116 lines
2.5 KiB
C
116 lines
2.5 KiB
C
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/*
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* OF helpers for the I2C API
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*
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* Copyright (c) 2008 Jochen Friedrich <jochen@scram.de>
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*
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* Based on a previous patch from Jon Smirl <jonsmirl@gmail.com>
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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 as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*/
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#include <linux/i2c.h>
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#include <linux/of.h>
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struct i2c_driver_device {
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char *of_device;
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char *i2c_type;
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};
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static struct i2c_driver_device i2c_devices[] = {
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{ "dallas,ds1374", "rtc-ds1374" },
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};
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static int of_find_i2c_driver(struct device_node *node,
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struct i2c_board_info *info)
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{
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int i, cplen;
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const char *compatible;
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const char *p;
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/* 1. search for exception list entry */
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for (i = 0; i < ARRAY_SIZE(i2c_devices); i++) {
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if (!of_device_is_compatible(node, i2c_devices[i].of_device))
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continue;
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if (strlcpy(info->type, i2c_devices[i].i2c_type,
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I2C_NAME_SIZE) >= I2C_NAME_SIZE)
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return -ENOMEM;
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return 0;
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}
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compatible = of_get_property(node, "compatible", &cplen);
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if (!compatible)
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return -ENODEV;
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/* 2. search for linux,<i2c-type> entry */
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p = compatible;
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while (cplen > 0) {
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if (!strncmp(p, "linux,", 6)) {
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p += 6;
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if (strlcpy(info->type, p,
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I2C_NAME_SIZE) >= I2C_NAME_SIZE)
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return -ENOMEM;
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return 0;
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}
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i = strlen(p) + 1;
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p += i;
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cplen -= i;
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}
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/* 3. take fist compatible entry and strip manufacturer */
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p = strchr(compatible, ',');
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if (!p)
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return -ENODEV;
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p++;
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if (strlcpy(info->type, p, I2C_NAME_SIZE) >= I2C_NAME_SIZE)
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return -ENOMEM;
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return 0;
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}
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void of_register_i2c_devices(struct i2c_adapter *adap,
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struct device_node *adap_node)
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{
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void *result;
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struct device_node *node;
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for_each_child_of_node(adap_node, node) {
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struct i2c_board_info info = {};
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const u32 *addr;
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int len;
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addr = of_get_property(node, "reg", &len);
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if (!addr || len < sizeof(int) || *addr > (1 << 10) - 1) {
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printk(KERN_ERR
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"of-i2c: invalid i2c device entry\n");
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continue;
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}
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info.irq = irq_of_parse_and_map(node, 0);
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if (info.irq == NO_IRQ)
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info.irq = -1;
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if (of_find_i2c_driver(node, &info) < 0) {
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irq_dispose_mapping(info.irq);
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continue;
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}
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info.addr = *addr;
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request_module(info.type);
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result = i2c_new_device(adap, &info);
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if (result == NULL) {
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printk(KERN_ERR
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"of-i2c: Failed to load driver for %s\n",
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info.type);
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irq_dispose_mapping(info.irq);
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continue;
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}
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}
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}
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EXPORT_SYMBOL(of_register_i2c_devices);
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