diff options
Diffstat (limited to 'drivers/i2c/busses/i2c-pxa.c')
| -rw-r--r-- | drivers/i2c/busses/i2c-pxa.c | 1031 |
1 files changed, 1031 insertions, 0 deletions
diff --git a/drivers/i2c/busses/i2c-pxa.c b/drivers/i2c/busses/i2c-pxa.c new file mode 100644 index 000000000000..a72d28365297 --- /dev/null +++ b/drivers/i2c/busses/i2c-pxa.c @@ -0,0 +1,1031 @@ +/* + * i2c_adap_pxa.c + * + * I2C adapter for the PXA I2C bus access. + * + * Copyright (C) 2002 Intrinsyc Software Inc. + * Copyright (C) 2004-2005 Deep Blue Solutions Ltd. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + * + * History: + * Apr 2002: Initial version [CS] + * Jun 2002: Properly seperated algo/adap [FB] + * Jan 2003: Fixed several bugs concerning interrupt handling [Kai-Uwe Bloem] + * Jan 2003: added limited signal handling [Kai-Uwe Bloem] + * Sep 2004: Major rework to ensure efficient bus handling [RMK] + * Dec 2004: Added support for PXA27x and slave device probing [Liam Girdwood] + * Feb 2005: Rework slave mode handling [RMK] + */ +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/i2c.h> +#include <linux/i2c-id.h> +#include <linux/init.h> +#include <linux/time.h> +#include <linux/sched.h> +#include <linux/delay.h> +#include <linux/errno.h> +#include <linux/interrupt.h> +#include <linux/i2c-pxa.h> + +#include <asm/hardware.h> +#include <asm/irq.h> +#include <asm/arch/i2c.h> +#include <asm/arch/pxa-regs.h> + +struct pxa_i2c { + spinlock_t lock; + wait_queue_head_t wait; + struct i2c_msg *msg; + unsigned int msg_num; + unsigned int msg_idx; + unsigned int msg_ptr; + unsigned int slave_addr; + + struct i2c_adapter adap; +#ifdef CONFIG_I2C_PXA_SLAVE + struct i2c_slave_client *slave; +#endif + + unsigned int irqlogidx; + u32 isrlog[32]; + u32 icrlog[32]; +}; + +/* + * I2C Slave mode address + */ +#define I2C_PXA_SLAVE_ADDR 0x1 + +/* + * Set this to zero to remove all debug statements via dead code elimination. + */ +#undef DEBUG + +#if 0 +#define DBGLVL KERN_INFO +#else +#define DBGLVL KERN_DEBUG +#endif + +#ifdef DEBUG + +struct bits { + u32 mask; + const char *set; + const char *unset; +}; +#define BIT(m, s, u) { .mask = m, .set = s, .unset = u } + +static inline void +decode_bits(const char *prefix, const struct bits *bits, int num, u32 val) +{ + printk("%s %08x: ", prefix, val); + while (num--) { + const char *str = val & bits->mask ? bits->set : bits->unset; + if (str) + printk("%s ", str); + bits++; + } +} + +static const struct bits isr_bits[] = { + BIT(ISR_RWM, "RX", "TX"), + BIT(ISR_ACKNAK, "NAK", "ACK"), + BIT(ISR_UB, "Bsy", "Rdy"), + BIT(ISR_IBB, "BusBsy", "BusRdy"), + BIT(ISR_SSD, "SlaveStop", NULL), + BIT(ISR_ALD, "ALD", NULL), + BIT(ISR_ITE, "TxEmpty", NULL), + BIT(ISR_IRF, "RxFull", NULL), + BIT(ISR_GCAD, "GenCall", NULL), + BIT(ISR_SAD, "SlaveAddr", NULL), + BIT(ISR_BED, "BusErr", NULL), +}; + +static