295 lines
6.3 KiB
C
295 lines
6.3 KiB
C
/*
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* I2C driver for PKUnity-v3 SoC
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* Code specific to PKUnity SoC and UniCore ISA
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*
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* Maintained by GUAN Xue-tao <gxt@mprc.pku.edu.cn>
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* Copyright (C) 2001-2010 Guan Xuetao
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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/module.h>
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#include <linux/kernel.h>
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#include <linux/err.h>
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#include <linux/slab.h>
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#include <linux/types.h>
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#include <linux/delay.h>
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#include <linux/i2c.h>
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#include <linux/init.h>
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#include <linux/clk.h>
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#include <linux/platform_device.h>
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#include <linux/io.h>
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#include <mach/hardware.h>
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/*
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* Poll the i2c status register until the specified bit is set.
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* Returns 0 if timed out (100 msec).
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*/
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static short poll_status(unsigned long bit)
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{
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int loop_cntr = 1000;
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if (bit & I2C_STATUS_TFNF) {
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do {
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udelay(10);
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} while (!(readl(I2C_STATUS) & bit) && (--loop_cntr > 0));
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} else {
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/* RXRDY handler */
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do {
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if (readl(I2C_TAR) == I2C_TAR_EEPROM)
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msleep(20);
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else
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udelay(10);
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} while (!(readl(I2C_RXFLR) & 0xf) && (--loop_cntr > 0));
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}
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return (loop_cntr > 0);
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}
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static int xfer_read(struct i2c_adapter *adap, unsigned char *buf, int length)
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{
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int i2c_reg = *buf;
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/* Read data */
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while (length--) {
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if (!poll_status(I2C_STATUS_TFNF)) {
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dev_dbg(&adap->dev, "Tx FIFO Not Full timeout\n");
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return -ETIMEDOUT;
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}
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/* send addr */
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writel(i2c_reg | I2C_DATACMD_WRITE, I2C_DATACMD);
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/* get ready to next write */
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i2c_reg++;
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/* send read CMD */
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writel(I2C_DATACMD_READ, I2C_DATACMD);
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/* wait until the Rx FIFO have available */
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if (!poll_status(I2C_STATUS_RFNE)) {
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dev_dbg(&adap->dev, "RXRDY timeout\n");
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return -ETIMEDOUT;
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}
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/* read the data to buf */
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*buf = (readl(I2C_DATACMD) & I2C_DATACMD_DAT_MASK);
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buf++;
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}
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return 0;
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}
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static int xfer_write(struct i2c_adapter *adap, unsigned char *buf, int length)
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{
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int i2c_reg = *buf;
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/* Do nothing but storing the reg_num to a static variable */
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if (i2c_reg == -1) {
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printk(KERN_WARNING "Error i2c reg\n");
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return -ETIMEDOUT;
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}
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if (length == 1)
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return 0;
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buf++;
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length--;
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while (length--) {
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/* send addr */
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writel(i2c_reg | I2C_DATACMD_WRITE, I2C_DATACMD);
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/* send write CMD */
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writel(*buf | I2C_DATACMD_WRITE, I2C_DATACMD);
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/* wait until the Rx FIFO have available */
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msleep(20);
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/* read the data to buf */
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i2c_reg++;
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buf++;
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}
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return 0;
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}
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/*
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* Generic i2c master transfer entrypoint.
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*
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*/
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static int puv3_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg *pmsg,
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int num)
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{
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int i, ret;
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unsigned char swap;
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/* Disable i2c */
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writel(I2C_ENABLE_DISABLE, I2C_ENABLE);
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/* Set the work mode and speed*/
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writel(I2C_CON_MASTER | I2C_CON_SPEED_STD | I2C_CON_SLAVEDISABLE, I2C_CON);
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writel(pmsg->addr, I2C_TAR);
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/* Enable i2c */
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writel(I2C_ENABLE_ENABLE, I2C_ENABLE);
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dev_dbg(&adap->dev, "puv3_i2c_xfer: processing %d messages:\n", num);
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for (i = 0; i < num; i++) {
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dev_dbg(&adap->dev, " #%d: %sing %d byte%s %s 0x%02x\n", i,
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pmsg->flags & I2C_M_RD ? "read" : "writ",
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pmsg->len, pmsg->len > 1 ? "s" : "",
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pmsg->flags & I2C_M_RD ? "from" : "to", pmsg->addr);
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if (pmsg->len && pmsg->buf) { /* sanity check */
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if (pmsg->flags & I2C_M_RD)
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ret = xfer_read(adap, pmsg->buf, pmsg->len);
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else
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ret = xfer_write(adap, pmsg->buf, pmsg->len);
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if (ret)
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return ret;
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}
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dev_dbg(&adap->dev, "transfer complete\n");
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pmsg++; /* next message */
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}
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/* XXX: fixup be16_to_cpu in bq27x00_battery.c */
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if (pmsg->addr == I2C_TAR_PWIC) {
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swap = pmsg->buf[0];
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pmsg->buf[0] = pmsg->buf[1];
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pmsg->buf[1] = swap;
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}
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return i;
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}
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/*
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* Return list of supported functionality.
