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/* $Id: bbc_i2c.c,v 1.2 2001/04/02 09:59:08 davem Exp $
* bbc_i2c.c: I2C low-level driver for BBC device on UltraSPARC-III
* platforms.
*
* Copyright (C) 2001 David S. Miller (davem@redhat.com)
*/
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/types.h>
#include <linux/slab.h>
#include <linux/sched.h>
#include <linux/wait.h>
#include <linux/delay.h>
#include <linux/init.h>
#include <asm/oplib.h>
#include <asm/ebus.h>
#include <asm/spitfire.h>
#include <asm/bbc.h>
#include "bbc_i2c.h"
/* Convert this driver to use i2c bus layer someday... */
#define I2C_PCF_PIN 0x80
#define I2C_PCF_ESO 0x40
#define I2C_PCF_ES1 0x20
#define I2C_PCF_ES2 0x10
#define I2C_PCF_ENI 0x08
#define I2C_PCF_STA 0x04
#define I2C_PCF_STO 0x02
#define I2C_PCF_ACK 0x01
#define I2C_PCF_START (I2C_PCF_PIN | I2C_PCF_ESO | I2C_PCF_ENI | I2C_PCF_STA | I2C_PCF_ACK)
#define I2C_PCF_STOP (I2C_PCF_PIN | I2C_PCF_ESO | I2C_PCF_STO | I2C_PCF_ACK)
#define I2C_PCF_REPSTART ( I2C_PCF_ESO | I2C_PCF_STA | I2C_PCF_ACK)
#define I2C_PCF_IDLE (I2C_PCF_PIN | I2C_PCF_ESO | I2C_PCF_ACK)
#define I2C_PCF_INI 0x40 /* 1 if not initialized */
#define I2C_PCF_STS 0x20
#define I2C_PCF_BER 0x10
#define I2C_PCF_AD0 0x08
#define I2C_PCF_LRB 0x08
#define I2C_PCF_AAS 0x04
#define I2C_PCF_LAB 0x02
#define I2C_PCF_BB 0x01
/* The BBC devices have two I2C controllers. The first I2C controller
* connects mainly to configuration proms (NVRAM, cpu configuration,
* dimm types, etc.). Whereas the second I2C controller connects to
* environmental control devices such as fans and temperature sensors.
* The second controller also connects to the smartcard reader, if present.
*/
#define NUM_CHILDREN 8
struct bbc_i2c_bus {
struct bbc_i2c_bus *next;
int index;
spinlock_t lock;
void *i2c_bussel_reg;
void *i2c_control_regs;
unsigned char own, clock;
wait_queue_head_t wq;
volatile int waiting;
struct linux_ebus_device *bus_edev;
struct {
struct linux_ebus_child *device;
int client_claimed;
} devs[NUM_CHILDREN];
};
static struct bbc_i2c_bus *all_bbc_i2c;
struct bbc_i2c_client {
struct bbc_i2c_bus *bp;
struct linux_ebus_child *echild;
int bus;
int address;
};
static int find_device(struct bbc_i2c_bus *bp, struct linux_ebus_child *echild)
{
int i;
for (i = 0; i < NUM_CHILDREN; i++) {
if (bp->devs[i].device == echild) {
if (bp->devs[i].client_claimed)
return 0;
return 1;
}
}
return 0;
}
static void set_device_claimage(struct bbc_i2c_bus *bp, struct linux_ebus_child *echild, int val)
{
int i;
for (i = 0; i < NUM_CHILDREN; i++) {
if (bp->devs[i].device == echild) {
bp->devs[i].client_claimed = val;
return;
}
}
}
#define claim_device(BP,ECHILD) set_device_claimage(BP,ECHILD,1)
#define release_device(BP,ECHILD) set_device_claimage(BP,ECHILD,0)
static struct bbc_i2c_bus *find_bus_for_device(struct linux_ebus_child *echild)
{
struct bbc_i2c_bus *bp = all_bbc_i2c;
while (bp != NULL) {
if (find_device(bp, echild) != 0)
break;
bp = bp->next;
}
return bp;
}
struct linux_ebus_child *bbc_i2c_getdev(int index)
{
struct bbc_i2c_bus *bp = all_bbc_i2c;
struct linux_ebus_child *echild = NULL;
int curidx = 0;
while (bp != NULL) {
struct bbc_i2c_bus *next = bp->next;
int i;
for (i = 0; i < NUM_CHILDREN; i++) {
if (!(echild = bp->devs[i].device))
break;
if (curidx == index)
goto out;
echild = NULL;
curidx++;
}
bp = next;
}
out:
if (curidx == index)
return echild;
return NULL;
}
struct bbc_i2c_client *bbc_i2c_attach(struct linux_ebus_child *echild)
{
struct bbc_i2c_bus *bp = find_bus_for_device(echild);
struct bbc_i2c_client *client;
if (!bp)
return NULL;
