491 lines
11 KiB
C
491 lines
11 KiB
C
/* $Id: bbc_i2c.c,v 1.2 2001/04/02 09:59:08 davem Exp $
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* bbc_i2c.c: I2C low-level driver for BBC device on UltraSPARC-III
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* platforms.
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*
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* Copyright (C) 2001 David S. Miller (davem@redhat.com)
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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/types.h>
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#include <linux/slab.h>
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#include <linux/sched.h>
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#include <linux/wait.h>
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#include <linux/delay.h>
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#include <linux/init.h>
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#include <linux/interrupt.h>
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#include <asm/oplib.h>
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#include <asm/ebus.h>
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#include <asm/spitfire.h>
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#include <asm/bbc.h>
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#include "bbc_i2c.h"
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/* Convert this driver to use i2c bus layer someday... */
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#define I2C_PCF_PIN 0x80
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#define I2C_PCF_ESO 0x40
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#define I2C_PCF_ES1 0x20
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#define I2C_PCF_ES2 0x10
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#define I2C_PCF_ENI 0x08
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#define I2C_PCF_STA 0x04
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#define I2C_PCF_STO 0x02
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#define I2C_PCF_ACK 0x01
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#define I2C_PCF_START (I2C_PCF_PIN | I2C_PCF_ESO | I2C_PCF_ENI | I2C_PCF_STA | I2C_PCF_ACK)
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#define I2C_PCF_STOP (I2C_PCF_PIN | I2C_PCF_ESO | I2C_PCF_STO | I2C_PCF_ACK)
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#define I2C_PCF_REPSTART ( I2C_PCF_ESO | I2C_PCF_STA | I2C_PCF_ACK)
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#define I2C_PCF_IDLE (I2C_PCF_PIN | I2C_PCF_ESO | I2C_PCF_ACK)
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#define I2C_PCF_INI 0x40 /* 1 if not initialized */
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#define I2C_PCF_STS 0x20
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#define I2C_PCF_BER 0x10
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#define I2C_PCF_AD0 0x08
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#define I2C_PCF_LRB 0x08
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#define I2C_PCF_AAS 0x04
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#define I2C_PCF_LAB 0x02
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#define I2C_PCF_BB 0x01
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/* The BBC devices have two I2C controllers. The first I2C controller
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* connects mainly to configuration proms (NVRAM, cpu configuration,
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* dimm types, etc.). Whereas the second I2C controller connects to
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* environmental control devices such as fans and temperature sensors.
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* The second controller also connects to the smartcard reader, if present.
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*/
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#define NUM_CHILDREN 8
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struct bbc_i2c_bus {
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struct bbc_i2c_bus *next;
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int index;
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spinlock_t lock;
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void __iomem *i2c_bussel_reg;
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void __iomem *i2c_control_regs;
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unsigned char own, clock;
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wait_queue_head_t wq;
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volatile int waiting;
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struct linux_ebus_device *bus_edev;
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struct {
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struct linux_ebus_child *device;
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int client_claimed;
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} devs[NUM_CHILDREN];
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};
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static struct bbc_i2c_bus *all_bbc_i2c;
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struct bbc_i2c_client {
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struct bbc_i2c_bus *bp;
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struct linux_ebus_child *echild;
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int bus;
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int address;
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};
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static int find_device(struct bbc_i2c_bus *bp, struct linux_ebus_child *echild)
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{
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int i;
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for (i = 0; i < NUM_CHILDREN; i++) {
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if (bp->devs[i].device == echild) {
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if (bp->devs[i].client_claimed)
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return 0;
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return 1;
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}
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}
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return 0;
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}
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static void set_device_claimage(struct bbc_i2c_bus *bp, struct linux_ebus_child *echild, int val)
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{
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int i;
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for (i = 0; i < NUM_CHILDREN; i++) {
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if (bp->devs[i].device == echild) {
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bp->devs[i].client_claimed = val;
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return;
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}
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}
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}
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#define claim_device(BP,ECHILD) set_device_claimage(BP,ECHILD,1)
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#define release_device(BP,ECHILD) set_device_claimage(BP,ECHILD,0)
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static struct bbc_i2c_bus *find_bus_for_device(struct linux_ebus_child *echild)
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{
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struct bbc_i2c_bus *bp = all_bbc_i2c;
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while (bp != NULL) {
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if (find_device(bp, echild) != 0)
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break;
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bp = bp->next;
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}
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return bp;
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}
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struct linux_ebus_child *bbc_i2c_getdev(int index)
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{
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struct bbc_i2c_bus *bp = all_bbc_i2c;
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struct linux_ebus_child *echild = NULL;
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int curidx = 0;
