diff options
Diffstat (limited to 'drivers/i2c/busses/i2c-keywest.c')
| -rw-r--r-- | drivers/i2c/busses/i2c-keywest.c | 763 |
1 files changed, 763 insertions, 0 deletions
diff --git a/drivers/i2c/busses/i2c-keywest.c b/drivers/i2c/busses/i2c-keywest.c new file mode 100644 index 00000000000..dd0d4c46314 --- /dev/null +++ b/drivers/i2c/busses/i2c-keywest.c @@ -0,0 +1,763 @@ +/* + i2c Support for Apple Keywest I2C Bus Controller + + Copyright (c) 2001 Benjamin Herrenschmidt <benh@kernel.crashing.org> + + Original work by + + Copyright (c) 2000 Philip Edelbrock <phil@stimpy.netroedge.com> + + 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 program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program; if not, write to the Free Software + Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. + + Changes: + + 2001/12/13 BenH New implementation + 2001/12/15 BenH Add support for "byte" and "quick" + transfers. Add i2c_xfer routine. + 2003/09/21 BenH Rework state machine with Paulus help + 2004/01/21 BenH Merge in Greg KH changes, polled mode is back + 2004/02/05 BenH Merge 64 bits fixes from the g5 ppc64 tree + + My understanding of the various modes supported by keywest are: + + - Dumb mode : not implemented, probably direct tweaking of lines + - Standard mode : simple i2c transaction of type + S Addr R/W A Data A Data ... T + - Standard sub mode : combined 8 bit subaddr write with data read + S Addr R/W A SubAddr A Data A Data ... T + - Combined mode : Subaddress and Data sequences appended with no stop + S Addr R/W A SubAddr S Addr R/W A Data A Data ... T + + Currently, this driver uses only Standard mode for i2c xfer, and + smbus byte & quick transfers ; and uses StandardSub mode for + other smbus transfers instead of combined as we need that for the + sound driver to be happy +*/ + +#include <linux/config.h> +#include <linux/module.h> +#include <linux/kernel.h> +#include <linux/ioport.h> +#include <linux/pci.h> +#include <linux/types.h> +#include <linux/delay.h> +#include <linux/i2c.h> +#include <linux/init.h> +#include <linux/mm.h> +#include <linux/timer.h> +#include <linux/spinlock.h> +#include <linux/completion.h> +#include <linux/interrupt.h> + +#include <asm/io.h> +#include <asm/prom.h> +#include <asm/machdep.h> +#include <asm/pmac_feature.h> +#include <asm/pmac_low_i2c.h> + +#include "i2c-keywest.h" + +#undef POLLED_MODE + +/* Some debug macros */ +#define WRONG_STATE(name) do {\ + pr_debug("KW: wrong state. Got %s, state: %s (isr: %02x)\n", \ + name, __kw_state_names[iface->state], isr); \ + } while(0) + +#ifdef DEBUG +static const char *__kw_state_names[] = { + "state_idle", + "state_addr", + "state_read", + "state_write", + "state_stop", + "state_dead" +}; +#endif /* DEBUG */ + +static int probe; + +MODULE_AUTHOR("Benjamin Herrenschmidt <benh@kernel.crashing.org>"); +MODULE_DESCRIPTION("I2C driver for Apple's Keywest"); +MODULE_LICENSE("GPL"); +module_param(probe, bool, 0); + +#ifdef POLLED_MODE +/* Don't schedule, the g5 fan controller is too + * timing sensitive + */ +static u8 +wait_interrupt(struct keywest_iface* iface) +{ + int i; + u8 isr; + + for (i = 0; i < 200000; i++) { + isr = read_reg(reg_isr) & KW_I2C_IRQ_MASK; + if (isr != 0) + return isr; + udelay(10); + } + return isr; +} +#endif /* POLLED_MODE */ + +static void +do_stop(struct keywest_iface* iface, int result) +{ + write_reg(reg_control, KW_I2C_CTL_STOP); + iface->state = state_stop; + iface->result = result; +} + +/* Main state machine for standard & standard sub mode */ +static void +handle_interrupt(struct keywest_iface *iface, u8 isr) +{ + int ack; + + if (isr == 0) { + if (iface->state != state_stop) { + pr_debug("KW: Timeout !