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*/
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static u32 puv3_i2c_func(struct i2c_adapter *adapter)
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{
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return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
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}
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static struct i2c_algorithm puv3_i2c_algorithm = {
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.master_xfer = puv3_i2c_xfer,
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.functionality = puv3_i2c_func,
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};
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/*
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* Main initialization routine.
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*/
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static int __devinit puv3_i2c_probe(struct platform_device *pdev)
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{
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struct i2c_adapter *adapter;
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struct resource *mem;
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int rc;
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mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
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if (!mem)
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return -ENODEV;
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if (!request_mem_region(mem->start, resource_size(mem), "puv3_i2c"))
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return -EBUSY;
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adapter = kzalloc(sizeof(struct i2c_adapter), GFP_KERNEL);
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if (adapter == NULL) {
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dev_err(&pdev->dev, "can't allocate inteface!\n");
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rc = -ENOMEM;
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goto fail_nomem;
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}
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snprintf(adapter->name, sizeof(adapter->name), "PUV3-I2C at 0x%08x",
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mem->start);
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adapter->algo = &puv3_i2c_algorithm;
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adapter->class = I2C_CLASS_HWMON;
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adapter->dev.parent = &pdev->dev;
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platform_set_drvdata(pdev, adapter);
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adapter->nr = pdev->id;
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rc = i2c_add_numbered_adapter(adapter);
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if (rc) {
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dev_err(&pdev->dev, "Adapter '%s' registration failed\n",
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adapter->name);
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goto fail_add_adapter;
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}
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dev_info(&pdev->dev, "PKUnity v3 i2c bus adapter.\n");
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return 0;
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fail_add_adapter:
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platform_set_drvdata(pdev, NULL);
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kfree(adapter);
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fail_nomem:
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release_mem_region(mem->start, resource_size(mem));
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return rc;
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}
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static int __devexit puv3_i2c_remove(struct platform_device *pdev)
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{
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struct i2c_adapter *adapter = platform_get_drvdata(pdev);
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struct resource *mem;
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int rc;
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rc = i2c_del_adapter(adapter);
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if (rc) {
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dev_err(&pdev->dev, "Adapter '%s' delete fail\n",
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adapter->name);
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return rc;
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}
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put_device(&pdev->dev);
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platform_set_drvdata(pdev, NULL);
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mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
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release_mem_region(mem->start, resource_size(mem));
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return rc;
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}
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#ifdef CONFIG_PM
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static int puv3_i2c_suspend(struct platform_device *dev, pm_message_t state)
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{
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int poll_count;
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/* Disable the IIC */
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writel(I2C_ENABLE_DISABLE, I2C_ENABLE);
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for (poll_count = 0; poll_count < 50; poll_count++) {
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if (readl(I2C_ENSTATUS) & I2C_ENSTATUS_ENABLE)
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udelay(25);
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}
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return 0;
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}
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static int puv3_i2c_resume(struct platform_device *dev)
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{
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return 0 ;
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}
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#else
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#define puv3_i2c_suspend NULL
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#define puv3_i2c_resume NULL
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#endif
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static struct platform_driver puv3_i2c_driver = {
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.probe = puv3_i2c_probe,
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.remove = __devexit_p(puv3_i2c_remove),
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.suspend = puv3_i2c_suspend,
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.resume = puv3_i2c_resume,
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.driver = {
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.name = "PKUnity-v3-I2C",
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.owner = THIS_MODULE,
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}
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};
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module_platform_driver(puv3_i2c_driver);
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MODULE_DESCRIPTION("PKUnity v3 I2C driver");
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MODULE_LICENSE("GPL v2");
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MODULE_ALIAS("platform:puv3_i2c");
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