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while (bp != NULL) {
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struct bbc_i2c_bus *next = bp->next;
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int i;
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for (i = 0; i < NUM_CHILDREN; i++) {
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if (!(echild = bp->devs[i].device))
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break;
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if (curidx == index)
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goto out;
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echild = NULL;
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curidx++;
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}
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bp = next;
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}
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out:
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if (curidx == index)
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return echild;
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return NULL;
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}
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struct bbc_i2c_client *bbc_i2c_attach(struct linux_ebus_child *echild)
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{
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struct bbc_i2c_bus *bp = find_bus_for_device(echild);
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struct bbc_i2c_client *client;
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if (!bp)
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return NULL;
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client = kmalloc(sizeof(*client), GFP_KERNEL);
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if (!client)
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return NULL;
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memset(client, 0, sizeof(*client));
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client->bp = bp;
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client->echild = echild;
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client->bus = echild->resource[0].start;
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client->address = echild->resource[1].start;
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claim_device(bp, echild);
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return client;
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}
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void bbc_i2c_detach(struct bbc_i2c_client *client)
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{
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struct bbc_i2c_bus *bp = client->bp;
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struct linux_ebus_child *echild = client->echild;
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release_device(bp, echild);
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kfree(client);
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}
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static int wait_for_pin(struct bbc_i2c_bus *bp, u8 *status)
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{
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DECLARE_WAITQUEUE(wait, current);
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int limit = 32;
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int ret = 1;
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bp->waiting = 1;
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add_wait_queue(&bp->wq, &wait);
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while (limit-- > 0) {
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u8 val;
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set_current_state(TASK_INTERRUPTIBLE);
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*status = val = readb(bp->i2c_control_regs + 0);
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if ((val & I2C_PCF_PIN) == 0) {
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ret = 0;
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break;
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}
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msleep_interruptible(250);
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}
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remove_wait_queue(&bp->wq, &wait);
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bp->waiting = 0;
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current->state = TASK_RUNNING;
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return ret;
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}
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int bbc_i2c_writeb(struct bbc_i2c_client *client, unsigned char val, int off)
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{
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struct bbc_i2c_bus *bp = client->bp;
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int address = client->address;
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u8 status;
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int ret = -1;
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if (bp->i2c_bussel_reg != NULL)
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writeb(client->bus, bp->i2c_bussel_reg);
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writeb(address, bp->i2c_control_regs + 0x1);
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writeb(I2C_PCF_START, bp->i2c_control_regs + 0x0);
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if (wait_for_pin(bp, &status))
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goto out;
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writeb(off, bp->i2c_control_regs + 0x1);
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if (wait_for_pin(bp, &status) ||
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(status & I2C_PCF_LRB) != 0)
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goto out;
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writeb(val, bp->i2c_control_regs + 0x1);
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if (wait_for_pin(bp, &status))
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goto out;
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ret = 0;
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out:
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writeb(I2C_PCF_STOP, bp->i2c_control_regs + 0x0);
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return ret;
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}
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int bbc_i2c_readb(struct bbc_i2c_client *client, unsigned char *byte, int off)
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{
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struct bbc_i2c_bus *bp = client->bp;
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unsigned char address = client->address, status;
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int ret = -1;
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if (bp->i2c_bussel_reg != NULL)
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writeb(client->bus, bp->i2c_bussel_reg);
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writeb(address, bp->i2c_control_regs + 0x1);
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writeb(I2C_PCF_START, bp->i2c_control_regs + 0x0);
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if (wait_for_pin(bp, &status))
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goto out;
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writeb(off, bp->i2c_control_regs + 0x1);
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if (wait_for_pin(bp, &status) ||
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(status & I2C_PCF_LRB) != 0)
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goto out;
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writeb(I2C_PCF_STOP, bp->i2c_control_regs + 0x0);
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address |= 0x1; /* READ */
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writeb(address, bp->i2c_control_regs + 0x1);
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writeb(I2C_PCF_START, bp->i2c_control_regs + 0x0);
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if (wait_for_pin(bp, &status))
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goto out;
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/* Set PIN back to one so the device sends the first
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* byte.
