile I2C adapter", sizeof(i2c->adap.name));
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i2c->adap.algo_data = &i2c->algo;
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i2c->adap.dev.parent = &dev->dev;
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i2c->algo = i2c_versatile_algo;
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i2c->algo.data = i2c;
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if (dev->id >= 0) {
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/* static bus numbering */
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i2c->adap.nr = dev->id;
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ret = i2c_bit_add_numbered_bus(&i2c->adap);
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} else
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/* dynamic bus numbering */
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ret = i2c_bit_add_bus(&i2c->adap);
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if (ret >= 0) {
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platform_set_drvdata(dev, i2c);
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return 0;
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}
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iounmap(i2c->base);
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err_free:
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kfree(i2c);
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err_release:
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release_mem_region(r->start, r->end - r->start + 1);
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err_out:
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return ret;
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}
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static int i2c_versatile_remove(struct platform_device *dev)
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{
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struct i2c_versatile *i2c = platform_get_drvdata(dev);
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platform_set_drvdata(dev, NULL);
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i2c_del_adapter(&i2c->adap);
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return 0;
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}
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static struct platform_driver i2c_versatile_driver = {
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.probe = i2c_versatile_probe,
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.remove = i2c_versatile_remove,
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.driver = {
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.name = "versatile-i2c",
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.owner = THIS_MODULE,
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},
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};
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static int __init i2c_versatile_init(void)
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{
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return platform_driver_register(&i2c_versatile_driver);
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}
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static void __exit i2c_versatile_exit(void)
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{
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platform_driver_unregister(&i2c_versatile_driver);
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}
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subsys_initcall(i2c_versatile_init);
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module_exit(i2c_versatile_exit);
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MODULE_DESCRIPTION("ARM Versatile I2C bus driver");
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MODULE_LICENSE("GPL");
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MODULE_ALIAS("platform:versatile-i2c");
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