client = kmalloc(sizeof(*client), GFP_KERNEL);
if (!client)
return NULL;
memset(client, 0, sizeof(*client));
client->bp = bp;
client->echild = echild;
client->bus = echild->resource[0].start;
client->address = echild->resource[1].start;
claim_device(bp, echild);
return client;
}
void bbc_i2c_detach(struct bbc_i2c_client *client)
{
struct bbc_i2c_bus *bp = client->bp;
struct linux_ebus_child *echild = client->echild;
release_device(bp, echild);
kfree(client);
}
static int wait_for_pin(struct bbc_i2c_bus *bp, u8 *status)
{
DECLARE_WAITQUEUE(wait, current);
int limit = 32;
int ret = 1;
bp->waiting = 1;
add_wait_queue(&bp->wq, &wait);
while (limit-- > 0) {
u8 val;
current->state = TASK_INTERRUPTIBLE;
*status = val = readb(bp->i2c_control_regs + 0);
if ((val & I2C_PCF_PIN) == 0) {
ret = 0;
break;
}
schedule_timeout(HZ/4);
}
remove_wait_queue(&bp->wq, &wait);
bp->waiting = 0;
current->state = TASK_RUNNING;
return ret;
}
int bbc_i2c_writeb(struct bbc_i2c_client *client, unsigned char val, int off)
{
struct bbc_i2c_bus *bp = client->bp;
int address = client->address;
u8 status;
int ret = -1;
if (bp->i2c_bussel_reg != NULL)
writeb(client->bus, bp->i2c_bussel_reg);
writeb(address, bp->i2c_control_regs + 0x1);
writeb(I2C_PCF_START, bp->i2c_control_regs + 0x0);
if (wait_for_pin(bp, &status))
goto out;
writeb(off, bp->i2c_control_regs + 0x1);
if (wait_for_pin(bp, &status) ||
(status & I2C_PCF_LRB) != 0)
goto out;
writeb(val, bp->i2c_control_regs + 0x1);
if (wait_for_pin(bp, &status))
goto out;
ret = 0;
out:
writeb(I2C_PCF_STOP, bp->i2c_control_regs + 0x0);
return ret;
}
int bbc_i2c_readb(struct bbc_i2c_client *client, unsigned char *byte, int off)
{
struct bbc_i2c_bus *bp = client->bp;
unsigned char address = client->address, status;
int ret = -1;
if (bp->i2c_bussel_reg != NULL)
writeb(client->bus, bp->i2c_bussel_reg);
writeb(address, bp->i2c_control_regs + 0x1);
writeb(I2C_PCF_START, bp->i2c_control_regs + 0x0);
if (wait_for_pin(bp, &status))
goto out;
writeb(off, bp->i2c_control_regs + 0x1);
if (wait_for_pin(bp, &status) ||
(status & I2C_PCF_LRB) != 0)
goto out;
writeb(I2C_PCF_STOP, bp->i2c_control_regs + 0x0);
address |= 0x1; /* READ */
writeb(address, bp->i2c_control_regs + 0x1);
writeb(I2C_PCF_START, bp->i2c_control_regs + 0x0);
if (wait_for_pin(bp, &status))
goto out;
/* Set PIN back to one so the device sends the first
* byte.
*/
(void) readb(bp->i2c_control_regs + 0x1);
if (wait_for_pin(bp, &status))
goto out;
writeb(I2C_PCF_ESO | I2C_PCF_ENI, bp->i2c_control_regs + 0x0);
*byte = readb(bp->i2c_control_regs + 0x1);
if (wait_for_pin(bp, &status))
goto out;
ret = 0;
out:
writeb(I2C_PCF_STOP, bp->i2c_control_regs + 0x0);
(void) readb(bp->i2c_control_regs + 0x1);
return ret;
}
int bbc_i2c_write_buf(struct bbc_i2c_client *client,
char *buf, int len, int off)
{
int ret = 0;
while (len > 0) {
int err = bbc_i2c_writeb(client, *buf, off);
if (err < 0) {
ret = err;
break;
}
len--;
buf++;
off++;
}
return ret;
}
int bbc_i2c_read_buf(struct bbc_i2c_client *client,
char *buf, int len, int off)
{
int ret = 0;
while (len > 0) {
int err = bbc_i2c_readb(client, buf, off);
if (err < 0) {
ret = err;
break;
}
len--;
buf++;
off++;
}
return ret;
}
EXPORT_SYMBOL(bbc_i2c_getdev);
EXPORT_SYMBOL(bbc_i2c_attach);
EXPORT_SYMBOL(bbc_i2c_detach);
EXPORT_SYMBOL(bbc_i2c_writeb);
EXPORT_SYMBOL(bbc_i2c_readb);
EXPORT_SYMBOL(bbc_i2c_write_buf);
EXPORT_SYMBOL(bbc_i2c_read_buf);
static void bbc_i2c_interrupt(int irq, void *dev_id, struct pt_regs *regs)
{
struct bbc_i2c_bus *bp = dev_id;
/* PIN going from set to clear is the only event which
* makes the i2c assert an interrupt.