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*/
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(void) readb(bp->i2c_control_regs + 0x1);
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if (wait_for_pin(bp, &status))
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goto out;
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writeb(I2C_PCF_ESO | I2C_PCF_ENI, bp->i2c_control_regs + 0x0);
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*byte = readb(bp->i2c_control_regs + 0x1);
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if (wait_for_pin(bp, &status))
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goto out;
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ret = 0;
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out:
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writeb(I2C_PCF_STOP, bp->i2c_control_regs + 0x0);
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(void) readb(bp->i2c_control_regs + 0x1);
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return ret;
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}
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int bbc_i2c_write_buf(struct bbc_i2c_client *client,
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char *buf, int len, int off)
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{
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int ret = 0;
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while (len > 0) {
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int err = bbc_i2c_writeb(client, *buf, off);
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if (err < 0) {
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ret = err;
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break;
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}
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len--;
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buf++;
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off++;
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}
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return ret;
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}
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int bbc_i2c_read_buf(struct bbc_i2c_client *client,
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char *buf, int len, int off)
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{
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int ret = 0;
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while (len > 0) {
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int err = bbc_i2c_readb(client, buf, off);
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if (err < 0) {
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ret = err;
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break;
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}
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len--;
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buf++;
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off++;
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}
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return ret;
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}
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EXPORT_SYMBOL(bbc_i2c_getdev);
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EXPORT_SYMBOL(bbc_i2c_attach);
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EXPORT_SYMBOL(bbc_i2c_detach);
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EXPORT_SYMBOL(bbc_i2c_writeb);
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EXPORT_SYMBOL(bbc_i2c_readb);
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EXPORT_SYMBOL(bbc_i2c_write_buf);
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EXPORT_SYMBOL(bbc_i2c_read_buf);
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static irqreturn_t bbc_i2c_interrupt(int irq, void *dev_id, struct pt_regs *regs)
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{
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struct bbc_i2c_bus *bp = dev_id;
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/* PIN going from set to clear is the only event which
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* makes the i2c assert an interrupt.
