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linux/arch/ppc64/kernel/pmac_low_i2c.c
Linus Torvalds 1da177e4c3 Linux-2.6.12-rc2 
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!
2005-04-16 15:20:36 -07:00

523 lines
12 KiB
C
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/*
* arch/ppc/platforms/pmac_low_i2c.c
*
* Copyright (C) 2003 Ben. Herrenschmidt (benh@kernel.crashing.org)
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*
* This file contains some low-level i2c access routines that
* need to be used by various bits of the PowerMac platform code
* at times where the real asynchronous & interrupt driven driver
* cannot be used. The API borrows some semantics from the darwin
* driver in order to ease the implementation of the platform
* properties parser
*/
#undef DEBUG
#include <linux/config.h>
#include <linux/types.h>
#include <linux/sched.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/adb.h>
#include <linux/pmu.h>
#include <asm/keylargo.h>
#include <asm/uninorth.h>
#include <asm/io.h>
#include <asm/prom.h>
#include <asm/machdep.h>
#include <asm/pmac_low_i2c.h>
#define MAX_LOW_I2C_HOST 4
#ifdef DEBUG
#define DBG(x...) do {\
printk(KERN_DEBUG "KW:" x); \
} while(0)
#else
#define DBG(x...)
#endif
struct low_i2c_host;
typedef int (*low_i2c_func_t)(struct low_i2c_host *host, u8 addr, u8 sub, u8 *data, int len);
struct low_i2c_host
{
struct device_node *np; /* OF device node */
struct semaphore mutex; /* Access mutex for use by i2c-keywest */
low_i2c_func_t func; /* Access function */
unsigned int is_open : 1; /* Poor man's access control */
int mode; /* Current mode */
int channel; /* Current channel */
int num_channels; /* Number of channels */
void __iomem *base; /* For keywest-i2c, base address */
int bsteps; /* And register stepping */
int speed; /* And speed */
};
static struct low_i2c_host low_i2c_hosts[MAX_LOW_I2C_HOST];
/* No locking is necessary on allocation, we are running way before
* anything can race with us
*/
static struct low_i2c_host *find_low_i2c_host(struct device_node *np)
{
int i;
for (i = 0; i < MAX_LOW_I2C_HOST; i++)
if (low_i2c_hosts[i].np == np)
return &low_i2c_hosts[i];
return NULL;
}
/*
*
* i2c-keywest implementation (UniNorth, U2, U3, Keylargo's)
*
*/
/*
* Keywest i2c definitions borrowed from drivers/i2c/i2c-keywest.h,
* should be moved somewhere in include/asm-ppc/
*/
/* Register indices */
typedef enum {
reg_mode = 0,
reg_control,
reg_status,
reg_isr,
reg_ier,
reg_addr,
reg_subaddr,
reg_data
} reg_t;
/* Mode register */
#define KW_I2C_MODE_100KHZ 0x00
#define KW_I2C_MODE_50KHZ 0x01
#define KW_I2C_MODE_25KHZ 0x02
#define KW_I2C_MODE_DUMB 0x00
#define KW_I2C_MODE_STANDARD 0x04
#define KW_I2C_MODE_STANDARDSUB 0x08
#define KW_I2C_MODE_COMBINED 0x0C
#define KW_I2C_MODE_MODE_MASK 0x0C
#define KW_I2C_MODE_CHAN_MASK 0xF0
/* Control register */
#define KW_I2C_CTL_AAK 0x01