\n"); + do_stop(iface, -EIO); + } + if (iface->state == state_stop) { + ack = read_reg(reg_status); + if (!(ack & KW_I2C_STAT_BUSY)) { + iface->state = state_idle; + write_reg(reg_ier, 0x00); +#ifndef POLLED_MODE + complete(&iface->complete); +#endif /* POLLED_MODE */ + } + } + return; + } + + if (isr & KW_I2C_IRQ_ADDR) { + ack = read_reg(reg_status); + if (iface->state != state_addr) { + write_reg(reg_isr, KW_I2C_IRQ_ADDR); + WRONG_STATE("KW_I2C_IRQ_ADDR"); + do_stop(iface, -EIO); + return; + } + if ((ack & KW_I2C_STAT_LAST_AAK) == 0) { + iface->state = state_stop; + iface->result = -ENODEV; + pr_debug("KW: NAK on address\n"); + } else { + /* Handle rw "quick" mode */ + if (iface->datalen == 0) { + do_stop(iface, 0); + } else if (iface->read_write == I2C_SMBUS_READ) { + iface->state = state_read; + if (iface->datalen > 1) + write_reg(reg_control, KW_I2C_CTL_AAK); + } else { + iface->state = state_write; + write_reg(reg_data, *(iface->data++)); + iface->datalen--; + } + } + write_reg(reg_isr, KW_I2C_IRQ_ADDR); + } + + if (isr & KW_I2C_IRQ_DATA) { + if (iface->state == state_read) { + *(iface->data++) = read_reg(reg_data); + write_reg(reg_isr, KW_I2C_IRQ_DATA); + iface->datalen--; + if (iface->datalen == 0) + iface->state = state_stop; + else if (iface->datalen == 1) + write_reg(reg_control, 0); + } else if (iface->state == state_write) { + /* Check ack status */ + ack = read_reg(reg_status); + if ((ack & KW_I2C_STAT_LAST_AAK) == 0) { + pr_debug("KW: nack on data write (%x): %x\n", + iface->data[-1], ack); + do_stop(iface, -EIO); + } else if (iface->datalen) { + write_reg(reg_data, *(iface->data++)); + iface->datalen--; + } else { + write_reg(reg_control, KW_I2C_CTL_STOP); + iface->state = state_stop; + iface->result = 0; + } + write_reg(reg_isr, KW_I2C_IRQ_DATA); + } else { + write_reg(reg_isr, KW_I2C_IRQ_DATA); + WRONG_STATE("KW_I2C_IRQ_DATA"); + if (iface->state != state_stop) + do_stop(iface, -EIO); + } + } + + if (isr & KW_I2C_IRQ_STOP) { + write_reg(reg_isr, KW_I2C_IRQ_STOP); + if (iface->state != state_stop) { + WRONG_STATE("KW_I2C_IRQ_STOP"); + iface->result = -EIO; + } + iface->state = state_idle; + write_reg(reg_ier, 0x00); +#ifndef POLLED_MODE + complete(&iface->complete); +#endif /* POLLED_MODE */ + } + + if (isr & KW_I2C_IRQ_START) + write_reg(reg_isr, KW_I2C_IRQ_START); +} + +#ifndef POLLED_MODE + +/* Interrupt handler */ +static irqreturn_t +keywest_irq(int irq, void *dev_id, struct pt_regs *regs) +{ + struct keywest_iface *iface = (struct keywest_iface *)dev_id; + unsigned long flags; + + spin_lock_irqsave(&iface->lock, flags); + del_timer(&iface->timeout_timer); + handle_interrupt(iface, read_reg(reg_isr)); + if (iface->state != state_idle) { + iface->timeout_timer.expires = jiffies + POLL_TIMEOUT; + add_timer(&iface->timeout_timer); + } + spin_unlock_irqrestore(&iface->lock, flags); + return IRQ_HANDLED; +} + +static void +keywest_timeout(unsigned long data) +{ + struct keywest_iface *iface = (struct keywest_iface *)data; + unsigned long flags; + + pr_debug("timeout !