*/
if (bp->waiting &&
!(readb(bp->i2c_control_regs + 0x0) & I2C_PCF_PIN))
wake_up(&bp->wq);
}
static void __init reset_one_i2c(struct bbc_i2c_bus *bp)
{
writeb(I2C_PCF_PIN, bp->i2c_control_regs + 0x0);
writeb(bp->own, bp->i2c_control_regs + 0x1);
writeb(I2C_PCF_PIN | I2C_PCF_ES1, bp->i2c_control_regs + 0x0);
writeb(bp->clock, bp->i2c_control_regs + 0x1);
writeb(I2C_PCF_IDLE, bp->i2c_control_regs + 0x0);
}
static int __init attach_one_i2c(struct linux_ebus_device *edev, int index)
{
struct bbc_i2c_bus *bp = kmalloc(sizeof(*bp), GFP_KERNEL);
struct linux_ebus_child *echild;
int entry;
if (!bp)
return -ENOMEM;
memset(bp, 0, sizeof(*bp));
bp->i2c_control_regs = ioremap(edev->resource[0].start, 0x2);
if (!bp->i2c_control_regs)
goto fail;
if (edev->num_addrs == 2) {
bp->i2c_bussel_reg = ioremap(edev->resource[1].start, 0x1);
if (!bp->i2c_bussel_reg)
goto fail;
}
bp->waiting = 0;
init_waitqueue_head(&bp->wq);
if (request_irq(edev->irqs[0], bbc_i2c_interrupt,
SA_SHIRQ, "bbc_i2c", bp))
goto fail;
bp->index = index;
bp->bus_edev = edev;
spin_lock_init(&bp->lock);
bp->next = all_bbc_i2c;
all_bbc_i2c = bp;
entry = 0;
for (echild = edev->children;
echild && entry < 8;
echild = echild->next, entry++) {
bp->devs[entry].device = echild;
bp->devs[entry].client_claimed = 0;
}
writeb(I2C_PCF_PIN, bp->i2c_control_regs + 0x0);
bp->own = readb(bp->i2c_control_regs + 0x01);
writeb(I2C_PCF_PIN | I2C_PCF_ES1, bp->i2c_control_regs + 0x0);
bp->clock = readb(bp->i2c_control_regs + 0x01);
printk(KERN_INFO "i2c-%d: Regs at %p, %d devices, own %02x, clock %02x.\n",
bp->index, bp->i2c_control_regs, entry, bp->own, bp->clock);
reset_one_i2c(bp);
return 0;
fail:
if (bp->i2c_bussel_reg)
iounmap(bp->i2c_bussel_reg);
if (bp->i2c_control_regs)
iounmap(bp->i2c_control_regs);
kfree(bp);
return -EINVAL;
}
static int __init bbc_present(void)
{
struct linux_ebus *ebus = NULL;
struct linux_ebus_device *edev = NULL;
for_each_ebus(ebus) {
for_each_ebusdev(edev, ebus) {
if (!strcmp(edev->prom_name, "bbc"))
return 1;
}
}
return 0;
}
extern void bbc_envctrl_init(void);
extern void bbc_envctrl_cleanup(void);
static int __init bbc_i2c_init(void)
{
struct linux_ebus *ebus = NULL;
struct linux_ebus_device *edev = NULL;
int index = 0;
if (tlb_type != cheetah || !bbc_present())
return -ENODEV;
for_each_ebus(ebus) {
for_each_ebusdev(edev, ebus) {
if (!strcmp(edev->prom_name, "i2c")) {
if (!attach_one_i2c(edev, index))
index++;
}
}
}
if (!index)
return -ENODEV;
bbc_envctrl_init();
return 0;
}
static void __exit bbc_i2c_cleanup(void)
{
struct bbc_i2c_bus *bp = all_bbc_i2c;
bbc_envctrl_cleanup();
while (bp != NULL) {
struct bbc_i2c_bus *next = bp->next;
free_irq(bp->bus_edev->irqs[0], bp);
if (bp->i2c_bussel_reg)
iounmap(bp->i2c_bussel_reg);
if (bp->i2c_control_regs)
iounmap(bp->i2c_control_regs);
kfree(bp);
bp = next;
}
all_bbc_i2c = NULL;
}
module_init(bbc_i2c_init);
module_exit(bbc_i2c_cleanup);
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