#define KW_I2C_CTL_XADDR 0x02
#define KW_I2C_CTL_STOP 0x04
#define KW_I2C_CTL_START 0x08
/* Status register */
#define KW_I2C_STAT_BUSY 0x01
#define KW_I2C_STAT_LAST_AAK 0x02
#define KW_I2C_STAT_LAST_RW 0x04
#define KW_I2C_STAT_SDA 0x08
#define KW_I2C_STAT_SCL 0x10
/* IER & ISR registers */
#define KW_I2C_IRQ_DATA 0x01
#define KW_I2C_IRQ_ADDR 0x02
#define KW_I2C_IRQ_STOP 0x04
#define KW_I2C_IRQ_START 0x08
#define KW_I2C_IRQ_MASK 0x0F
/* State machine states */
enum {
state_idle,
state_addr,
state_read,
state_write,
state_stop,
state_dead
};
#define WRONG_STATE(name) do {\
printk(KERN_DEBUG "KW: wrong state. Got %s, state: %s (isr: %02x)\n", \
name, __kw_state_names[state], isr); \
} while(0)
static const char *__kw_state_names[] = {
"state_idle",
"state_addr",
"state_read",
"state_write",
"state_stop",
"state_dead"
};
static inline u8 __kw_read_reg(struct low_i2c_host *host, reg_t reg)
{
return readb(host->base + (((unsigned int)reg) << host->bsteps));
}
static inline void __kw_write_reg(struct low_i2c_host *host, reg_t reg, u8 val)
{
writeb(val, host->base + (((unsigned)reg) << host->bsteps));
(void)__kw_read_reg(host, reg_subaddr);
}
#define kw_write_reg(reg, val) __kw_write_reg(host, reg, val)
#define kw_read_reg(reg) __kw_read_reg(host, reg)
/* Don't schedule, the g5 fan controller is too
* timing sensitive
*/
static u8 kw_wait_interrupt(struct low_i2c_host* host)
{
int i, j;
u8 isr;
for (i = 0; i < 100000; i++) {
isr = kw_read_reg(reg_isr) & KW_I2C_IRQ_MASK;
if (isr != 0)
return isr;
/* This code is used with the timebase frozen, we cannot rely
* on udelay ! For now, just use a bogus loop
*/
for (j = 1; j < 10000; j++)
mb();
}
return isr;
}
static int kw_handle_interrupt(struct low_i2c_host *host, int state, int rw, int *rc, u8 **data, int *len, u8 isr)
{
u8 ack;
DBG("kw_handle_interrupt(%s, isr: %x)\n", __kw_state_names[state], isr);
if (isr == 0) {
if (state != state_stop) {
DBG("KW: Timeout !\n");
*rc = -EIO;
goto stop;
}
if (state == state_stop) {
ack = kw_read_reg(reg_status);
if (!(ack & KW_I2C_STAT_BUSY)) {
state = state_idle;
kw_write_reg(reg_ier, 0x00);
}
}
return state;
}
if (isr & KW_I2C_IRQ_ADDR) {
ack = kw_read_reg(reg_status);
if (state != state_addr) {
kw_write_reg(reg_isr, KW_I2C_IRQ_ADDR);
WRONG_STATE("KW_I2C_IRQ_ADDR");
*rc = -EIO;
goto stop;
}
if ((ack & KW_I2C_STAT_LAST_AAK) == 0) {
*rc = -ENODEV;
DBG("KW: NAK on address\n");
return state_stop;
} else {
if (rw) {
state = state_read;
if (*len > 1)
kw_write_reg(reg_control, KW_I2C_CTL_AAK);
} else {
state = state_write;
kw_write_reg(reg_data, **data);
(*data)++; (*len)--;
}
}
kw_write_reg(reg_isr, KW_I2C_IRQ_ADDR);
}
if (isr & KW_I2C_IRQ_DATA) {
if (state == state_read) {
**data = kw_read_reg(reg_data);
(*data)++; (*len)--;
kw_write_reg(reg_isr, KW_I2C_IRQ_DATA);
if ((*len) == 0)
state = state_stop;
else if ((*len) == 1)
kw_write_reg(reg_control, 0);