\n"); + spin_lock_irqsave(&iface->lock, flags); + handle_interrupt(iface, read_reg(reg_isr)); + if (iface->state != state_idle) { + iface->timeout_timer.expires = jiffies + POLL_TIMEOUT; + add_timer(&iface->timeout_timer); + } + spin_unlock_irqrestore(&iface->lock, flags); +} + +#endif /* POLLED_MODE */ + +/* + * SMBUS-type transfer entrypoint + */ +static s32 +keywest_smbus_xfer( struct i2c_adapter* adap, + u16 addr, + unsigned short flags, + char read_write, + u8 command, + int size, + union i2c_smbus_data* data) +{ + struct keywest_chan* chan = i2c_get_adapdata(adap); + struct keywest_iface* iface = chan->iface; + int len; + u8* buffer; + u16 cur_word; + int rc = 0; + + if (iface->state == state_dead) + return -ENXIO; + + /* Prepare datas & select mode */ + iface->cur_mode &= ~KW_I2C_MODE_MODE_MASK; + switch (size) { + case I2C_SMBUS_QUICK: + len = 0; + buffer = NULL; + iface->cur_mode |= KW_I2C_MODE_STANDARD; + break; + case I2C_SMBUS_BYTE: + len = 1; + buffer = &data->byte; + iface->cur_mode |= KW_I2C_MODE_STANDARD; + break; + case I2C_SMBUS_BYTE_DATA: + len = 1; + buffer = &data->byte; + iface->cur_mode |= KW_I2C_MODE_STANDARDSUB; + break; + case I2C_SMBUS_WORD_DATA: + len = 2; + cur_word = cpu_to_le16(data->word); + buffer = (u8 *)&cur_word; + iface->cur_mode |= KW_I2C_MODE_STANDARDSUB; + break; + case I2C_SMBUS_BLOCK_DATA: + len = data->block[0]; + buffer = &data->block[1]; + iface->cur_mode |= KW_I2C_MODE_STANDARDSUB; + break; + default: + return -1; + } + + /* Turn a standardsub read into a combined mode access */ + if (read_write == I2C_SMBUS_READ + && (iface->cur_mode & KW_I2C_MODE_MODE_MASK) == KW_I2C_MODE_STANDARDSUB) { + iface->cur_mode &= ~KW_I2C_MODE_MODE_MASK; + iface->cur_mode |= KW_I2C_MODE_COMBINED; + } + + /* Original driver had this limitation */ + if (len > 32) + len = 32; + + if (pmac_low_i2c_lock(iface->node)) + return -ENXIO; + + pr_debug("chan: %d, addr: 0x%x, transfer len: %d, read: %d\n", + chan->chan_no, addr, len, read_write == I2C_SMBUS_READ); + + iface->data = buffer; + iface->datalen = len; + iface->state = state_addr; + iface->result = 0; + iface->read_write = read_write; + + /* Setup channel & clear pending irqs */ + write_reg(reg_isr, read_reg(reg_isr)); + write_reg(reg_mode, iface->cur_mode | (chan->chan_no << 4)); + write_reg(reg_status, 0); + + /* Set up address and r/w bit */ + write_reg(reg_addr, + (addr << 1) | ((read_write == I2C_SMBUS_READ) ? 0x01 : 0x00)); + + /* Set up the sub address */ + if ((iface->cur_mode & KW_I2C_MODE_MODE_MASK) == KW_I2C_MODE_STANDARDSUB + || (iface->cur_mode & KW_I2C_MODE_MODE_MASK) == KW_I2C_MODE_COMBINED) + write_reg(reg_subaddr, command); + +#ifndef POLLED_MODE + /* Arm timeout */ + iface->timeout_timer.expires = jiffies + POLL_TIMEOUT; + add_timer(&iface->timeout_timer); +#endif + + /* Start sending address & enable interrupt*/ + write_reg(reg_control, KW_I2C_CTL_XADDR); + write_reg(reg_ier, KW_I2C_IRQ_MASK); + +#ifdef POLLED_MODE + pr_debug("using polled mode...