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*/
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if (bp->waiting &&
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!(readb(bp->i2c_control_regs + 0x0) & I2C_PCF_PIN))
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wake_up(&bp->wq);
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return IRQ_HANDLED;
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}
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static void __init reset_one_i2c(struct bbc_i2c_bus *bp)
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{
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writeb(I2C_PCF_PIN, bp->i2c_control_regs + 0x0);
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writeb(bp->own, bp->i2c_control_regs + 0x1);
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writeb(I2C_PCF_PIN | I2C_PCF_ES1, bp->i2c_control_regs + 0x0);
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writeb(bp->clock, bp->i2c_control_regs + 0x1);
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writeb(I2C_PCF_IDLE, bp->i2c_control_regs + 0x0);
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}
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static int __init attach_one_i2c(struct linux_ebus_device *edev, int index)
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{
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struct bbc_i2c_bus *bp = kmalloc(sizeof(*bp), GFP_KERNEL);
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struct linux_ebus_child *echild;
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int entry;
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if (!bp)
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return -ENOMEM;
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memset(bp, 0, sizeof(*bp));
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bp->i2c_control_regs = ioremap(edev->resource[0].start, 0x2);
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if (!bp->i2c_control_regs)
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goto fail;
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if (edev->num_addrs == 2) {
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bp->i2c_bussel_reg = ioremap(edev->resource[1].start, 0x1);
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if (!bp->i2c_bussel_reg)
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goto fail;
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}
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bp->waiting = 0;
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init_waitqueue_head(&bp->wq);
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if (request_irq(edev->irqs[0], bbc_i2c_interrupt,
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SA_SHIRQ, "bbc_i2c", bp))
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goto fail;
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bp->index = index;
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bp->bus_edev = edev;
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spin_lock_init(&bp->lock);
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bp->next = all_bbc_i2c;
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all_bbc_i2c = bp;
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entry = 0;
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for (echild = edev->children;
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echild && entry < 8;
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echild = echild->next, entry++) {
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bp->devs[entry].device = echild;
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bp->devs[entry].client_claimed = 0;
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}
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writeb(I2C_PCF_PIN, bp->i2c_control_regs + 0x0);
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bp->own = readb(bp->i2c_control_regs + 0x01);
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writeb(I2C_PCF_PIN | I2C_PCF_ES1, bp->i2c_control_regs + 0x0);
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bp->clock = readb(bp->i2c_control_regs + 0x01);
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printk(KERN_INFO "i2c-%d: Regs at %p, %d devices, own %02x, clock %02x.\n",
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bp->index, bp->i2c_control_regs, entry, bp->own, bp->clock);
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reset_one_i2c(bp);
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return 0;
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fail:
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if (bp->i2c_bussel_reg)
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iounmap(bp->i2c_bussel_reg);
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if (bp->i2c_control_regs)
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iounmap(bp->i2c_control_regs);
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kfree(bp);
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return -EINVAL;
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}
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static int __init bbc_present(void)
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{
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struct linux_ebus *ebus = NULL;
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struct linux_ebus_device *edev = NULL;
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for_each_ebus(ebus) {
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for_each_ebusdev(edev, ebus) {
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if (!strcmp(edev->prom_name, "bbc"))
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return 1;
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}
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}
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return 0;
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}
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extern int bbc_envctrl_init(void);
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extern void bbc_envctrl_cleanup(void);
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static void bbc_i2c_cleanup(void);
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static int __init bbc_i2c_init(void)
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{
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struct linux_ebus *ebus = NULL;
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struct linux_ebus_device *edev = NULL;
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int err, index = 0;
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if ((tlb_type != cheetah && tlb_type != cheetah_plus) ||
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!bbc_present())
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return -ENODEV;
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for_each_ebus(ebus) {
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for_each_ebusdev(edev, ebus) {
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if (!strcmp(edev->prom_name, "i2c")) {
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if (!attach_one_i2c(edev, index))
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index++;
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}
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}
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}
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if (!index)
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return -ENODEV;
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err = bbc_envctrl_init();
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if (err)
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bbc_i2c_cleanup();
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return err;
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}
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static void bbc_i2c_cleanup(void)
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{
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struct bbc_i2c_bus *bp = all_bbc_i2c;
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bbc_envctrl_cleanup();
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while (bp != NULL) {
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struct bbc_i2c_bus *next = bp->next;
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free_irq(bp->bus_edev->irqs[0], bp);
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if (bp->i2c_bussel_reg)
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iounmap(bp->i2c_bussel_reg);
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if (bp->i2c_control_regs)
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iounmap(bp->i2c_control_regs);
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kfree(bp);
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bp = next;
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}
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all_bbc_i2c = NULL;
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}
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module_init(bbc_i2c_init);
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module_exit(bbc_i2c_cleanup);
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MODULE_LICENSE("GPL");
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