} else if (state == state_write) {
ack = kw_read_reg(reg_status);
if ((ack & KW_I2C_STAT_LAST_AAK) == 0) {
DBG("KW: nack on data write\n");
*rc = -EIO;
goto stop;
} else if (*len) {
kw_write_reg(reg_data, **data);
(*data)++; (*len)--;
} else {
kw_write_reg(reg_control, KW_I2C_CTL_STOP);
state = state_stop;
*rc = 0;
}
kw_write_reg(reg_isr, KW_I2C_IRQ_DATA);
} else {
kw_write_reg(reg_isr, KW_I2C_IRQ_DATA);
WRONG_STATE("KW_I2C_IRQ_DATA");
if (state != state_stop) {
*rc = -EIO;
goto stop;
}
}
}
if (isr & KW_I2C_IRQ_STOP) {
kw_write_reg(reg_isr, KW_I2C_IRQ_STOP);
if (state != state_stop) {
WRONG_STATE("KW_I2C_IRQ_STOP");
*rc = -EIO;
}
return state_idle;
}
if (isr & KW_I2C_IRQ_START)
kw_write_reg(reg_isr, KW_I2C_IRQ_START);
return state;
stop:
kw_write_reg(reg_control, KW_I2C_CTL_STOP);
return state_stop;
}
static int keywest_low_i2c_func(struct low_i2c_host *host, u8 addr, u8 subaddr, u8 *data, int len)
{
u8 mode_reg = host->speed;
int state = state_addr;
int rc = 0;
/* Setup mode & subaddress if any */
switch(host->mode) {
case pmac_low_i2c_mode_dumb:
printk(KERN_ERR "low_i2c: Dumb mode not supported !\n");
return -EINVAL;
case pmac_low_i2c_mode_std:
mode_reg |= KW_I2C_MODE_STANDARD;
break;
case pmac_low_i2c_mode_stdsub:
mode_reg |= KW_I2C_MODE_STANDARDSUB;
break;
case pmac_low_i2c_mode_combined:
mode_reg |= KW_I2C_MODE_COMBINED;
break;
}
/* Setup channel & clear pending irqs */
kw_write_reg(reg_isr, kw_read_reg(reg_isr));
kw_write_reg(reg_mode, mode_reg | (host->channel << 4));
kw_write_reg(reg_status, 0);
/* Set up address and r/w bit */
kw_write_reg(reg_addr, addr);
/* Set up the sub address */
if ((mode_reg & KW_I2C_MODE_MODE_MASK) == KW_I2C_MODE_STANDARDSUB
|| (mode_reg & KW_I2C_MODE_MODE_MASK) == KW_I2C_MODE_COMBINED)
kw_write_reg(reg_subaddr, subaddr);
/* Start sending address & disable interrupt*/
kw_write_reg(reg_ier, 0 /*KW_I2C_IRQ_MASK*/);
kw_write_reg(reg_control, KW_I2C_CTL_XADDR);
/* State machine, to turn into an interrupt handler */
while(state != state_idle) {
u8 isr = kw_wait_interrupt(host);
state = kw_handle_interrupt(host, state, addr & 1, &rc, &data, &len, isr);
}
return rc;
}
static void keywest_low_i2c_add(struct device_node *np)
{
struct low_i2c_host *host = find_low_i2c_host(NULL);
u32 *psteps, *prate, steps, aoffset = 0;
struct device_node *parent;
if (host == NULL) {
printk(KERN_ERR "low_i2c: Can't allocate host for %s\n",
np->full_name);
return;
}
memset(host, 0, sizeof(*host));
init_MUTEX(&host->mutex);
host->np = of_node_get(np);
psteps = (u32 *)get_property(np, "AAPL,address-step", NULL);
steps = psteps ? (*psteps) : 0x10;
for (host->bsteps = 0; (steps & 0x01) == 0; host->bsteps++)
steps >>= 1;
parent = of_get_parent(np);
host->num_channels = 1;
if (parent && parent->name[0] == 'u') {
host->num_channels = 2;
aoffset = 3;
}
/* Select interface rate */
host->speed = KW_I2C_MODE_100KHZ;