void decode_ISR(unsigned int val) +{ + decode_bits(DBGLVL "ISR", isr_bits, ARRAY_SIZE(isr_bits), val); + printk("\n"); +} + +static const struct bits icr_bits[] = { + BIT(ICR_START, "START", NULL), + BIT(ICR_STOP, "STOP", NULL), + BIT(ICR_ACKNAK, "ACKNAK", NULL), + BIT(ICR_TB, "TB", NULL), + BIT(ICR_MA, "MA", NULL), + BIT(ICR_SCLE, "SCLE", "scle"), + BIT(ICR_IUE, "IUE", "iue"), + BIT(ICR_GCD, "GCD", NULL), + BIT(ICR_ITEIE, "ITEIE", NULL), + BIT(ICR_IRFIE, "IRFIE", NULL), + BIT(ICR_BEIE, "BEIE", NULL), + BIT(ICR_SSDIE, "SSDIE", NULL), + BIT(ICR_ALDIE, "ALDIE", NULL), + BIT(ICR_SADIE, "SADIE", NULL), + BIT(ICR_UR, "UR", "ur"), +}; + +static void decode_ICR(unsigned int val) +{ + decode_bits(DBGLVL "ICR", icr_bits, ARRAY_SIZE(icr_bits), val); + printk("\n"); +} + +static unsigned int i2c_debug = DEBUG; + +static void i2c_pxa_show_state(struct pxa_i2c *i2c, int lno, const char *fname) +{ + printk(DBGLVL "state:%s:%d: ISR=%08x, ICR=%08x, IBMR=%02x\n", fname, lno, ISR, ICR, IBMR); +} + +#define show_state(i2c) i2c_pxa_show_state(i2c, __LINE__, __FUNCTION__) +#else +#define i2c_debug 0 + +#define show_state(i2c) do { } while (0) +#define decode_ISR(val) do { } while (0) +#define decode_ICR(val) do { } while (0) +#endif + +#define eedbg(lvl, x...) do { if ((lvl) < 1) { printk(DBGLVL "" x); } } while(0) + +static void i2c_pxa_master_complete(struct pxa_i2c *i2c, int ret); + +static void i2c_pxa_scream_blue_murder(struct pxa_i2c *i2c, const char *why) +{ + unsigned int i; + printk("i2c: error: %s\n", why); + printk("i2c: msg_num: %d msg_idx: %d msg_ptr: %d\n", + i2c->msg_num, i2c->msg_idx, i2c->msg_ptr); + printk("i2c: ICR: %08x ISR: %08x\ni2c: log: ", ICR, ISR); + for (i = 0; i < i2c->irqlogidx; i++) + printk("[%08x:%08x] ", i2c->isrlog[i], i2c->icrlog[i]); + printk("\n"); +} + +static inline int i2c_pxa_is_slavemode(struct pxa_i2c *i2c) +{ + return !(ICR & ICR_SCLE); +} + +static void i2c_pxa_abort(struct pxa_i2c *i2c) +{ + unsigned long timeout = jiffies + HZ/4; + + if (i2c_pxa_is_slavemode(i2c)) { + printk(DBGLVL "i2c_pxa_transfer: called in slave mode\n"); + return; + } + + while (time_before(jiffies, timeout) && (IBMR & 0x1) == 0) { + unsigned long icr = ICR; + + icr &= ~ICR_START; + icr |= ICR_ACKNAK | ICR_STOP | ICR_TB; + + ICR = icr; + + show_state(i2c); + + msleep(1); + } + + ICR &= ~(ICR_MA | ICR_START | ICR_STOP); +} + +static int i2c_pxa_wait_bus_not_busy(struct pxa_i2c *i2c) +{ + int timeout = DEF_TIMEOUT; + + while (timeout-- && ISR & (ISR_IBB | ISR_UB)) { + if ((ISR & ISR_SAD) != 0) + timeout += 4; + + msleep(2); + show_state(i2c); + } + + if (timeout <= 0) + show_state(i2c); + + return timeout <= 0 ? I2C_RETRY : 0; +} + +static int i2c_pxa_wait_master(struct pxa_i2c *i2c) +{ + unsigned long timeout = jiffies + HZ*4; + + while (time_before(jiffies, timeout)) { + if (i2c_debug > 1) + printk(DBGLVL "i2c_pxa_wait_master: %ld: ISR=%08x, ICR=%08x, IBMR=%02x\n", + (long)jiffies, ISR, ICR, IBMR); + + if (ISR & ISR_SAD) { + if (i2c_debug > 0) + printk(DBGLVL "i2c_pxa_wait_master: Slave detected\n"); + goto out; + } + + /* wait for unit and bus being not busy, and we also do a + * quick check of the i2c lines themselves to ensure they've + * gone high... + */ + if ((ISR & (ISR_UB | ISR_IBB)) == 0 && IBMR == 3) { + if (i2c_debug > 0) + printk(DBGLVL "i2c_pxa_wait_master: done\n"); + return 1; + } + + msleep(1); + } + + if (i2c_debug > 0) + printk(DBGLVL "i2c_pxa_wait_master: did not free\n"); + out: + return 0; +} + +static int i2c_pxa_set_master(struct pxa_i2c *i2c) +{ + if (i2c_debug) + printk(DBGLVL "I2C: setting to bus master\n"); + + if ((ISR & (ISR_UB | ISR_IBB)) != 0) { + printk(DBGLVL "set_master: unit is busy\n"); + if (!i2c_pxa_wait_master(i2c)) { + printk(DBGLVL "set_master: error: unit busy\n"); + return I2C_RETRY; + } + } + + ICR |= ICR_SCLE; + return 0; +} + +#ifdef CONFIG_I2C_PXA_SLAVE +static int i2c_pxa_wait_slave(struct pxa_i2c *i2c) +{ + unsigned long timeout = jiffies + HZ*1; + + /* wait for stop */ + + show_state(i2c); + + while (time_before(jiffies, timeout)) { + if (i2c_debug > 1) + printk(DBGLVL "i2c_pxa_wait_slave: %ld: ISR=%08x, ICR=%08x, IBMR=%02x\n", + (long)jiffies, ISR, ICR, IBMR); + + if ((ISR & (ISR_UB|ISR_IBB|ISR_SAD)) == ISR_SAD || + (ICR & ICR_SCLE) == 0) { + if (i2c_debug > 1) + printk(DBGLVL "i2c_pxa_wait_slave: done\n"); + return 1; + } + + msleep(1); + } + + if (i2c_debug > 0) + printk(DBGLVL "i2c_pxa_wait_slave: did not free\n"); + return 0; +} + +/* + * clear the hold on the bus, and take of anything else + * that has been configured + */ +static void i2c_pxa_set_slave(struct pxa_i2c *i2c, int errcode) +{ + show_state(i2c); + + if (errcode < 0) { + udelay(100); /* simple delay */ + } else { + /* we need to wait for the stop condition to end */ + + /* if we where in stop, then clear... */ + if (ICR & ICR_STOP) { + udelay(100); + ICR &= ~ICR_STOP; + } + + if (!i2c_pxa_wait_slave(i2c)) { + printk(KERN_ERR "i2c_pxa_set_slave: wait timedout\n"); + return; + } + } + + ICR &= ~(ICR_STOP|ICR_ACKNAK|ICR_MA); + ICR &= ~ICR_SCLE; + + if (i2c_debug) { + printk(DBGLVL "ICR now %08x, ISR %08x\n", ICR, ISR); + decode_ICR(ICR); + } +} +#else +#define i2c_pxa_set_slave(i2c, err) do { } while (0) +#endif + +static void i2c_pxa_reset(struct pxa_i2c *i2c) +{ + pr_debug("Resetting I2C Controller Unit\n"); + + /* abort any transfer currently under way */ + i2c_pxa_abort(i2c); + + /* reset according to 9.8 */ + ICR = ICR_UR; + ISR = I2C_ISR_INIT; + ICR &= ~ICR_UR; + + ISAR = i2c->slave_addr; + + /* set control register values */ + ICR = I2C_ICR_INIT; + +#ifdef CONFIG_I2C_PXA_SLAVE + printk(KERN_INFO "I2C: Enabling slave mode\n"); + ICR |= ICR_SADIE | ICR_ALDIE | ICR_SSDIE; +#endif + + i2c_pxa_set_slave(i2c, 0); + + /* enable unit */ + ICR |= ICR_IUE; + udelay(100); +} + + +#ifdef CONFIG_I2C_PXA_SLAVE +/* + * I2C EEPROM emulation. + */ +static struct i2c_eeprom_emu eeprom = { + .size = I2C_EEPROM_EMU_SIZE, + .watch = LIST_HEAD_INIT(eeprom.watch), +}; + +struct i2c_eeprom_emu *i2c_pxa_get_eeprom(void) +{ + return &eeprom; +} + +int i2c_eeprom_emu_addwatcher(struct i2c_eeprom_emu *emu, void *data, + unsigned int addr, unsigned int size, + struct i2c_eeprom_emu_watcher *watcher) +{ + struct i2c_eeprom_emu_watch *watch; + unsigned long flags; + + if (addr + size > emu->size) + return -EINVAL; + + watch = kmalloc(sizeof(struct i2c_eeprom_emu_watch), GFP_KERNEL); + if (watch) { + watch->start = addr; + watch->end = addr + size - 1; + watch->ops = watcher; + watch->data = data; + + local_irq_save(flags); + list_add(&watch->node, &emu->watch); + local_irq_restore(flags); + } + + return watch ? 0 : -ENOMEM; +} + +void i2c_eeprom_emu_delwatcher(struct i2c_eeprom_emu *emu, void *data, + struct i2c_eeprom_emu_watcher *watcher) +{ + struct i2c_eeprom_emu_watch *watch, *n; + unsigned long flags; + + list_for_each_entry_safe(watch, n, &emu->watch, node) { + if (watch->ops == watcher && watch->data == data) { + local_irq_save(flags); + list_del(&watch->node); + local_irq_restore(flags); + kfree(watch); + } + } +} + +static void i2c_eeprom_emu_event(void *ptr, i2c_slave_event_t event) +{ + struct i2c_eeprom_emu *emu = ptr; + + eedbg(3, "i2c_eeprom_emu_event: %d\n", event); + + switch (event) { + case I2C_SLAVE_EVENT_START_WRITE: + emu->seen_start = 1; + eedbg(2, "i2c_eeprom: write initiated\n"); + break; + + case I2C_SLAVE_EVENT_START_READ: + emu->seen_start = 0; + eedbg(2, "i2c_eeprom: read initiated\n"); + break; + + case I2C_SLAVE_EVENT_STOP: + emu->seen_start = 0; + eedbg(2, "i2c_eeprom: received stop\n"); + break; + + default: + eedbg(0, "i2c_eeprom: unhandled event\n"); + break; + } +} + +static int i2c_eeprom_emu_read(void *ptr) +{ + struct i2c_eeprom_emu *emu = ptr; + int ret; + + ret = emu->bytes[emu->ptr]; + emu->ptr = (emu->ptr + 1) % emu->size; + + return ret; +} + +static void i2c_eeprom_emu_write(void *ptr, unsigned int val) +{ + struct i2c_eeprom_emu *emu = ptr; + struct i2c_eeprom_emu_watch *watch; + + if (emu->seen_start != 0) { + eedbg(2, "i2c_eeprom_emu_write: setting ptr %02x\n", val); + emu->ptr = val; + emu->seen_start = 0; + return; + } + + emu->bytes[emu->ptr] = val; + + eedbg(1, "i2c_eeprom_emu_write: ptr=0x%02x, val=0x%02x\n", + emu->ptr, val); + + list_for_each_entry(watch, &emu->watch, node) { + if (!watch->ops || !watch->ops->write) + continue; + if (watch->start <= emu->ptr && watch->end >= emu->ptr) + watch->ops->write(watch->data, emu->ptr, val); + } + + emu->ptr = (emu->ptr + 1) % emu->size; +} + +struct i2c_slave_client eeprom_client = { + .data = &eeprom, + .event = i2c_eeprom_emu_event, + .read = i2c_eeprom_emu_read, + .write = i2c_eeprom_emu_write +}; + +/* + * PXA I2C Slave mode + */ + +static void i2c_pxa_slave_txempty(struct pxa_i2c *i2c, u32 isr) +{ + if (isr & ISR_BED) { + /* what should we do here? */ + } else { + int ret = i2c->slave->read(i2c->slave->data); + + IDBR = ret; + ICR |= ICR_TB; /* allow next byte */ + } +} + +static void i2c_pxa_slave_rxfull(struct pxa_i2c *i2c, u32 isr) +{ + unsigned int byte = IDBR; + + if (i2c->slave != NULL) + i2c->slave->write(i2c->slave->data, byte); + + ICR |= ICR_TB; +} + +static void i2c_pxa_slave_start(struct pxa_i2c *i2c, u32 isr) +{ + int timeout; + + if (i2c_debug > 0) + printk(DBGLVL "I2C: SAD, mode is slave-%cx\n", + (isr & ISR_RWM) ? 'r' : 't'); + + if (i2c->slave != NULL) + i2c->slave->event(i2c->slave->data, + (isr & ISR_RWM) ? I2C_SLAVE_EVENT_START_READ : I2C_SLAVE_EVENT_START_WRITE); + + /* + * slave could interrupt in the middle of us generating a + * start condition... if this happens, we'd better back off + * and stop holding the poor thing up + */ + ICR &= ~(ICR_START|ICR_STOP); + ICR |= ICR_TB; + + timeout = 0x10000; + + while (1) { + if ((IBMR & 2) == 2) + break; + + timeout--; + + if (timeout <= 0) { + printk(KERN_ERR "timeout waiting for SCL high\n"); + break; + } + } + + ICR &= ~ICR_SCLE; +} + +static void i2c_pxa_slave_stop(struct pxa_i2c *i2c) +{ + if (i2c_debug > 2) + printk(DBGLVL "ISR: SSD (Slave Stop)\n"); + + if (i2c->slave != NULL) + i2c->slave->event(i2c->slave->data, I2C_SLAVE_EVENT_STOP); + + if (i2c_debug > 2) + printk(DBGLVL "ISR: SSD (Slave Stop) acked\n"); + + /* + * If we have a master-mode message waiting, + * kick it off now that the slave has completed. + */ + if (i2c->msg) + i2c_pxa_master_complete(i2c, I2C_RETRY); +} +#else +static void i2c_pxa_slave_txempty(struct pxa_i2c *i2c, u32 isr) +{ + if (isr & ISR_BED) { + /* what should we do here? */ + } else { + IDBR = 0; + ICR |= ICR_TB; + } +} + +static void i2c_pxa_slave_rxfull(struct pxa_i2c *i2c, u32 isr) +{ + ICR |= ICR_TB | ICR_ACKNAK; +} + +static void i2c_pxa_slave_start(struct pxa_i2c *i2c, u32 isr) +{ + int timeout; + + /* + * slave could interrupt in the middle of us generating a + * start condition... if this happens, we'd better back off + * and stop holding the poor thing up + */ + ICR &= ~(ICR_START|ICR_STOP); + ICR |= ICR_TB | ICR_ACKNAK; + + timeout = 0x10000; + + while (1) { + if ((IBMR & 2) == 2) + break; + + timeout--; + + if (timeout <= 0) { + printk(KERN_ERR "timeout waiting for SCL high\n"); + break; + } + } + + ICR &= ~ICR_SCLE; +} + +static void i2c_pxa_slave_stop(struct pxa_i2c *i2c) +{ + if (i2c->msg) + i2c_pxa_master_complete(i2c, I2C_RETRY); +} +#endif + +/* + * PXA I2C Master mode + */ + +static inline unsigned int i2c_pxa_addr_byte(struct i2c_msg *msg) +{ + unsigned int addr = (msg->addr & 0x7f) << 1; + + if (msg->flags & I2C_M_RD) + addr |= 1; + + return addr; +} + +static inline void i2c_pxa_start_message(struct pxa_i2c *i2c) +{ + u32 icr; + + /* + * Step 1: target slave address into IDBR + */ + IDBR = i2c_pxa_addr_byte(i2c->msg); + + /* + * Step 2: initiate the write. + */ + icr = ICR & ~(ICR_STOP | ICR_ALDIE); + ICR = icr | ICR_START | ICR_TB; +} + +/* + * We are protected by the adapter bus semaphore. + */ +static int i2c_pxa_do_xfer(struct pxa_i2c *i2c, struct i2c_msg *msg, int num) +{ + long timeout; + int ret; + + /* + * Wait for the bus to become free. + */ + ret = i2c_pxa_wait_bus_not_busy(i2c); + if (ret) { + printk(KERN_INFO "i2c_pxa: timeout waiting for bus free\n"); + goto out; + } + + /* + * Set master mode. + */ + ret = i2c_pxa_set_master(i2c); + if (ret) { + printk(KERN_INFO "i2c_pxa_set_master: error %d\n", ret); + goto out; + } + + spin_lock_irq(&i2c->lock); + + i2c->msg = msg; + i2c->msg_num = num; + i2c->msg_idx = 0; + i2c->msg_ptr = 0; + i2c->irqlogidx = 0; + + i2c_pxa_start_message(i2c); + + spin_unlock_irq(&i2c->lock); + + /* + * The rest of the processing occurs in the interrupt handler. + */ + timeout = wait_event_timeout(i2c->wait, i2c->msg_num == 0, HZ * 5); + + /* + * We place the return code in i2c->msg_idx. + */ + ret = i2c->msg_idx; + + if (timeout == 0) + i2c_pxa_scream_blue_murder(i2c, "timeout"); + + out: + return ret; +} + +/* + * i2c_pxa_master_complete - complete the message and wake up. + */ +static void i2c_pxa_master_complete(struct pxa_i2c *i2c, int ret) +{ + i2c->msg_ptr = 0; + i2c->msg = NULL; + i2c->msg_idx ++; + i2c->msg_num = 0; + if (ret) + i2c->msg_idx = ret; + wake_up(&i2c->wait); +} + +static void i2c_pxa_irq_txempty(struct pxa_i2c *i2c, u32 isr) +{ + u32 icr = ICR & ~(ICR_START|ICR_STOP|ICR_ACKNAK|ICR_TB); + + again: + /* + * If ISR_ALD is set, we lost arbitration. + */ + if (isr & ISR_ALD) { + /* + * Do we need to do anything here? The PXA docs + * are vague about what happens. + */ + i2c_pxa_scream_blue_murder(i2c, "ALD set"); + + /* + * We ignore this error. We seem to see spurious ALDs + * for seemingly no reason. If we handle them as I think + * they should, we end up causing an I2C error, which + * is painful for some systems. + */ + return; /* ignore */ + } + + if (isr & ISR_BED) { + int ret = BUS_ERROR; + + /* + * I2C bus error - either the device NAK'd us, or + * something more serious happened. If we were NAK'd + * on the initial address phase, we can retry. + */ + if (isr & ISR_ACKNAK) { + if (i2c->msg_ptr == 0 && i2c->msg_idx == 0) + ret = I2C_RETRY; + else + ret = XFER_NAKED; + } + i2c_pxa_master_complete(i2c, ret); + } else if (isr & ISR_RWM) { + /* + * Read