diff options
Diffstat (limited to 'arch/powerpc/platforms/powermac/low_i2c.c')
| -rw-r--r-- | arch/powerpc/platforms/powermac/low_i2c.c | 523 |
1 files changed, 523 insertions, 0 deletions
diff --git a/arch/powerpc/platforms/powermac/low_i2c.c b/arch/powerpc/platforms/powermac/low_i2c.c new file mode 100644 index 00000000000..f3f39e8e337 --- /dev/null +++ b/arch/powerpc/platforms/powermac/low_i2c.c @@ -0,0 +1,523 @@ +/* + * 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); + |