\n"); + /* State machine, to turn into an interrupt handler */ + while(iface->state != state_idle) { + unsigned long flags; + + u8 isr = wait_interrupt(iface); + spin_lock_irqsave(&iface->lock, flags); + handle_interrupt(iface, isr); + spin_unlock_irqrestore(&iface->lock, flags); + } +#else /* POLLED_MODE */ + pr_debug("using interrupt mode...\n"); + wait_for_completion(&iface->complete); +#endif /* POLLED_MODE */ + + rc = iface->result; + pr_debug("transfer done, result: %d\n", rc); + + if (rc == 0 && size == I2C_SMBUS_WORD_DATA && read_write == I2C_SMBUS_READ) + data->word = le16_to_cpu(cur_word); + + /* Release sem */ + pmac_low_i2c_unlock(iface->node); + + return rc; +} + +/* + * Generic i2c master transfer entrypoint + */ +static int +keywest_xfer( struct i2c_adapter *adap, + struct i2c_msg *msgs, + int num) +{ + struct keywest_chan* chan = i2c_get_adapdata(adap); + struct keywest_iface* iface = chan->iface; + struct i2c_msg *pmsg; + int i, completed; + int rc = 0; + + if (iface->state == state_dead) + return -ENXIO; + + if (pmac_low_i2c_lock(iface->node)) + return -ENXIO; + + /* Set adapter to standard mode */ + iface->cur_mode &= ~KW_I2C_MODE_MODE_MASK; + iface->cur_mode |= KW_I2C_MODE_STANDARD; + + completed = 0; + for (i = 0; rc >= 0 && i < num;) { + u8 addr; + + pmsg = &msgs[i++]; + addr = pmsg->addr; + if (pmsg->flags & I2C_M_TEN) { + printk(KERN_ERR "i2c-keywest: 10 bits addr not supported !\n"); + rc = -EINVAL; + break; + } + pr_debug("xfer: chan: %d, doing %s %d bytes to 0x%02x - %d of %d messages\n", + chan->chan_no, + pmsg->flags & I2C_M_RD ? "read" : "write", + pmsg->len, addr, i, num); + + /* Setup channel & clear pending irqs */ + write_reg(reg_mode, iface->cur_mode | (chan->chan_no << 4)); + write_reg(reg_isr, read_reg(reg_isr)); + write_reg(reg_status, 0); + + iface->data = pmsg->buf; + iface->datalen = pmsg->len; + iface->state = state_addr; + iface->result = 0; + if (pmsg->flags & I2C_M_RD) + iface->read_write = I2C_SMBUS_READ; + else + iface->read_write = I2C_SMBUS_WRITE; + + /* Set up address and r/w bit */ + if (pmsg->flags & I2C_M_REV_DIR_ADDR) + addr ^= 1; + write_reg(reg_addr, + (addr << 1) | + ((iface->read_write == I2C_SMBUS_READ) ? 0x01 : 0x00)); + +#ifndef POLLED_MODE + /* Arm timeout */ + iface->timeout_timer.expires = jiffies + POLL_TIMEOUT; + add_timer(&iface->timeout_timer); +#endif + + /* Start sending address & enable interrupt*/ + write_reg(reg_ier, KW_I2C_IRQ_MASK); + write_reg(reg_control, KW_I2C_CTL_XADDR); + +#ifdef POLLED_MODE + pr_debug("using polled mode...\n"); + /* State machine, to turn into an interrupt handler */ + while(iface->state != state_idle) { + u8 isr = wait_interrupt(iface); + handle_interrupt(iface, isr); + } +#else /* POLLED_MODE */ + pr_debug("using interrupt mode...\n"); + wait_for_completion(&iface->complete); +#endif /* POLLED_MODE */ + + rc = iface->result; + if (rc == 0) + completed++; + pr_debug("transfer done, result: %d\n", rc); + } + + /* Release sem */ + pmac_low_i2c_unlock(iface->node); + + return completed; +} + +static u32 +keywest_func(struct i2c_adapter * adapter) +{ + return I2C_FUNC_SMBUS_QUICK | I2C_FUNC_SMBUS_BYTE | + I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA | + I2C_FUNC_SMBUS_BLOCK_DATA; +} + +/* For now, we only handle combined mode (smbus) */ +static struct i2c_algorithm keywest_algorithm = { + .name = "Keywest i2c", + .id = I2C_ALGO_SMBUS, + .smbus_xfer = keywest_smbus_xfer, + .master_xfer = keywest_xfer, + .functionality = keywest_func, +}; + + +static int +create_iface(struct device_node *np, struct device *dev) +{ + unsigned long steps; + unsigned bsteps, tsize, i, nchan, addroffset; + struct keywest_iface* iface; + u32 *psteps, *prate; + int rc; + + if (pmac_low_i2c_lock(np)) + return -ENODEV; + + psteps = (u32 *)get_property(np, "AAPL,address-step", NULL); + steps = psteps ? (*psteps) : 0x10; + + /* Hrm... maybe we can be smarter here */ + for (bsteps = 0; (steps & 0x01) == 0; bsteps++) + steps >>= 1; + + if (np->parent->name[0] == 'u') { + nchan = 2; + addroffset = 3; + } else { + addroffset = 0; + nchan = 1; + } + + tsize = sizeof(struct keywest_iface) + + (sizeof(struct keywest_chan) + 4) * nchan; + iface = (struct keywest_iface *) kmalloc(tsize, GFP_KERNEL); + if (iface == NULL) { + printk(KERN_ERR "i2c-keywest: can't allocate inteface !\n"); + pmac_low_i2c_unlock(np); + return -ENOMEM; + } + memset(iface, 0, tsize); + spin_lock_init(&iface->lock); + init_completion(&iface->complete); + iface->node = of_node_get(np); + iface->bsteps = bsteps; + iface->chan_count = nchan; + iface->state = state_idle; + iface->irq = np->intrs[0].line; + iface->channels = (struct keywest_chan *) + (((unsigned long)(iface + 1) + 3UL) & ~3UL); + iface->base = ioremap(np->addrs[0].address + addroffset, + np->addrs[0].size); + if (!iface->base) { + printk(KERN_ERR "i2c-keywest: can't map inteface !\n"); + kfree(iface); + pmac_low_i2c_unlock(np); + return -ENOMEM; + } + +#ifndef POLLED_MODE + init_timer(&iface->timeout_timer); + iface->timeout_timer.function = keywest_timeout; + iface->timeout_timer.data = (unsigned long)iface; +#endif + + /* Select interface rate */ + iface->cur_mode = KW_I2C_MODE_100KHZ; + prate = (u32 *)get_property(np, "AAPL,i2c-rate", NULL); + if (prate) switch(*prate) { + case 100: + iface->cur_mode = KW_I2C_MODE_100KHZ; + break; + case 50: + iface->cur_mode = KW_I2C_MODE_50KHZ; + break; + case 25: + iface->cur_mode = KW_I2C_MODE_25KHZ; + break; + default: + printk(KERN_WARNING "i2c-keywest: unknown rate %ldKhz, using 100KHz\n", + (long)*prate); + } + + /* Select standard mode by default */ + iface->cur_mode |= KW_I2C_MODE_STANDARD; + + /* Write mode */ + write_reg(reg_mode, iface->cur_mode); + + /* Switch interrupts off & clear them*/ + write_reg(reg_ier, 0x00); + write_reg(reg_isr, KW_I2C_IRQ_MASK); + +#ifndef POLLED_MODE + /* Request chip interrupt */ + rc = request_irq(iface->irq, keywest_irq, SA_INTERRUPT, "keywest i2c", iface); + if (rc) { + printk(KERN_ERR "i2c-keywest: can't get IRQ %d !\n", iface->irq); + iounmap(iface->base); + kfree(iface); + pmac_low_i2c_unlock(np); + return -ENODEV; + } +#endif /* POLLED_MODE */ + + pmac_low_i2c_unlock(np); + dev_set_drvdata(dev, iface); + + for (i=0; i<nchan; i++) { + struct keywest_chan* chan = &iface->channels[i]; + u8 addr; + + sprintf(chan->adapter.name, "%s %d", np->parent->name, i); + chan->iface = iface; + chan->chan_no = i; + chan->adapter.id = I2C_ALGO_SMBUS; + chan->adapter.algo = &keywest_algorithm; + chan->adapter.algo_data = NULL; + chan->adapter.client_register = NULL; + chan->adapter.client_unregister = NULL; + i2c_set_adapdata(&chan->adapter, chan); + chan->adapter.dev.parent = dev; + + rc = i2c_add_adapter(&chan->adapter); + if (rc) { + printk("i2c-keywest.c: Adapter %s registration failed\n", + chan->adapter.name); + i2c_set_adapdata(&chan->adapter, NULL); + } + if (probe) { + printk("Probe: "); + for (addr = 0x00; addr <= 0x7f; addr++) { + if (i2c_smbus_xfer(&chan->adapter,addr, + 0,0,0,I2C_SMBUS_QUICK,NULL) >= 0) + printk("%02x ", addr); + } + printk("\n"); + } + } + + printk(KERN_INFO "Found KeyWest i2c on \"%s\", %d channel%s, stepping: %d bits\n", + np->parent->name, nchan, nchan > 1 ? "s" : "", bsteps); + + return 0; +} + +static int +dispose_iface(struct device *dev) +{ + struct keywest_iface *iface = dev_get_drvdata(dev); + int i, rc; + + /* Make sure we stop all activity */ + if (pmac_low_i2c_lock(iface->node)) + return -ENODEV; + +#ifndef POLLED_MODE + spin_lock_irq(&iface->lock); + while (iface->state != state_idle) { + spin_unlock_irq(&iface->lock); + msleep(100); + spin_lock_irq(&iface->lock); + } +#endif /* POLLED_MODE */ + iface->state = state_dead; +#ifndef POLLED_MODE + spin_unlock_irq(&iface->lock); + free_irq(iface->irq, iface); +#endif /* POLLED_MODE */ + + pmac_low_i2c_unlock(iface->node); + + /* Release all channels */ + for (i=0; i<iface->chan_count; i++) { + struct keywest_chan* chan = &iface->channels[i]; + if (i2c_get_adapdata(&chan->adapter) == NULL) + continue; + rc = i2c_del_adapter(&chan->adapter); + i2c_set_adapdata(&chan->adapter, NULL); + /* We aren't that prepared to deal with this... */ + if (rc) + printk("i2c-keywest.c: i2c_del_adapter failed, that's bad !\n"); + } + iounmap(iface->base); + dev_set_drvdata(dev, NULL); + of_node_put(iface->node); + kfree(iface); + + return 0; +} + +static int +create_iface_macio(struct macio_dev* dev, const struct of_match *match) +{ + return create_iface(dev->ofdev.node, &dev->ofdev.dev); +} + +static int +dispose_iface_macio(struct macio_dev* dev) +{ + return dispose_iface(&dev->ofdev.dev); +} + +static int +create_iface_of_platform(struct of_device* dev, const struct of_match *match) +{ + return create_iface(dev->node, &dev->dev); +} + +static int +dispose_iface_of_platform(struct of_device* dev) +{ + return dispose_iface(&dev->dev); +} + +static struct of_match i2c_keywest_match[] = +{ + { + .name = OF_ANY_MATCH, + .type = "i2c", + .compatible = "keywest" + }, + {}, +}; + +static struct macio_driver i2c_keywest_macio_driver = +{ + .name = "i2c-keywest", + .match_table = i2c_keywest_match, + .probe = create_iface_macio, + .remove = dispose_iface_macio +}; + +static struct of_platform_driver i2c_keywest_of_platform_driver = +{ + .name = "i2c-keywest", + .match_table = i2c_keywest_match, + .probe = create_iface_of_platform, + .remove = dispose_iface_of_platform +}; + +static int __init +i2c_keywest_init(void) +{ + of_register_driver(&i2c_keywest_of_platform_driver); + macio_register_driver(&i2c_keywest_macio_driver); + + return 0; +} + +static void __exit +i2c_keywest_cleanup(void) +{ + of_unregister_driver(&i2c_keywest_of_platform_driver); + macio_unregister_driver(&i2c_keywest_macio_driver); +} + +module_init(i2c_keywest_init); +module_exit(i2c_keywest_cleanup); |