prate = (u32 *)get_property(np, "AAPL,i2c-rate", NULL);
if (prate) switch(*prate) {
case 100:
host->speed = KW_I2C_MODE_100KHZ;
break;
case 50:
host->speed = KW_I2C_MODE_50KHZ;
break;
case 25:
host->speed = KW_I2C_MODE_25KHZ;
break;
}
host->mode = pmac_low_i2c_mode_std;
host->base = ioremap(np->addrs[0].address + aoffset,
np->addrs[0].size);
host->func = keywest_low_i2c_func;
}
/*
*
* PMU implementation
*
*/
#ifdef CONFIG_ADB_PMU
static int pmu_low_i2c_func(struct low_i2c_host *host, u8 addr, u8 sub, u8 *data, int len)
{
// TODO
return -ENODEV;
}
static void pmu_low_i2c_add(struct device_node *np)
{
struct low_i2c_host *host = find_low_i2c_host(NULL);
if (host == NULL) {
printk(KERN_ERR "low_i2c: Can't allocate host for %s\n",
np->full_name);
return;
}
memset(host, 0, sizeof(*host));
init_MUTEX(&host->mutex);
host->np = of_node_get(np);
host->num_channels = 3;
host->mode = pmac_low_i2c_mode_std;
host->func = pmu_low_i2c_func;
}
#endif /* CONFIG_ADB_PMU */
void __init pmac_init_low_i2c(void)
{
struct device_node *np;
/* Probe keywest-i2c busses */
np = of_find_compatible_node(NULL, "i2c", "keywest-i2c");
while(np) {
keywest_low_i2c_add(np);
np = of_find_compatible_node(np, "i2c", "keywest-i2c");
}
#ifdef CONFIG_ADB_PMU
/* Probe PMU busses */
np = of_find_node_by_name(NULL, "via-pmu");
if (np)
pmu_low_i2c_add(np);
#endif /* CONFIG_ADB_PMU */
/* TODO: Add CUDA support as well */
}
int pmac_low_i2c_lock(struct device_node *np)
{
struct low_i2c_host *host = find_low_i2c_host(np);
if (!host)
return -ENODEV;
down(&host->mutex);
return 0;
}
EXPORT_SYMBOL(pmac_low_i2c_lock);
int pmac_low_i2c_unlock(struct device_node *np)
{
struct low_i2c_host *host = find_low_i2c_host(np);
if (!host)
return -ENODEV;
up(&host->mutex);
return 0;
}
EXPORT_SYMBOL(pmac_low_i2c_unlock);
int pmac_low_i2c_open(struct device_node *np, int channel)
{
struct low_i2c_host *host = find_low_i2c_host(np);
if (!host)
return -ENODEV;
if (channel >= host->num_channels)
return -EINVAL;
down(&host->mutex);
host->is_open = 1;
host->channel = channel;
return 0;
}
EXPORT_SYMBOL(pmac_low_i2c_open);
int pmac_low_i2c_close(struct device_node *np)
{
struct low_i2c_host *host = find_low_i2c_host(np);
if (!host)
return -ENODEV;
host->is_open = 0;
up(&host->mutex);
return 0;
}
EXPORT_SYMBOL(pmac_low_i2c_close);
int pmac_low_i2c_setmode(struct device_node *np, int mode)
{
struct low_i2c_host *host = find_low_i2c_host(np);
if (!host)
return -ENODEV;
WARN_ON(!host->is_open);
host->mode = mode;
return 0;
}
EXPORT_SYMBOL(pmac_low_i2c_setmode);
int pmac_low_i2c_xfer(struct device_node *np, u8 addrdir, u8 subaddr, u8 *data, int len)
{
struct low_i2c_host *host = find_low_i2c_host(np);
if (!host)
return -ENODEV;
WARN_ON(!host->is_open);
return host->func(host, addrdir, subaddr, data, len);
}
EXPORT_SYMBOL(pmac_low_i2c_xfer);
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