mode. We have just sent the address byte, and + * now we must initiate the transfer. + */ + if (i2c->msg_ptr == i2c->msg->len - 1 && + i2c->msg_idx == i2c->msg_num - 1) + icr |= ICR_STOP | ICR_ACKNAK; + + icr |= ICR_ALDIE | ICR_TB; + } else if (i2c->msg_ptr < i2c->msg->len) { + /* + * Write mode. Write the next data byte. + */ + IDBR = i2c->msg->buf[i2c->msg_ptr++]; + + icr |= ICR_ALDIE | ICR_TB; + + /* + * If this is the last byte of the last message, send + * a STOP. + */ + if (i2c->msg_ptr == i2c->msg->len && + i2c->msg_idx == i2c->msg_num - 1) + icr |= ICR_STOP; + } else if (i2c->msg_idx < i2c->msg_num - 1) { + /* + * Next segment of the message. + */ + i2c->msg_ptr = 0; + i2c->msg_idx ++; + i2c->msg++; + + /* + * If we aren't doing a repeated start and address, + * go back and try to send the next byte. Note that + * we do not support switching the R/W direction here. + */ + if (i2c->msg->flags & I2C_M_NOSTART) + goto again; + + /* + * Write the next address. + */ + IDBR = i2c_pxa_addr_byte(i2c->msg); + + /* + * And trigger a repeated start, and send the byte. + */ + icr &= ~ICR_ALDIE; + icr |= ICR_START | ICR_TB; + } else { + if (i2c->msg->len == 0) { + /* + * Device probes have a message length of zero + * and need the bus to be reset before it can + * be used again. + */ + i2c_pxa_reset(i2c); + } + i2c_pxa_master_complete(i2c, 0); + } + + i2c->icrlog[i2c->irqlogidx-1] = icr; + + ICR = icr; + show_state(i2c); +} + +static void i2c_pxa_irq_rxfull(struct pxa_i2c *i2c, u32 isr) +{ + u32 icr = ICR & ~(ICR_START|ICR_STOP|ICR_ACKNAK|ICR_TB); + + /* + * Read the byte. + */ + i2c->msg->buf[i2c->msg_ptr++] = IDBR; + + if (i2c->msg_ptr < i2c->msg->len) { + /* + * If this is the last byte of the last + * message, send a STOP. + */ + if (i2c->msg_ptr == i2c->msg->len - 1) + icr |= ICR_STOP | ICR_ACKNAK; + + icr |= ICR_ALDIE | ICR_TB; + } else { + i2c_pxa_master_complete(i2c, 0); + } + + i2c->icrlog[i2c->irqlogidx-1] = icr; + + ICR = icr; +} + +static irqreturn_t i2c_pxa_handler(int this_irq, void *dev_id, struct pt_regs *regs) +{ + struct pxa_i2c *i2c = dev_id; + u32 isr = ISR; + + if (i2c_debug > 2 && 0) { + printk(DBGLVL "i2c_pxa_handler: ISR=%08x, ICR=%08x, IBMR=%02x\n", + isr, ICR, IBMR); + decode_ISR(isr); + } + + if (i2c->irqlogidx < sizeof(i2c->isrlog)/sizeof(u32)) + i2c->isrlog[i2c->irqlogidx++] = isr; + + show_state(i2c); + + /* + * Always clear all pending IRQs. + */ + ISR = isr & (ISR_SSD|ISR_ALD|ISR_ITE|ISR_IRF|ISR_SAD|ISR_BED); + + if (isr & ISR_SAD) + i2c_pxa_slave_start(i2c, isr); + if (isr & ISR_SSD) + i2c_pxa_slave_stop(i2c); + + if (i2c_pxa_is_slavemode(i2c)) { + if (isr & ISR_ITE) + i2c_pxa_slave_txempty(i2c, isr); + if (isr & ISR_IRF) + i2c_pxa_slave_rxfull(i2c, isr); + } else if (i2c->msg) { + if (isr & ISR_ITE) + i2c_pxa_irq_txempty(i2c, isr); + if (isr & ISR_IRF) + i2c_pxa_irq_rxfull(i2c, isr); + } else { + i2c_pxa_scream_blue_murder(i2c, "spurious irq"); + } + + return IRQ_HANDLED; +} + + +static int i2c_pxa_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num) +{ + struct pxa_i2c *i2c = adap->algo_data; + int ret, i; + + for (i = adap->retries; i >= 0; i--) { + ret = i2c_pxa_do_xfer(i2c, msgs, num); + if (ret != I2C_RETRY) + goto out; + + if (i2c_debug) + printk(KERN_INFO "Retrying transmission\n"); + udelay(100); + } + i2c_pxa_scream_blue_murder(i2c, "exhausted retries"); + ret = -EREMOTEIO; + out: + i2c_pxa_set_slave(i2c, ret); + return ret; +} + +static struct i2c_algorithm i2c_pxa_algorithm = { + .name = "PXA-I2C-Algorithm", + .id = I2C_ALGO_PXA, + .master_xfer = i2c_pxa_xfer, +}; + +static struct pxa_i2c i2c_pxa = { + .lock = SPIN_LOCK_UNLOCKED, + .wait = __WAIT_QUEUE_HEAD_INITIALIZER(i2c_pxa.wait), + .adap = { + .name = "pxa2xx-i2c", + .id = I2C_ALGO_PXA, + .algo = &i2c_pxa_algorithm, + .retries = 5, + }, +}; + +static int i2c_pxa_probe(struct device *dev) +{ + struct pxa_i2c *i2c = &i2c_pxa; + struct i2c_pxa_platform_data *plat = dev->platform_data; + int ret; + +#ifdef CONFIG_PXA27x + pxa_gpio_mode(GPIO117_I2CSCL_MD); + pxa_gpio_mode(GPIO118_I2CSDA_MD); + udelay(100); +#endif + + i2c->slave_addr = I2C_PXA_SLAVE_ADDR; + +#ifdef CONFIG_I2C_PXA_SLAVE + i2c->slave = &eeprom_client; + if (plat) { + i2c->slave_addr = plat->slave_addr; + if (plat->slave) + i2c->slave = plat->slave; + } +#endif + + pxa_set_cken(CKEN14_I2C, 1); + ret = request_irq(IRQ_I2C, i2c_pxa_handler, SA_INTERRUPT, + "pxa2xx-i2c", i2c); + if (ret) + goto out; + + i2c_pxa_reset(i2c); + + i2c->adap.algo_data = i2c; + i2c->adap.dev.parent = dev; + + ret = i2c_add_adapter(&i2c->adap); + if (ret < 0) { + printk(KERN_INFO "I2C: Failed to add bus\n"); + goto err_irq; + } + + dev_set_drvdata(dev, i2c); + +#ifdef CONFIG_I2C_PXA_SLAVE + printk(KERN_INFO "I2C: %s: PXA I2C adapter, slave address %d\n", + i2c->adap.dev.bus_id, i2c->slave_addr); +#else + printk(KERN_INFO "I2C: %s: PXA I2C adapter\n", + i2c->adap.dev.bus_id); +#endif + return 0; + + err_irq: + free_irq(IRQ_I2C, i2c); + out: + return ret; +} + +static int i2c_pxa_remove(struct device *dev) +{ + struct pxa_i2c *i2c = dev_get_drvdata(dev); + + dev_set_drvdata(dev, NULL); + + i2c_del_adapter(&i2c->adap); + free_irq(IRQ_I2C, i2c); + pxa_set_cken(CKEN14_I2C, 0); + + return 0; +} + +static struct device_driver i2c_pxa_driver = { + .name = "pxa2xx-i2c", + .bus = &platform_bus_type, + .probe = i2c_pxa_probe, + .remove = i2c_pxa_remove, +}; + +static int __init i2c_adap_pxa_init(void) +{ + return driver_register(&i2c_pxa_driver); +} + +static void i2c_adap_pxa_exit(void) +{ + return driver_unregister(&i2c_pxa_driver); +} + +module_init(i2c_adap_pxa_init); +module_exit(i2c_adap_pxa_exit); |