diff options
Diffstat (limited to 'drivers/sbus/char/bbc_i2c.c')
| -rw-r--r-- | drivers/sbus/char/bbc_i2c.c | 488 |
1 files changed, 488 insertions, 0 deletions
diff --git a/drivers/sbus/char/bbc_i2c.c b/drivers/sbus/char/bbc_i2c.c new file mode 100644 index 00000000000..1c8b612d823 --- /dev/null +++ b/drivers/sbus/char/bbc_i2c.c @@ -0,0 +1,488 @@ +/* $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 <linux/interrupt.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 __iomem *i2c_bussel_reg; + void __iomem *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; + + set_current_state(TASK_INTERRUPTIBLE); + *status = val = readb(bp->i2c_control_regs + 0); + if ((val & I2C_PCF_PIN) == 0) { + ret = 0; + break; + } + msleep_interruptible(250); + } + 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 irqreturn_t 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); + + return IRQ_HANDLED; +} + +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 int bbc_envctrl_init(void); +extern void bbc_envctrl_cleanup(void); +static void bbc_i2c_cleanup(void); + +static int __init bbc_i2c_init(void) +{ + struct linux_ebus *ebus = NULL; + struct linux_ebus_device *edev = NULL; + int err, 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; + + err = bbc_envctrl_init(); + if (err) + bbc_i2c_cleanup(); + return err; +} + +static void 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); |